The comparison of the healing performance of polyurethane-modified bitumen mixtures

Considering much distresses occurring at the surface of the asphalt roads, self-healing phenomenon attracted much attention because of reducing the road surface distresses and its benefits. The use of polymers, which are mainly used to improve the properties of asphalt mixtures, is one of the ways to increase self-healing properties. In this study, four polymer-modified bitumen mixtures were made applying the most common polyurethanes (by combining three different types of polymers and a nanographene particle). Then the mixtures were exposed to long-term aging under PAV to be evaluated in situations where less healing occurs. Finally, by performing a time sweep test and measuring the shear complex modulus (G *) before and after the rest period, the healing rate of these mixtures was measured and compared. By examining the results, it was found that the TDI-CO polymer-modified mixture is the best mixture for bitumen healing.