Laboratory Evaluation on Performance of Crumb Rubber SMA
Crumb rubber modified (CRM) asphalt with crumb rubber of scrap tire has higher viscosity, better flexibility, outstanding anti-fatiguing and anti-aging properties. This paper mainly investigated material design and performance evaluation of CRM asphalt SMA mixture. Brookfield Viscosity test is used to ascertain the adoption of fiber in CR-SMA. Because of resilient volume swelling of asphalt rubber mortar, gap-coarse grade must be adopted in asphalt rubber concrete to provide enough free space. This paper amends material composition and grade proportions range of adapted CR-SMA depending on the special characteristic of CRM asphalt. After confirming best grade of CR-SMA, this paper adopted Marshall Method to design Job Mix Formula (JMF) of surface layer CR-SMA13 in Beijing airport south line expressway. The best CRM asphalt content and feasible gradation middle value were obtained by Marshall Test and volume parameter calculation. During performance evaluation phase, other two SMA usually used in Beijing region is added, including SBS modified asphalt SMA, Trinidad Lake asphalt (TLA) and SBS modified asphalt SMA. By evaluations of high temperature performance, low temperature performance, moisture sensitivity and so on. The results indicate that pavement performance of CR-SMA is excellent, and have no distinct difference compared with the other two SMA.
Y. M. Dong and Y. Q. Tan, "Laboratory Evaluation on Performance of Crumb Rubber SMA", Advanced Materials Research, Vols. 168-170, pp. 1749-1755, 2011