FHWA/TX lF IMPACT OF AGGREGATE GRADATION AND TYPE ON ASPHALT MIXTURE CHARACTERISTICS. Research Report 1158-lF. Final

Transcription

1 1. Report No. 2. Government Accession No. FHWA/TX lF 4. Title nd Subtitle IMPACT OF AGGREGATE GRAATION AN TYPE ON ASPHALT MIXTURE CHARACTERISTICS Technicl Report ocumenttion Pge 3. Recipient's Ctlog No. 5. Report te November Performing Orgniztion Code I :;--:--:-"7"":--:::------,,.,-----: ! 8. P erlorming Orgniztion Report No. 7. Author 1 sl rren Glenn Hzlett nd Thoms w. Kennedy 9. Performing Orgon i ztion Nme ond Address ~enter for Trnsporttion Reserch rhe University of Texs t Austin \ustin, Texs ~ ~ 2. Sponsoring Agency Nme nd Address Cexs Stte eprtment of Highwys nd Public Trnsporttion, Trnsporttion Plnning ivision, 0. Box ustin, Texs Supplementry Notes Reserch Report 1158-lF 10. Work Unit No. (TRAIS) 11. Controct or Grnt No. Reserch Study / Type of Report nd Period Covered Finl 14. Sponsoring Agency Code :tudy conducted in coopertion with the U. s. eprtment of Trnsporttion, Federl Highwy Administrtion. Reserch Study Title: "Impct of Aggregte Grdtion nd Type on Asphlt Mixture Chrcteristics" 6. Abstrct This report ddresses the impct of ggregte grdtion nd type on Hot Mix sphltic Concrete (HMAC) chrcteristics. Severl different, but relted, topics re covered, nd results from severl experiments re presented. An overview of MAC is presented, covering fctors ffecting mixture chrcteristics nd performnee in ddition to review of the literture relting to ggregte grdtion nd ype. The results of study of construction dt from the Texs Stte eprtment f Highwys nd Public Trnsporttion (SHPT) re presented. Two lbortory tudies were conducted relting to sphlt content, ggregte grdtion, nd ggrete type. The summrized results nd interprettions of these results re ncluded. The economic impct of specifiction chnges currently proposed by the HPT to improve HMAC qulity is ddressed. Finlly, conclusions nd recommendtions re drwn bsed on ll preceding mteril. 1 Key Words )t Mix Asphltic Concrete (HMAC), 5phltic content, ggregte cdtion, ggregte type, economic npct 18. istribution Sttement No restrictions. This document is vilble to the public through the Ntionl Technicl Informtion Service, Springfield, Virgini l. Security Clssif. (of this report) 20. Security Cluif. (of this pge) 21. No. of Pges 22. Price 1clssified Unclssified 106 rm OT F <S-72l Reproduction of completed pge uthorized

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3 IMPACT OF AGGREGATE GRAATION AN TYPE ON ASPHALT MIXTURE CHARACTERISTICS by rren Glenn Hzlett Thoms W. Kennedy Reserch Report Number F Reserch Project Impct of Aggregte Grdtion nd Type on Asphlt Mixture Chrcteristics conducted for Texs Stte eprtment of Highwys nd Public Trnsporttion in coopertion with the U. S. eprtment of Trnsporttion Federl Highwy Administrtion by the CENTER FOR TRANSPORTATION RESEARCH Bureu of Engineering Reserch TIIE UNIVERSITY OF TEXAS AT AUSTIN November 1990

4 The contents of this report reflect the views of the uthors, who re responsible for the fcts nd the ccurcy ofthedtpresentedherein. Thecontentsdonotnecessrily reflect the officil views or policies of the Federl Highwy Administrtion or the Stte eprtment of Highwys nd Public Trnsporttion. This report does not constitute stndrd, specifiction, or regultion. There ws no invention or discovery conceived or ftrst ctully reduced to prctice in the course of or under this contrct, including ny rt, method, process, mchine, mnufcture, design or composition of mtter, or ny new nd useful improvement thereof, or ny vriety of plnt which is or my be ptentble under the ptent lws of the United Sttes of Americ or ny foreign country. 11

5 PREFACE This is the first nd finl report for Reserch Study , "Impct of Aggregte Grdtion nd Type on Asphltic Mixture Chrcteristics." The report contins: literture serch reltive to Hot Mix Asphlt Concrete (HMAC) chrcteristics, especilly VMA; n investigtion of the current production of HMAC in Texs with respect to voids in the minerl ggregte (VMA); the results of lbortory investigtions to determine the effects of ggregte grdtion nd type on HMAC properties; nd n investigtion of the economic consequences of including VMA in specifictions for HMAC. The uthors wish to cknowledge the ssistnce of nd generous support from vrious individuls nd orgniztions. Support of the Texs Stte eprtment of Highwys nd Public Trnsporttion nd the Federl Highwy Administrtion mde this reserch possible. Much pprecition is extended to Pul Krugler of the Texs Stte eprtment of Highwys nd Public Trnsporttion for his input during the reserch project. Also, cknowledgement is due the Austin, Odess, nd Wco istricts for supplying mterils for experimentl evlution. Thnks re extended to members of the Center for Trnsporttion Reserch stff-in prticulr, Mssoud Mortzvi, Bill Elmore, Eugene Betts, nd Jim Angnos. November 1990 rren G. Hzlett Thoms W. Kennedy ABSTRACT This report ddresses the impct of ggregte grdtion nd type on Hot Mix Asphltic Concrete (HMAC) chrcteristics. Severl different, but relted, topics re covered, nd results from severl experiments re presented. An overview of HMAC is presented, covering fctors ffecting mixture chrcteristics nd performnce, in ddition to review of the literture relting to ggregte grdtion nd type. The results of study of construction dt from the Texs Stte eprtment of Highwys nd Public Trnsporttion (SHPT) re presented. Two lbortory studies were conducted relting to sphlt content, ggregte grdtion, nd ggregte type. The summrized results nd interprettions of these results re included. The economic impct of specifictions chnges currently proposed by the SHPT to improve HMAC qulity is ddressed. Finlly, conclusions nd recommendtions re drwn bsed on ll preceding mteril. Key Word<;: Hot Mix Asphltic Concrete (HMAC), sphltic content, ggregte grdtion, ggregte type, economic impct SlJMMARY This report ddresses the impct of ggregte grdtion nd type on Hot Mix Asphltic Concrete (HMAC) chrcteristics. Topics covered re summrized s follows: (1) An overview of HMAC, covering fctors ffecting mixture chrcteristics nd performnce, nd review of the literture relting to ggregte grdtion nd type. (2) A study of construction dt from the Texs Stte eprtment of Highwys nd Public Trnsporttion (SHPT). (3) Two lbortory studies relting to sphlt content, ggregte grdtion, nd ggregte type. (4) Economic impct of specifiction chnges currently proposed by the Texs SHPT. (5) Conclusions nd recommendtions drwn from previous sections. m

6 IMPLEMENTATION STATEMENT This repon provides informtion bout fctors ffecting HMAC chrcteristics, especilly VMA. The repon explores the current production of HMAC in Texs nd experiments relted to fctors ffecting VMA. The likely economic impct of VMA specifictions on HMAC prices in Texs is lso explored. The informtion from this report cn be used to evlute the VMA of mixtures in Texs for comprison purposes. The repon contins list of progressive mesures to be tken for mixtures with insufficient VMA which re likely to produce VMA chnges. The economic evlution my be used to estimte the effects of VMA specifictions for HMAC on the production price of HMAC nd possible implictions for future funding nd supply. iv

7 TABLE OF CONTENTS PREFACE..._... iii ABSTRACT..._... iii SUMMARY... iii IMPLEMENTATION STA1EMENT... iv CHAPTER 1. INTROUCTION... 1 CHAPTER2. BACKGRO~LITERATUREREVillW Hot Mix Asphlt Concrete--Components, Performnce, nd Economics... 2 Asphlt... 2 Air Voids... 2 Aggregle... 3 Compction... 3 HMAC Performnce..._...'"... 3 Economics... 3 Reserch Pertining to Aggregte Grdtion nd Type...'"... 3 VMA... 3 VMA Clcultions... 4 Altemle VMA elerlnintions... 4 Voidge Reduction Fctors... 4 Prticle Pcking Using Actul Aggregte...'"... 5 Mximum-ensity Grding Curves... 5 evelopment of the 0.45 Power Chrt... 5 Alternte Mximum-ensity Line... 6 VMA nd Mximrun-ensity Lines... 6 From the Asphlt Institute... 6 From Field... 6 From Asphlt-The Mgzine of the Asphlt Institute... 6 From Griffith nd Klls... 7 From Griffith nd Klls... 7 From M:Leod... 7 From Acou... 7 From Edge... 7 From the Asphlt Institute ES Stte Requirements... 8 esign Methods... 8 VMA... 8 SUllUllry... 8 v

8 CHAP1ER 3. EVALUATION OF CURRENT GRAATIONS USE IN TEXAS Projects with esign Infonntion..._._... 9 Grdtion Plots..._.._... 9 evition nd Other Prmeter efinitions... 9 Trends... u _._ Aggregte Type As-Built Infonntion (Projects with Sufficient esign nd As-Built t) Grdtion Plots..._ Trends Comprison of esign to As-Built SwnmryofSignificntFindings CHAPTER 4 LABORATORY EVALUATION OF VARIATION IN MIX PROPERTIES WITH ASPHALT CONTENT AN AGGREGATE GRAATION iscussion of Fctoril Experiments Effect of Vribles Field Level Possl'bilities Optimum Asphlt nd VMA etennintions nd Comprisons \'MA nd Grdtion evition Prmeters Summry of Significnt Findings CHAPTER 5. LABORATORY EVALUATION OF AGGREGATE SUBSTITIJTION ON VMA Experiment escription Sttisticl Anlysis of Optimum Asphlt Content nd VMA Experimentl Interprettion VMA nd evition Prmeters Significnce of Aggregte Bulk Specific Grvity Summry of Significnt Findings CHAPTER 6. ECONOMIC IMP ACT OF SPECIFICATION CHANGES Proposed Specifiction Chnges Mster Grdtion Limits Uncrushed Fine Aggregte Limit Minimum Percent VMA Economic Impct of Specifiction Olnges HUS MIH WUS OANU Economic Impct Summry CHAPTER 7. CONCLUSIONS/RECOMMENATIONS Conclusions froln Studying the Project 1197 tbse Conclusions from Lbortory Fctoril Experimenttion Conclusions from Evlution of Aggregte Substitution Conclusions from Economic Evlution Recommendtions REFERENCES vi

9 APPENIX A. MIXTURE ESIGNS-ESIGN ATA AN EVIATION ATA APPENIX B POWER GRAATION CHARTS FOR ESIGN MIXTURES APPENIX C. ESIGN1RENS APPENIX. ESIGNMIX1URES-VMAANAGGREGATETYPE APPENIX E. FIEL MIXTURES-FIEL ATA AN EVIATION ATA APPENIX F POWER GRAATION CHARTS FOR HEL MIXTURES APPENIX G. FIEL1RENS...'" APPENIX H. AGGREGATE GRAATION INFORMATION FOR FACTORIAL EXPERIMENTS APPENIX I. APPENIX J. STATISTICAL ANALYSIS OF LABORATORY FACTORIAL EXPERIMENTS OF ASPHALT CONTENT AN AGGREGATE GRAATION ON SELECTE MIX11JRE PROPERTIES POWER CHARTS WITH OPTIMUM ASPHALT CONTENTS AN VMA'S FOR FACTORIAL EXPERIMENT MIXTURES APPENIX K. AGGREGATE SUBS1TIUTION ATA vii

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11 CHAPTER 1. INTROUCTION In September 1987, the Texs Stte eprunent of Highwys nd Public Trnsporttion (SHP'I) contrcted with The University of Texs t Austin Center for Trnsporttion Reserch, under Reserch Study , to investigte ggregte grdtions nd types used by the eprtment for hot mix sphltic concrete (HMAC). The SHPT ws prepring to updte the Stndrd Specifictions for Construction of Highwys, Streets nd Bridges nd ws prticulrly interested in knowing the effect of including "Voids in the Minerl Aggregte" (VMA) requirements in specifictions for hot mix sphltic concrete. To ddress the concerns nd interests of the SHPT, the formulted objectives of this study were s follows: to review HMAC chrcteristics, especilly VMA, in the literture; to investigte the current production of HMAC in Texs with respect to VMA nd to develop correltions between VMA nd HMAC prmeters; to conduct lbortory investigtions to determine the effects of ggregte grdtion nd type on HMAC properties; nd to investigte the economic consequences of including VMA in specifictions for HMAC. This is the first nd finl report for Reserch Study , "Impct of Aggregte Grdtion nd Type on Asphltic Mixture Chrcteristics." The scope of this study nd report is s shown below: (1) Bckground-literture review, (2) Evlution of current grdtions used in Texs; (3) Lbortory evlution of vrition in mix properties with sphlt content nd ggregte grdtion; (4) Lbortory evlution of ggregte substitution on VMA; (5) Economic impct of specifiction chnges; nd (6) Conclusions/recommendtions. "Bckground-Literture Review" involves review of the literture pertining to ggregte grdtion nd type nd their effects on mixture properties s well s review of the requirements of selected other sttes which ddress ggregte grdtion. uring the 1987 construction seson, the SHPT collected consrruction dt for 92 hot mix sphltic concrete (HMAC) mixtures. The Center for Trnsporttion Reserch, in Reserch Study , orgnized these dt into dtbse nd performed some preliminry nlysis to describe the current production of hot mix sphltic concrete. "Evlution of Current Grdtions Used in Texs" describes n nlysis of this construction dtbse s it reltes to the focus of this project. Initilly, this project ws lso to ddress long-term pvement performnce of projects contined in the Reserch Study dtbse, but the SHPT hs decided to conduct their own nlysis of the long-term pvement perforrnnce for consrruction projects included in this dtbse. Specilly trined deprunent personnel nd equipment will be used uniformly cross the stte, nd the informtion from Reserch Study will be used for long-term pvement performnce studies nd pvement mngement. Therefore, Reserch Study will not ddress the long-term pvement performnce spects of ggregte grdtion nd type on HMAC. "Lbortory Evlution of Vrition in Mix Properties with Asphlt Content nd Aggregte Grdtion" detils the nlysis of mixture properties of two HMAC designs, ech design obtined from different SHPT district, nd ech with vritions in ggregte grdtion nd sphlt content. "Lbortory Evlution of Aggregte Substitution on VMA" consists of lbortory evlution of one mixture design with substitution of one of the component ggregtes with one of two others, to evlute chnges in design prmeters. "Economic Impct of Specifictio~ Chnges" is discussion of the economic impct of chnges to specifictions currently being proposed by the Texs SHPT. "Conclusions/Recommendtions" is summry of the significnt results obtined from the project phses nd ny recommendtions mde bsed on these results.

12 CHAPTER 2. BACKGROUN-LITERATURE REVIEW The literture review is divided into three res reltive to the objectives of this study. Informtion bsic to understnding HMAC is initilly ddressed. Next, reserch pertining to ggregte grdtion nd type, with specil emphsis on VMA nd mximum density grding curves, is investigted. Finlly, the requirements of vrious stte highwy deprtments, with respect to mixture design procedures nd VMA, re summrized. HOT MIX ASPHALT CONCRETE COMPONENTS, PERFORMANCE, AN ECONOMICS HMAC consists of combintion of ggregte, sphlt cement, nd ir voids. The production of HMAC involves blending different types nd sizes of ggregte, heting, nd coting with sphlt cement. This mteril is then trnsported to the rod site, plced on the rodwy in uniform thickness, nd compcted to form prt of the rod structure. Mnipultion of the three components of HMAC cn result in wide vritions in the stbility nd durbility of the mixture. Also, vritions in mixture properties cn occur with vritions in compction. The three components of HMAC nd compction re interrelted, nd mnipulting one component to chnge the stbility of mixture my hve detrimentl effects on durbility nd vice vers. A good rod will support the lods plced on it, lst long time, nd be economicl. Hot Mix Asphlt Concrete (HMAC) is one of the most widely-used rod building mterils in the world, nd, if designed correctly, will demonstrte the chrcteristics desired in rod. Correedy designing n HMAC is not n esy tsk since the mixture chrcteristics needed for lod support nd longterm durbility re often t odds with ech other. The mteril must be designed to rrive t compromise which will best fulfill these needs. The rod chrcteristic of "supporting the lods plced on it" is brod requirement which encompsses resistnce to filure due to both permnent deformtion nd lod stress (tensile, compressive, nd sher). This is essentilly the sme chrcteristic tht Jimenez nd deppoll describe s stbility, which will be used to describe this chrcteristic. The rod chrcteristic mening "lst long time" is nother brod requirement which will be described by "durbility... urbility encompsses ftigue resistnce (repeted lod) nd resistnce to environmentl effects such s temperture, moisture, oxidtion, nd time (exmples: therml crcking nd stripping). ASPHALT Asphlt is the binder which holds n HMAC together. For good HMAC durbility, one needs to use s much sphlt cement in the mixture s possible. This gives greter resistnce to sphlt ging (oxidtion) nd wter dmge. Also, there is evidence in the literturel1,7.5 to indicte tht incresed sphlt content results in greter ftigue life. Too much sphlt, however, cn result in bleeding or flushing of the pvement surfce (sphlt migrtes to the surfce, resulting in reduced surfce friction), s well s in n unstble pvement which is unble to crry lods without permnent deformtion. Too little sphlt results in n HMAC prone to sphlt oxidtion nd subsequent mix embrittlement, less resistnce to moisture dmge, nd decresed ftigue life. Insufficient sphlt cn lso initilly produce mix which is unble to withstnd the lod stresses plced on it. Therefore, either too little or too much sphlt cn result in decresed pvement life. The optimum mount of sphlt for given hot mix must be determined by blncing the beneficil nd detrimentl effects of sphlt content on mixture. Most mixture designs use the philosophy, "Use s much sphlt s possible without detrimentl loss of stbility."ll AIR VOIS Air voids re criticl prt of mixture nd provide insurnce ginst bleeding or flushing of the pvement surfce (sphlt migrtes to the surfce, resulting in reduced surfce friction), s well s ginst n unstble pvement which is unble to crry lods without permnent deformtion. High ir void contents decrese durbility by iding sphlt oxidtion. High ir voids cn lso enble further compction in service by trffic nd result in permnent deformtion. Low ir void contents my llow bleeding or flushing nd instbility to tke plce. Most design procedures tke into ccount the detrimentl effects of extremes in ir void content by plcing upper nd lower limits on ir voids. The Mrshll mix design method clls for ir voids in the rnge of 3 to 5 percent. The SHPT Hveem design criteri cll for 3 or 4 percent ir voids, depending on how the percentge of ir voids is clculted.l6 These limits were set to blnce the detrimentl nd beneficil effects of ir void content for the mjority of mixtures nd were derived from experience over time. 2

13 3 AGGREGATE Aggregte forms the skeleton or the supporting structure of n HMAC nd, s such, is responsible for the mjority of the lod-bering cpcity of the mixture. Most HMAC is composed of continuously-grded ggregte blended from severl different sizes nd types of ggregte. Aggregte cn be of different geologic origin, cn result from different methods of production, nd cn represent specific sizes of the production. As such, virtully ll mixes re different with respect to ggregte grdtion nd type. Aggregte chrcteristics which my differ include: size distribution, shpe, surfce texture, surfce re, sphlt bsorption, nd chemicl/minerlogic composition. When combining three or more seprte ggregtes, ll of which my hve different chrcteristics, one cn see how complicted the study of mixture ggregte grdtion cn become. Aggregte cn ffect the mixture properties in mny wys. Prticle shpe nd surfce texture of the ggregte ply lrge prt in how closely the ggregtes my be compcted. Evidence suggests tht rounded prticles result in "more compctble" mix.s Rough surfce texture results in less compctbility, nd the ssocited higher surfce res require more sphlt for the sme ftlm thickness.6 Certin ggregtes re lso more prone to moisture dmge thn others. There re mny other ggregte-induced effects, such s mixture tenderness, but the exct cuses re hrd to quntify becuse of the complexities of ggregtes. COMPACTION Compction is externl to the mteril itself, but plys just s n importnt role in HMAC mixture performnce s do the ingredients. Most mix design procedures utilize some form of stndrd compction technique which insures tht the designed mixture hs the cpbility of being compcted to the rnge desired (not too much nd not too little). The performnce of the finl product is function of the degree of compction ttined on the rodwy. Assuming the mixture ingredients re cpble of performing stisfctorily, the degree of compction cn result either in stble nd durble rodwy component or in premture filure. Adequte compction will result in proper utiliztion of the sphlt s binder in the mixture, n ir void content low enough to preclude erly sphlt oxidtion nd exclude moisture from the mix, nd ggregtes consolidted enough to provide the stbility necessry to resist further consolidtion under norml trffic conditions. Indequte compction my result in mix which will be prone to sphlt oxidtion, moisture dmge, nd lower ftigue life, one which will exhibit instbility due to consolidtion under trffic nd, ultimtely, erly filure. HMAC PERFORMANCE As cn be seen from the foregoing prgrphs, mixture performnce is influenced by mny vribles which re interrelted. Asphlt, ir voids, ggregte, nd compction work in combintion to produce mteril which will perform stisfctorily s rodwy component. Chnging ny of the components in the mixture, or their reltive proportions, my result in substntil chnges in the properties of tht mixture due to other interrelted vribles. As n exmple, incresing the sphlt content of given mixture my result in lower-thn-expected ir voids becuse of more sphlt in the mixture nd incresed compctbility of the ggregte from lubriction effects of the sphlt This could result in more durble pvement (less prone to sphlt oxidtion nd moisture dmge, with higher resistnce to ftigue crcking due to repeted loding), but could lso result in instbility of the mixture (prone to permnent deformtion due to plstic flow). The ctul effects depend on how sensitive the mixture is to chnges in sphlt content from the design or bseline condition. ECONOMICS The lst chrcteristic desired in rodwy is tht it be economicl. The gol of ny mixture design procedure is to produce mixture tht stisfies durbility nd stbility requirements nd lso is economicl. Mixture design procedures do this by llowing the use of locl (low trnsporttion costs) ggregtes s long s they produce mixtures meeting the design criteri which re, t lest in theory, devised to provide stbility nd durbility. RESEARCH PERTAINING TO AGGREGATE GRAATION AN TYPE Aggregtes, their grdtion, nd their type hve been studied for mny yers. The studies hve been bsed on trends in the industry, experience with mixes plced on the rodwy, nd lbortory experiments. The results hve developed mny interesting concepts, but most conclusions hve been mde in generic terms. Two concepts which hve received the most ttention re Voids in the Minerl Aggregte (VMA) nd Mximum ensity Grding Curves. VMA Voids in the minerl ggregte (VMA) is mesure of the mount of void spce vilble between the ggregtes of compcted HMAC. This void spce consists of the spce vilble for sphlt, which gives durbility nd cohesiveness to the mixture, nd ir voids--insurnce ginst sphlt migrtion nd subsequent instbility of the pvement. The VMA is function of ggregte chrcteristics, sphlt chrcteristics, the proportions of sphlt nd ggregte in the mixture, nd compction.

14 4 As such, VMA must be determined bsed on ctul compcted specimens of the mterils nd proportions of interest. If one uses stndrd compction technique, VMA my be studied without compction s vrible. Becuse VMA is indictive of the mount of spce vilble for sphlt nd ir within given mixture, it is included in HMAC specifictions by mny highwy gencies. The Asphlt Institute, in its publiction.. Mix esign Methods for Asphltic Concrete nd Other Hot Mix Types," 1 recommends minimum VMAs for HMAC bsed on the nominl mximum prticle size of the ggregte in Mrshll mix design. The lrger the nominl mximum prticle size, the lower the minimum VMA required. This recommendtion is bsed on work by Mcleod, 18 which ws published in ASTM Specil Technicl Publiction No. 252 in where VMA CALCULATIONS VMA currently is determined by the formul: VMA = 100- G * %Agg GAgg G = ctul specific grvity of compcted mixture, %Agg = percentge of ggregte in the mixture by weight (100-%Asphlt), nd G Agg = bulk specific grvity of ggregtes, or G Agg = effective specific grvity of ggregtes. There hs been some question concerning which GAgg should be used in the eqution. The controversy revolves round whether pores in the ggregte, which cn bsorb sphlt, should be included s prt of the VMA. The sphlt bsorbed into these pores is effectively lost in terms of sphlt vilble for use s binder in the mixture. Mny reserchersl,2,6 use the bulk specific grvity of the ggregte in the bove VMA definition, which excludes ggregte pore volume s prt of VMA. They view VMA s the spce vilble in compcted mixture for sphlt, which functions s binder, nd ir. Other reserchers prefer to use the effective specific grvity of the ggregte in the bove VMA definition insted of the bulk specific grvity of the ggregte.11,19 This includes the ggregte pore volume which bsorbs sphlt s prt of the VMA. Some reserchers view VMA s the spce vilble for ir nd sph1t, whether or not the sphlt functions s binder. For ggregtes which do not bsorb sphlt, the two VMA clcultions will yield identicl results, but s sphlt bsorption increses, using the effective specific grvity of the ggregte will yield higher VMA clcultions. Using the bulk specific grvity of the ggregte produces VMA vlues representing the spce vilble for sphlt nd ir in the mixture fter ll sphlt bsorption hs been stisfied. If bsorptive ggregtes re used, there my seem to be discrepncy between the mount of sphlt used nd the mount of vilble room for sphlt (VMA-Air Voids). The volume of sphlt used could be more thn the room vilble for sphlt s determined by VMA. The discrepncy is not rel, since in using the bulk specific grvity of the ggregte for VMA clcultion, the volume of sphlt bsorbed is not included. For this study, the bulk specific grvity of the ggregte will be used for ll VMA clcultions. ALTERNATE VMA ETERMINATIONS There hve been severl procedures developed for determining the VMA directly from the ggregte nd not clculting the VMA from n ctul compcted specimen of the HMAC. Procedures include generic voidge reduction fctors nd ctul prticle pcking techniques. VOIAGE REUCTION FACTORS Hudson nd vis, 12 in pper presented to AAPf in 1965, developed method of determining the VMA of mixture bsed on the ggregte grdtion. This pproch uses prticle pcking nd void-ftlling principles in which smll-size prticles, with inherent voids in their pcked volumes, fill void spces in lrger-size pcked prticles; this blend fills voids in still-lrger-size pcked prticles. There is n optimum percentge of ech size component to product minimum voids in the entire blend resulting in minimum VMA. Adding more or less thn the optimum percentge of ech component will cuse the blend to exhibit more thn the minimum VMA. Hudson nd vis used the rtio of cumultive percent pssing successive sieve sizes nd derived voidge reduction fctors to ultimtely clculte the Aggregte Voidge of the mixture. Voidge reduction fctors were derived for certin generic ggregte types, nd their use depends on the use of specific sieve sizes to describe the ggregte grdtion. Comprisons of clculted Aggregte Voidge with VMA determined in Bureu of Public Rods dt showed resonble correltion (rnge of differences between clculted nd BPR VMA vlues were -1.2 to +0.7). This method is resonble; however, the Voidge Reduction Fctors for the vrious ggregte types re too generic to result in more ccurte results. There re too mny ggregte types nd resulting shpes nd surfce textures for generic fctors to pply ccurtely. Jimenez nd deppo,ll in 1986 report for the Arizon eprtment of Trnsporttion, developed mixture design procedure bsed in prt on the concepts developed by Hudson nd vis. In this mix design

15 5 process, ggregte grdtion is used to clculte VMA using Voidge Reduction Fctors, nd ggregte surfce re is determined using Surfce Are Fctors. The optimum mixture proportions re selected bsed on the VMA of the ggregte (the VMA is the ultimte VMA of the mixture nd not tht currently used in specifictions) nd sphlt content required to give dequte film thickness. Jimenez nd deppo report good correltion of optimum sphlt determintions for mixtures from severl highwy deprtments from round the country (R2::0.79), but lower correltion for mixtures from the Arizon eprtment of Trnsporttion (R2=0.18). This my be due to the generic Voidge Reduction Fctors nd Surfce Are Fctors being more pplicble to the ntion s whole (wide vriety of ggregtes) nd less pplicble to Arizon ggregtes. PARTICLE PACKING USING ACTUAL AGGREGATE Shnn nd Ro,IO in 1984 pper submitted to the Indin Rods Congress, describe method of determintion of ggregte voids in multi-component ggregte blends using prticle pcking nd void chrcteristics. The process involves determining the minimum percent voids in two-component blend of the two lrgest ggregte sizes nd then treting this optimized blend s one component nd finding the optimum blend with the next smllest component The process proceeds until ll sizes re represented in the finl blend. This finl blend would represent the minimum VMA for those ggregtes. The process cn be djusted to clculte the VMA of ny ggregte blend in the sme mnner. The procedure utilizes the oven dry bulk specific grvity (BSG 0 d) of the ggregte blend in question nd its ry Rodded Unit Weight (RUW) to clculte the percent voids. This procedure is similr to the one used in the concrete industry to chieve ner-minimum ggregte voids for "filter block effect" in the design of portlnd cement concrete to be plced by pumping. A "filter block effect" results when the ggregte hs so few voids tht s concrete pump moves the fluid portion of the mixture (wter), the solid portion (ggregte nd cement prticles) must be crried long with it A problem in using this procedure for HMAC design is tht individul ggregtes, which in themselves represent rnge of sizes, my produce inccurte ry Rodded Unit Weights owing to segregtion. To ddress this problem, blends of consecutive ggregte sizes would hve to be mde to form "new" ggregtes, limiting segregtion effects in the RUW determintion. This would gretly complicte the process of voids determintion for n HMAC ggregte blend. Another problem is tht this procedure does not tke into ccount the lubricting effect sphlt hs on VMA, since this procedure tests only the dry ggregtes. Griffith nd KJJsS reported dt obtined from two ggregte blends tested similrly in 1957 nd found the procedure not to be relible method of determining ggregte voids in bituminous mixtures. This my be due to segregtion, sphlt lubriction, or procedurl differences. This procedure does ddress some spects which hve been downplyed by the Void Reduction Fctor methods, nmely ggregte shpe nd surfce texture. Since the ctul ggregte is used, the ctul shpe nd surfce texture chrcteristics nd their impct on the ggregte voids is tken into ccount To chieve specified void content, the process would involve tril nd error. MAXIMUM-ENSITY GRAING CURVES Mximum-ensity Grding Curves re methods to grphiclly depict the mximum-density cpbility of selected ggregte sizes. Actul ggregte grdtions my be compred with the mximum-density curve to see where devitions from the mximum-density line occur. HMAC ggregte grdtions with certin types of devitions from the mximum-density line hve been found to exhibit specific problems, most notbly mixture tenderness. It is suggested tht djusting the ctul grdtion in reltion to the mximum-density line my solve some HMAC problems. Other observtions regrding devitions from the mximum-density line re sid to give more room in the mixture for sphlt (VMA) nd hence increse HMAC durbility. Mximum-density grding curves tke into ccount only the stndrd sieve sizes normlly used in HMAC specifictions. As such, mximum-density curves do not tke ggregte shpe or surfce texture into ccount. EVELOPMENT OF THE 0.45 POWER CHART In 1962, Goode nd Lufsey,l3 of the Bureu of Public Rods, proposed the use of new chrt to disply ggregte grdtion nd mximum density. The new chrt would replce the trditionl mximum-density chrt, which expressed the percentge pssing (rithmetic scle) versus the sieve size (logrithmic scle). According to Goode nd Lufsey, the trditionl "logrithmic grdtion chrt" yielded mximum-density line s "deeply sgging curve, the shpe of which is hrd to define." The new Goode nd Lufsey chrt ws bsed on the development of n eqution to describe the mximum density of n ggregte grdtion. The eqution ws: P=IOO* (~) 0.4 5

16 6 where M = mximum size of ggregte in microns, S = size of opening for prticulr sieve, nd P = percent pssing the prticulr sieve. If the percent pssing prticulr sieve size is plotted rithmeticlly, versus the sieve size rised to the 0.45 power, the resulting mximum-grdtion curve is line extending from 0 (zero) percent pssing the 0 (zero) sieve size through the ctul percent retined on the nominl mximum sieve size (nominl mximum sieve size is the lrgest stndrd sieve size which ctully retins ny prticles) nd continuing to intersect the 100 percent pssing line. The sieve size indicted t the 100 percent pssing point is termed the effective mximum ggregte size for the mixture. The effective mximum ggregte size my not be one of the stndrd sieve sizes. Goode nd Lufsey used this new chrt in the study of "tender" mixtures, defined s mixtures which conform to specifictions, but which cn not be compcted in the norml mnner becuse they re slow in developing sufficient stbility to withstnd the weight of rolling equipment. They observed tht mny "tender" mixes displyed "hump" or positive devition from the mximum-density line t or ner the No. 30 sieve. They concluded tht this "hump," produced by n excess of fme snd, resulted in lower compcted densities nd decresed stbility due to seprtion of corse ggregte nd less corse ggregte interlock. With further lb work, they found tht hump t the No. 30 sieve size (with other things being equl) resulted in incresed VMA nd lower Mrshll Stbility. They concluded tht the hump "my be contributing fctor towrd the unstisfctory behvior of mixtures" nd is, therefore, undesirble. In 1989, Kndhl20 reported tht designers t highwy gencies were using three vritions of the "mximum density line." One of the lines used is defined s Goode nd Lufsey proposed in The other two lines represent vritions or lternte interprettions of the line. They ll begin t 0 (zero) percent pssing the 0 (zero) sieve size, but differ in the loction of the end-point for the mximum sieve size. This indictes tht some disgreement or confusion exists regrding the definition nd use of mximum-density lines. ALTERNATE MAXIMUM-ENSITY LINE In 1987,.E. Edge14 of the Asphlt Institute noted tht the 0.45 power mximum-density chrt (now known s the FHWA 0.45 Power Chrt) indictes tht more mteril pssing the No. 200 sieve should be used thn most highwy gencies choose to use. He thought nother mximum-density line bsed on the 0.45 Power Chrt might be more pproprite. His ide ws "mximum-density line" formed by " stright line drwn between the desired percent pssing the No. 200 sieve nd the desired percent pssing the nominl mximum sieve size." He even went further to sy tht "stright line drwn between ny two sieve sizes describes mximum-density grding between those two sizes." This ide could be extended to sy tht ny specific ggregte grdtion hs mximum-density line formed by drwing line from the ctul percent pssing the No. 200 sieve to the ctul percent retined on the nominl mximum sieve size. In this mnner, ech grdtion hs its own mximum-density curve. VMA AN MAXIMUM-ENSITY LINES In theory, ny ggregte grdtion tht flls on the "mximum-density line" results in the mximum ggregte density possible for the ggregte sizes represented. Mximum ggregte density lso mens minimum VMA. Consequently, ny devition from the mximum-density line implies tht the VMA of the mixture is more thn the minimum. Mny reserchers hve studied VMA nd devitions from the mximum-density line nd mde generl sttements regrding how vrious ggregte sizes ffect VMA nd how devitions from the mximum-density line ffect the VMA. A list of some of these observtions nd conclusions follows. FROM TilE ASPHALT INSTJTUTEl Grdings tht closely pproch the mximum density line must be djusted wy from it within cceptble limits to increse the VMA. As generl pproch to obtining higher VMA the ggregte grding should be djusted by dding more corse or fine ggregte. FROMF/EW2 For ggregtes of borderline minimum VMA, the VMA increses by 0.5% for every 5% increse in pss 4.75mm (No.4) sieve mteril. For ggregtes of good VMA, the VMA increses by 0.8% for every 5% increse in pss 4.75mm (No.4) sieve mteril. An increse of 1% pss 75 mm (No. 200) sieve lowers the voids nd VMA by 0.8%. Angulr corse ggregte prticles will provide for higher VMA thn rounded prticles. FROM ASPI/ALT-TIIE MAGAZiNE OF TilE ASPHALT INSTJTUTE3 An increse in the volume concentrtion of stone in mix corresponds to decrese in VMA.

17 7 FROM GRJFFUH AN KAU.AS4 Incresed ngulrity nd roughness of surfce texture of fine ggregte produced incresed minimum percent ggregte voids in sphltic concrete mixes compcted by the methods specified for the Mrshll nd Hveem methods. FROM GRIFFITH AN KAU.AS5 For given ggregte, grdtion, nd compction method, void vlues normlly decrese with incresing sphlt contents to minimum vlue nd then increse s the incresed mount of sphlt prevents ggregte prticles from chieving their most intimte contct This occurs even though ir voids still exist in the mix. The seprtion of ggregte prticles by incresed mounts of sphlt, fter minimum void vlues hve been reched, ffects the strength chrcteristics or mix by decresing its bility to withstnd shering stresses. Stbility tests such s the Mrshll nd Hveem generlly indicte stbility decreses for sphlt contents greter thn tht necessry for producing minimum ggregte voids in mix. Selection of n optimum sphlt content for given mix, using the criteri of the Mrshll nd Hveem methods of mix design, normlly results in n sphlt content ner, or slightly less thn, the mount required to produce minimum ggregte voids. Therefore, the optimum sphlt content ppers to be closely relted to the voids in the minerl ggregte. Furthermore, the sphlt content is lmost directly proportionl to the mount of ggregte voids for minerl ggregtes hving low sphlt bsorption. The uncrushed grvel mix specimens, s group, indicted lower ggregte voids thn the crushed rock mixes through the grdtions investigted. Corse ggregte prticle shpe, whether the ggregtes re crushed or uncrushed, hs considerble influence on ggregte voids, prticulrly when the corse frctions re greter thn 50%. Aggregte voids in compcted sphlt pving mixes vry in logicl nd orderly fshion. Actul vlues, however, re primrily dependent upon type nd grdtion of the ggregte, sphlt content nd method of compction. FROM MCLEO6 Incresing the percent of fine ggregte in dense grded bituminous concrete, the percent of voids in the minerl ggregte cn be substntilly incresed. When rnge of ir voids nd minimum percent ge of VMA re specified this utomticlly estblishes minimum bitumen content by weight for the pving mixture. FROMACOTfB The stte of Illinois chieved significnt improvements in HMAC properties by incresing the VMA. The VMA increse ws ccomplished by moving the grdtion wy from the mximum density line. This involved substituting corse crushed snd for fme nturl snd. FROM EGE14 The 0.45 curve will probbly not hve sufficient VMA to llow n dequte coting of the ggregte nd still hve 3 to 5% ir voids in the design mix. To increse the VMA, continuous grding curve either bove or below the 0.45 curve my be incorported. A grdtion below the 0.45 curve will be hrsher grded mix, nd subject to segregtion. A grdtion bove the 0.45 curve will increse the VMA but usully not s drmtic s going below the 0.45 line. The rtio of the mteril pssing the No. 30 sieve but retined on the No. 200 to the mteril pssing the No. 8 sieve but retined on the No. 200 sieve cn defme the deprture from the 0.45 curve in the fine ggregte frction. (This signls hump possibly indictive of tender mix problems.) FROM THE ASPHALT INSTITUTE ES-Jl5 A poor ggregte grdtion often is leding contributor to tender (slow-setting), or unstble mixes. Tender mixes re frequently typified by n excess of the middle-size snd frction in the mteril pssing the 4.75mm (No.4) sieve. A hump in the grding curve cused by the excess snd could pper on nerly ny sieve below the 4.75mm (No.4) nd bove the 150mm (No. 100). If there is devition exceeding 3 percent upwrd from stright line drwn from the origin of n 0.45-power grding chrt to the point t which the grdtion line crosses the 4.75mm (No. 4) sieve line, tenderness difficulties might be nticipted. This condition is most criticl when occurring ner the 600mm (No. 30) sieve. This devition in the grding curve is nerly lwys ccompnied by reltively low mount of mteril pssing the 75mm (No. 200) sieve in tender mixes. Mny of the observtions nd conclusions re bsed on the results of work with specific ggregte grdtions, re generic in nture, nd do hve exceptions. Some of the exceptions re no doubt due to the mximum density line concept being unble to tke prticle shpe nd texture into ccount

18 8 STATE REQUIREMENTS Stte highwy deprtments use different design methods nd hve different VMA requirements. This section summrizes the current prctices of the sttes. ESIGN METHOS A pper presented to AAPr in 1985 by Kndhl nd Koehler17 summrizes the current prctices of stte highwy deprtments with regrd to mixture design procedures with specil emphsis on Mrshll design criteri. Thirty-eight sttes use the Mrshll mix design procedures, ten use the Hveem method, one uses grdtion specifictions only, nd Texs uses the "Texs Method." VMA Kndhl nd Koehler found tht of the 38 sttes using the Mrshll design method. only 16 hd requirements for VMA. Of the 16 sttes with VMA requirements, only 7 clculted the VMA in the mnner recommended by the Asphlt Institute which tkes into ccount the effective sphlt content. Tble 2.1 shows stte VMA requirements obtined from the survey by Kndhl nd Koehler, supplemented by the newest known developments (39 sttes now use the Mrshll design method). Kndhl nd Koehler reported tht the Pennsylvni OT's experience with VMA for their most commonly used surfce course (3/8-in. nominl mximum size) show mny mixtures would fil to meet the Asphlt Institute guidelines of 16 percent VMA. The Pennsylvni OT recommends 16 percent VMA but will ccept mix if 90 percent of the project VMA determintions exceed 15 percent. The suggestion is tht for locl conditions using locl ggregtes, the Asphlt Institute recommendtions my be difficult to chieve, nd it my be necessry for some gencies to lower the requirements in order to get economicl mixtures. Oklhom. which uses Hveem Mix design nd is similr to Texs in the specimen compction technique (gyrtory), hs VMA requirements. The VMA guidelines re the sme s those proposed by the Asphlt Institute (exmple: VMA=l6 for 3/8-in. nominl mximum size), even though they were developed for use with Mrshll mixture design. Oklhom found tht to meet the VMA requirements more mnufctured snds hd to be used thn nturl, more rounded snds. SUMMARY This chpter discussed the interreltionships tht exist between the components of HMAC nd how they cn ffect the function nd life of the pvement. VMA, mximum-density grding curves, nd the connection between them both were explored. Finlly, the prctices of the vrious stte highwy deprtments with respect to mixture design procedures nd VMA requirements were summrized. The result of the literture investigtion hs shown tht. while there is bsic greement on mny cuses of pvement distress nd filure, there is gret del of disgreement on VMA nd mximum density grding curves. Much work is yet to be done with bituminous mixtures. TABLE 2.1. VMA REQUIREMENTS FOR COMMONLY USE SURFACE MIXTURES FOR STATES USING MARSHALL MIXTURE ESIGN Nominl Mximum Aggregte Size VMA VMA Stte (ln.) (min) ~ Arizon 1( Arknss 1(2 14 elwre 3/8 16 Florid 3/8 15 Illinois 1(2 15 Indin 1(2 15 Iow 1(2 15 Mrylnd 3/8 16 Michign 1( New Jersey 3/4-1( New Mexico 1(2-3/ North kot 3/4 18 Ohio 3/8 16 Pennsylvni Vermont 3/8 1( Vrrgini 1( W.Vrrgini 3/ Wisconsin 1(2 15 Wyoming 3/4-1/

19 CHAPTER 3. EVALUATION OF CURRENT GRAATIONS USE IN TEXAS uring the 1987 construction seson, construction dt were obtined for 92 hot mix sphltic concrete (HMAC) mixtures from 18 districts nd were orgnized into dtbse by the Center for Trnsporttion Reserch in its Reserch Study The dtbse represents unique opportunity to study in detil construction dt from lrge number of projects nd to develop snpshot of current production of HMAC in the stte of Texs. This chpter focuses on the construction dt in this dtbse nd on n nlysis of certin spects which re relevnt to this project nd of interest to the SHPT. The 1197 dtbse contins informtion provided by the district responsible for the execution of ech project. All of the informtion requested for ech project ws not lwys vilble; therefore, the dtbse does not include ll informtion of interest for ll projects. Much of the current interest of the SHPT is in projects for which the HMAC design informtion is present. It is lso desirble to compre design informtion with s-built informtion. Therefore, the nlysis of the dtbse informtion will be conducted in four sections. The first section will nlyze projects from the dtbse for which relible HMAC design informtion ws obtined. The second, involving s-built informtion, will nlyze subset of those first-section projects with sufficient s-built informtion vilble. The third section will compre the design informtion with s-built informtion for projects for which both re vilble. The lst section will summrize significnt findings of the previous sections. Becuse of n insufficient number of projects using mix types other thn Types C nd, nd becuse Types C nd represent the vst mjority of surfce mixes used, nlyses will cover only these two mixture types. PROJECTS WITH ESIGN INFORMATION HMAC design informtion ws obtined for 8 Type C mixtures nd 24 Type mixtures. The nlysis performed for these projects involves the following: (1) plots of grdtions s compred with two different 0.45 power mximum-density lines; (2) summry of severl methods used to describe devition of grdtion from mximum-density line nd other prmeters; (3) nlysis of possible trends between grdtion devitions from mximum-density lines nd other mixture prmeters versus design VMA; nd (4) nlysis of ggregte type versus design VMA. Tbles A.1 nd A.2 in Appendix A show design informtion, mximum-density line devitions, nd other descriptive prmeters which were either clculted or obtined from the Project 1197 dtbse for Type C nd Type mixtures, respectively. Tble 0.1 in Appendix shows ggregte type informtion obtined from the Project 1197 dtbse for these projects. The informtion in these tbles forms the bsis for the nlysis of the mixture designs. GRAATION PWTS As stted in Chpter 2, there re severl "mximumdensity" lines in use to describe the mximum-density cpbility in given mixture. This pper will investigte two mximum-density lines-the Goode nd Lufsey proposed line, nd line developed s n extension of the concepts proposed by Edge. Both lines re bsed on the use of the 0.45 power chrt in which the percent pssing prticulr sieve size is plotted rithmeticlly versus the sieve size rised to the 0.45 power. The difference between the two mximum-density lines lies in the definition of the points describing the line. The Goode nd Lufsey points re t 0 (zero) percent pssing the 0 (zero) sieve size nd the ctul percent retined on the nominl mximum sieve size. The Edge concept mximum-density line definition points re the ctul percent pssing the No. 200 sieve nd the ctul percent retined on the nominl mximum sieve size. Thus, the two definitions result in two different mximum-density lines, the difference being the lower point describing the line. For this pper, the Goode nd Lufsey line will be referred to s the "old" mximum-density line, nd the Edge concept line will be referred to s the "modified" mximum-density line. The 0.45 power chrts for the design grdtions of the 32 mixtures re plotted in Appendix B. These chrts show the design grdtion nd both "old" nd "modified" mximum-density lines. A grdtion plotting below given mximum-density line indictes the mixture is corser thn "mximum-density" grdtion. A grdtion plotting bove given mximum-density line indictes the mixture is finer thn "mximum-density" grdtion. A grdtion crossing mximum-density line is more difficult to quntify. It could be corser in one re nd finer in nother. For Type C mixtures in Figs B.l to B.8, most grdtions cross the "old" line, but re finer thn the "modified" line. For Type mixtures in Figs B.9 to B.32, mny grdtions cross the "modified" line, but re corser thn the "old" line. Most of the Type mixtures 9

20 10 tht cross the "old" mximum-density line would be clssified by the Asphlt Institute s hving "hump" in the grdtion curve round the #40 sieve. According to their criteri, these mixtures could suffer from tenderness problems. EVIATION A.N OTHER PA.RA.METER EFINITIONS In ddition to grdtion informtion for ll mixture designs, Tbles A. I nd A.2 in Appendix A show other mixture prmeters nd severl mesures of devition from both mximum-density lines. Below is description of ech prmeter. VMA VMA ws clculted from mixture-design informtion obtined from mnul serch of hrd-copy files used to ssemble the Project 1197 dtbse. The ctul design informtion needed to clculte VMA, though not required by the dtbse, ws subsequently withdrwn by mny of the districts from the project informtion they submitted. VMA ws the one piece of informtion criticl to this study; consequently, ny project for which VMA could not be clculted ws not used in ny nlysis. ASPHALT CONTENT esign sphlt content ws found either by mnul serch of records or in the Project 1197 dtbse. It is importnt to note tht this is design sphlt content nd my not be tht which is ctully used in the field. The design sphlt content provides strting point for field opertions nd my be djusted in the field. PVF Percent of Voids Filled with sphlt (PVF) ws clculted by knowing the VMA nd the design ir void criterion used to select the sphlt content. This criterion is either 4 percent ir voids if Rice specific grvity is used for the mximum specific grvity, or 3 percent ir voids if clculted theoreticl specific grvity bsed on component specific grvities is used. For this dt, 3 percent ws used by the districts for ll projects, even though in some cses Rice grvities were used. PVF ws clculted s follows: (VMA - Air Void esign Criteri)* 100 PVF= VMA where ll terms re s previously defined. EVIATIONS FROM "OW" AN "NEW' MAXIMUM-ENSrrY lines Severl ttempts were mde to quntify devitions from the mximum-density lines. Four different mesures were developed, nd ech ws pplied to both the "old" nd "modified" mximum-density lines. The first three were bsed on compring the percent pssing the stndrd sieve sizes, while the fourth used n re technique. The first devition mesure ws sum of the differences in percent pssing, between the mximumdensity line nd the ctul grdtion, for ll stndrd sieves. Appendix A shows these s OLL SUM(LINE ACT) nd MOL SUM(LINE-ACT). In this mesure, positive devitions nd negtive devitions from the mximum-density line will cncel out; therefore, smll vlue my indicte either smll devition from the mximum-density line or lrger devitions on both sides of the line. Figure 3.1 shows n exmple of complictions which cn develop when using this devition mesure. The two displyed grdtions, long with the "old" mximum-density line, result in the sme vlue for OLL SUM(LINE-ACT). The sme cn lso be sid of the "modified" line. The second devition mesure ws sum of the bsolute vlues of differences in percent pssing, between the mximum-density line nd the ctul grdtion, for ll stndrd sieves. Appendix A shows these s OLL SUM(ABS(LINE-ACT)) nd MOL SUM(ABS(LINE ACT)). In this mesure, smll vlues indicte smll devitions from the line, but one cnnot tell the difference between grdtion tht crosses the line nd one tht is entirely on one side of the line. Figure 3.2 shows the "old" mximum-density line nd two grdtions which both result in OLL SUM(ABS(LINE-ACT)) = 31. The third devition mesure ws sum of the squres of the differences in percent pssing, between the mximum-density line nd the ctul grdtion, for ll stndrd sieves. Appendix A shows these s OLL SUM((LINE-ACT)A2) nd MOL SUM((LINE ACT)A2). This mesure is similr to the bsolute vlue of the differences, except tht lrger devitions contribute 0 c:: c:;; (/).. ""?ft ~ '.... : ~~~u...,,,,. ~, uuu~h~~, ~ ou ~ u +HH< ' +.. u-1 ~ '.....J._. ~ ~. ~. T ~ : o~~._. ~ ~~--- #200 #40 #10 #4 318 in. 112 in. #80 Sieve Size Fig 3.1. Grdtions with equl sums of devitions.

21 11 more to the vlue thn smll devitions (smll vlues men smll devitions from the line). It hs the sme problems; nmely, one cnnot tell the difference between grdtion tht crosses the line nd one tht is entirely on one side of the line. Figure 3.2 shows the "old" mximum-density line nd two grdtions which both result in OLL SUM((LINE-ACT)"2) = 193. The lst devition mesure developed ws bsed on the re between the mximum-density lines nd the ctul grdtion. Appendix A shows these s AREA(OL-ACT) nd AREA(MO-ACT). A Microsoft EXCEL spredsheet ws developed which grphiclly integrted the re between the curves. When the ctul grdtion ws entered, both "old" nd "modified" mximum-density lines were clculted, integrtion between the ctul grdtion curve nd ech mximum-density line ws performed for successive sieve sizes, nd the totl res were summed. This process results in devition mesure which more ccurtely determines the difference between mximum-density line nd the ctul grdtion. Figure 3.3 shows the "old" mximum-density line for two grdtions which result in virtully the sme re between the ctul grdtion nd the mximum-density line. The exmples given in figures for the other three devition mesures do not result in equl res between ctul grdtions nd mximum-density lines. Thus, the re mesure more dequtely represents the true devition from the mximum-density line. FINENESS MOULUS The Fineness Modulus is defined s the summtion of the cumultive percent retined on ll stndrd sieves from #4 to #200, ll divided by 100. The Fineness Modulus of the ctul grdtion ws subtrcted from the Fineness Modulus of the "old" or "modified" mximumdensity line to rrive t nother prmeter for compring grdtions. This prmeter resulted in vlue which indicted whether the ctul grdtion ws, overll, corser or finer thn the mximum-density line for tht grdtion. These vlues re listed in Appendix A s FM(OL L) FM(ESIGN) nd FM(MO L)-FM(ESIGN). This method hs some of the sme pitflls s the sums of differences, bsolute vlues of differences, nd squres of differences in tht since devitions cn cncel out, grdtions with lrge differences cn hve the sme vlue. SAN RATIO A fml prmeter studied ws the snd rtio, defined s the rtio of fine snd ( -#40 to +#200 ) to totl snd (-#10 to +#200). It is thought tht this rtio cn be relted to VMA development. TRENS Figures C.l to C.43 in Appendix C present grphs developed to show reltionships between vrious grdtion mesures nd VMA. These grphs depict combined dt (combined types C nd ) nd dt for individul mixture types (C nd ). ASPHALT CONTENT Figures C. I to C.3 show design VMA versus design sphlt content. A correltion exists (R2 = 0.49, 0.59, nd 0.43) between the design sphlt content nd VMA. Furthermore, for those mixtures where sphlt bsorption dt could be found (very few hd this informtion), mixtures with the most devition from the correltion line hd higher sphlt bsorption. These high bsorption mixtures dversely ffect the overll correltion. Excluding high-bsorption mixes would most likely result in much better correltion nd supports the sttement by Griffith nd Klls tht "sphlt content is lmost directly proportionl to the mount of ggregte voids for minerl ggregtes hving low sphlt bsorption." c: v.; (I) co.. ~ ~N i ~-L... ~ t j G~;ri; t~~-~~= t-, -;;;;~_-:~:.- == ::J:.T :J 1...,...,...,..."...,;----'- 0id' Mximum ' >-- -- '- -,J"~,.-_: _ _ _-_._._._ _ _ _ _ _ _-.;-_ _-~~~-~~~---~~f.: _ _ _ _ _ _ _r_ _-_ _-_-_J...;...;...,.,: ~... t i...; ; _,~:o: J::~oo~: :=TJ. J #200 #40 #80 #10 #4 Sieve Size 318 in. 112 in. 80 g' 60 v.; (I) co.. ::.e #200 #40 #10 #4 318 in. 112 in. #80 Sieve Size Fig 3.2. Grdtions with equl sum AS (ev) & Sum (ev)"2. Fig 3.3. Grdtions of equl re (ctul grdtion nd mximum density).

22 12 PVF Figures C.4 to C.6 show the reltionship of esign VMA nd PVF. Correltions for Type C, Type, nd Types C nd combined re very good (R~l.OOO). The reson for this is the method of clcultion nd the design ir void criteri. Since PVF is tht percentge of the VMA tken up by sphlt, it cn be clculted by subtrcting the ir void content from the VMA, multiplying by 100, nd dividing by the VMA. The Hveem design procedure specifies tht the optimum sphlt content is tht sphlt content resulting in 3 percent ir voids (4 percent if designing by Rice specific grvity) nd cceptble Hveem Stbility. The use of this criteri results in very nrrow rnge of PVF for design. Figure 3.4 below shows PVF histogrm nd some descriptive sttistics for the 32 totl designs vilble. OW MAXIMUM-ENSrrY LINE SUM(LINE-ACT) OW MAXIMUM-ENSITY LINE SUM(ABS(LINE ACT)) OW MAXIMUM-ENSrrY LINE SUM((liNE ACT)2) VMA versus Old Mximum ensity Line Sum(Line Act), Sum(ABS(Line-Act)), nd Sum((Line-Act)2) for 1)'pe C& mixtures, Type C mixtures, nd Type mixtures re shown in Figs C.7 to C. IS. There is no reson to expect tht one type of mixture should hve correltion nd nother should not, except for lck of sufficient dt (especilly Type C). Generlly, no useful correltions re seen in these plots. Most plots resemble "shotgun" ptterns. Type C mixtures hve more similr grdtions s seen in 0.45 power chrt plots, thn the Type mixtures. This, s well s the smller number of dt points, my be the reson some correltions (lbeit poor) re obtined. AREA BE/WEEN OW MAXIMUM-ENSITY line AN ACIVAL GRAATION Figures C.l6 to C.18 disply VMA versus Are Between Old Mximum-ensity Line nd Aclul Grdtion. Better correltions re seen, but, gin, "shotgun" pttern best describes the results. 1)'pe C mixtures show higher correltion (R~.567), but the smll number of dt points nd severl points off the correltion line render this mesure questionble s predictor of VMA. MOIFIE MAXIMUM-ENSrrY line SUM(liNE-ACT) MOIFIE MAXIMUM-ENSrrY line SUM(ABS(liNE-ACT)) MOIFIE MAXIMUM-ENSrrY line SUM((LINE-ACT)2) VMA versus Modified Mximum-ensity Line Sum(Line-Act), Sum(ABS(Line-Act)), nd Sum((Line Act)2) for Type C nd mixtures, Type C mixtures, nd Type mixtures re shown in Figs C.l9 to C.27. Agin, there is no reson to expect tht one type of mixture should hve correltion nd nother should not, except for lck of sufficient dt (especilly 1)'pe C). Generlly, no useful correltions re seen in these plots; however, slight improvements re seen over the sme mesures using the "old" mximum-density line. Most plots still resemble "shotgun" ptterns. AREA BE/WEEN MOIFIE MAXIMUM ENSITY line AN ACTUAL GRAATION Plots of VMA versus Are Between Modified Mximum-ensity Line nd Aclul Grdtion re found in Figs C.28 to C.30. No useful trends re developed. Any correltions re essentilly the sme or only slightly improved over the sme mesure using the "old" mximum-density line. 1U ~ 8 0 ~ C 6 (I).c 0 ~ 4 C.c E ~ 2 0 Men= 79.1 (J = 1.75 Rnge = 75.4 to esign PVF Fig 3.4. Histogrm of design PVF. FM(OW MAXIMUM-ENSrrY LINE) FM(ESIGN) FM(MOIFIE MAXIMUM-ENSITY line) FM(ESIGN) VMA versus Fineness Modulus of the "Old" nd "Modified" Mximum-ensity Lines re shown in Figs C.31 to C.36. No useful correltions re obtined using these mesures. The similrity of the Type C designs ccounts for the incresed correltion fctors seen with these mixtures. The correltions dispper when ll mixtures re plotted. The bsic "shotgun" pttern is evident once more. SAN RATIO VMA versus Snd Rtio, seen in Figs C.37 to C.39, fils to discriminte between high nd low VMA mixtures. This mesure might be useful for reserch on "tender" mixtures, which is beyond the scope of this project.

23 13 MATERIAL PASSING #200 SIEVE OR UST Figures C.40 to C.43 show VMA versus mteril pssing the #200 sieve. In using the Voidge Reduction Concept, one would expect VMA to be highly dependent on the mount of mteril pssing the #200 sieve. When one looks t both Types C nd mixtures combined, this is not evident. Type C mixtures lone do show some evidence of this dependency. When one dt JXJint is eliminted from the dt set, one sees very good correltion between the mount of mterils pssing the #200 sieve nd VMA (R2:0.831). MULTIPLEREGRES~ON Multiple regression ws performed for the prmeters discussed bove to investigte whether combintions of mesures could predict VMA for Types C nd mixtures. It ws thought tht ny correltions should be pplicble to ll mixes; therefore, individul mixture types were not investigted in this mnner. These multiple regression nlyses were unsuccessful in improving VMA prediction. Combintions of mesures usully mde correltions worse, insted of better, nd the sttisticl significnce of the combintions ws low. This indictes tht for this dt nd the prmeters used, combintions were no better thn individul prmeters s mens of predicting VMA. AGGREGATE TYPE The Project 1197 dtbse contins bsic informtion on ggregte type for 8 of the 8 Type C, nd for 22 of the 24 Type, mixtures. This informtion my be found in Appendix. Sufficient informtion ws deemed vilble to conduct nlysis of vrince (ANOVA) of ggregte type on VMA. The projects were divided into two groups bsed on ggregte type. One group consisted of mixtures contining grvel (rounded prticles) s com}x)nent of the mixture. The other group consisted of mixtures contining ggregtes other thn grvel (crushed prticles such s limestone nd sndstone). The clssifiction ws bsed solely on the type of corse ggregte, intermedite ggregte, nd ggregte screenings present in the mixture. Field snd ws not used s bsis for clssifiction since only limited dt were vilble. Anlysis of vrince (ANOVA) ws performed seprtely for Types C nd mixtures yielding the ANOVA nlysis shown in the next column. The ANOVA nlysis gives low vlues of the F sttistic which trnsltes into high p-vlues. These p-vlues (numbers between 0 nd 1) indicte the probbility tht VMA ws not effected by ggregte type. For these dt, the probbility of no effect of ggregte type on VMA is 0.63 (63 percent) for Type C mixtures nd (75.8 percent) for Type mixtures. These dt therefore show no sttisticlly significnt difference in VMA bsed on ggregte type. Type C ANOVAof Aggregte Type on VMA Source dr SS MS F..L Aggregte Type (Grvel= 1, Other 0) Error Totl Type ANOVA or Aggregte Type on VMA Source ~ SS ~ F _f_ Aggregte Type (Grvel= 1, Other= 0) Error Totl In the pst, reserchers hve reported tht rounded ggregtes tend to produce lower VMA's. This is not evident from Project 1197 dt. The lower VMA's could be cused by the vrious ggregte types present, differences in shpe nd texture of ggregtes, the smll mount of dt vilble, incomplete dtbse informtion, incorrect ggregte type informtion present in the dtbse, or effects from the field snd which were not included in nlysis. AS-BUILT INFORMATION (PROJECTS WITH SUFFICIENT ESIGN AN AS BUILT ATA) Of the 8 Type C nd 24 Type mixtures for which dequte design informtion ws obtined, 2 Type C nd 11 Type mixtures lso hd sufficient s-built dt for nlysis. The nlysis for these projects involves the following: (1) plots of grdtions s compred to two different 0.45 power mximum-density lines; nd (2) nlysis of possible trends between grdtion devitions from mximum-density lines nd other mixture prmeters versus design VMA. Tbles E. I nd E.2 in Appendix E show s-built informtion, mximum-density line devitions, nd other descriptive prmeters either clculted or obtined from the Project 1197 dtbse for Type C nd Type mixtures respectively. The prmeters investigted re the sme s those investigted for the design informtion with the exception of Fineness Modulus mesures. Fineness Modulus ws not deemed pproprite for the s-built dt becuse the ggregte grdtions represent verges over the course of the project. The informtion in Appendix E forms the bsis of the following interprettion of grdtion chrts nd trends. GRAATION PLOTS The 0.45 power chrts for the design grdtions of the 13 mixtures re plotted in Appendix F. These chrts show the design grdtion nd both "old" nd "modified" mximum-density lines.

24 14 Most 0.45 power plots show the sme generl shpe for s-built s they did for design grdtions. Some vribility in the grdtion plots is expected becuse the vlues represent project verges which incorporte the norml vribility of the HMAC plnt If design proportions of ggregtes re dhered to in the field, one would expect the s-bnilt grdtions to exhibit some ggregte degrdtion in the mix plnt, resulting in somewht finer mixes' being plced thn being designed. On compring the design nd the s-built 0.45 power plots, mny mixes do exhibit this degrdtion (corse prticles become smller prticles). There re some mixes which do not show this phenomenon, nd for these mixtures it is believed tht n effort ws mde to compenste for expected degrdtion or to djust for this s the project progressed. The Type s-built grdtions re quite complex, with the grdtion line crossing the "old," "modified," or both mximum-density lines. TRENS Figures 0.1 to 0.12 in Appendix G re grphs depicting reltionships between vrious grdtion mesures nd VMA for the s-built projects. Only Type mixtures were used to investigte trends for s-built mixtures since only two Type C mixtures were vilble. It is importnt to understnd tht the field VMA represents HMAC which ws plnt-mixed but lbortorycompcted. Thus this field VMA does not represent the VMA ctully on the rod. The specimens were compcted under controlled lbortory temperture nd compction conditions. The design procedure results in mixture which forms the strting point for field mixture production. In mny cses the sphlt content nd grdtion re modified in the field to reflect plnt conditions, mixture chrcteristics, nd field experience. Becuse the design proportions re chnged mny times, one would expect ny trends seen in the design mixtures to be less pprent in the s-bnilt mixtures. The projects investigted in this report confirmed this expecttion. ASPHALT CONTENT Figure 0.1 shows field VMA versus s-built sphlt content. The resonble correltion seen in design for Type mixtures, R2::0.47, is reduced to R2::0.215 for field mixtures. PVF Figure 0.2 shows the reltionship of field VMA nd field PVF for Type mixtures. The PVF ws obtined from the Project 1197 dtbse nd ws determined in the sme mnner s design, except tht the ctul ir void content for the molded specimens ws used. ifferences in sphlt content, grdtion, nd possibly other prmeters such s moisture content, resulted in different ir void contents thn the 3 percent (4 percent for Rice Grvity) specified in the design procedure. The correltion between VMA nd PVF is, consequently, lower. OW MAXIMUM-ENSnY UNE SUM(UNE-ACT) OW MAXIMUM-ENSnY UNE SUM(ABS(UNE ACI')) OW MAXIMUM-ENSnY UNE SUM((UNE ACT)2) AREA BEIWEEN OW MAXIMUM-ENSnY UNE AN ACTUAL GRAATION MOIFIE MAXIMUM-ENSnY UNE SUM(UNE-ACI') MOIFIE MAXIMUM-ENSnY UNE SUM(ABS(UNE-ACI')) MOIFIE MAXJMUM-ENSnY UNE SUM(ABS(UNE-ACT)2) AREA BEIWEEN MOIFIE MAXIMUM ENSnY UNE AN ACTUAL GRAATION SAN RATIO MATERIAL PASSING #200 SIEVE OR UST Figures 0.3 to 0.12 show field VMA versus devitions from the "old" nd "modified" mximum-density lines, snd rtio, nd mteril pssing the #200 sieve. No discernible pttern or correltion is obtined from ny of these prmeters. COMPARISON OF ESIGN TO AS-BUILT For the l3 projects (2 Type C nd 11 Type ) for which both design nd s-built dt were vilble, the design nd field VMA's were compred. Figure 3.5 shows plot of design VMA nd field VMA for ech project. In ll but one cse, the design VMA is higher thn the field VMA. Figure 3.6 shows histogrm nd descriptive sttistics for the difference between the design nd field VMA's from ech project The histogrm looks resonbly normlly distributed nd shows men difference between design nd field VMA's of The histogrm offers more evidence tht design VMA's re higher thn field VMA's. A sttisticl nlysis ws performed using the T-test to determine whether the men difference of 1.54 ws sttisticlly significnt. The T-test for m= 1.54, s:=0.88, nd n=13 (df=l2) yields t-vlue of Where m is the smple men, s is the smple stndrd devition, nd n is number of observtions in the smple. This high t vlue indictes there is less thn 1-in-10,000 chnce tht this difference in VMA's is strictly coincidence. One concludes tht field VMA's s whole re less thn design VMA's.

25 15 SUMMARY OF SIGNIFICANT FININGS Some comments which cn be mde s result of the studies conducted in this chpter re given below. (1) The use of 0.45 power plots cn be useful in describing n ggregte grdtion nd ny "mximumdensity" lines used. The power plots cn be used to visully compre res or the distnce between the "mximum-density" line for severl mixtures or severl grdtions resulting from vrious combintions of the sme ggregtes. (2) Severl mesures of grdtion devition from ny chosen mximum-density line my be developed. One must relize the shortcomings of devition prmeters used. The re between mximumdensity line nd the ctul grdtion is the better of the developed prmeters. (3) VMA versus esign Asphlt Content is resonbly correlted nd if sphlt bsorption is tken into ccount. the correltion would likely be better. This observtion is consistent with engineering literture which indictes tht VMA is proportionl to sphlt content for non-bsorptive ggregtes. (4) In the design process, the use of Hveem design criteri yields nrrow rnge of PVF. (5) Tken s whole, the 32 studied mixture designs filed to yield useful correltions relting design VMA to ny of the developed devition prmeters or other fctors such s fineness modulus, snd rtio, or percent pssing the #200 sieve. (6) The nlysis of vrince of ggregte type (obtined from the Project 1197 dtbse) on design VMA showed no sttisticlly significnt difference between ggregte type nd design VMA for the mixtures investigted. This lck of difference could be cused by the vrious ggregte types present, differences in shpe nd texture of ggregtes, the smll mount of dt vilble, incomplete dtbse informtion, incorrect ggregte type informtion present in the dtbse, or effects from the field snd which were not included in nlysis. (7) Asphlt content djustments, nd minor ggregte differences, which cn occur in the field, ffect the field VMA nd PVF. These chnges contribute to poor correltion of field VMA with field sphlt content nd field PVF. (8) Field dt studied yielded no useful correltions relting field VMA to ny of the developed devition prmeters or other fctors such s fineness modulus, snd rtio, or percent pssing the #200 sieve. (9) Field VMA's re significntly lower thn design VMA's. Some useful informtion ws obtined from studying the 1197 dtbse. Informtion concerning VMA, design sphlt content, nd design PVF is significnt nd relevnt Other nlyses proved fruitless. Looking for correltions mong VMA nd other prmeters for ll designs together is n oversimplifiction of how ggregte nd sphlt ffect VMA. There re mny fctors which cnnot be mesured in such simple terms. For design mixtures, these include prticle shpe nd prticle texture. For field mixtures, one my dd more, such s moisture content nd ggregte degrdtion in the mixing process. Ech mixture hs chrcteristics unique to tht sphlt-ggregte combintion, nd ech mixture generlly cnnot be compred to other mixtures in terms of VMA. 18 esign (LM I LM) 17 Field (PM ILM) < ~ 14 > Individul Project 5 <I> 4 c: 0 ~... Q) 3 <I> Q).0 E ::I 2 0 Men= esign VMA- Field VMA Fig 3.5. VMA-design nd field. Fig 3.6. esign-lield VMA histogrm.

26 CHAPTER 4. LABORATORY EVALUATION OF VARIATION IN MIX PROPERTIES WITH ASPHALT CONTENT AN AGGREGATE GRAATION A lbortory evlution of vrition in mix properties with sphlt content nd ggregte grdtion ws performed using one HMAC design from ech of two Stte eprtment of Highwys nd Public Trnsporttion (SHP'I) districts. The districts selected were istrict 6, Odess. nd istrict 14, Austin. For ech design, ggregtes, sphlt, nd design prmeters were obtined. The lbortory work for ech district mixture consisted of set of fctoril experiments of ggregte grdtion nd sphlt content on number of mixture properties. The properties chosen for investigtion were VMA, ir voids, indirect tensile strength nd secnt modulus t filure, Mrshll stbility nd flow, nd Hveem stbility. The optimum mixture proportions, s reported by the district (mix design), were used s the bse point, nd chnges were mde to investigte effects on the bove mixture properties. The istrict 6 investigtion used three levels of sphlt content nd two levels of ggregte grdtion. The istrict 14 investigtion used three levels of sphlt content nd three levels of ggregte grdtion. Asphlt levels were chosen s mixture design optimum, optimum plus 1 percent sphlt, nd optimum minus 1 percent sphlt. The istrict 6 ggregte grdtion levels were the design grdtion nd "corser" grdtion obtined by dding more corse ggregte t the expense of the fine ggregte (screenings). The istrict 14 ggregte grdtion levels were the design grdtion, "corser" grdtion (s corse s the current specifiction will llow with the ggregtes), nd "fmer" grdtion (s fine s the current specifiction will llow with the ggregtes). The terms "corser" nd "fmer" re qulittive terms used to describe the grdtion chnge with respect to the design grdtion. Informtion for ll ggregte grdtion levels ppers in Appendix H. Twelve compcted specimens of lbortorymixed HMAC were fbricted for ech sphlt level t ech grdtion for ech of the two district evlutions. Since mesuring ir voids nd VMA is non-destructive, mesurement for ech specimen ws tken, nd the set of twelve ws then broken down into four groups of three specimens for the remining four tests. Sttisticl nlysis (nlysis of vrince) of the dt from the experiments ws performed using M1NITAB sttisticl softwre on The University of Texs' Instructionl VAX computer. Using the nlysis of vrince, F-tests were performed to determine if chnges in sphlt content nd/or ggregte grdtion resulted in sttisticlly significnt differences in the mixture properties. Where significnt differences were indicted owing to fctor used t three levels, multiple-comprison test ws used to indicte which levels of the fctor produced significntly different results. The dt from fctoril experimenttion nd the ssocited sttisticl nlysis pper in Appendix I. ISCUSSION OF FACTORIAL EXPERIMENTS Tbles 4.1 nd 4.2 below re sttisticl summries of the two sets of fctoril experiments bsed on the nlyses of vrince in Appendix I. The set of experiments shows tht one my lter some mixture properties by chnging sphlt content nd/ or ggregte grdtion. Mny of the chnges seen re expected events, such s incresed sphlt content resulting TABLE 4.1. ISTRICT 6 STATISTICAL ANALYSIS SUMMARY Fctor Affecting Mixture Property Property Asphlt Content Aggregte Grdtion VMA X Air Voids X X Resilient Modulus Mrshll Stbility X Mrshll Flow X X Indirect Tensile Sttength X X Secnt Filure X X Hveem Stbility X X TABLE 4.2. ISTRICT 14 STATISTICAL ANALYSIS SUMMARY Fctor Affecting Mixture Property Property AsphJt Content Aggregte Grdtion VMA X X Air Voids X X Resilient Modulus X Mrshll Stbility X Mrshll Flow X X Indirect Tensile Sttength X X Secnt Modulus@ Filure Hveem Stbility X X ANOVA indicted significnt interction between fctors, invlidting the use off-tests for the min effects. 16

27 in decresed ir voids. Indeed, some of these phenomen fonn the bsis of the Hveem nd Mrshll mixture design procedures. It is not the intention of this project to indicte tht increses or decreses in specific properties re beneficil or detrimentl to pving mixture, even though some properties my be indictive of pvement life or performnce. No conclusions will be drwn regrding the property vlues exhibited by ny of the experimentl mixtures. A study of the results of the fctoril experiments requires the considertion of two questions. First, does the nture of the vribles (sphlt content nd ggregte grdtion) hve n impct on the outcome of the nlysis of vrince, nd. second, do the levels used in the fctoril represent possible field use of the mterils? EFFECT OF VARIABLES The nture of the vribles my hve n impct on the differences seen in n ANOVA. Asphlt content is quntittive vrible; tht is, number cn be used to describe the sphlt content level nd discrete levels cn be chosen with mesurble difference between levels. The difference in sphlt content which results in significnt chnge in mesured properties cn be "quntified." This type of vrible esily lends itself to interprettion in n nlysis of vrince. Alterntely, ggregte grdtion is qulittive vrible nd s such there is no wy to specify, in.. mesurble" tenns, the difference which exists between two grdtions. Grdtion or prticle size distribution, s used to describe the ggregte in n HMAC, consists of percentges pssing nd/or retined on number of different stndrd sieve sizes. If two ggregtes hve different percentges pssing certin sieve sizes, one cn sy they re different, but not how different Even two ggregtes with the sme percentges pssing the stndrd sieve sizes will probbly not hve the sme prticle size distribution between ny two stndrd sieves. Sttisticlly significnt differences in HMAC properties owing to ggregte grdtion re function of how much the grdtion is chnged. As result, qulittive vribles such s ggregte grdtion re not s esily interpreted in n nlysis of vrince. FlEW LEVEL POSSIBiliTIES A fctoril experiment, s conducted for this project, does not represent chnges which would be considered for use in the field. While ggregte grdtion nd sphlt content re not tied together in the fctoril experiment, they re linked in the design procedure which detennines the.. optimum" sphlt content for specific ggregte grdtion. As n exmple, the SHPT Hveem design procedure specifies "optimum" sphlt content s the point t which gyrtory compcted specimen exhibits 3 percent ir voids (or 4 percent depending on the method of detennintion of the mximum theoreticl specific grvity) nd dequte Hveem stbility. Consequently, chnging the ggregte grdtion will most likely result in chnge in optimum sphlt content. With this in mind, some of the fctoril dt were reviewed so tht the optimum sphlt content for ech grdtion nd the VMA t the optimum sphlt content could be predicted. OPTIMUM ASPHALT AN VMA ETERMINATIONS AN COMPARISONS The optimum sphlt content, corresponding VMA's, nd the 95 percent confidence intervl (C for ech were predicted for ll grdtions used in the fctoril experiments...optimum" predictions were mde using MINITAB regression nlysis of the experimentl dt nd the Texs SHPT Hveem design criteri ( 4 percent ir voids bsed on Rice specific grvity). The results re presented in Tble 4.3 below. The.. optimum" predictions nd the 95 percent confidence intervls were both obtined when the pproprite regression nlysis nd prediction instructions were given to MINITAB. The 95 percent confidence intervl is the rnge in which one is 95 percent sure the ctul popultion verge lies. This mens there is less thn 1-in-20 chnce tht the ctul optimum vlue lies outside this rnge. If the 95 percent CI's for two predictions overlp, then there is insufficient evidence to indicte tht sttisticlly significnt difference exists between the two predicted property vlues t the 95 percent confidence level. For the bove dt, the istrict 6 grdtions show overlpping 95 percent crs for both optimum sphlt content nd VMA. The difference between the two grdtions ws not lrge enough to produce sttisticlly significnt differences in optimum sphlt content or VMA. The difference in the predicted vlues could be due to rndom error. The istrict 14 dt do not show overlpping 95 percent CI's for either sphlt content or VMA for ny of the TABLE 4.3. OPTIMUM ASPHALT CONTENTS, VMA'S, AN 95 PERCENT CI'S Fctoril Grdtions istrict 6 esign Grdtion Corse Grdtion istrict 14 esign Grdtion Grdtion #2 Grdtion #3 Optimum Asphlt Asphlt VMA@ VMA 95% CI OptAC 95% CI

28 18 three grdtions. The three grdtions were sufficiently different to produce sttisticlly different sphlt contents nd VMA's. VMA AN GRAATION EVIATION PARAMETERS In Chpter 3, mixtures from cross T~xs hd mny uncontrolled vribles which resulted in no one developed prmeter correlting well with VMA. The mixtures nd subsequent specimens used for fctoril nlyses were mde in mnner which controlled mny of these vribles. For ech district fctoril set, the sme ggregtes were used, nd ll lbortory-controllble conditions were identicl. If comprisons re mde for ech istrict's mixtures t "optimum" sphlt content, the min uncontrolled vrible is ggregte grdtion. Since the sme ggregtes were used, merely in different proportions, one could rtionlize tht differences in prticle shpe, surfce texture, nd surfce re between the different grdtions were minimized. Therefore, one (or some) of the devition prmeters my now be indictive of chnges in VMA. Appendix J shows ech grdtion used for ech district fctoril on 0.45 power chrt. These grdtion chrts show visully the differences in the grdtions used. Both "old" nd "modified" mximum-density lines, optimum sphlt content, nd corresponding VMA re shown on ech chrt. Appendix H contins the devition prmeters clculted for ech grdtion. The Appendix H grdtion devition prmeters hve the sme definitions s re used in Chpter 3. Tble 4.4, in the next column, shows summry of the "optimum" VMA nd the devition prmeters for ech grdtion, tken from the previous section nd from Appendix H. Chpter 3 discussed the vrious problems with individul devition prmeters nd proposed tht the re between mximum-density curve nd the ctul grdtion is the prmeter most representtive of the devition of the ctul grdtion from the mximum-density line. Therefore, this prmeter will be studied for the fctoril grdtions. The istrict 6 dt showed tht s the grdtion chnged from the design to the corse grdtion, the re prmeter (indeed, ll devition prmeters clculted) incresed, for both "old" nd "modified" mximumdensity lines. The VMA decresed from the design to the corse grdtion. The previous section showed tht this difference in VMA ws not sttisticlly significnt No useful informtion or correltion cn be developed from these dt. The istrict 14 dt showed sttisticlly significnt differences in VMA. The VMA incresed from Grdtion #3, to the esign Grdtion, to Grdtion #2. The vlues of re between the "old" mximum-density line nd ctul grdtion do not trck the development of TABLE 4.4. VMAAN EVIATION PARAMETERS Mx en Mx en Prmeter ~ Old Mod -6 esign Grdtion 12.9 SUM(L-A) SUM(ABS(L A)) SUM(L-A)" Are MAX & ACf Corse Grdtion SUM(L-A) SUM(ABS(L-A)) SUM(L-A)" Are MAX & ACf esign Grdtion 14.7 SUM(L-A) SUM(ABS(L- A)) SUM(L-A)" Are MAX & Acr Grdtion # SUM(L-A) SUM(ABS(L-A)) SUM(L-A)" Are MAX & ACf Grdtion # SUM(L-A) SUM(ABS(L- A)) SUM(L-A)" Are MAX & ACf VMA. However, s the re between the "modified" mximum-density line nd the ctul grdtion increses, so does VMA. SUMMARY OF SIGNIFICANT FININGS Some comments which cn be mde s result of the studies conducted in this chpter re listed below. ( 1) ifferences in Hot Mix Asphltic Concrete mteril properties cn be chieved through chnging sphlt content nd/or ggregte grdtion. (2) Aggregte grdtion is qulittive vrible, nd, becuse it is, differences in properties resulting from grdtion chnges re function of how much chnge is mde in the grdtion. There re no current mesures of grdtion chnge. (3) Comprisons of lbortory mixtures re more relistic if they re compred t optimum sphlt content, use the sme ggregtes (with only the proportions vrying), nd use uniform lbortory conditions nd procedures. (4) Grdtions used for the istrict 6 fctoril experiments filed to show ny sttisticlly

29 19 significnt differences in optimum sphlt content nd corresponding VMA. They lso filed to show ny reltionship between VMA nd grdtion devition prmeters. One reson no reltionships were developed my be the sttisticl insignificnce of optimum sphlt content nd VMA differences between the two grdtions used. (5) Grdtions used for the istrict 14 fctoril experiments showed sttisticlly significnt differences in optimum sphlt content nd corresponding VMA. They lso showed reltionship between VMA nd the re between the "modified" mximum-density line nd the grdtion (incresed re corresponded to incresed VMA). The literturel,l,8,14 indictes tht for mixtures with insufficient VMA, moving the grdtion "wy" from the mximum-density line should yield higher VMA vlues. The mximum-density line which is discussed in the literture is wht this study describes s the "old" mximum-density line. The experimentl dt do not indicte tht devition from this "old" line results in n increse in VMA. The dt suggest tht the "modified" mximum-density line my be the more pproprite mximum-density line to use for grdtion djustment to chnge the VMA. More work with mny different mixtures is needed to verify this observtion. However, currently, if mixture ws deficient in VMA, the first step in rectifying the problem might be to djust the ggregte grdtion wy from the "modified" mximum-density line nd see if the VMA ws incresed.

30 CHAPTER 5. LABORATORY EVALUATION OF AGGREGATE SUBSTITUTION ON VMA A lbortory evlution of VMA vrition with ggregte type ws conducted to exmine the possible effects of ggregte minerlogy. The investigtion involved using bseline HMAC design nd substituting, individully, one of two lternte ggregtes to determine if chnges in VMA were produced. EXPERIMENT ESCRIPTION One HMAC design, including ll mterils nd proportions, from Texs SHPf istrict 9 (Wco), ws obtined for use s the bseline design. Four ggregte frctions were used in this design-- corse limestone, n intermedite limestone, fine limestone (screenings), nd locl field snd. All of the limestone ws crushed nd ll originted from the sme pit. This limestone ws recognized s being reltively soft nd reltively high in sphlt bsorption. Two lternte crushed fine ggregtes (screenings) were chosen for substitution into the bseline design. Ech lternte screenings ws substituted for the originl to determine if VMA differences were produced. One fine ggregte (screenings), recognized s hrd limestone with little sphlt bsorption, ws obtined from source in the re of Chico, Texs. The other fine ggregte (screenings), rhyolite recognized s hving high sphlt bsorption, ws obtined from the Odess, Texs, re. All of the screenings used, rrnged from softest to hrdest, were design limestone, Chico limestone, nd Odess rhyolite. The gol of the experiment ws to emphsize the differences in ggregtes s opposed to grdtion. As such, differences in sphlt bsorption my hve plyed prt in determining optimum sphlt content, but differences in VMA t optimum sphlt content were ssumed to be function of the ggregte minerlogy. Aggregte minerlogy would include such fctors s hrdness, surfce texture, nd prticle shpe s well s chemicl composition. Although intuitively included in ggregte minerlogy, chemicl composition should ply miniml role in determining the physicl chrcteristic ofvma. To enble ggregte minerlogy to be the min uncontrolled vrible (when ggregte substitutions were mde), the grdtion hd to be held s constnt s possible. To ccomplish this, the design screenings were wet-sieved to wsh off ll minus #200 sieve mteril clinging to lrger sizes which resulted in the true grdtion contribution from the screenings. Both the hrd limestone nd rhyolite screenings for substitution were lso wet-sieved nd the components subsequently dried to provide clen, seprted mterils for substitution. Substitution ws mde ccording to the wetsieve nlysis of the design limestone screenings. Substituted totl mixture grdtions s close to the design grdtion s possible were ttined using the stndrd sieve sizes for mixture design nd 0.45 power chrts. Aggregte grdtion informtion for ech mixture is presented in Tbles K.1 to K.3. These tbles lso include the grdtion devition informtion. Since ggregte substitution resulted in identicl grdtions for the stndrd sieves, the devition prmeters for ll three mixtures re the sme. The 0.45 power chrt for the mixtures is shown in Fig K.l. Only one chrt is necessry since ll three mixtures hve the sme grdtion within the limits of the stndrd sieve sizes. All three ggregte mixtures were evluted for ir voids, VMA, nd Hveem stbility with the design sphlt t the reported "optimum" sphlt content (5.8 percent), "optimum" plus 1 percent, nd "optimum" minus 1 percent The results of this experiment re shown in Tble K.4. The mixture using the hrd limestone screenings substitution ws evluted only t the reported "optimum" sphlt content nd t "optimum" minus 1 percent. STATISTICAL ANALYSIS OF OPTIMUM ASPHALT CONTENT AN VMA t in Tble K.4 provide bsis for reevluting the originl "optimum" sphlt content nd determining new "optimum" sphlt content for the substituted mixtures (bsed on the SHPf Hveem design criteri of 4 percent ir voids using Rice specific grvity nd dequte Hveem stbility) nd the corresponding VMA. Regression nlysis using MINITAB sttisticl softwre predicted these vlues. Tble 5.1 gives the optimum sphlt contents of ech mixture, the corresponding VMA's, nd the 95 percent confidence intervl for both vlues. All "optimum" mixtures proved to hve dequte Hveem stbility. A study of this tble shows the sphlt contents re slightly different, but the 95 percent confidence intervls ll overlp ech other. This indictes tht there is no sttisticlly significnt difference between the optimum sphlt contents of ll three mixtures. Mking the ggregte substitutions did not significntly chnge the sphlt demnd. The ggregte with the recognized high sphlt bsorption did hve the highest clculted optimum sphlt, which my explin the wider rnge for the 95 percent confidence intervl (it is more sensitive to chnges in sphlt content thn the others). The VMA's of the optimum mixtures differed more from ech other thn did the sphlt contents. None of the 95 percent confidence intervls for VMA overlp, 20

31 21 TABLE 5.1. OPTIMUM ASPHALT CONTENTS, VMA'S, AN 95 PERCENT CI'S Aggregte Optimum Asphlt VMA Grdtions Asphlt 9S%CI OptAC 95%CI istrict 9 esign esign w/hrd LS esign w/rhyolite indicting tht ggregte substitution resulted in sttisticlly different VMA's. EXPERIMENTAL INTERPRETATION In this experiment, substitution of ggregte screenings of different minerlogy did not produce sttisticlly significnt differences in optimum sphlt content, but did produce sttisticlly significnt differences in VMA. It is interesting to note tht s the hrdness of the screenings progressed from soft to hrd, the VMA t optimum sphlt content incresed. One possible explntion for this phenomenon is tht softer mterils my degrde more during mixing nd compction. uring this degrdtion the shrper edges ssocited with crushed mterils my be broken off softer ggregte prticles, resulting in more rounded ggregtes which could be compcted more esily nd produce lower VMA. The informtion from Chpter 3 which showed decrese in VMA from design to production mixtures my lso be mnifesttion of this phenomenon. VMA AN EVIATION PARAMETERS The ggregte substitutions were devised to result in the sme grdtion when using stndrd sieves. This produced one 0.45 power chrt to represent ll three mixtures. Consequently, the clculted devition prmeters were the sme for ll three mixtures. Since the VMA's were different but hd the sme devition prmeters, one must conclude tht VMA is dependent on more thn just grdtion lone. It would be erroneous to compre the devition prmeters of mixtures of different ggregte types nd then mke conclusions cross the bord regrding the differences in devition prmeter vlues needed to effect specific chnge in VMA. t in this chpter reinforce the Chpter 3 conclusion tht cross-the-bord comprisons of mixtures contining different ggregtes nd different grdtions do not result in ny correltions between VMA nd grdtion devition prmeters. Only by controlling the mny fctors ffecting VMA cn vlid comprisons be mde. SIGNIFICANCE OF AGGREGATE BULK SPECIFIC GRAVITY The ggregte substitution grdtion tbles (Tbles K.l to K.3) show tht the only difference mong the three ggregte mixtures ws the difference in the bulk specific grvity of the screenings, which in tum ffected the overll mixture bulk specific grvity. Consequently, VMA clcultions re highly dependent on the ggregte bulk specific grvity used. Chpter 2 discussed the problem of whether ggregte pores which bsorb sphlt should be included in VMA (which ggregte specific grvity to use), but did not ddress the importnce of ccurcy in choosing specific grvity. Fieid2 showed tht errors in the bulk specific grvity cn produce significnt differences in clculted VMA. In prticulr, he concluded tht the specific-grvity determintion of the fine-ggregte portion (i.e., ggregte screenings) ws the most prone to error. This is true becuse judgment must be mde s to when the ggregte is sturted-surfce dry. For the ggregte substitution experiment, the ggregtes were chnged, which chnged not only the ggregte bulk specific grvities but lso the minerlogy of the screenings. VMA clcultions respond only to the prmeters used in their clcultion-nmely, the specific grvity of compcted specimens, the percent of ggregte in the mixture, nd the bulk specific grvity of the ggregte. The fctors influenced by minerlogycompctbility, bsorption, etc.-re reflected in the ctul specific grvity of compcted specimens. The percentge of ggregte is known (especilly in lbortory specimens). The ggregte bulk specific grvity is the wek link in the VMA clcultion. If specifictions for VMA re used for HMAC nd specific mixture fils to chieve the minimum specifiction requirements, the first priority should be to determine if the VMA problem is rel or possibly brought on by the use of inccurte ggregte bulk specific grvities. In relity, ggregtes my chnge slightly in specific grvity over the course of job (prticulrly lrge jobs). Errors in procedure or clcultion my lso result in inccurte specific grvities' being used initilly. Only fter ensuring tht the problem is rel should other, more drstic mesures be tken. SUMMARY OF SIGNIFICANT FININGS Some comments which cn be mde s result of the study conducted in this chpter re:

32 22 (1) VMA is ffected by so mny vribles tht to investigte one vrible involves controlling ll others s much s possible to be ble to isolte tht one vrible's effects. (2) This project segment ttempted to control the ggregte grdtion to investigte the effect of ggregte minerlogy on VMA. This ws done by mnufcturing "new" ggregtes for substitution into chosen design which conformed to the sme grdtion within the limits of current prctice. This type of ggregte substitution could not be relisticlly done in the field. Field substitution would involve replcement of one ggregte frction for nother (e.g., Screenings #2 replcing Screenings #l) which would not hve the sme grdtion nd would result in chnge in the totl grdtion of the mixture. (3) The ggregte substitution in this experiment did not result in sttisticlly different "optimum" sphlt contents, but did result in sttisticlly significnt differences in VMA. (4) The VMA's in the experimentl mixtures incresed s hrder fine ggregte (screenings) replced softer fme ggregte (screenings). This my be due to the brekdown of the softer prticles during mixing nd compction, resulting in more compctble ggregtes. (5) Since the sme 0.45 power chrt could be used for ll three mixtures, ech bd the sme vlues for clculted grdtion devition prmeters. This would men tht there re not bsolute limits on ny of the devition prmeters investigted, principle which could pply to ll mixtures cross the bord. If ny devition prmeter cn be used to indicte VMA development, the vlues would be mixture-specific. (6) Accurte bujk specific grvities re criticl to ccurte VMA clcultions. Mixtures with "filing" VMA's should be checked for ccurte bulk specific grvity determintions (i.e., the problem is rel) before more drstic mesures re tken to chieve the specifiction requirements.

33 CHAPTER 6. ECONOMIC IMPACT OF SPECIFICATION CHANGES The Texs Stte eprtment of Highwys nd Public Trnsporttion is currently in the process of revising specifictions for their publiction Stndrd Specifictions for Construction of Highwys, Streets nd Bridges. Specifictions for hot mix sphltic concrete re included in this revision. The proposed specifictions for HMAC incorporte severl significnt chnges which re designed to improve the qulity of HMAC in Texs. The chnges, while designed to improve qulity, my impct the cost of hot mix in the stte. The proposed chnges nd their probble effect on HMAC cost will be covered in this chpter. PROPOSE SPECIFICATION CHANGES There re three mjor chnges proposed for HMAC specifictions. These chnges include: (I) nrrowing the specifiction mster grdtion limits for mixture types; (2) limiting the use of field snd or other uncrushed fine ggregte to mximum of 15 percent; nd (3) requiring minimum percent VMA for ech mixture type. MASTER GRAATION LIMITS The mster grdtion limits for ll mixture types will be nrrowed. The nrrower limits will provide smller window to which design grdtions must conform. Becuse of this improvement, grdtions wilt be "well grded," nd consequently the chnce of hving gpgrded mixtures should be lessened. The new grdtion limits will lso reduce the possibility nd/or severity of hump in the grdtion (0.45 power chrt) round the #40 sieve, which hs been linked to tender mixture problems. Figure 6.1 shows n exmple of the mster grdtion limit chnges proposed for Type mixtures. Tolernces #200 #40 #80 #10 #4 Sieve Size 318 in. 112 in. Fig 6.1. Type mster grdtion limits. will still pply to production mixtures; "design" grdtion my be ner or t the mster grdtion limits nd production mixtures my fll outside those limits to the extent the tolernces llow. UNCRUSHE FINE AGGREGATE UMIT A mximum of 15 percent field snd or other uncrushed fine ggregte is included in the proposed specifiction for ll mixtures. Field snd or uncrushed fine ggregte is usully reported in the literture s contributing to lower VMA's. The mechnism my ct s lubricnt (e.g., bll berings), incresing the compctbility nd thereby mking it hrder to obtin VMA in mixture. Becuse of the sieve sizes inherent in these mterils, they contribute to forming the "hump" in the grdtion curve ssocited with tender mixtures. They lso contribute to incresed surfce re, resulting in thinner sphlt films for the sme sphlt content In their effect on mixtures, the specifiction chnges limiting uncrushed ggregte nd nrrowing mster grdtion limits will work together. Nrrowing of the mster grdtion limits will probbly utomticlly limit the mount of uncrushed fine ggregte (field snd) which cn be used in mixture. Likewise, limiting the mount of uncrushed fine ggregte (field snd) will bring mixture grdtion closer to the proposed mster grdtion limits. MINIMUM PERCENT VMA Requirements for minimum percent VMA in HMAC design re included in the proposed specifictions. The inclusion of VMA in the specifiction will replce the sphlt content rnge requirements in the current specifiction. The Texs design procedure (Hveem) requires tht n optimum mixture contin fixed ir void content. Utilizing n sphlt content rnge in specifiction my result in the use of less sphlt thn is necessry to provide dequte film thicknesses. This my led to lower ftigue resistnce, more rpid sphlt ging, nd subsequent decrese in the life of the pvement. VMA (s clculted by the SHPT) is mesure of the volume vilble in compcted mixture for ir nd effective sphlt (sphlt used s binder). VMA minus the ir void content results in the volume of effective sphlt. Minimum limits on VMA effectively provide minimum limits on sphlt content. As VMA goes up, so does the minimum sphlt requirement. As the nominl ggregte size of mixture decreses, the surfce re increses, requiring more sphlt 23

34 24 to mintin the sme sphlt film thicknesses. Thus, VMA requirement which increses s nominl mximum ggregte size decreses, provides sliding scle for minimum sphlt content by volume nd thereby controls minimum sphlt film thicknesses. Accordingly, the proposed VMA requirements do increse with decresing nominl mximum ggregte size. Specific VMA requirements were set up in the sme mnner s the Asphlt Institute limits, while lso recognizing tht the Texs gyrtory compction technique is likely to result in slightly denser compcted specimens thn the Mrshll hmmer. The proposed minimum limits re set t 1 to 2 VMA percentge points lower thn Asphlt Institute recommendtions to ccount for these differences. The ctul limits re shown in Tble 6.1. The limits re specified only to the nerest whole number, resulting in rounding to the nerest whole number for design requirements. As n exmple, 'TyPe mixture exhibiting 13.5 percent VMA would be rounded up to 14 for specifiction purposes nd would, therefore, be cceptble. A Type mixture exhibiting 13.4 percent VMA would be rounded to 13 nd would fil to meet the specifiction requirements. TABLE 6.1. PROPOSE VMA SPECIFICATION REQUIREMENTS Mixture Type A B C F Nominl Mximum Aggregte Size (in.) 1-1/2 1 7/8 1/2 3/8 VMA (%) IS The impct of VMA requirements on HMAC opertions cross the stte my be substntil. For the 24 'TyPe designs investigted in this project, 5 would fil to meet the VMA specifiction criteri. Since the VMA requirement currently pplies to the design phse only, these 5 filing mixtures would hve required redesign, possibly chnging the individul ggregte percentges or clling for substitution of other ggregtes which would enble the mixtures to stisfy the VMA requirement. Currently no informtion exists bout the performnce of these 5 mixtures s compred to those with dequte VMA. ECONOMIC IMPACT OF SPECIFICATION CHANGES Implementtion of the proposed specifiction chnges could result in incresed costs for HMAC. Although the exct economic implictions re impossible to estimte, one cn ssume tht some HMAC designs will not incur ny dditionl costs, while other mixtures will require chnges t considerble expense to comply with the specifictions. The types of chnges tht will enble specific mixtures to meet the proposed specifictions my best be shown in severl exmples. Four Type mixtures from vrious loctions in Texs were chosen from the HMAC projects used in this investigtion. Ech ws nlyzed for complince with the proposed specifiction. Tble 6.2 shows the proposed specifiction limits nd the dt from ech project used for nlysis. For mixtures where specifiction non-complince hs been determined, the vlues re outlined in double lines. Ech mixture will be discussed individully s to possible ctions necessry to bring the mixture into complince with the proposed specifiction. 21HUS83 This mixture shows oon-complince in severl res. It does not comply with ny of the three mjor proposed chnges to the current specifiction (grdtion mster limits, field snd or uncrushed fine ggregte limit, nd VMA). The grdtion flls outside the specifiction on only one sieve, nd this size is one for which field snd is the usul contributor. Thus, if the field snd ws reduced to the 15 percent limit, the grdtion would probbly be within the proposed limits. There my be question bout whether the concrete snd used in this design could be clssified s uncrushed fine ggregte. If so, this would require tht this mteril be replced by crushed ggregte. The economic impct of djusting the field snd frction should be miniml. The VMA minimum represents significnt problem for this mixture. Adjusting the ggregte grdtion wy from the modified mximum-density line my result in some increse in VMA nd should be tried frrst. The mixture uses ll nturl mterils (not crushed), which in the literture hs been shown to result in low VMA's. This mixture is from the Phrr istrict, locted in the Rio Grnde Vlley, where nturl, uncrushed river ggregtes re used extensively. In order to chieve dequte VMA, it my be necessry to use crushed ggregtes in the mixture. If ggregte substitution is needed to chieve VMA, substntil economic impct my be relized, prticulrly if ggregtes must be huled in from other res of the stte for this purpose. Incresed ggregte nd trnsporttion costs would increse the production cost of the HMAC, resulting in higher bid prices from the contrctor. This prticulr mix my be one which could suffer from lower pvement life becuse of the low sphlt content used. Incresed VMA will require the use of more sphlt. Since sphlt is the highest cost ingredient in HMAC, this increse in sphlt demnd my prove to be the chnge which most ffects the HMAC price. 12MIH45 This mixture does not comply with ny of the three mjor proposed chnges to the current specifiction

35 25 TABLE 6.2. MIXTURE SPECIF1CATION ANALYSIS ATA Proposed 'II Pss Spedftctlon 21HUS83 1!2 in /8 in. ' #4 ' #10 ' ' I #80 ' #200 ' Aggr(%) Corse Or 40% IMGr 18% Uncrusbed Fine Cone. Snd Aggregte 22% (Field Snd) Field Snd 15%Mx 20% VMA 14Min 12.2 AC(%) 4.0 l2mih4s 3WUS82 loanuls lB I 29.o I Polish Limestone Sndstone 30% 33% 62% Limestone 1M Snd stone 30% 32% LSScm. SSScm. 20% 38% Field Snd 20% (grdtion mster limits, field snd or uncrushed fine ggregte limit, nd VMA). The grdtion flls outside the specifction limits on one sieve. This size is one for which field snd is usully mjor contributor. Thus, if the field snd ws reduced to the 15 percent limit, the grdtion would probbly be within the proposed limits. This prticulr mixture is from the Houston istrict, which hs to import most ggregtes other thn field snd from sources outside the district. Reducing the field snd would require n increse in other more costly imported ggregtes, but the ctul economic impct would probbly be smll since it would require only n incrementl increse in the mount of ggregte lredy imported. This mixture does not comply with the minimum VMA. A decrese in the field snd my result in improved VMA but will probbly not solve the problem lone, since the VMA is significntly lower thn the proposed specifiction minimum. Initilly, one my try to djust the grdtion wy from the modifted mximumdensity line. This, long with decresed field snd, my help the VMA problem. If these ctions-which cuse miniml economic impct-fil to increse the VMA to complince, ggregte replcement is the next step. All ggregtes except the field snd re lredy crushed, so substitution with different or hrder crushed ggregte my help. Since the Houston istrict imports mjority of the corse ggregtes it uses, t reltively high cost, the economic impct of chnging ggregtes will be lessened becuse the trnsporttions costs (representing the lrgest prt of the ggregte cost) will not chnge drsticlly. Incresed VMA will result in greter sphlt demnd nd incresed cost for sphlt. 3WUS82 This mixture shows non-complince in two res. It does not comply either with the grdtion mster limits or with the field snd limit. It does meet the requirements for VMA. The grdtion devitions re in the size rnges mostly ffected by the field snd. If the field snd in this mixture is reduced to 15 percent, with djustments to one or more of the other ggregtes, both grdtion nd field snd would meet the specifictions while probbly not dversely ffecting the VMA. The economic impct should be miniml, since only minor chnges in ggregte percentges re ll tht is needed. Asphlt costs would probbly not chnge significntly for this mixture since VMA need not be incresed. This design shows tht even mixtures which would meet the VMA requirements my need djustments to comply with ll specifictions. JOANU28 This mixture lredy complies with ll proposed specifiction requirements. It meets the mster grdtion limits, is composed of 100 percent crushed ggregtes, nd hs sufficient VMA. No dditionl cost would be incurred for this mixture. ECONOMICIMPACTSUMMARY Any chnge in mix design which results in the use of more expensive ggregtes to chieve sufficient VMA or

36 26 more crushed ggregtes t the expense of field snd will result in n increse in cost. 1be impct of this cost my be miniml or my be significnt, depending on the difference in ggregte nd trnsporttion costs between originl nd lternte ggregtes. Trnsporttion costs will be the lrgest prt of ny HMAC cost increse owing to djustments in the ggregtes used. Any chnge in mix design which results in the use of more sphlt will result in n increse in cost. Incresing VMA requires incresing the sphlt content. Since sphlt is the single most costly ingredient in HMAC, costs would increse ccordingly. Absorption of sphlt lso plys prt in the mount of sphlt ctully used. The use of highly bsorptive ggregtes will increse sphlt demnd. Absorbed sphlt is lost for use s binder. The use of less bsorptive ggregtes in plce of more bsorptive ones my be strtegy for contrctors to lower the sphlt demnd of mixture while still providing dequte sphlt films on the ggregte. A combintion of fctors mkes determining ctul effects on sphlt costs for specific mixture difficult to determine. With respect to Texs s whole, some generl comments my be mde which will ffect the sttewide verge price which the SHPT pys for HMAC. More sphlt will be used thn is used currently, resulting in incresed sttewide cost. Also, more crushed ggregtes will be used, resulting in incresed ggregte trnsporttion costs. There my lso be dditionl demnd for hrder nd less bsorptive ggregtes, resulting in shift to different ggregte suppliers. Some ggregtes my no longer be economicl, or they my be impossible to use nd my lter the supply-nd-demnd sitution. 1be likely result is incresed ggregte costs.

37 CHAPTER 7. CONCLUSIONS/RECOMMENATIONS The focus of this study ws ggregte grdtion, ggregte type, nd their effects on mixture chrcteristics, in prticulr VMA. As stted in Chpter 1, the objectives of the study were to: conduct literture serch reltive to HMAC chrcteristics, especilly VMA; investigte the current production of HMAC in Texs with respect to VMA, nd develop correltions between VMA nd HMAC prmeters; conduct lbortory investigtions to determine the effects of ggregte grdtion nd type on HMAC properties; nd investigte the economic consequences of including VMA in specifictions for HMAC. The literture serch proved tht there is much work to be done in order to fully understnd HMAC. The work done to ddress the other objectives yielded the following conclusions nd recommendtions. CONCLUSIONS FROM STUYING THE PROJECT 1197 ATABASE (1) A clcultion (integrtion) of the re between grdtion nd corresponding mximum-density line on 0.45 power plot describes the mount of devition between the two better thn ny other devition prmeter used in this study. (2) When studying design mixtures s whole, VMA nd design sphlt content re resonbly correlted, nd if sphlt bsorption were tken into ccount, the correltion would be better. This grees with the literture, tht is, design sphlt content nd VMA were found to be proportionl for non-bsorptive ggregtes. (3) Hveem design criteri yields nrrow rnge of Percent of Voids Filled with sphlt (PVF). This occurs in prt becuse the optimum sphlt content is specified t prticulr ir void contenl (4) Fctors ffecting VMA re complex. Trying to estblish correltions between VMA nd mix design properties for the entire popultion of mix designs is n oversimplifiction of how ggregte nd sphlt ffect VMA. There re mny fctors ffecting VMA which cn not be described in such simple terms. Individul mixtures exhibit chrcteristics unique to tht sphlt-ggregte combintion, nd they generlly cnnot be compred to other mixtures in terms of VMA. (5) Correltions between VMA nd sphlt content or PVF re significntly reduced in field mixtures since vritions in sphlt content nd ggregte djustments re mde in the field. (6) Field VMA's (plnt-mixed, lb-molded) re significntly lower thn the corresponding design VMA's. CONCLUSIONS FROM LABORATORY FACTORIAL EXPERIMENTATION (1) ifferences in Hot Mix Asphltic Concrete mteril properties cn be chieved through chnging sphlt content nd/or ggregte grdtion. This ws expected nd is documented in the literture. (2) Aggregte grdtion is qulittive vrible which mkes nlyzing differences in properties difficult becuse of grdtion chnges. (3) To compre mixtures, s mny vribles s possible must be controlled. Comprisons re more relistic if mixes use the sme ggregtes (just vry the proportions), hve uniform lbortory conditions, nd re compred t "optimum" sphlt content. (4) The grdtion differences used in the istrict 6 evlution were not sufficient to produce sttisticlly significnt differences in VMA. No reltionship ws developed between VMA nd grdtion devition prmeters. (5) The grdtion differences used in the istrict 14 evlution were significnt enough to produce sttisticlly significnt differences in VMA. Also, s the re between the ctul grdtion nd the "modified" mximum-density line incresed, the VMA incresed. (6) The "modified" mximum-density line, s defined in this report, my be more pproprite for grdtion djustment to enhnce VMA thn the line developed by Goode nd Lufsey. CONCLUSIONS FROM EVALUATION OF AGGREGATE SUBSTITUTION (1) In the experiment conducted, ggregte substitution did not result in sttisticlly different "optimum" sphlt contents, but did result in sttisticlly significnt differences in VMA. (2} VMA's incresed s hrder fine ggregte (screenings) replced softer fine ggregte (screenings). A rtionl explntion for this my be tht the brekdown of softer ggregte prticles during mixing nd compction results in more compctible ggregtes nd lower VMA's. (3) Any correltions which might exist between VMA nd ggregte devition prmeters (re between grdtion nd "modified" mximum-density line) re mixture-specific. No specific prmeter differences will result in specific VMA chnges. (4) Accurte bulk specific grvities re criticl to ccurte VMA clcultions. 27

38 28 CONCLUSIONS FROM ECONOMIC EVALUATION (l) Any mix design chnge which results in the use of more expensive ggregtes to chieve VMA or to replce field snd will result in incresed cost to the contrctor nd subsequently to the SHPf. (2) Incresing VMA requires the use of more sphlt. Incresing sphlt content results in incresed cost of the mixture. (3) Implementtion of the specifiction chnges proposed by the SHPf will likely result in sttewide vemge increse in HMAC costs. This is due to the probbility tht more sphlt will be used sttewide nd more crushed ggregtes will be used to replce less expensive locl ggregtes. (4) Some relignment of ggregte suppliers is likely becuse of chnging demnds for ggregte usge. This too my result in incresed HMAC prices. RECOMMENATIONS (I) It is believed tht the re between the "modified" mximum-density line nd the ctul grdtion my be useful tool by which to djust gmdtions on mixture-specific bsis to increse VMA. The experimentl dt ssembled in this project indicte this, but more work should be done using mny more mixtures to verify this phenomenon. (2) Since the bulk specific grvity significntly influences the clcultion of VMA, steps should be tken to insure the ccumcy of bulk specific gmvity determintions. This my be done through sttewide monitoring progrm. (3) If specific mixture hs insufficient VMA, the following procedure is recommended, first to verify tht problem exists nd then to mke chnges to itx:rese the VMA: () Check the ccumcy of the bulk specific gmvities involved in the VMA clcultions. (b) If it is determined tht VMA problem truly exists, djust the ggregte grdtion wy from the "modified" mximum-density line. This my increse VMA. Severl different djustments my be needed to scertin the effecton VMA. (c) If grdtion djustment fils to increse the VMA sufficiently, ggregte substitution my be used. More crushed mterils, hrder mterils, or minerlogiclly different mterils my be used. (d) If tken to extremes, ggregte substitution my result in totl redesign of the mixture. This procedure progresses from the lest costly to the most costly mesures nd is tril-nd-error process which termintes when the desired VMA is ttined. (4) The specifiction chnges proposed by the SHPf seem sound, nd, while likely to result in higher sttewide costs, should result in more dumble pvements. You get wht you py for.

39 REFERENCES 1. The Asphlt Institute, Mix esign Methods for As- 12. Hudson, S. B., nd vis, R. L., "Reltionship of phlt Concrete nd Other Hot-Mix Types, Aggregte Voidge to GI3dtion," Proceedings, Mnul Series No.2 (MS-2), AAPT, Field, F., "Voids in the Minerl Aggregte: Test 13. Goode, J. F., nd Lufsey, L.A., "A New Grphicl Methods nd Specifiction Criteri," Report Chrt for Evluting Aggregte Grdtions," EM-21, C.T.A.A., 1978, Revised Apri Proceedings,AAPT, vis, J., "Lrge Stone Asphlt Perfonns Under 14. Edge,. E., "The 0.45 Grding Curve, A is- Sher Conditions," AsphJI.-The Mgzine of course," Asphlt Institute Internl Corresponthe Asphlt Institute, Vol 2, No.2, Fll1988. dence, November Griffith, J. M., nd Klls, B. F., "Influence of Fine 15. The Asphlt Institute, esign of Hot Asphlt Mix- Aggregtes on Asphltic Concrete Pving Mix- tures, Eductionl Series No.3 (ES-3), tures," Proceedings, HRB, Texs Stte eprtment of Highwys nd Public 5. Griffith, J. M., nd Klls, B. F., "Aggregte Voids Trnsporttion, Mnul of Testing Procedures, Chrcteristics in Asphlt Pving Mixes," Pro ceedings, HRB, Kndhl, P. S., nd Koehler, W. S., "Mrshll Mix 6. McLeod, N. W., "Reltionships Between ensity, esign Method: Current Prctices," Proceed- Bitumen Content, nd Voids Properties of Com- ings, AAPT, pcted Bituminous Pving Mixtures," Proceed- 18. McLeod, N. W., "Void Requirements for enseings, HRB, Grded Bituminous Pving Mixtures," ASTM 1. Monrow, R. W., "Hevy Wheel Lods Prompt Spe- Specil Technicl Publiction No. 252, cil Mix esigns in Iow," Rods nd Bridges, 19. McGennis, R. B., "VMA Requirements," Asphlt Jnury Institute Internl Correspondence, Mrch Acott, M., "Tody's Trffic Clls for Hevy uty 20. Kndhl, P. S., "Mximum ensity Line: Which Asphlt Mixes," Rods nd Bridges, Jnury One Should Be Used?," Ntionl Center for As phlt Technology, Asphlt Technology News, 9. "Computer Techniques for Identifying eficient nd Flll989. Optimum JMF Specifictions for Asphlt Pve- 21. Ott, L., An Introduction to Sttisticl Methods nd ments," Better Rods, Vol 53, Issue 3, Mrch t Anlysis, Third Edition, PWS-Kent Pub fishing Compny, Boston, Shrm, R. P., nd Ro, S. K., "Comprison of Ag- 22. Texs Stte eprtment of Highwys nd Public gregte GI3dings for Highwys Bsed on Their Trnsporttion, Stndrd Specifictions for Con- Voids Chrcteristics," Indin Rods Congress, struction of Highwys, Streets nd Bridges, Highwy Reserch Bulletin, Issue N23, Jiminez, R. A., nd deppo,. A., "Asphlt Concrete Mix esign," Arizon eprtment of Trnsporttion Report Number: FHWAIAZ , June

40

41 APPENIX A. MIXTURE ESIGNS-ESIGN ATA AN EVIATION ATA TABLE A.l. TYPE C MIXTURES Sieves ('Jf~P) ClLMSH19 C5LUUS84- Cl4BUS28-7/ / / Sieves ('Ji~P) OldM:xen OldM:xen OldM:xen 7/8 5/ / Sieves ( 'Jfl P) ModM:xen Mod M:xen Mod Mx en 7/8 5/ / VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old L Sum((Line-Act)l\2) Are (Old-Act) Mod L Sum(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum((Line-Act)l\2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) 0.20 O.o Snd Rtio

42 32 TABLEA.l. TYPE C MIXTURES (CONTINUE) Sleves(%P) C16JUS2.8A- C16JUS2.8B- C18IH / '13.7 ' Sieves (%P) OidMxen Old Mx en Old Mx en Sieves(%P) ModMxen ModMxen ModMxen VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old L Sum((Line-Act)l\2) Are (Old-Act) Mod L Sum(Line-Act) -' Mod L Sum (ABS(Line-Act)) ' Mod L Sum((Line-Act)l\2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

43 33 TABLE A.l. TYPE C MIXTURES (CONTINUE) Sieves (%P) Cl9MUS59 Cl9PUS59 7/ / / Sieves (%P) Old Mx en Old Mx en 7/ / Sleves(%P) Mod Mx en Mod Mx en 7/ / VMAesign PVF Asphlt Content Old L Swn(Line-Act) Old L Swn(ABS(Line-Act)) Old L Swn((Line-Act)A2) Are (Old-Act) Mod L Swn(Line-Act) Mod L Swn (ABS(Line-Act)) Mod L Swn((Line-Act)A2) Are (Mod-Act) FM (Old L}-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

44 34 TABLE A.2. TYPE MIXTURES Sleves('JIP) lfnus82- lhushso- llmus82-1! / A A Sleves('JIP) Old Mx en Old Mx en OldMxen l!l 3/ Sleves('JIP) Mod Mx en Mod Mx en ModMxen 1!2 3/ VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old L Sum((Line-Act)'\2) Are (Old-Act) Mod L Sum(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum((Line-Act)'\2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

45 35 TABLEA.2. TYPE MIXTURES (CONTINUE) Sieves (%P) 3WUS81-4CUS60- SGAFM65-1/ / Sleves(%P) Old Mx en Old Mx en Old Mx en 1/2 3/ Sieves (%P) ModMxen ModMxen Mod Mx en 1/2 3/ VMAesign PVF Asphlt Content Old L Swn(Line-Act) Old L Swn(ABS(Line-Act)) Old L Swn((Line-Act)l\2) Are (Old-Act) Mod L Swn(Line-Act) Mod L Swn (ABS(Line-Act)) Mod L Swn((Line-Act)l\2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

46 36 TABLE A.l. TYPE MIXTURES (CONTINUE) Sleves(%P) 5LUUS84-5GAUS84- loanu28-1/ / Sleves(%P) Old Mx en Old Mx en Old Mx en 1/2 3/ Sieves (%P) Mod Mx en ModMxen Mod Mx en 1/2 3/ VMAesign PVF Asphlt Content Old L Swn(Line-Act) Old L Swn(ABS(Line-Act)) Old L Swn((Line-Act)'\2) Are (Old-Act) Mod L Swn(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Swn((Line-Act)"2) Are (Mod-Act) FM (Old L)..FM (esign) FM (Mod L)-FM (esign) Snd Rtio

47 37 TABLE A.2. TYPE MIXTURES (CONTINUE) Sieves('.!f~P) llgfm17- llmfm13- llmih45-1/ / Sieves ('.!f~p) Old Mx en Old Mx en Old Mx en 1/2 3/ Sieves ('.!f~p) Mod Mx en Mod Mx en ModMxen 1/2 3/ VMAesign PVF Asphlt Content Old L Swn(Line-Act) Old L Swn(ABS(Line-Act)) Old LSwn((Line-Act)"2) Are (Old-Act) Mod L Swn(Line-Act) Mod L Swn (ABS(Line-Act)) Mod L Swn((Line-Act)"2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

48 38 TABLE A.l. TYPE MIXTURES (CONTINUE) Sleves(%P) 16NSH44-16RUS17-16RUS718-1( / Sleves(%P) Old Mx en Old Mx en Old Mx en 1(2 3/ Sleves(%P) Mod Mx en Mod Mx en ModMxen 1(2 3/ VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old LSum((Line-Act)"'2) Are (Old-Act) Mod L Sum(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum((Line-Act)"'2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

49 39 TABLE A.l. TYPE MIXTURES (CONTINUE) Sleves(%P) l7bsh21- l7bsh36- l9cuss9-1/ / Steves(%P) Old Mx en Old Mx en Old Mx en 1/2 3/ l Sleves(%P) Mod Mx en ModMxen ModMxen 1/2 3/ VMAesign PVF Asphlt Content Old L Swn(Line-Act) Old L Swn(ABS(Line-Act)) Old L Swn((Line-Act)l\.2) Are (Old-Act) Mod L Swn(Line-Act) Mod L Swn (ABS(Line-Act)) Mod L Swn((Line-Act)l\.2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

50 40 TABLE A.2. TYPE MIXTURES (CONnNUE) Sleves(%P) 11CFM14-11HUSX3-11SFM75-1( Sleves(%P) OldMuen OldMuen OldMuen 1( Sleves(%P) Mod Mx en ModMuen Mod Mx en 1( VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old L Sum((Line-Act)l\2) Are (Old-Act) Mod L Sum(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum((Line-Act)l\2) Are (Mod-Act) PM (Old L)-FM (esign) PM (Mod L)-FM (esign) Snd Rtio

51 41 TABLE A.l. TYPE MIXTURES (CONTINUE) Sleves(%P) 23BFM45-23LU190- l4cus6:z.. 1{ Sleves(%P) Old Mx en Old Mx en Old Mx en 1{ Sieves (%P) Mod Mx en Mod Mx en ModMxen 1{ VMAesign PVF Asphlt Content Old L Sum(Line-Act) Old L Sum(ABS(Line-Act)) Old L Sum((Line-Act)"2) Are (Old-Act) Mod L Sum(Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum((Line-Act)"2) Are (Mod-Act) FM (Old L)-FM (esign) FM (Mod L)-FM (esign) Snd Rtio

52 APPENIX B POWER GRAATION CHARTS FOR ESIGN MIXTURES 0~~~--~ _--~--~ 0 #200 #40 #10 #4 3/8 in. 5/8 in. 7/8 in. #80 Sieve Size 100 """!... ~ ; ~"~'[ ~f2 L """ #' LL: ~ / ~r ~... 0 #200 #40 #10 #4 3/8 in. 5/8 in. 7/8 in. 180 Sieve Size / Fig B.l. C1LMSH19-. Fig B.3. Cl4BUS ~~~--~--~----._--~--~ 0 #200 #40 #10 #4 3/8 in. 5/8 in. 7/8 in. 180 Sieve Size 0&-~~--~--~----._--~--~ 0 #200 #40 #80 #10 #4 3/8 in. 5/8 in. 7/8 in. Sieve Size Fig B.2. C5LUUS84-. Fig B.4. Cl6JUS28A-. 42

53 ~~~ ~----~--~ 0 #200 #40 #10 #4 3Jl3 in. 5Jl3 in. 7Jl3 in. #80 Sieve Size o~--~----~--_.----~----._--~ 0 #200 #40 #10 #4 3Jl3 in. 5Jl3 in. 718 in. #80 Sieve Size Fig B.S. Cl6JUS28B-. Fig 8.7. C19MUSS r r..- r ~r....,...., e ~60'"'"'+ i! ;... 1~...,,.~,...,... ;. 'iii (I) 0.. "' ~40~----- ~ -i -~ ~~... :... ;... ~.. 20 #1 0 #4 3Jl3 in. 5Jl3 in. 7 Jl3 in. Sieve Size o--~~----~--_.----~----~--~ 0 #200 #40 #10 #4 318 in. 5Jl3 in. 718 in. #80 Sieve Size Fig 8.6. C18IH63-. Fig 8.8. C19PUS59-.

54 44 g,: ~IH~:~~~t-~=~t=--=-r =-f(-j ~ 40 ~~-.,..., < u; ~~ l l~ 20,... r-.. :! 1200 #40 #80 #10 #4 Sieve Size 3/B in. 1/2 in. #200 # #10 #4 Sieve Size 3/B in. 112 in. Fig FNUS82-. Fig LMUS g 60 ~ ~ ( ~ r" l ~ ~ ~f,i 17 ;' ~ #200 #40 #80 f p. A'.,J.V...P'" #10 #4 Sieve Size,... Ji... 3/B in. 1/2 in #40 #80 #10 #4 Sieve Size 3/B in. 112 in. Fig HUSH50-. Fig WUS82-.

55 45! ~ ~ 60 c;;.. _.): ::- -;!:~~~~ #200 #40 #80 #10 14 Sieve Size 318 in. 112 in #40 #80 #10 14 Sieve Size 318 in. 112 in. Fig B.l3. 4CUS60-. Fig B.lS. SGAUS84. #200 #40 #80 #10 #4 Sieve Size 318 in. 112 in # #10 #4 Sieve Size 318 in. 112 in. Fig B.14. SGAFM6S. Fig B.16. SLUUS84.

56 46 #200 #40 #80 #10 #4 Sieve Size 3/Sin. 1121n. #200 #40 #80 #10 #4 Sieve Size 3/Sin. 112 in. Fig ANU28-. Fig MFM13-. #200 #40 #80 #10 #4 Sieve Size 3/8 in. 112 in #40 #80 #10 #4 Sieve Size 3/8 in. 112 in. Fig GFM17-. Fig MIH45-.

57 # #4 Sieve Size 3/8 in. 112 in. #200 #40 #10 #4 #80 Sieve Size 3/8 in. 112 in. Fig B.21. l6nsh44-. Fig B.23. l6rus77b # Sieve Size 3/8 in. 112 in. # # Sieve Size 3/8 in. 112 in. Fig B.22. l6rus77-. Fig B.24. l7bsh21-.

58 g' 60 u; Cl) ~ ~ 40 ~ 0 20 #200 #40 #80 #10 #4 Sieve Size 318 in. 1fl in #40 #80 #10 #4 Sieve Size 318 in. 1fl ln. Fig l78sh36-. Fig CFM14-. #200 #40 #80 #10 #4 Sieve Size 318 in. 1fl in. #200 #40 #80 #10 #4 Sieve Size 318 in. 1fl in. Fig l9cus59-. Fig HUS83-.

59 49 #200 #40 #80 #10 #4 Sieve Size 3/8 in. 112 in. #200 #40 #80 #10 #4 Sieve Size 3/8 in. 112 in. Fig SFM7S-. Fig LU190-. #200 #40 #80 #10 #4 Sieve Size 3/8 in. 112 ln. #200 #40 #80 #10 #4 Sieve Size 3/81n. 112 in. Fig FM4S-. Fig CUS62-.

60 APPENIX C. ESIGN TRENS 18 y = x R"2= y = x R"2 = c: 16 0 "Ci) (I) Cl 15 <C :E > c: 16 0 "Ci) Gll c 15 <C :E > Asphlt Content Asphlt Content 7 Fig C.l. VMA versus C & sphlt content. Fig C.3. VMA versus sphlt content. 17 y = x R"2=0.590 y = x e - 2x"2 R"2 = c: 16,!;!I (I) Gll Cl 15 <C ~ t3~~~~_.~~~l-~~~~~~~ Asphlt Content PVF Fig C.2. VMA versus C sphlt content. Fig C.4. VMA versus C & PVF. 50

61 51 c: 01 c;; G) Cl 15 < ~ > y = x e- 2x"2 R"2= PVF c: c;; G) c::qs < ~ > [1 [1 [1 [1 [1 Cl [1[1 e [1 [1 [1 [1 [1 [1 'be [1 :J cr:p [1 [1 [ Old Mx ensity Line Sum (Line- Act) Fig C.S. VMA versus C PVF. Fig C.7. C & OLSUM(L A). y = x e - 2x"2 R"2= y = e- 2x RA2 = [ [1 [1 [1 [ PVF Fig C.6. VMA versus PVF. Fig C.8. VMA versus C OLSUM(L-A).

62 y == x R"2 == c c 16 c c c c:: 16 Cl c:: u; Cl c Cl) c u; Cl) 015 e 0 <C :l cc <C 15 c ~ c c cc ~ > 14 > c c 14 c c 13 c c c c 12 c c Old Mx ensity Line Sum (Line -Act) Old Mx ensity Line Sum (ABS (Line- Act)) Fig C.9. VMA versus OLSUM(L-A). Fig C.ll. VMA versus C OLSUMABS(L-A). c:: c c Cl "(ii Q) c c 015 <C c c c c c ~ cc cc > 14 c cc cc c c c I} 17 c c c:: 16 Cl u; c c ~ 15 <C c c c Ill c ~ c c cc > 14 c c 13 8 c 13 c c c c c 12~--~--~--~--~--~--~--~~ Old Mx ensity line Sum (ABS(Line- Act)) I} 12~--~----~--_.----~ ~ 20 ~ ~ w Old Mx ensity Line Sum (ABS (line- Act)) Fig C.lO. VMA versus C& OLSUMABS(L-A). Fig C.12. VMA versus OLSUMABS(L-A).

63 53 y = e - 3x RA2 = tp C\1 400 < po c::: 16 :t C I 300 tp 'ii) en B c::: C3 15 :.:J <C -200 ~ E 10 > 14 ::;, en -l 100 r:pl :_ -o VMA esign Old Mx ensity Line Sum {(Line- Act)"2) Fig C.lJ. VMA versus C& OLSUM(L-A)l. Fig C.lS. VMA versus OLSUM(L-A)l y"' x RA2 = c::: C c::: 16 'ii) C en 'ii) 0 15 C315 <C ~ <C > ~ > 14 E QJ Old Mx ensity Line Sum ((Line- Act)"2) Are Between Old Mx ensity & Actul Fig C.14. VMA versus C OLSUM(L-A)l. Fig C.16. VMA versus C& AREA(OL-ACT).

64 y = x R"2= ~._--~~_.~~--~._._~~_.~ 0! 1J 12 1A 1 1! 2J 22 Are Between Old Mx ensity & Actul 13 J 9 lill 12~--~~----._~~~~~_.--~~ Mod Mx ensity Line Sum (line -Act) Fig C.l7. VMA versus C AREA(OL-ACT). Fig C.l9. C& MOSUM(L-A) c: 16.!2' (I) (I) 0 15 < e ~ 14 J 13 tb Are Between Old Mx ensity & Actul y = e 2x R"2= ~~0--~----~~--~~-w~ ~0--~--~ Mod Mx ensity Line Sum (Line- Act) Fig C.l8. VMA versus AREA(OL-ACT). Fig C.20. VMA versus C MOSUM(L-A).

65 c;; c: < J 9 :e fill > Mod Mx ensity Line Sum (Line -Act) c: Cl c;; c: 0 15 < :e > 17 y = e- 2x R"'2= Mod Mx ensity Line Sum (ABS (Line- Act)) Fig C.21. VMA versus MOSUM(L-A). Fig C.23. VMA versus C MOSUMABS(L A). 516 c;; ~ < 15 :e > y = e- 2x R"2= Mod Mx ensity line Sum (ABS (Line -Act)) c: 16 Cl c;; c: 0 15 < :e > y = e- 2x R 11 2= ~~~~~~~~~~~~~~~~ Mod Mx ensity Line Sum (ABS (line- Act)) Fig C.22. VMA versus C& MOSUMABS(L-A). Fig C.24. VMA versus MOSUMABS(L-A).

66 y = e 3x R 11 2 = y = noOe - 3x RA2 = c: 16 r::::: c;; Q) 0 15 <C :E > 14 12~--L-~~~~--~~~--~~~--~ Mod Mx ensity Line Sum ((Line- Act)"2) Fig C.25. VMA versus C& MOSUM(L-A)2. Fig C.27. VMA versus MOSUM(L-A)2. c: Cl c;; ~ 15 <C :E > Mod Mx ensity Line Sum ((Line- Act)"2) 18 y = x R 11 2 = c: 16 Cl c;; Q) 015 <C :E > 'i:j Are Between Mod Mx ensity & Actul 4 Fig C.26. VMA versus C MOSUM(L A)2. Fig C.28. VMA versus C& AREA(MO-ACT).

67 57 c 0 en G) 0 15 <C :;! > y = x R"2= Are Between Mod Mx ensity & Actul c 16 0 en G) 015 <C c C m :;! m > 14 e 13 c.::p c c 12 -o.5.().4 -o.3.().2.().1 FM (Old Mx ensity Line)- FM (esign) 0.0 Fig C.29. VMA versus C AREA(MO-ACT). Fig C.31. VMA versus C& FM(OL-ACT) y = x R"2 =0.099 y = x R 11 2=0.323 c: 16 0 en G) 0 15 ~ > ~--~--~--~~~--~--~--~~ Are Between Mod Mx ensity & Actul c 0 en ~15 <C ~ 14 c c -o FM (Old L) - FM (esign) 0.1 Fig C.30. VMA versus AREA(MO-ACT). Fig C.32. VMA versus C FM(OL-ACT).

68 58 y = x R-.. 2= ~.5 til -{).4 -{),3 -{).2 -{).1 FM (Old Mx ensity Line) - FM (esign) 14 13~~--~--_... ~--~--~ u u u u u FM (Mod L) - FM (esign) Fig C.33. VMA versus FM(OL-ACT). Fig C.3S. VMA versus C FM(MO-ACT) 'iii G) 0 rp <C 15 B ~ > g {).2 -{) FM (Mod L)- FM (esign) B g 12~--~--~--~-----~--h---~~_.--~ -{),2 -{), FM (Mod Mx ensity Line)- FM (esign) Fig C.34. VMA versus C& FM(MO-ACT). Fig C.36. VMA versus FM(MO-ACT).

69 59 IJ IJ IJ IJ 17 IJ IJ IJ 8 18, 16 c;; (I) 0 15 IJ IJ me IJ < IJ m IJ IJ ::::::!! > IJ IJ IJ'O IJ Eb 14 IJ 13 ~ 13 l:b IJ IJ IJ IJ 12 IJ Snd Rtio Snd Rtio IJ IJ IJ IJ IJ IJ IJ 8 IJ Fig C.37. VMA versus C& SAN RATIO. Fig C.39. VMA versus SAN RATIO. c: 0) "(;; (I) IJ IJ IJ 015 IJ ell IJIJ IJ < IJ ::::::!! IJ IJ IJ IJ > IPc 14 drl IJ fl 13 IJ IJ c IJ IJ IJ 12 IJ Snd Rtio -200 (% by Wt) IJ IJ IJ IJ IJ Fig C.38. VMA versus C SAN RATIO. Fig C.40. VMA versus C &-#200.

70 60 c: u; C> Q) <( 15 ~ > c...,._ Possible Outlier 14 J (% by Wt) 6 7,16 u; Q) c 15 <( ~ > 14 E (% by Wt) Fig C.41. VMA versus C-#200. Fig C.43. VMA versus y = x R 11 2 = _L-~~~~~~~~--~~~--~ (o/o by Wt) Fig C.42. VMA versus C-#200( -OUTLIER).

71 APPENIX. ESIGN MIXTURES-VMA AN AGGREGATE TYPE TABLE.l. ESIGN MIXTURES-VMAAN AGGREGATE TYPE Aggregte Type Project VMA Corse Intenned Screenings Field Snd C1LMSH Sndstone Sndstone Sndstone River Snd C5LUUS Cliche Limestone SilSnd C14BUS Sndstone Limestone Silic C16JUS28A 13.7 Limestone Limestone Limestone C16JUS28B 13.7 Limestone Limestone Limestone C18IH Limestone Pe Grvel C19MUS SilGrvel SilGrvel SilGrvel C19PUS Sit Grvel Sit Grvel SilGrvel 1FNUS Sndstone Sndstone lhush Sndstone Sndstone 1LMUS Sndstone Sndstone 3WUS Limestone Sndstone Limestone 4CUS Limestone Limestone 5GAFM Limestone Limestone Sil Snd 5LUUS Cliche Limestone Sil Snd 5GAUS Cliche Cliche 10ANU Sndstone Sndstone 12GFM Limestone Limestone 12MFM Sndstone Limestone Limestone 12MIH Limestone Limestone Limestone 16NSH Sndstone CrGrvel ol Grvel 16RUS CrGrvel CrGrvel 16RUS77B 14.8 CrGrvel Cr Grvel 17BSH Limestone Limestone l7bsh Limestone Limestone 19CUS Sndstone Sndstone Sndstone 21CFM HUS Grvel Grvel Cone Snd 21SFM Grvel Grvel ConcSnd 23BFM Limestone 23LU Limestone Limestone Limestone Sil Snd 24CUS

72 APPENIX E. FIEL MIXTURES-FIEL ATA AN EVIATION ATA TABLE E.l. TYPE C MIXTURES Sieves(% P) C1LMSH19-E C14BUS28-E / Sieves(% P) Old Mx en Old Mx en 7/ / A Sieves(% P) Mod Mx en Mod Mx en 7/ / VMA PVF Asphlt Content Old L Smn ( Line-Act) Old L Smn (ABS(Line- Act)) Old L Smn ((Line - Act)h2) Are (Old -Act) Mod L Smn (Line -Act) Mod L Smn (ABS(Line- Act)) Mod L Smn ((Line - Act)h2) Are (Mod - Act) Snd Rtio (Fine/fotl)

73 63 TABLE E.2. TYPE MIXTURES Sleves(%P) lfnus81 E lhusrso-e llmus81 E. 1/ / Sieves (%P) OldMxen Old Mx en OldMxen 1/2 3/ Sieves (%P) ModMxen ModMxen ModMxen 1/2 3/ VMA Plnt Mix-Lb Mold PVF Asphlt Content Old L Sum (Line-Act) Old L Sum (ABS(Line-Act)) Old L Sum ((Line-Act)"2) Are (Old-Act) Mod L Sum (Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum ((Line-Act)"2) Are (Mod-Act) Snd Rtio

74 64 TABLE E.2. TYPE MIXTURFS Sleves(%P) 3WUS8l-E SGAUSS4-E 10ANU28-E 1{ / Sleves(%P) Old Mx en Old M:x en Old Mx en 1{2 3/ lo Sleves(%P) Mod Mx en Mod Mx en Mod Mx en 1{2 3/ VMA Plnt Mix-Lb Mold PVF Asphlt Content Old LSum (Line-Act) Old L Sum (ABS(Line-Act)) Old L Sum ((Line-Act)l\2) Are (Old-Act) Mod L Sum (Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum ((Line-Act)l\2) Are (Mod-Act) Snd Rtio

75 65 TABLE E.2. TYPE MIXTURES Sieves (%P) l2gfm17-e l2mfm13-e l2mih45 E 1( / Sieves (%P) OldM:xen Old Mx en Old Mx en 1/2 3/ Sieves (%P) Mod Mx en ModM:xen Mod Mx en 1/2 3/ VMA Plnt Mix-Lb Mold PVF Asphlt Content Old L Sum (Line-Act) Old L Sum (ABS(Line-Act)) Old L Sum ((Line-Act)/"2) Are (Old-Act) Mod L Sum (Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum ((Line-Act)ll2) Are (Mod-Act) Snd Rtio

76 66 TABLE E.l. TYPE MIXTURES Sieves (%P) 19CUS59-B 023LU190-B 1! / Sieves (%P) OLMAXBN OLMAXBN lfl 3/ Sieves (%P) MOMAXBN MOMAXBN 1!1 3/ VMA Plnt Mix-Lb Mold PVF Asphlt Content Old L Swn (Line-Act) Old L Swn (ABS(Line-Act)) Old L Swn ((Line-Act)A2) Are (Old-Act) Mod L Swn (Line-Act) Mod L Sum (ABS(Line-Act)) Mod L Sum ((Line-Act)A2) Are (Mod-Act) Snd Rtio

77 APPENIX F POWER GRAATION CHARTS FOR FIEL MIXTURES 100 y v, ;;,l... _ j 1 ~: ~tlt=::~t~::lllll:.,l......,~, ! en ~ I! l 8!. i ; l : '#- 40 -"~ t + r ---~-~ ; ,f "--...,..., II, 20 j..! #~".. l.....!.... i i.. {! 0.! Sieve Size 318 in. 518 in. 7181n. : --nt---=.::r=.~~_:f.=-.. m..::.ollll 11"'----.,... w.. C : =tf l : : en! i < ' ~.E f' t... f'... _..... r i... t'l"""'j "-... :.. 1 #200 #40 #80... ~r -- "'"" ".. i F...,... t..., #10 #4 Sieve Si.ze Fig F.l. CILMSH19-E. Fig F.3. 1FNUS82-E. 20 i ~ 0 o 12ixl' #~0 #10 #4 318 in. 518 in. 718 in. #80 Sieve Size 0&-~~----~----~----~~ #10 Sieve Size Fig F.2. C14BUS28-E. Fig F.4. lhushso-e. 67

78 68 #200 #40 #80 #10 #4 Sieve Size 318 in. 1/2 in. 0~~~~ ~ ~-----~ #200 #40 #10 #4 318 ln. 1/21n. 180 Sieve Size Fig F.S. 1LMUS82-E. Fig F.7. 5GAUS84-E c c;; (1,) s 0.. ~ 0 c c;; (1,) s 0.. ~ 20 #200 #40 #80 #10 #4 Sieve Size #10 #4 3/8 in. 112 in. Sieve Size Fig F.6. 3WUS82-E. Fig F.8. loanu28-e.

79 69 #200 #40 #80 #10 #4 Sieve Size #200 #40 #80 #10 #4 Sieve Size Fig F.9. l2gfm17-e. Fig F.ll. 12MIH45-E gto u; "" U) 0.. eft 40 u; ~ -.;e. 20 Sieve Size 318 in. 112 in # #10 #4 Sieve Size 318ln. 1/2 in. Fig F.lO. l2mfm13-e. Fig F.l2. 19CUS59-E.

80 en en 8!. Sieve Size Fig F.l3. 23LUI90-E.

81 APPENIX G. FIEL TRENS ""Q 0 16 ::z 15.J::l "'...J I ::z -~ c:: "' 0: i 13 > y = x R"2 = Asphlt Content 5.6 ""Q 16 0 ::z 15.J::l "'...J I ::z -~ c:: "' 0: i 13 > Old Mx ensity Line S1,1m (line - Act) 40 Fig G.l. VMA vs sphlt content. Fig G.J. VMA vs OLSUM(L- A)..J::l ~ I ::z -~ c:: "' 0: <C 13 ~ y = e- 2x R"2= PVF ""Q 0 16 ::z 15.J::l ~ I ::z -~ c:: "' 0: <C 13 ~ Old Mx ensity Line Sum (ABS (line- Act)) 40 Fig G.2. VMA vs PVF. Fig G.4. VMA vs OLSUMABS(L- A). 71

82 72 16.CI ~ I.~ 14 ~ 1: co 0:: < 13 ~ > 12~--~----~----._--~----~--~ Old Mx ensity Line Sum ((Line- Act)"2).CI ~ I.~ 14 ~ 1: co 0:: < 13 ~ > 12~------~------L ~----~ Mod Mx ensity Une Sum (Line -Act) B Fig G.S. VMA vs OLSUM(L- A)"2. Fig G.7. VMA vs MO SUM(L-A). :E 0 16 ~ 15.CI ~ I.~ 14 ~ 1: co 0:: < 13 ~ > 12~------~------L ~----~ Are (Old Mx ensity- Actul) 16 -o 0 ~ 15.CI c.s ~ I.~ 14 ~ -c: c.s 0:: < 13 ~ > 12~--_.----~----~--_.----~--~ Mod Mx ensity Line Sum (ABS(Line- Act)) Fig G.6. VMA vs AREA( OL -ACT). Fig G.8. VMA vs MOSUMABS(L- A).

83 73 -~ is: < 13 ~ 12~--_.----~----~--_.----~--~ Mod Mx ensity Line Sum ((Line- Acty 2) 12~--_.----~----~--~----~--~ Snd Rtio Fig G.9. VMA vs MOSUM(L- A)"2. Fig G.ll. VMA vs SAN RATIO. 16 "0 0 :E 15.c ~ I.?:S 14 :E -c:.i'!j! 0.. < 13 :E > Are (Mod Mx ensity- Actul) 16 "0 0 :E 15.c ~ I -~ 14 :E -c: <U is: < 13 :E B > Fig G.lO. VMA vs AREA (MO -ACT). Fig G.l2. VMA vs -#200.

84 APPENIX H. AGGREGATE GRAATION INFORMATION FOR FACTORIAL EXPERIMENTS TABLE H.l. ISTRICT 6 ESIGN GRAATION INFORMATION Grdtion t esign Grd. Corse Scms Comb Sieve RbyoHte Fine Snd Grd (%).J!L J!L.J!L / /2 + 3/ / # #10+ # # #80+# # Totl Bulk Spgr Clc: +# #10 +# # Combined lnd Combined Bulk Spgr = Mx en Clc's sgn Sieve Mx en Mx en Grd Sieves Sieves A0,45 Old Mod %Pss 7/ / / / # # # # # evition Ck: Sum(L-A) Sum (ABS(I.A)) Sum ((L-A)A2) Are Mx & Act

85 75 TABLE H.2. ISTRICT 6 COARSE GRAATION INFORMATION Grdtion t Corse Grd. Corse Scrns Comb RhyoUte Fine Snd Grd Sieve (%) (%).J!L J.!L /l /l+ 3/ /8 +1# #4+# #10+# #40+# #80+# # Totl Bulk Spgr Clc +# #10 +# # Combined Ind Combined Bulk Spgr = Mx en Clc's sgn Sieve Mx en Mx en Grd Sieves Sieves "0.45 Old Mod %Pss 7/ / /l / # # # # # evition Ck Sum(L-A) Sum (ABS(L-A)) Sum ((L-A)A2) Are Mx & Act

86 76 TABLE H.3. ISTRICT 14 ESIGN GRAATION INFORMATION Grdtion t esign Grd. Type"C" Type "" Type "F" Scms Snd Comb Sieve Corse Weir Corse Weir Im Weir Floe Weir Berdoll Fine Grd (%) (%) (%) (%) (%) J!L / / /8 +## #4 +# #10+# l.l #40+# #80+# # Totl Bulk Spgr Clc: +# #10 +# # Combined lnd Combined Bulk Spgr = Mx en Clc:'s sgn Sieve Mx en Mx en Grd Sieves Sieves "OAS Old Mod %Pss ! / # # # # # evition Clc: Sum(L-A) Sum (ABS(L-A)) Sum ((L-A)I\2) Are Mx & Act

87 77 TABLE H.4. ISTRICT 14 GRAATION NO.2 INFORMATION Grdtion t Grdtion #2 'fype"c" Type"" 'type "F" Scms Snd Comb Sieve Corse Weir Corse Weir ImWelr Fine Weir Berdoll Fine Grd ('II) ('II) (IJ,) ('II) ('II) J!L / / /8 +* *4 +# #10+* *40+# #80+# # Totl Bulk Spgr Clc +# #10 +# # Combined Ind Combined Bulk Spgr = Mx en Clc's sgn Sieve Mx en Mx en Grd Sieves Sieves "0.45 Old Mod CJ, Pss fl / * # * # # evition Clc Sum(L-A) Sum (ABS(L-A)) Sum ((L-A)"2) Are Mx & Act

88 78 TABLE H.S. ISTRICT 14 GRAATION NO. 3 INFORMATION Grdtion t Grdtion #3 Type"C" Type"" Type "F" Scms Snd Comb Corse Weir Corse Weir ImWelr Fine Weir Berdoll Fine Grd Sieve (%) (%) (%) (%) (%) (%) / / /8 +3/ /8 +1# #4+# #10+1# #40+ # #80+# # Totl Bulk Spgr Cle +# #10 +# # Combined Ind Combined Bulk Spgr = Mx en Clc's sgn Sieve Mx en Mx en Grd Sieves Sieves Old Mod %Pss 7/ / { / # # # # # evition Cle Sum(L-A) Sum (ABS(L-A)) Sum ((L-A)"2) Are Mx & Act

89 APPENIX I. STATISTICAL ANALYSIS OF LABORATORY FACTORIAL EXPERIMENTS OF ASPHALT CONTENT AN AGGREGATE GRAATION ON SELECTE MIXTURE PROPERTIES STATISTICAL ANALYSES OF FACTO RIAL EXPERIMENTS t nd corresponding sttisticl nlyses from ech of the fctoril experiments from both istrict mixture designs re presented. All sttisticl tests re done t the 95% confidence level (=0.05). For ll properties investigted, nlysis of vrince (F-tests) re presented where pproprite. The nlysis of vrince (ANOVA) is sttisticl procedure used to indicte whether differences in property due to chnges in one or more fctors re relly different or could be ttributed to rndom vrition. If the nlysis of vrince indictes significnt differences exist due to fctor for which three levels were used, multiple comprisons procedure is used to indicte which levels differ significntly. VMA is of specil interest to the Highwy eprtment nd the testing progrm resulted in more dt for VMA, therefore descriptive sttistics for ech level of both fctors re presented. PROCEURES USE FOR THE STATISTICAL TESTS ANALYSIS OF VARIANCE F-TESTS The procedure for conducting F-tests to determine significnce clls first for exmining the interction of sphlt content nd ggregte grdtion. If the interction is not significnt or is significnt but orderly, F-tests for the min effects of sphlt content nd ggregte grdtion will be meningful nd my proceed. If the interction is significnt nd not orderly, the usefulness of the F-test for the min effects is in doubl The tests in these nlyses require comprison to tbulted F vlues. The F vlues depend on the number of degrees of freedom ssocited with the effect investigted ndm for the error ssocited with the nlysis. The F vlues needed for the following nlyses re: F*(2,66) = 3.14, F*(1,66) = 3.99, F*(2,12) = 3.89, F*(l,l2) = 4.75, F*(2,99) = 3.09, F*(4,99) = 2.46, F*(2,18) = 3.55, nd F*(4,18) =2.93, where "*" mens the vlue ws obtined from sttisticl tble. MULTIPLE COMPARISONS If the ANOVA nlysis (F-test) indictes significnt differences in property exist due to fctor for which only two levels were used, one cn sy which level resulted in higher or lower vlues. If the ANOVA nlysis (F-test) indictes significnt differences in property exist due to fctor for which three levels were used, it only mens tht t lest one level resulted in sttisticlly significnt differences, but not which one or ones re differenl One must use multiple comprisons procedure to determine this. For this dt the use of the Fisher's Lest Significnt ifference Test with unooo)ed error nd interction (enough degrees of freedom re present in the denomintor) is pproprite. It is quick nd less complicted thn others, but s the number of comprisons increses the effective confidence level is lower. With only three levels, the compromise is not much. ISTRICT 6 ANALYSIS VOIS IN THE MINERAL AGGREGATE In viewing the dt, one cn mke the following comments: (I) Incresing sphlt content seems to results in incresed VMA. (2) ifferences due to ggregte grdtion re difficult to discern. TABLE 1.1. ATA FOR THE 3X2 FACTORIAL EXPERIMENT OF VMA Asp bit Content (%) esign Grdtion Corse Grdtion

90 80 ESCRIPTWE STATISTICS The following descriptive sttistics were obtined from MINITAB. References re such tht 5.2, 6.2, nd 7.2 refer to sphlt content nd G nd CG refer to esign Grdtion nd Corse Grdtion respectively. 1i MS!!! M!l!!!!!! ~ ~ 5.2-G G G CG CG CQ The descriptive sttistics intuitively indicte differences in VMA with sphlt content, but probbly not with grdtion. ANALYSIS OF VARIANCE The ANOVA tble from the two wy nlysis of vrince follows: Source.!!!. _. [_ MS _L Asphlt Content Aggr Grdtion Interction Error Totl ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,66) = 3.14 > F = 0.30, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*(2,66) = 3.14 < F = , one concludes tht there re significnt differences in VMA due to sphlt content. c) Finlly, test for no difference between ggregte grdtions. Since F*(l,66) = 3.99 > F = 0.47, insufficient evidence exists to indicte differences in VMA due to ggregte grdtion. ifferences in VMA: 5.2 & 6.2 = 0.26 > LS 6.2 & >LS 5.2 & 7.2 = 0.93 >LS 5.2% < 6.2% 6.2%< 7.2% 5.2% <7.2% This comprison procedure indictes the sphlt contents ll produce VMA's significntly different.m!! Mx from ech other AIR VOIS TABLE 1.2. ATA FOR THE 3X2 FACTORIAL EXPERIMENT OF AIR VOIS Aspblt Coutent _f!l esign Grdtion Corse Grdtion MULTIPLE COMPARISONS PROCEURE (ASPHALT CONTENT- VMA) LS= t* /2..J2s2Jn with t*(/2=0.025, df=66) = ANALYSIS OF VARIANCE The ANOVA tble from the two wy nlysis of vrince follows: s2 = (from ANOVA) n=24 LS= using both G & CG shows: Asphlt Content Averge VMA Source.!!!. _. [_ MS!_ Asphlt Content Aggr Grdtion Interction Error Totl ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since

91 81 F*(2,66) = 3.14 > F = 0.32, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*(2,66) = 3.14 < F = , one concludes tht there re significnt differences in Air Voids due to sphlt content. c) Finlly, test for no difference between ggregte grdtions. Since F*(l,66) = 3.99 < F = 6.716, one concludes tht there re significnt differences in Air Voids due to ggregte grdtion. MULTIPLE COMPARISONS PROCEURE (ASPHALT CONTENT -AIR VOIS) LS= t*/l..j2s2fn with t*(./2=0.025, df=66) = s2 = (from ANOVA) n=24 LS= using both G & CG shows: Asphlt Content ifferences in VMA: 5.2 & 6.2 = 1.69 > LS 6.2 & 7.2 = 1.56 >LS 5.2 & 7.2 = 3.25 >LS Averge Air Voids % >6.2% 6.2% >7.2% 5.2% >7.2% This comprison procedwe indictes the sphlt contents ll produce Air Voids significntly different from ech other. RESIUENT MOULUS TABLE I.3. ATA FOR THE 3X2 FACTORIAL EXPERIMENT OF RESILIENT MOULUS (PSI) Asphlt Content esign Corse (%) Grdtion Grdtion , , , , , , , , , , , , , , , , , ,687 In viewing the dt one cn see no generl trends for this sphlt-ggregte combintion. ANALYSIS OF VARIANCE The ANOVA tble from the two wy nlysis of vrince follows: Soun:e.!!!.. ss MS _L Asphlt Content E E Aggr Grdtion E E Interction E E Error E E + 10 Totl E + 11 ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,12) = 3.89 > F = 0.107, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*(2,12) = 3.89 > F = 0.634, one concludes tht there re not significnt differences in Resilient Modulus due to sphlt content. c) Finlly, test for no difference between ggregte grdtions. Since F*(1,12) = 4.75 > F = 0.635, one concludes tht there re not significnt differences in Resilient Modulus due to ggregte grdtion. MARSHAU STABIUTY AN FWW TABLE I.4. ATA FOR THE 3X2 FACTORIAL EXPERIMENT OF MARSHALL STABILITY AN FLOW esign Corse Asphlt Grdtion Grdtion Content Mrshll Mrshll (%) Stb(%) Flow Stb(%) Flow , , , , , , , , , , , , , , , In viewing the dt, the generl trends for this sphlt-ggregte combintion seem to be: 1) Incresing sphlt content results in decresed Stbility. Flow chnges due to sphlt content re difficult to determine. 2) The "corser" ggregte grdtion results in decresed Flow. Stbility chnges due to ggregte chnges re difficult to determine. ANALYSIS OF VARIANCE FOR MARSHALL STABIUTY The ANOV A tble from the two wy nlysis of vrince for Mrshll Stbility follows:

92 82 Source..!!!.. ss MS _L Asphlt Content E E Aggr Grdtion 1 16,140 16, Interction 2 6,462 3, Error ,151 16,096 Totl E+6 ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,12) = 3.89 > F = 0.201, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*(2,12) = 3.89 < F = 48.37, one concludes tht there re significnt differences in Mrshll Stbility due to sphlt content. c) Finlly, test for no difference between ggregte grdtions. Since F*(l,12) = 4.75 > F = 1.003, one concludes tht there re not significnt differences in Mrshll Stbility due to ggregte grdtion. MULTIPLE COMPARISONS PROCEURE (ASPHALT CONTENT-- MARSHALL STABILITY) LS= t*/2 v2s2/n with t*(/2=0.025, df=12) = s2 = 16,096 (from ANOVA) n=6 LS= using both G & CG shows: Asphlt Content Averge Mrshll Stbility 5.2 3, , ,290 ifferences in Stbility: 5.2 & >LS 5.2% > 6.2% This comprison procedure indictes the sphlt contents of 5.2% nd 6.2% produce Mrshll Flow vlues 6.2 & 7.2 = 300 >LS 6.2% > 7.2% 5.2 & 7.2 = 717 >LS 5.2% > 7.2% significntly different from 7.2%, but the 5.2% nd 6.2% This comprison procedure indictes the sphlt con do not differ significntly from ech other. tents ll produce Mrshll Stbility's significntly differ- r , ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,12) = 3.89 > F = 0.368, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*{2,12) = 3.89 < F = 4.77, one concludes tht there re significnt differences in Mrshll Flow due to sphlt content t the 95% confidence level. At the 97.5% confidence level F*(2,12)=5.10. At this level one would sy tht differences in Mrshll Flow due to sphlt content re not sttisticlly significnt. c) Finlly, test for no difference between ggregte grdtions. Since F*{l,12) = 4.75 > F = , one concludes tht there re significnt differences in Mrshll Flow due to ggregte grdtion. MULTIPLE COMPARISONS PROCEURE (ASPHALT CONTENT- MARSHAU FWW) LS= t*12 v2s2/n with t*{/2=0.025, df=12) = s2 = 1.06 (from ANOVA) n=6 LS= 1.29 using both G & CG shows: Asphlt Content ifferences in Flow: 5.2 & 6.2 = 0.16 <LS 6.2 & 7.2 = 1.66 >LS 5.2 & 7.2 = 1.50 >LS Averge Mrshll Flow %> 7.2% 5.2%>7.2% ent from ech other. For this dt, incresing sphlt content decreses the Mrshll Stbility. ANALYSIS OF VARIANCE FOR MARSHAU FLOW The ANOVA tble from the two-wy nlysis of vrince for Mrshll Flow follows: Source..!!!......L..ML _F_ Asphlt Content Aggr Grdtion Interction Error Totl TABLE 1.5. ATA FOR THE 3X2 FACTORIAL EXPERIMENT OF INIRECT TENSILE STRENGTH AN SECANT MOULUS AT FAILURE esign Corse Asphlt Grdtion Grdtion Content Secnt Mod Secnt Mod (%) Str (psi) (psi@ fll) Str (psi) (psi@ fll) , , , , , , , , , , , , , , , , , ,919

93 83 INIRECT TENSILE STRENGTH AN SECANT MOULUS AT FAILURE In viewing the dt one cn see the generl ttends for this sphlt-ggregte combintion re: 1) Incresing sphlt content results in pek in ITS t 6.2%, nd decresed Secnt Modulus. 2) The "corser" ggregte grdtion results in decresed ITS nd incresed Secnt Modulus. Source..!!!. _.ML _F_ Asphlt Content 2 1, Aggr Grdtion 1 5, , Interction Error 12 1, Totl 17 8,250.5 This comprison procedure indictes the sphlt contents of 5.2% nd 6.2% produce Indirect Tensile Strengths significntly different from 7.2%, but the 5.2% nd 6.2% do not differ significntly from ech other. ANALYSIS OF VARIANCE FOR SECANT MOULUS AT F AlLURE The ANOVA tble from the two wy nlysis of vrince for Secnt Modulus t Filure follows: Source..!!!. ss MS _F_ Asphlt Content E E Aggr Grdtion E E Interction E E Error E E + 6 Totl E+9 ANALYSIS OF VARIANCE FOR INIRECT TENSILE STRENGTH The ANOVA tble from the two wy nlysis of vrince for Indirect Tensile Sttength follows: ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,12) = 3.89 > F = 0.333, insufficient evidence exists to indicte n interction between Asphlt Content nd Grdtion. b) Next, test for no difference between sphlt contents. Since F*(2,12) = 3.89 < F = 7.92, one concludes tht there re significnt differences in Indirect Tensile Strength due to sphlt content c) Finlly, test for no difference between ggregte grdtions. Since F*(l,l2) = 4.75 > F = 57.36, one concludes tht there re significnt differences in Indirect Tensile Strength due to ggregte grdtion. MULTIPLE COMPARISONS PROCEURE (ASPHALT CONTENT -ITS) LS= t*12.j2s2/n with t*(/2=0.025, df=l2) = s2 = 96.1 (from ANOVA) n=6 LS= 12.3 using both 00 & CG shows: Asphlt Content ifferences in ITS: 5.2 & 6.2 = 8.6 < LS 6.2 & 7.2 = 22.3 >LS 5.2 & 7.2 = 13.5 >LS Averge ITS % > 7.2% 5.2%>7.2% - ) The first test of significnce is for interction between Asphlt Content nd Grdtion. Since F*(2,12) = 3.89 < F = 16.1, evidence exists to indicte n interction between Asphlt Content nd Grdtion. Figure 1.1 indictes n orderly interction between sphlt content nd grdtion, therefore F-test for the min effects re still meningful. 40,000 - ~ E 30,000 ::3 ~ 20,000 :; '8 ~ c 10,000 B Cl) en Asphlt Content Fig secnt modulus interction. b) Next, test for no difference between sphlt contents. Since F*(2,12) = 3.89 < F = 86.42, one concludes tht there re significnt differences in Secnt Modulus t Filure due to sphlt content t the 95% confidence level. c) Finlly, test for no difference between ggregte grdtions. Since F*(l,12) = 4.75 > F = 512.8, one concludes tht there re significnt differences in Secnt Modulus t Filure due to ggregte grdtion.