A Test Method to Evaluate the Adhesive Property between Asphalt and Aggregate Based on Simulating Actual Working Conditions

Abstract

The adhesive property between asphalt and aggregate is a crucial factor that affects the resistance of asphalt pavement to moisture damage. In this study, by simulating the actual working conditions of asphalt–aggregate bonding characteristics, test equipment was developed and a method for evaluating the adhesive properties between asphalt and aggregate—the brush damage test—was proposed. A steel-wire brush as the brush type, a total of 0.5 kg/m2 asphalt content, 70 °C as the maintenance temperature, and 4 h as the maintenance time, as well as mass loss rate (ML) of specimens before and after brushing, were used as the evaluation index. The brush damage test was conducted on five commonly used asphalt binders and two commonly used aggregates. Finally, the results of the brush damage test were analyzed in comparison with those of a binder bond strength (BBS) test. It was indicated that the evaluation results for the adhesive properties between asphalt and aggregate were not consistent under the two test methods. The pull-off tensile strength under dry conditions (POTSdry) and under wet conditions (POTSwet) when ignoring the influence of the texture of aggregate did not reflect the adhesive properties. ΔPOTS, representing the ability of asphalt to resist the loss of adhesion strength due to moisture damage, can be used to evaluate the adhesion properties between asphalt and aggregate. Under appropriate conditions, the brush damage test has the advantages of simple operation, high credibility, and good discrimination.