Pretreatment of Crumb Rubber with a Silane Coupling Agent to Improve Asphalt Rubber Performance

There are known problems of dissolution, consistency of performance, segregation, and instability with the crumb rubber currently used in asphalt for road engineering. A silane coupling agent (KH550) solution was therefore used to pretreat the crumb rubber so as to improve its interfacial characteristics. The effects of KH550 on the properties of asphalt rubber were studied using high- and low-temperature performance tests, temperature sensitivity test, and compatibility test. On the basis of these tests, the optimum concentration of KH550 pretreated crumb rubber is 1.0%. The surface properties and micromodifications of the treated crumb rubber were analyzed using scanning electron microscopy and an infrared spectrometer. The performance and economic benefit of the modified asphalt rubber was compared to styrene-butadiene-styrene (SBS) modified asphalt, and it was found that KH550 pretreated crumb rubber is able to significantly improve the high-temperature performance of asphalt rubber, thus offering notable potential economic benefits.