High-temperature failure of porous asphalt mixture under wheel loading based on 2D air void structure analysis

• Published in: Construction & building materials Vol. 252; p. 119051
• Main Authors: Ma, Xiang, Zhou, Peisheng, Jiang, Jiwang, Hu, Xuquan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20.08.2020
• Subjects: 2D image analysis; Air void structure; High-temperature failure; Porous asphalt mixture; Wheel tracking test; Porous asphalt mixture; Wheel tracking test; 2D image analysis; High-temperature failure; Air void structure
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.119051

•The 2D image analysis was used to measure the internal structure change during the wheel tracking test.•The long and short axis ratio of air voids presents a growing trend with the increasing loading time.•The freeze-thaw cycles has severe influence on the rutting resistance of porous asphalt concrete. A modified wheel tracking test was produced to investigate the high-temperature failure of porous asphalt mixture under wheel loading. The sectional images of specimens, which were cured in different conditions, were acquired and analyzed by 2D image analysis after different loading times. Air voids with reference to size were divided into small void, medium void and large void. Air void indices in the sectional images, such as void number, total void area (TVA) as well as long and short axis ratio (L/S), were obtained. Based on the multi-factor analysis of variance method, the sensitivity of air void indices to curing conditions and loading times was evaluated, and a linear regression model was produced to investigate the relationship between air void indices and the average rutting depth. The results show that the air void indices including small void number (SVN), small void area (SVA), TVA and L/S were significantly affected by the loading time. The linear regression shows that the product of SVN, TVA and L/S could successfully evaluate the high-temperature failure of porous asphalt mixture during the wheel loading.