ABSTRACT
Employing Rubber Modified Asphalt (RMA) into pavement construction becomes increasingly popular. Research on the ageing mechanism of RMA can provide theoretical and technical support for prolonging its service life. RMA is a kind of blend, and its ageing mechanism is complex. However, most studies are limited to the macroscopic variations in the blend properties between pre—and post-ageing. Therefore, further progress need to be achieved from a new perspective. Rubber Powder Modifier (RPM) is an important component of RMA, but its behavior characteristic has received little attention during ageing process of RMA, which provides direction for this study. The Pressurized Ageing Vessel (PAV) test, enriched by different time gradients (0 h, 10 h, 20 h, 40 h, 60 h, 80 h), was conducted to prepare RMA samples at different ageing extents. Subsequently, the RPMs were extracted from their corresponding RMA samples by trichloroethylene. To investigate the behavior characteristic of RPM, tests on extraction content, crosslink density and apparent morphology were conducted. Results indicate that RPM degrades obviously with the ageing of RMA. In addition, Infrared (IR) spectrum was used for correlation analysis. It is found that the S = O (sulfoxide group) index of RPM has a dramatic increase during the RMA oxidation, and the oxidation behavior of RPM is consistent with that of RMA.
