Improving the short-term aging resistance of asphalt by addition of crumb rubber radiated by microwave and impregnated in epoxidized soybean oil

The study was initiated to investigate the anti-aging performance of asphalt modified by crumb rubber impregnated in epoxidized soybean oil (ESO). For this laboratory study, the crumb rubber was radiated by microwave and then impregnated in ESO. The asphalt modified by crumb rubber impregnated in ESO was aged using a rolling thin film oven method (RTFO). The properties of this asphalt were evaluated from the perspective of penetration, softening point, ductility, mass loss and viscosity test. Also, the anti-aging mechanism of asphalt modified by crumb rubber impregnated in ESO was discussed. The results showed that the asphalt modified by crumb rubber impregnated in ESO had an edge over the microwave radiated crumb rubber modified asphalt in terms of high temperature stability, low temperature ductility and anti-aging performance. The reasons are: (1) the polarity oil contained in the ESO can infiltrate into the asphalt and supply oil to the aging asphalt due to oxidation; (2) the compound, which had three-dimensional network structure, was generated when the opening-ring reaction between epoxy bond in ESO and unsaturated bond in asphalt took place. As a result, the compatibility of crumb rubber and asphalt was improved; the structure of cumber rubber modified asphalt was stabilized.