Performance of chip seals using local and minimally processed aggregates for preservation of low traffic volume roadways

Transcription

1 Intrnational Journal of Civil Enginring and Construction Scinc 2014; 1(1): 9-17 Publishd onlin April 20, 2014 ( Prformanc of chip sals using local and minimally procssd aggrgats for prsrvation of low traffic volum roadways Scott Shulr Dpartmnt of Construction Managmnt, Colorado Stat Univrsity, Fort Collins, USA addrss Kywords Chip Sal, Low Volum Traffic, Marginal Aggrgats Rcivd: Fbruary 26, 2014 Rvisd: April 15, 2014 Accptd: April 16, 2014 Citation Scott Shulr. Prformanc of Chip Sals Using Local and Minimally Procssd Aggrgats for Prsrvation of Low Traffic Volum Roadways. Intrnational Journal of Civil Enginring and Construction Scinc. Vol. 1, No. 1, 2014, pp Abstract Many roadways in th world ar in locations without high quality aggrgats. Thrfor, high quality aggrgats must b transportd to ths locations whn pavmnt construction or prsrvation activitis ar ndd. This transportation incrass th cost of pavmnt construction and prsrvation in ths aras of th stat. Incrasd costs oftn man that timly pavmnt prsrvation activitis ar postpond. This postponmnt lads to dtrioration of th infrastructur and, ultimatly, incrasd costs. In addition, many of th pavmnts rquiring prsrvation ar low volum facilitis. Ths low volum roads may not rquir th vry high quality aggrgats ncssary on highr traffic volum facilitis. Thrfor, if mor conomical local aggrgats could b dmonstratd to prform accptably, pavmnt prsrvation could b accomplishd within budgt at appropriat intrvals. This would sav costs in both th short and th long trms. Chip sals ar usd xtnsivly by many road authoritis for xtnding pavmnt lif. Chip sals utilizing locally availabl and minimally procssd aggrgats should b a mor conomical pavmnt prsrvation tratmnt than chip sals constructd with highr quality, mor xpnsiv aggrgats. Although chip sals constructd on high traffic roadways rquir high quality, crushd and approximatly singl-sizd aggrgats, low traffic roadways may not dmand such matrials to prform accptably. Thrfor, an xprimnt was dsignd to dmonstrat th prformanc of chip sals constructd using two diffrnt aggrgats on two low volum stat highways. Th control aggrgat was th matrial routinly usd for chip sal construction and th scond aggrgat was a matrial that did not mt spcifications for gradation or fractur. Construction of th tst sctions was conductd by agncy maintnanc forcs in Condition survys wr prformd to dtrmin pr-chip sal condition and thn priodically for th nxt thr yars to track prformanc. Two fiv hundrd foot long valuation sctions wr locatd within ach tst pavmnt for ach aggrgat rsulting in two thousand lan-ft of tst ara for ach roadway. Rsults of th xprimnt aftr thr yars of srvic indicat no significant diffrnc in prformanc btwn th aggrgats. Distrss in both pavmnts is limitd to a rturn of transvrs and longitudinal cracks, but with low prcntags of chip loss. Som limitd aras of th pavmnts also contain longitudinal flushing straks whr distributor nozzls may not hav bn adjustd corrctly and highr quantitis of asphalt wr applid. Basd on th rsults of this rsarch it appars that locally availabl, minimally

2 10 Scott Shulr: Prformanc of Chip Sals Using Local and Minimally Procssd Aggrgats for Prsrvation of Low Traffic Volum Roadways procssd aggrgats can b succssfully applid as chip sal aggrgat on low volum roadways. Th rport includs a rcommndd chip sal dsign procdur, aggrgat and construction spcification for low traffic volum roadways. 1. Introduction Many roadways in th world ar in locations without high quality aggrgats. Thrfor, high quality aggrgats must b transportd to ths locations whn pavmnt construction or prsrvation activitis ar ndd. This transportation incrass th cost of pavmnt construction and prsrvation in ths parts of th stat. Incrasd costs oftn man that timly pavmnt prsrvation activitis ar postpond. This postponmnt lads to dtrioration of th infrastructur and, ultimatly, incrasd costs. In addition, many of th pavmnts rquiring prsrvation ar low volum facilitis. Ths low volum roads may not rquir th vry high quality aggrgats ncssary on highr traffic volum facilitis. Thrfor, if mor conomical local aggrgats could b dmonstratd to prform accptably, pavmnt prsrvation could b accomplishd at appropriat intrvals and within budgt. Both short and long trm savings would rsult. Chip sals ar usd xtnsivly by roadway authoritis for xtnding pavmnt lif. Chip sals utilizing locally availabl and minimally procssd aggrgats may b a mor conomical pavmnt prsrvation tratmnt than chip sals constructd with highr quality, mor xpnsiv aggrgats. Although chip sals constructd on high traffic roadways rquir high quality, crushd and approximatly singl-sizd aggrgats, low traffic roadways may not dmand such matrials to prform accptably. Thrfor, an xprimnt was dsignd to dmonstrat th prformanc of chip sals constructd using two diffrnt aggrgats on two low volum stat highways. Th control aggrgat was th matrial routinly usd for chip sal construction and th scond aggrgat was a matrial that did not mt spcifications for gradation or fractur Objctivs 1. Construct chip sal tst and control sctions using locally availabl and minimally procssd aggrgats and documnt th prformanc of ths pavmnts for thr conscutiv yars. 2. Dvlop and/or adopt monitoring and documntation procdurs for valuating th prformanc of th tst sctions. 3. Dvlop or adopt a dsign procdur, aggrgat spcifications, and construction guidlins for chip sals constructd with local, minimally procssd aggrgats on low traffic volum roadways. 2. Litratur Rviw Thr is a significant amount of information availabl on chip sal dsign, construction and prformanc. From two dsign mthods by Hanson in Nw Zaland (Hanson, ) and Karby (Karby, 1953) in Txas, most mthods usd today can b tracd (McLod, 1960, 1969; Pottr and Church, 1976; Marais, 1981; Epps, 1981). Ths mthods ar ssntially basd on th concpt that aggrgat in a chip sal should b as on-sizd as possibl and that mbdmnt of th aggrgat in th asphalt bindr should occupy a spcific prcntag of th aggrgat dimnsion. How th aggrgat dimnsion is dtrmind and how th volum of asphalt bindr is calculatd vary btwn mthods but usually rquir masuring th gradation of th aggrgat in ordr to obtain th avrag last dimnsion (ALD) in th cas of th Hanson mthod or th unit wight, spcific gravity and sprad quantity in th cas of Karby. Th shap of th aggrgat is considrd important and is masurd using th Flakinss Indx in th cas of th Hanson mthod and th prcnt mbdmnt is varid as a function of traffic for both mthods. Howvr, although both of ths mthods ar rational procdurs, basd on sound nginring principls, thy hav bn shown to produc diffrnt rsults whn applid to th sam aggrgats and mulsions on th sam pavmnt (Shulr, 1998). Onc th chip sal has bn dsignd, how it prforms during construction and in arly lif undr traffic is th gratst concrn. Loss of chips during construction lads to construction dlays and loss of chips during arly trafficking may lad to vhicular damag. Thrfor, rducing this potntial has bn a focus of rsarch. Bnson (Bnson and Gallaway, 1953) valuatd th ffcts of various factors on th rtntion of covr ston on chip sals. Among othr factors this study valuatd th ffcts of covr ston and asphalt quantity, aggrgat gradation, tim btwn asphalt and aggrgat application, and dust and moistur contnt of chips on rtntion of covr ston. Th typ of bindr usd in th chip sal can hav an ffct on prformanc. Studis hav bn conductd to masur bindr viscosity as function of chip siz, prcoatd or not, damp or dry (Kari, 1962; Major, 1965; Kandhal, 1991) and mak rcommndations rgarding th optimum consistncy for dsird prformanc. In addition, th prformanc of th chip sal aftr long trm trafficking can b affctd by th proprtis of th covr ston and th substrat pavmnt. A procss of valuating th ability of th substrat pavmnt to rsist chip pntration is practicd in th UK and Africa (Hitch, 1981; Colwill, t al, 1995). Prdicting arly chip rtntion has bn don using laboratory abrasion tsts, impact tsts, and traffic simulators (Kari, 1962; Shulr, 1996; Stroup-Gardinr, 1990; Davis, 1991). Th prformanc of chip sals has bn rportd by many (Jackson, 1990; Sbaaly, 1995; Tmpl, 2002; Chn,

3 Intrnational Journal of Civil Enginring and Construction Scinc 2014; 1(1): ; Jahrn, 2004; Gransbrg, 2005). soon add littl bnfit and applid too lat ar inffctiv Aggrgat Spcifications Th bst chip sal prformanc is obtaind whn aggrgat has th following charactristics (Caltrans Division of Maintnanc, 2003): Singl-sizd Clan Fr of clay Cubical (limitd flat particls) Crushd facs Compatibl with th slctd bindr typ. Aggrgats must b damp for mulsion us. Th aggrgat should b carfully analyzd to dtrmin its unit wight, spcific gravity, prcnt of voids, and scrn analysis. From th scrn analysis th avrag particl siz and ffctiv mat thicknss of th aggrgat is dtrmind by multiplying ach individual scrn siz by its individual prcntag and thn obtaining th sum of th products. (Karby, 1953). Aggrgat Clanlinss: Dusty and dirty aggrgat ultimatly lad to problms with aggrgat rtntion. Asphalt bindrs hav difficulty bonding to dirty or dusty aggrgat, causing th aggrgat to b dislodgd on opning to traffic (McLod 1969; Gransbrg & Jams, 2005). It is rcommndd that th aggrgat b sprayd with watr svral days bfor th start of th projct (Maintnanc Chip Sal Manual 2000, Gransbrg & Jams, 2005). Washing chip sal aggrgat with clan, potabl watr bfor application may assist in rmoving fin particls that will prvnt adhsion with th bindr. In addition, damp chips will assist th bindr in wtting th rock, thus incrasing mbdmnt (Maintnanc Chip Sal Manual, 2000, Gransbrg & Jams, 2005). In addition to washing with watr, ptrolum matrials ar somtims usd to clan th aggrgat bfor application. Ptrolum-basd matrials such as disl ful ar commonly usd to wash aggrgat in Australia and Nw Zaland (Sprayd Saling Guid 2004; Gransbrg & Jams, 2005). Dust on th aggrgat surfac is on of th major causs of aggrgat rtntion problms. Dust is dfind as th prcntag of fin matrial that passs th No. 200 siv. To improv th quality of th matrial, th prcntag of fins passing th No. 200 siv should b spcifid as a maximum of 1% at th tim of manufactur (Janisch & Gaillard, 1998). Th covr aggrgat for a sal coat should not hav a dust coat. Bttr rsults ar obtaind if th rock is damp whn it is applid. Th aggrgat should b dampnd in th stock pil (Washington Stat Dpartmnt of Transportation, 2003). Aggrgat shap: Flakinss: Th flakinss of th aggrgat particl is valuatd by dtrmining th prcntag of flat particls within th aggrgat. Th prfrrd shap of th covr aggrgat is cubical rathr than flaky. Flaky particls tnd to li on thir flat sid in th whl paths and tnd to li randomly in th lss traffickd aras. An xcssiv amount of flaky particls in a chip sal systm may caus th systm to bld in th whl paths and to b mor suscptibl to snow plow damag and aggrgat dislodgmnt in th lss traffickd aras. Th flakinss charactristic of th aggrgat is most oftn dtrmind using th Flakinss Indx. (Crotau, t al, 2005, Txas Tst Mthod Tx-224F). Gradation: Uniformly gradd aggrgats usually dvlop bttr intrlocking qualitis and provid latral support to adjacnt particls, thrby prvnting displacmnt from traction and friction of high spd traffic. (Karby, 1953). Th gradation of th aggrgat is assssd to dtrmin th avrag last dimnsion of an aggrgat. Th avrag last dimnsion of an aggrgat is influncd by th man siz of an aggrgat. An aggrgat is considrd coars if its gradation is positiond in th lowr part of th gradation band and fin if it is positiond in th uppr part. Accordingly, th man siz of th aggrgat varis from cours to fin gradations within th sam gradation band. Th optimal bindr spray rat for a singl chip sal systm may vary as much as tn prcnt btwn a coars aggrgat and a fin aggrgat vn whn both chips comply with th sam singl-siz gradation band. Th impact of th aggrgat gradation on th bindr rat is lss for th scondary layrs of multi-layr chip sal systms (Crotau, t al, 2005). 3. Exprimnt Dsign This xprimnt was dsignd to dtrmin if aggrgat charactristics affct prformanc of chip sals on low volum roads. To tst this hypothsis th prformanc of two aggrgats was valuatd on two two-lan stat highways. Thrfor, indpndnt variabls includd two aggrgats and two highways. This rsultd in a 2 x 2 factorial xprimnt. On aggrgat was th matrial routinly usd for chip sal construction by CDOT maintnanc with a history of accptabl prformanc. Th scond aggrgat rprsntd a locally availabl and marginal matrial not mting CDOT spcifications with unknown prformanc. Ths matrials will b idntifid as Control and Exprimntal, rspctivly. Tst sctions wr constructd on SH71 north of Snydr, CO and on SH59 south of Sdgwick, CO. Both of ths pavmnts ar rural, farm to markt two lan highways with 12 foot wid driving lans, no shouldrs on SH71 and 10 foot shouldrs on SH59. Traffic volums ar 360 AADT with 30 singl unit trucks and 120 combination trucks on SH71 and btwn 160 and 470 AADT with 20 singl unit trucks and 20 combination trucks on SH59. Evaluation sctions wr stablishd on ach highway to masur prformanc ovr tim for ach aggrgat bing

4 12 Scott Shulr: Prformanc of Chip Sals Using Local and Minimally Procssd Aggrgats for Prsrvation of Low Traffic Volum Roadways valuatd. Two 500 foot long valuation sctions wr stablishd for ach highway for ach aggrgat. This rsultd in four 500 foot long valuation sctions for ach highway or ight valuation sctions total. Analysis of this dsign is accomplishd using convntional analysis of varianc () tchniqus using th modl shown blow: Yijk = µ + Ai + εijk Whr, Y ijk = dpndnt variabl,. g. cracking, ravling, or chip loss µ = ovrall man A i = Effct du to ith aggrgat ε ijk = Random rror Th approximat locations of th valuation sctions on ach pavmnt ar shown in Figurs 1 and 2. Figur 1. Evaluation Sctions on SH71. sctions to dtrmin pr-chip sal condition. Ths survys wr conductd visually following th procdurs outlind by th Stratgic Highway Rsarch Program (SHRP 2003). Rsults of this survy ar shown in Appndix A and consistd primarily of longitudinal, transvrs, alligator cracking, and chip loss Matrials Th two aggrgats usd in this study wr obtaind from L. G. Evrist and McAt Construction. On aggrgat is rprsntativ of what is typically usd in astrn Colorado for chip sal construction on low volum roads. This is th control aggrgat. Th othr aggrgat is finr in gradation and lss procssd with rspct to crushing. This aggrgat is th xprimntal aggrgat. Th gradations, prcnt of fracturd facs and soundnss loss masurd for ach of ths aggrgats is shown in Tabl 1 and compard with th CDOT spcification for chip sal aggrgat and th Nbraska Dpartmnt of Roads (NDOR) Sction 1033 spcification for what is trmd armour coat by NDOR. Armour coat is a chip sal constructd with minimally procssd aggrgats for us on low volum roads. Asphalt mulsion usd on th projct was obtaind from Cobitco in Dnvr, CO with th proprtis shown in Tabl Construction Figur 2. Evaluation Sctions on SH59. Dpndnt Variabls Prformanc of th chip sals was valuatd by conducting visual condition survys of th sits aftr th wintr and bfor fall ach yar. Ths condition survys valuatd prformanc by masuring cracking, ravling and chip loss. 4. Mthodology Th procss usd to conduct this xprimnt consistd of th following stps: 1. Evaluat condition of th pavmnt in th ara of th valuation sctions prior to application of th chip sals. 2. Sampl th matrials usd for construction and dtrmin physical proprtis 3. Construct valuation sctions 4. Evaluat condition of th valuation sctions aftr wintr and bfor fall ach yar for thr yars Pavmnt Condition Prior to Construction of Tst Sctions Prior to construction of th tst sctions condition survys wr prformd in th aras of th valuation Construction of th tst sctions was conductd by CDOT Rgion 4 maintnanc forcs in th summr of Equipmnt utilizd consistd of a convntional asphalt distributor, slf-proplld aggrgat spradr and two pnumatic tird rollrs. Traffic control consistd of divrting traffic on ach of th two lan pavmnts around th chip sal oprations until th strngth of th mulsion was high nough to rsist chip dislodgmnt. Tabl 1. Aggrgats Usd in Exprimntal Chip Sal Evaluation Sctions. Siv Passing, % Control Exprimntal CDOT Spc NDOR 1033 ¾ 100 3/ L. A. Loss, % < 35 < 40 2 Fracturd Facs, % Soundnss Loss, % > 90 n/a 3 3 n/a < 12

5 Intrnational Journal of Civil Enginring and Construction Scinc 2014; 1(1): Tabl 2. Asphalt Emulsion. Proprty CRS-2P Spc Projct Tsts on Emulsion Viscosity, 50C, Saybolt-Furol, s Storag Stability, 24 hr, % max Particl Charg Tst Positiv Positiv Siv Tst, % max Dmulsibility, % min Oil Distillat by Volum, % max Rsidu by Evaporation, % min Tsts on Rsidu Pntration, 25C, 100g, 5s, dmm, min Solubility in TCE, % min Toughnss, in-lbs, min Tnacity, in-lbs, min Matrials application rats for SH71 valuation sctions wr 28 pounds pr squar yard for th control and 26 pounds pr squar yard for th xprimntal aggrgat. Emulsion was applid at 0.28 gallons pr squar yard for both control and xprimntal sctions. Chips on SH59 wr applid at 28 pounds pr squar yard for both control and xprimntal aggrgats and at 0.29 gallons pr squar yard for th mulsion. Dsign application rats wr stimatd using th Txas chip sal dsign procdur (Epps, t al, 1981). Rsults of this dsign ar shown in Tabl 3. This dsign procdur uss a on-squar yard board to stimat th quantity of chips rquird to covr th surfac on ston thick. Th asphalt quantity is stimatd by calculating th amount of asphalt to fill th voids btwn th chips to a spcific mbdmnt dpth. That rlationship is as follows: A = {5.61 [1.33Q/W][1-(W/(62.4G))] T + V}/ R Whr th trms ar as shown in Tabl 8 and, G = aggrgat spcific gravity, and R = mulsion rsidu, % Construction procdd with no difficultis for ithr tst pavmnt. Aggrgat mbdmnt was achivd aftr approximatly four passs of th pnumatic tird rollrs and vhicular traffic was allowd back onto th frsh chip sals aftr approximatly two hours from th tim of application. Th nvironmntal conditions at th tim of construction ar summarizd in Tabl 4. SH 71 SH 59 Control Exprimnt Control Exprimnt Corrction, V Emulsion, gsy * From Board Tst during laboratory dsign Location Tabl 4. Environmnt During Construction. Pavmnt Tmp, F Wathr SH Clar/Sun/Dry Wind 10 mph SH Clar/Sun/Dry 5 mph 4.4. Pavmnt Condition aftr Construction of Tst Sctions Evaluation sctions wr monitord to masur prformanc from th spring of until th fall of. Mthods usd to valuat prformanc wr visual condition survys conductd by walking along th shouldrs of th pavmnts and obsrving condition according to th mthods dscribd by SHRP (SHRP 2003) for th cracking and flushing and Epps, t al (Epps, t al, 1981) for th chip loss. Th rsults of ths survys ar shown in Figurs 3 to 7 for SH71 and Figurs 8 to 12 for SH59. Th valuation sctions ar prsntd sparatly on th graphs. That is, sctions 1 to 5 ar th first fiv, 100 foot long control sctions, sctions 6 to 10 ar th scond fiv, 100 foot long control sctions; sctions 11 to 15 ar th first fiv, 100 foot long xprimntal sctions, and sctions 16 to 20 ar th scond fiv, 100 foot long xprimntal sctions. Distrss in both pavmnts is limitd to a rturn of transvrs and longitudinal cracks to pr-chip sal conditions aftr approximatly 2.5 yars. Alligator cracking, which was only prsnt in th control sctions prior to tratmnt, has rturnd to approximatly 22 to 35 prcnt of that prsnt prior to tratmnt. Chip loss rangs from 0.35 to approximatly 0.50 prcnt of th ara of th valuation sctions. Som aras of th pavmnts also contain longitudinal flushing straks whr distributor nozzls may not hav bn adjustd corrctly and highr quantitis of asphalt wr applid. Th caus of this is not rlatd to ithr typ of chip, but is rportd for thoroughnss. Tabl 3. Dsign Quantitis for Matrials. SH 71 SH 59 Control Exprimnt Control Exprimnt Quantity of chips*, Q, psy Loos Unit Wight, W, pcf Dsign Embdmnt, , % Traffic Corrction, T Surfac Cracking Longitudinal Cracking-SH71 Figur 3. Longitudinal Cracking on SH71.

6 14 Scott Shulr: Prformanc of Chip Sals Using Local and Minimally Procssd Aggrgats for Prsrvation of Low Traffic Volum Roadways Cracking Transvrs Cracking-SH Longitudinal Cracking-SH59 Cracking Chips Flusing 4 35% 3 25% 2 15% 1 5% % 1.4% 1.2% % 0.6% 0.4% 0.2% 0. Figur 4. Transvrs Cracking on SH71. Alligator Cracking-SH71 Figur 5. Alligator Cracking on SH71. Chip Loss-SH71 Figur 6. Chip Loss on SH71. Flushing-SH71 Figur 7. Flushing on SH Figur 8. Longitudinal Cracking on SH59. Transvrs Cracking-SH59 Figur 9. Transvrs Cracking on SH59. Alligator Cracking-SH59 Figur 10. Alligator Cracking on SH59. Chip Loss-SH59 Figur 11. Chip Loss on SH59. Flushing-SH59 Figur 12. Flushing on SH59.

7 Intrnational Journal of Civil Enginring and Construction Scinc 2014; 1(1): Analysis Th rsults of th condition survys aftr thr yars srvic wr analyzd using convntional analysis of varianc tchniqus () to dtrmin whthr any significant diffrncs xist in prformanc for any of th valuation sctions. Th rsults of this analysis ar shown in Tabls 5 to 9 for SH71 and Tabls 10 to 14 for SH59. Th dpndnt variabl analyzd to dtrmin diffrncs in prformanc was th prcnt of th original distrss obsrvd for ach valuation sction at th nd of th prformanc priod in th fall of. For xampl, Tabl 5 indicats that th control sctions on SH71 had an avrag of 99 prcnt of th original longitudinal cracking rturning during th fall condition survy whil th xprimntal sctions had an avrag of 107 prcnt. Th indicats that at α=0.05 significanc, thr is no statistical diffrnc btwn ths valus, that is, th valu = 0.67 in this cas. This mans thr is only a 33 prcnt probability that a diffrnc xists btwn th cracking obsrvd in th control sction compard with th xprimnt sction. Tabl 5. for Longitudinal Cracking on SH71. SUMMAR Y Coun Avrag Varianc t Control Exprimnt Sourc of Btwn Total valu Tabl 6. for Transvrs Cracking on SH71. Count Avrag Varianc Control Exprimnt Sourc of valu Btwn Total Tabl 7. for Alligator Cracking on SH71. Coun Avrag Varianc t Control Control Sourc of Btwn Total Control 10 Exprimnt 10 valu Tabl 8. for Chip Loss on SH71. Coun t Avrag Varianc Tabl 9. for Flushing on SH71. Coun t Avrag Varianc Control Exprimnt Sourc of Btwn valu Total Tabl 10. for Longitudinal Cracking on SH59. Coun t Avrag Varianc Control Exprimnt Sourc Btwn Total of valu Sourc of Btwn valu Total

8 16 Scott Shulr: Prformanc of Chip Sals Using Local and Minimally Procssd Aggrgats for Prsrvation of Low Traffic Volum Roadways Tabl 11. for Transvrs Cracking on SH59. Coun t Avrag Varianc Control Exprimnt Sourc of Btwn valu Total Tabl 12. for Alligator Cracking on SH59. Coun Avrag Varianc t Control Sourc of valu Btwn Total Tabl 13. for Chip Loss on SH59. Count Avrag Varianc Control Exprimnt Sourc of valu Btwn Total Tabl 14. for Flushing on SH59. Count Avrag Varianc Control Exprimnt Sourc of valu Btwn Total A summary of th prvious rsults indicats th following: Prformanc Critria, % of Original at 3 Yars Tabl 15. mary of Rsults for SH71. Control Avrag Exprimnt Avrag valu Longitudinal Cracking Transvrs Cracking Alligator Cracking n/a n/a n/a Chip Loss Flushing Prformanc Critria, % of Original at 3 Yars Tabl 16. mary of Rsults for SH59. Control Avrag Exprimnt Avrag valu Longitudinal Cracking Transvrs Cracking Alligator Cracking n/a n/a n/a Chip Loss Flushing Conclusions 1. Locally availabl, minimally procssd aggrgats can b succssfully applid as chip sal aggrgat on low volum roadways. Aftr thr yars of srvic two xprimntal pavmnts providd th sam prformanc with rspct to cracking, chip loss and flushing for both control and xprimntal aggrgat chips. 2. Th dsign procdur usd to stimat aggrgat chip application quantity and mulsion spray rats matchd th actual quantitis placd rasonably wll and ths quantitis rsultd in accptabl prformanc for thr yars. 7. Rcommndations and Obsrvations Th dsign procdur rportd hrin providd good stimats of th chip and mulsion quantitis actually utilizd during construction and which rsultd in good prformanc of th chip sals during th analysis priod of thr yars. Longitudinal straking of th mulsion occurrd on both

9 Intrnational Journal of Civil Enginring and Construction Scinc 2014; 1(1): pavmnts which lad to flushing. This ovr application could hav bn causd by pluggd nozzls in parts of th spraybar, spraybar hight, or nozzls not adjustd to th sam angl. In addition, although chip loss was minimal, much of th loss occurrd at or nar th roadway cntrlin. An dg nozzl dsignd to provid half th fan of a full nozzl can b usd to rduc this potntial loss of chips. In som cass, tandm dump trucks dlivring chips to th aggrgat spradr ovrfilld th spradr hoppr and xcss chips wr applid to th surfac. Ths xcss chips may also hav bn a sourc of som of th flushing obsrvd. Rfrncs [1] Bnson, F., & Gallaway, B. (1953). Rtntion of covr ston by asphalt surfac tratmnts. Txas Enginring Exprimnt Station, 133, 1-58 [2] Caltrans, Chip Sals: Chaptr 5, Caltrans Division of Maintnanc. Oct [3] Chn, D., Lin, D., & Luo, H. (2003, August). Effctivnss of Prvntativ Maintnanc Tratmnts Using Fourtn SPS-3 Sits in Txas. Journal of Prformanc of Constructd Facilitis, [4] Colwill, D., & Mrcr, J., & Nicholl, J. (1995). U.K. Dsign Procdur for Surfac Drssing. Transportation Rsarch Rcord, 1507, [5] Davis, D., Stroup-Gardinr, M., Davis, K., and Epps, J.A. Evaluation of 1989 Chip Sal Tst Sctions on US 95A btwn Wabuska and Yrington, Nvada: Vol. 1. Univrsity of Nvada, Rno rport for Nvada dpartmnt of Transportation [6] Epps, J. A., Gallaway, B. M., and Hughs, C. H., Fild Manual on Dsign and Construction of Sal Coats, Txas Transportation Institut, Rsarch Rport , July, [7] Gransbrg, D; & Jams, D. (2005). Chip Sal Bst Practics. A NCHRP Synthsis 342 of Highway Practic. Transportation Rsarch Board, Washington D.C. [8] Hitch, L., (1981). Surfac Drssing in Dvloping Countris: Rsarch in Knya, Transport and Road Rsarch Laboratory: Crowthorn, Brkshir. [9] Hanson, F. M., Bituminous Surfac Tratmnts on Rural Highways, Procdings of th Nw Zaland Socity of Civil Enginrs, Vol. 21, , p 89. [10] Karby, J. P., Tsts and Thoris on Pntration Surfacs, Procdings, Highway Rsarch Board, Vol 32, [11] Jackson, D. (1990). Washington Stat Chip Sal Study. Transportation Rsarch Rcord, 1259, [12] Jahrn, C., and Bhling, K. R., (2004). Thin Maintnanc Surfac Tratmnts: Comparativ Study. Journal of th Transportation Rsarch Board, TRR 1866, pp [13] Janisch, D. & Gaillard, F. (1998). Minnsota Sal Coat Handbook, MN/RC , Minnsota Dpartmnt of Transportation, Maplwood, 112. [14] Kari, W. J., Coyn, L. D., and McCoy, P. E., (1962). Sal Coat Prformanc-Intrrlation of Variabls Establishd by Laboratory and Fild Studis, Procdings of th Association of Asphalt Paving Tchnologists, Vol 31, pp [15] Kandhal, P. & Mottr, J. (1991). Critria for Accpting Prcoatd Aggrgats for Sal Coats and Surfac Tratmnts. Transportation Rsarch Rcord 1300, [16] Maintnanc Chip Sal Manual, (2000). Montana Dpartmnt of Transportation, Hlna. [17] Major, N. G. (1965). A basis for slction of bindrs for chip saling. Nw Zaland Enginring, Vol 20, Issu 12, pp [18] Marais, C. P., Rational Dsign of th Singl Surfac Tratmnt Tchniqu for Road Maintnanc, Th Civil Enginr in South Africa, August, [19] McLod, N. (1960). Basic Principls for th Dsign and construction of Sal Coats and Surfac Tratmnts. Procdings of th Associuation of Asphalt Paving Tchnologist, 29, [20] McLod, N. W., Sal Coat Dsign, Procdings of th Association of Asphalt Paving Tchnologists, Vol. 38, Fbruary, [21] Pottr, J. L., and Church, M., Th Dsign of Sprayd Sals, Procdings of th Australian Road Rsarch Board, Vol 8, 1976, pp [22] Sbaaly, P. E., Lani, S., and Hand, A., (1995). Prformanc Modls for Flxibl Pavmnt Maintnanc Tratmnts, Journal of th Transportation Rsarch Board, TRR 1508, pp [23] Shulr, S., (1996). Chip Sals for High-Traffic Volum Asphalt Concrt Pavmnts, NCHRP Final Rport for Projct 14-8A, [24] Shulr, S. (1998). Dsign and Construction of Chip Sals for High Traffic Volum. Flxibl Pavmnt Rhabilitation and Maintnanc. ASTM Spcial Tchnical Publication (STP) Numbr Amrican Socity for Tsting and Matrials. Wst Conshohockn, PA. [25] Sprayd Saling Guid (2004). A676/104, Austroads, Sydny, Australia,, p 104. [26] Stroup-Gardinr, M, Nwcomb, D. E., Epps, J. A., and Paulsn, G. L. (1990). Laboratory Tst Mthods and Fild Corrlations for Prdicting th Prformanc of Chip Sals, Asphalt Emulsions, ASTM STP 1079, H. W. Muncy, Ed., ASTM, Philadlphia, PA, pp [27] Tmpl, W. (2002). Prformanc of Louisiana s Chip Sal and Microsurfacing Program. Transportation Rsarch Rcord, 1795, [28] Txas Tst Mthod Tx-224-F, Flakinss Indx. [29] Washington Stat Dpartmnt of Transportation. (2003, March). Asphalt Sal, Tchnology Transfr, 1-30.