Affiliation:
1. Civil Engineering Department, College of Engineering, University of Sulaimani, Sulaymaniyah 46001, Iraq
2. Civil Engineering Department, College of Engineering, University of Duhok, Duhok 42001, Iraq
Abstract
The most severe distresses in asphalt pavement are rutting, fatigue, and low-temperature cracking; therefore, to solve these problems, it is essential to modify asphalt binders in asphalt concrete mixtures. In this study, a comparison between using styrene-butadiene-styrene (SBS) and crumb rubber (CR) as modifiers for asphalt binders to overcome distress issues was conducted. Base and SBS or CR-modified binders were subjected to all conventional and Superpave binder tests. Engineering tests such as the Hamburg wheel tracker and indirect tensile strength ratio were also run to evaluate the engineering properties. The used SBS percentages were 1, 2, 3, 4, and 5%, while CR percentages were 3, 6, 9, 12, and 15% by total weight. The results showed lower penetration, higher softening point, viscosity, and elastic recovery for both additives. In addition, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests showed increasing values of both high and low temperatures of modified asphalt performance grade (PG) with increasing SBS or CR percent. The tensile strength ratio and Hamburg wheel tracker results showed the best engineering properties at 3% SBS or 9% CR, the optimum percent. A triple percentage of CR is needed to get the same effect of SBS for the asphalt mixture.
Subject
Management, Monitoring, Policy and Law,Renewable Energy, Sustainability and the Environment,Geography, Planning and Development,Building and Construction