Determination of J-integral of asphalt concrete based on SC(B) test configuration and image analysis

The J-integral of asphalt concrete is usually measured with multiple specimens used for fracture tests because crack growth is not usually monitored during the fracture test. This research uses an industry digital image camera to monitor the crack growth during the Semi-Circular Bend [SC(B)] fracture test for asphalt concrete. The crack length extension during the SC(B) fracture test is then calculated after testing by an image analysis method. Therefore, a single specimen method based on the SC(B) test configuration and image analysis is proposed to determine the J-integral of the asphalt concrete. The effects of test temperature, Nominal Maximum Aggregate Size (NMAS), binder type and loading rate on J-integral of asphalt concrete are investigated. The same factors' effects on fracture energy of asphalt concrete are also studied to detect the difference between the J-integral and fracture energy in quantifying fracture resistance of asphalt concrete. The following conclusions are made in this study: (1) J-integral can be measured using the SC(B) test configuration and image analysis method. (2) Test temperature and NMAS are the two significant factors which impact the J-integral of asphalt concrete. (3) The effect of NMAS on J-integral has the opposite trend compared to the effect of NMAS on fracture energy. (4) The polymer modification of binder and the loading rate affect the J-integral, but the effects are not statistically significant. (C) 2020 Elsevier Ltd. All rights reserved.