The effects of coarse aggregate cleanliness and moisture content on asphalt concrete compactability and moisture susceptibility.

789282394Final report; Jan. 11, 2008-Dec. 31, 2011.PDFTech ReportFHWA/MS-DOT-RD-11-208SS-208Asphalt concreteConcreteMoisture contentCompactibilityAggregatesMississippiMississippi. Dept. of TransportationWilliams, Kevin L.Howard, Isaac L.Cooley, L. AllenMississippi State UniversityMississippi. Dept. of Transportation. Research DivisionUnited States. Federal Highway AdministrationNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceUS Transportation CollectionTwelve field projects were studied where forty-four locations were evaluated to assess the cause orcauses of asphalt concrete that exhibits \ue2\u20ac\u2dctender zone\ue2\u20ac\u2122 characteristics (i.e. instability during compaction) and toinvestigate the tendency of these mixes to be susceptible to moisture damage over time. Data was collectedduring construction and samples were taken and used to conduct multiple laboratory tests. All field andlaboratory data was used to develop multiple regression equations to predict final in place air voids and moisturesusceptibility. The overall conclusion from the research was that compactability appeared to be predicted in areasonable manner while moisture susceptibility did not. The Methylene Blue test appears promising when usedin conjunction with moisture content (cold feed and mix moisture contents were measured) as a means ofproviding guidance for achieving higher in place density. The tensile strength ratio (TSR) test as performed inthis research on laboratory compacted specimens was found to be questionable in terms of its ability to predictfield moisture susceptibility