Comprehensive evaluation of the long-term performance of rubberized pavement, phase I : laboratory study of rubberized asphalt mix performance.

PDFTech ReportFHWA-GA-12-1119Asphalt rubberCrumb rubberHot mix paving mixturesPorous pavementsStone matrix asphaltPavement performanceLaboratory testsDurabilityRuttingGeorgiaGeorgia. Department of Transportation. Office of ResearchShen, JunanXie, ZhaoxingGeorgia Southern UniversityUnited States. Federal Highway AdministrationUS Transportation CollectionCrumb rubber, made from scrap tires, has been introduced into the production of different types of hotmix asphalt (HMA) in either a wet or dry process. In the wet process, the crumb rubber and binder arecompletely mixed to form asphalt rubber (AR), which is then mixed with aggregates in a drum. In thedry process, the crumb rubber is mixed directly with aggregates in the drum to produce an HMAcalled rubberized asphalt mix. This paper examines the long-term performance of porous Europeanmix (PEM) and stone matrix asphalt (SMA) pavements to which crumb rubber was added in the dryprocess. Test sections were visually inspected for surface distress, following the guidelines in theGeorgia Department of Transportation (GDOT) Pavement Condition Evaluation System (PACES)manual. Core samples were evaluated in the laboratory on selected physical and durability properties,including the void ratio, permeability, density, Cantabro loss, and Marshall stability Visual inspectionresults show that the performance of rubberized pavement almost equals that of polymer-modifiedPEM with no rutting, raveling, or cracking, while the Cantabro test showed a higher mass loss after 3years\ue2\u20ac\u2122 service. After 5 years\ue2\u20ac\u2122 service, the rubberized pavement performed slightly better to ruttingdepth, while other visual indicators remained the same. The rubberized SMA pavement had slightlyhigher Marshall stability and lower flow than the control SMA pavement, with similar effects on thepolymer-modified PEM\ue2\u20ac\u2122s surface performance