High temperature performance of SBS modified bio-asphalt

Crude oil-based asphalt supplies are shrinking while its demand is increasing rapidly; this, in turn, has led to an increase in the price of asphalt binder. As the price of asphalt increases, seeking for alternative and renewable binder resources, such as bio-asphalt, has become a hot research topic. However, the high temperature performances of bio-asphalt are unsatisfactory according to many previous studies. This study aims to enhance the high temperature performance of bio-asphalt by adding SBS into the matrix asphalt. Five types of SBS modified bio-asphalts were studied. Studies included their viscosity, anti rutting performance and temperature sensitivity through the rotational viscometer (RV) and dynamic shear rheometer (DSR). Among them, SBS dosage was 1% of SBS modified bio-asphalt and the 50 penetration grade binder was applied as the base binder. The bio-oil contents for the five types of binders were 0%, 5%, 10%, 15% and 20% by weight of the SBS modified bio-asphalt. It was found that SBS modified bioasphalt had higher viscosity than the base binder to some degree, and the effect of bio-oil on SBS biobinder viscosity was small when the bio-oil content and testing temperature were high. The mixing and compaction temperatures of SBS modified bio-asphalt were about the same as those of the 50# base binder when the bio-oil content was more than 10%. Before RTFO testing, the SBS bio-binder had more viscous characteristics and a lower anti-rutting performance, but was not significantly different from that of the base binder. However, an opposite trend was observed after the RTFO test. Meanwhile, SBS biobinder was less sensitive to temperature than the base binder and such sensitivity decreased with the increase in bio-oil content before RTFO. After RTFO, the temperature sensitivity of the SBS bio-binder was still lower than that of the 50# base binder when bio-oil content was less than 20%, and grew with the increase in bio-oil content. (C) 2017 Elsevier Ltd. All rights reserved.