Effect of Rejuvenating Agent on the Pavement Properties of Cold Recycled Mixture with Bitmen Emulsion

A traditional cold recycled mixture with bitumen emulsion (CRMB) has a relatively low cracking resistance and moisture susceptibility, which greatly limits its application scope. A rejuvenating agent was employed to improve the pavement properties of CRMB. To avoid the rejuvenating agent having an adverse effect on the new bitumen, reclaimed asphalt pavement (RAP) was firstly treated by the rejuvenating agent, and the effect of rejuvenating time on the pavement properties of CRMB was investigated. Results indicate that the addition of a rejuvenating agent can greatly improve the ductility and moisture susceptibility of CRMB. Meanwhile, although the rejuvenating agent can soften aged bitumen, the addition of a rejuvenating agent can still increase the indirect tensile strength of CRMB and does not greatly reduce the rutting resistance of CRMB. This phenomenon exists because the rejuvenating agent can be both beneficial to the membrane structure of the bitumen emulsion mastic and aged bitumen. It can also greatly improve the bonding interface between RAP and the bitumen emulsion mastic. The rejuvenating time between RAP and the rejuvenating agent can affect the pavement properties of CRMB. To obtain better pavement properties, the optimum recommended rejuvenating time is between 5 and 7 days. Overall, the addition of rejuvenating agent can be a good choice to improve the pavement properties of CRMB.