Effect of aging, testing temperature and relative humidity on adhesion between asphalt binder and mineral aggregate

The adhesion between asphalt binder and mineral aggregate directly determines the performance of asphalt pavement, which could be effected significantly affected by light, oxygen, water and other natural conditions. In order to investigate the effect of different environmental conditions on the adhesion between asphalt binder and mineral aggregate, virgin asphalt binder with 70 (0.1 mm) penetration and SBS modified asphalt before and after aging were used as test samples in this study. The effect of aging, testing temperature and relative humidity on adhesion between asphalt binder and mineral aggregate was quantitatively analyzed by using the surface energy theory. The results show that aging reduced the content of resin, increase the content of asphaltene, which resulted in the deterioration of adhesion performance of asphalt binder. The anti-aging performance of SBS modified asphalt was better than virgin asphalt binder in terms of adhesion. The work of adhesion between asphalt binder and mineral aggregate increased when the testing temperature of asphalt binder increased from 0 °C to 80 °C. The work of adhesion between virgin asphalt binder and material aggregate increased much higher than SBS modified asphalt. Asphalt binder was not sensitive to the change of relative humidity, but the total amount of surface energy parameters of the mineral aggregate decreases linearly with the relative humidity increasing. The work of adhesion between asphalt binder and granite aggregate was more likely to be affected by external gaseous water molecules. In order to simulate the real hydrodynamic pressure, the pull-off test was improved by adding ultrasonic wave. The ultrasonic tests' results show that the water invaded the interface between asphalt binder and material aggregate, accelerated the adhesion failure. A strong linear correlation exists between the work of adhesion and the ultrasonic pull-off strength.