Evaluation of shear bond for double-layer asphalt concrete samples based on shear test

Abstract

Asphalt concrete pavement often appears damaged such as rutting, fatigue crack, potholes, etc. at high air temperature, heavy rain in long time, or at locations with high traffic, large horizontal force, and poor-quality construction sites. This causes a deterioration in the service quality, leading to a lot of maintenance costs. These failures are often related to bond between layers of asphalt concrete. Therefore, this paper shows the evaluation results of shear bond of double-layer asphalt (with tack coat rate of 0, 0.2, 0.5, 0.8 l/m2) based on shear test at the experimental temperatures (25, 40, 60oC), normal pressure (0, 0.14, 0.2, 0.4, 0.6 MPa). The results show that, when the temperature increases from 25oC to 60oC, the shear bond between the asphalt layers decreases sharply. At 25oC, the average shear bond that tested with normal pressure of 0.6 MPa increases by 52.19% compared to that tested at pressure of 0 MPa. When the temperature reaches 60oC, the average shear bond that tested with normal pressure 0.6 MPa increases by 94.87% compared to that tested at 0 MPa pressure. At 25°C, non-tack coat samples have lowest shear bond. However, at 40oC and 60oC, the shear bond of 0.8 l/m2 tack coat-based samples reach the lowest value. At the same time, a regression equation between shear bond and input variables proposed by Minitab V17 software provides high reliability results.