Influence of interface bond strength on fracture resistance of geosynthetic-reinforced asphalt

Abstract

The incorporation of geosynthetic reinforcements during the rehabilitation of flexible pavements has significantly increased due to the ability of geosynthetic reinforcements to minimize reflective cracks. However, the performance of the geosynthetic-reinforced asphalt depends on the interface bond strength between the geosynthetic and the adjacent asphalt layers. Tack coat is generally used to maintain adequate bonding between the geosynthetic-reinforced asphalt layers. This study focusses on evaluating the influence of interface bond strength on the fracture resistance of geosynthetic-reinforced asphalt utilizing a new testing approach. The fracture resistance of geosynthetic-reinforced asphalt specimens was evaluated via cross-shear testing device, while interface bond strength was evaluated using interface shear strength testing. A Performance Grade (PG) 64-22 binder was applied as a tack coat at the geosynthetic-asphalt interface at four different rates that are relative to the asphalt retention capacity of the geosynthetic reinforcement. A fiberglass geocomposite was used as geosynthetic reinforcement in this study. The results indicate a correlation between interface shear strength tests and cross-shear tests, suggesting that the optimum tack coat rate is 125% of the asphalt retention capacity of the geosynthetic reinforcement to improve the fracture resistance as well as the interface bond strength of geosynthetic-reinforced asphalt layers.