Characterization of HMA mixtures containing high reclaimed asphalt pavement content with crumb rubber additives : [technical summary].

PDFTech ReportState Project No. 736-99-1574LTRC Project No. 09-1BHot mix paving mixturesAsphalt pavementsRecycled materialsCrumb rubberAsphalt additivesPerformance testsBend testsMix designLouisianaLouisiana Transportation Research CenterKing, BillLouisiana Transportation Research CenterNTL-HIGHWAY/ROAD TRANSPORTATION-DesignNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionWith the increase in hot mix asphalt (HMA) mixtures\ue2\u20ac\u2122 prices continuously climbing, highway agencies and owners are continuallysearching for methods to decrease material costs and maximize their benefi ts with no compromise in performance. One such methodis to develop innovative technology to incorporate waste and recycled materials, such as crumb rubber from waste tires and reclaimedasphalt pavement (RAP), in HMA mixtures. As HMA pavements age over time, the asphalt binders become hardened and oxidizedcausing premature cracking in pavements. Thus, the current limiting factor in increasing the percentages of RAP is the excessivestiff ness of the resulting HMA mixture. Rejuvenating additives are often used to soften the asphalt cement binder of RAP materialsand may enable the use of higher percentages of RAP in the fi nished product. Furthermore, absorption properties of crumb rubbermay be used to carry those additives to revitalize the properties of the aged binders