The cracking characteristics of the polymer-modified asphalt mixture before and after aging based on the digital image correlation technology

To study the effect of thermo-oxidative aging on the cracking characteristics of the crumb rubber asphalt mixture (CR-MA) and the styrene-butadienestyrene asphalt mixture (SBS-MA), the image acquisition of loading processes of the semi-circular bending (SCB) test of two polymer-modified asphalt mixtures was carried out by the digital image correlation (DIC) technology. The horizontal strain of test specimens during loading processes was calculated by the VIC-3D software. The new indexes for evaluating the mesocracking characteristic of asphalt mixtures were proposed. Through the bending beam rheological (BBR) test of asphalt and the contact angle measurement test of asphalt-aggregates, the cracking characteristics of CR-MA and SBS-MA were analyzed from two aspects of cohesion and adhesion failure before and after aging. The results indicated that the new indexes (the horizontal strain density D-E and the horizontal strain toughness J(E)) for evaluating the meso-cracking characteristic of asphalt mixtures had a good correlation with the results of BBR and the contact angle measurement test. The cracking resistance and adhesion of two polymer-modified asphalt were reduced after aging, which led to the decline in the cracking resistance of CR-MA and SBS-MA. The cracking resistance and adhesion of CR-modified asphalt were better than that of SBS-modified asphalt under the same conditions, which meant the cracking resistance of CR-MA was better than that of SBS-MA before and after aging. Compared with SBS-MA, CR-MA had more excellent anti-aging properties. (C) 2020 Elsevier Ltd. All rights reserved.