Experimental evaluation of crumb rubber and polyethylene integrated modified asphalt mixture upon related properties

Abstract

Due to the dramatic increase in traffic volume, asphalt pavements deteriorate gradually with the high-temperature rutting and low-temperature thermal cracking as two main failure modes. This paper focuses on the integrated modification of bituminous binders and asphalt mixtures with the aspect of improving the performance of asphalt pavement at both high and low in-service temperatures. The recycled crumb rubber (CR) and polyethylene (PE) were chosen as polymer agents in order to modify the bitumen property. Analysis on the rheological performance of modified bitumen indicated the addition of CR decreased the bitumen creep stiffness at low-temperature which in turn reduced the brittleness and cracking risk. Meanwhile, the addition of PE increased the bitumen stiffness at high-temperature which resulted in improved rutting resistance. With respect to the integrated modified bitumen, the addition of CR and PE cooperatively improved the bitumen properties at both high and low temperatures. In terms of the asphalt mixture, PE contributes to the permanent deformation resistance at high in-service temperature while the CR enhanced the flexibility at low in-service temperature. The integrated modified mixture prepared with CR and PE obtained significantly enhanced performance at both high and low in-service temperatures. Consequently, utilisation of these two recycled materials is able to improve the pavement properties reached to or even better than those prepared with styrene-butadiene-styrene modified bitumen.