Chemical characteristics of bio-asphalt and its rheological properties after CR/SBS composite modification

The non-renewable characteristics and growing demand for crude oil is prompting the development of alternative materials such as bio-asphalt for pavement engineering. In this study, the chemical compositions of bio-asphalt extracted from castor marked as SHB were evaluated by elemental analysis, infrared spectroscopy and molecular weight distribution analysis. Results revealed that the chemical compositions of SHB bio-asphalt were similar to those of petroleum asphalt, yet the former cannot be directly utilized in pavement construction. Therefore, crumb rubber (CR) and styrene-butadiene-styrene block copolymer (SBS) additives were incorporated into petroleum asphalt blended with bio-asphalt to prepare composite modified asphalt. The ultimate high- and low-temperature performances of the proposed composite modified asphalt indicated that the percentages of raw additive materials were 15% for SHB, 18% for CR and 2% for SBS. Rheological properties were further evaluated using master curves and Han curves, which have been found that SHB addition benefited the high- and low-temperature performances of the CR/SBS composite modified asphalt. (C) 2018 Elsevier Ltd. All rights reserved.