Date of this Version
Report # MATC-KSU: 452 Final Report 255--1121-0001-452
A recent rise in asphalt binder prices has led state agencies and contractors to use higher quantities of Reclaimed Asphalt Pavement (RAP). Besides being economic, sustainable, and environmentally friendly, RAP can be replaced for a portion of aggregates in Hot Mix Asphalt (HMA) where quality aggregates are scarce. In this project, the effect of increasing RAP percentage and using fractionated RAP (FRAP) in HMA mixture on moisture resistance, rutting, and fatigue cracking were evaluated. Mixtures with five different RAP and FRAP contents (20%, 30%, and 40% RAP, and 30% and 40% FRAP) were studied. The Hamburg Wheel Tracking Device (HWTD) Test (TEX-242-F), Kansas Standard Test Method KT-56 or modified Lottman Test, and Dynamic Modulus Test (AASHTO TP: 62-03) were used to predict moisture damage, rutting potential and fatigue cracking resistance of the mixes. HMA specimens were prepared based on Superpave HMA mix design criteria for 12.5 mm (1/2 inch) Nominal Maximum Aggregate Size (NMAS) and compacted using the Superpave gyratory compactor. Results of these tests showed that although mixture performance in the laboratory tests declined as the percentage of RAP increased in the mix, even mixtures with 40% RAP passed the minimum requirements in commonly used tests. When RAP is compared with FRAP, FRAP does not seem to improve performance of the HMA mixtures. This was largely confirmed by the statistical analysis. Mixtures with RAP performed more or less the same as or better than the mixtures with FRAP.