Interface bonding between hot-mix asphalt and various portland cement concrete surfaces laboratory assessment

Interface bonding between hot-mix asphalt (HMA) overlays and port-land cement concrete (PCC) pavements can be one of the most significant factors affecting overlay service life. In this study, a direct shear test device was built and used to investigate the characteristics of the HMA-PCC interface and to determine the interface shear strength. Several parameters affecting the interface performance were included in this study, such as HMA type, tack coat type, tack coat application rate, PCC surface texture, and temperature. The test results showed that the use of SS-lhP emulsion resulted in a greater interface bonding strength than the use of RC-70 cutback. Surface mix SM-9.5 was found to have a better interface strength than binder mix IM-19.0. Among the four residual application rates considered in this study, 0.05 gal/yd² was found to be the optimum rate, independent of test parameters. The direction of timing in the PCC surface was found to have no effect on interface shear strength at 20°C. At the optimum tack coat application rate, the PCC smooth surface showed a higher interface shear strength than tined surfaces. When tests were performed at the intermediate temperature range, as the temperature increased, the interface bonding strength decreased.