Effect of SBS and crumb rubber on asphalt modification: A review of the properties and practical application

Owing to the environmental protection potential and the desirable high performance capabilities, asphalt rubber (AR) and styrene-butadiene-styrene (SBS) modified asphalt have been widely used. However, the poor construction workability and segregation issues of AR, along with the exorbitant cost of SBS modified asphalt, are of the serious problems that plague their application scope. Moreover, SBS/crumb rubber (CR) modified asphalt is gradually becoming widespread and it therefore becomes incumbent to find appropriate ways to mitigate the issues that may limit its use. As a consequence, it becomes crucial to analyze the interaction between CR and SBS modifiers in the composite mixture, as well as evaluate the influence of modifier dosage on the performance of the modified asphalt. This study presents a comprehensive review of the effects of SBS modifier, CR modifier and composite SBS/CR on the performance of modified asphalts. Macro analysis and micro analysis, including analysis on the conventional physical properties, are carried out. It can uncover the interaction between modifier and asphalt, which reveals how the modifiers influence the properties of modified asphalts. This study will serve as a source of invaluable information to researchers, engineers, and designers, informing them the development, potential and challenges of the CR, SBS and SBS/CR modified asphalts, the optimum contents to attain the best performance along with the mechanism involved.