Investigation on the cohesion and adhesion behavior of high-viscosity asphalt binders by bonding tensile testing apparatus

The cohesion and adhesion behavior (CAB) in binder-aggregate interface are statistically related to asphalt pavement performance. Although numerous test methods have been developed to evaluate the CAB, the difficulties, such as the classification on failure types of CAB and decisions on test results, still need to be further investigated. In this study, a novel bonding tensile testing apparatus (BTTA) was proposed to investigate the feasibility of distinguishing CAB. Four types of high-viscosity asphalt binders were employed to test their CAB by BTTA, and the results were evaluated by stress-strain curves, tensile (yield) modulus, and fracture (yield) energy. The test reproducibility and influencing factors of BTTA were also investigated. Moreover, a comparison of CAB test results and a validation via the moisture sensitivity of porous asphalt concrete 13 mixtures were made. Results of good reproducibility show BTTA can well distinguish CAB. Thanks to this distinguishability, the decision criteria on validity of test results could be developed. The comparison of CAB test results show that it is of great necessity to distinguish cohesion and adhesion tests for more accurate results. Additionally, results of moisture sensitivity revealed the CAB results could well reflect the moisture sensitivity of asphalt mixture. The significance of this study lies in developing and validating a practical and effective way to distinguish the CAB in binderaggregate interface. (C) 2020 Elsevier Ltd. All rights reserved.