Autogenous self-healing properties of cement-stabilized macadam after microcracking

• Published in: Construction & building materials 2021-03, Vol.273, p.121737, Article 121737
• Main Authors: He, Miao, Yu, Zhonghui, Ma, Shibin, Kang, Aizhong, Zhang, Jing
• Format: Article
• Language: English
• Subjects: Autogenous self-healing; Cement-stabilized macadam; Mechanical properties; Microcracking; Microstructure
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.121737

•A control model for microcracking degree was established based on RSM.•The changes during the healing process were characterized quantitatively.•The microcracking degree had a more significant effect on healing characteristics.•CSM possesses good self-healing properties after precracking. Microcracking techniques can be applied to reduce the shrinkage stress of cement-stabilized macadam (CSM) and prevent cracking of the base course. Meanwhile, the microcracks will gradually heal without serious impact on the pavement during the base curing. In this study, a control model for microcracking degree under the coupling conditions of microcracking load, microcracking time and material properties was established according to the response surface method (RSM). Then specimens with ten working conditions were produced and tested to analyze the effects of microcracking time and degree on the healing of mechanical properties and mesoscopic structure, and the changes during the healing process were characterized quantitatively. The results showed that the degree of microcracking had a more significant effect on healing characteristics compared with the microcracking time. Microcracking was best controlled at 40%, and microcracking at 2 days of curing was relatively optimal. In addition, the final product coverage of the specimens with the microcracking degrees (30%, 40%, 50%) could exceed 90%. The analysis indicates that CSM possesses good self-healing properties after precracking.