Assessment of bonding behaviours between ultrathin surface layer and asphalt mixture layer using modified pull test

Abstract

This research used a modified pull test to characterize the bonding behaviour between ultrathin surface layer and underlying asphalt mixture layer. Epoxy-modified bitumen (EMB)-based surface layer, resin-based surface layer and cement-based surface layer were used to investigate the applicability of the self-designed pull test. These three types of ultrathin surface layers represent ultrathin surface layers with different stiffness values. Finite element method was performed to investigate the function of included circular cut during the specimen preparation. The pull tests were conducted at 0, 10 and 20 °C, under loading speed of 0.025 MPa/s. The test results indicated that the proposed pull test can be used to evaluate the bonding behaviours between ultrathin surface layer and asphalt mixture layer. But it is not suitable to test the adhesive strength at the interface when the interface is not the weakest area. Research results further illustrated that the EMB-based ultrathin surface layer can provide the best adhesive properties.