Factors Affecting the Viscosity of Crumb Rubber-Modified Asphalt

The effect of crumb rubber modifier (CRM) content, CRM particle size, mixing time, and curing temperature on the viscosity of crumb rubber-modified asphalt (CRMA) was studied. The results show that the viscosity of CRMA increases as CRM content is increased, and there is a critical point in CRM content (15%) significantly affecting the increased speed of viscosity. With a decrease in crumb rubber particle size, the maximal viscosity occurring in the entire process increases at first and then decreases. At different curing temperatures, three typical changes of the viscosity of CRMA over mixing time were found. Grey correlation analysis was applied to investigate the sensitivity of each factor influencing viscosity. The significance orders for the factors that influence the viscosity of CRMA are, in turn, CRM content, curing temperature, CRM particle size, and mixing time.