Effects of Curing Time and Reheating on Performance of Warm Stone-Matrix Asphalt

AbstractThe effects of curing time and reheating on the short-term performance of stone-matrix asphalt (SMA) mixtures with various warm-mix additives (i.e., Evotherm, Sasobit, and foamed asphalt) was evaluated in laboratory performance tests. The laboratory tests included complex modulus, loaded wheel track, indirect tensile (IDT) strength, and semicircular beam (SCB) fracture. In the tests, plant-produced mixes that were sampled from a field overlay project were compacted in the laboratory with and without reheating, and performance tests were conducted at various curing times after compaction. The effect of curing time on mixture characteristics was dependent on the mixture type and performance test considered. The mixtures containing warm-mix additives showed similar variations in mixture properties due to curing time compared to the control mixture. The reheating process caused asphalt mixtures to have greater modulus, tensile strength, and rutting resistance but smaller fracture resistance. Among the mixtures containing various warm-mix additives, the mixture containing Sasobit showed the relatively smallest changes in mixture properties attributable to reheating. Finally, it was discovered that the warm SMA mixtures showed variations in different performance characteristics, depending on the type of warm-mix additives and recycled materials, than the control mixture.