Durability of warm mix asphalt containing recycled asphalt mixtures

To potentially employ warm mix asphalt containing recycled asphalt mixture (WRAM) in pavement, aging tests, freeze-thaw cycle splitting tests, and fatigue tests were conducted to investigate the durabilities of WRAM produced using two chemical warm mix additives and the hot mix asphalt containing recycled asphalt mixture (HRAM). Both short-term and long-term aging were taken into account in the aging tests. Water stability and low temperature cracking resistance of aged mixtures were evaluated. The results show that WRAM suffering from the short-term aging exhibits a slight increase in the tensile strength ratio (T_SR), compared with the unaged WRAM, whereas the long-term aging results in a distinct reduction in the T_SR. Maximum bend tensile strains of the WRAM after short-term and long-term aging exhibit much more decrease than that of the unaged WRAM. The T_SR of the WRAM generally decreases with the increase of freeze-thaw cycles, however, the T_SR displays an obvious increase after three freeze-thaw cycles. After five freeze-thaw cycles, the WRAM exhibits a remarkable decrease in the T_SR. The fatigue lives of the WRAM and HRAM have similar sensitivity to the change of stress ratio. The WRAMs with two warm mix additives displays difference in the durability, whereas the WRAM has higher durability than that of the HRAM.