Effect of microcracking on the shrinkage cracking and durability performance of cement-treated macadam material

Abstract

ABSTRACT This study systematically investigates the effect of microcracking on the shrinkage performance and durability of cement-treated macadam (CTM). Microcracks formed in the early stage of microcracking can reduce reflection cracks generated in semi-rigid base asphalt pavements. The shrinkage characteristics and durability of CTM after microcracking are important to consider in the engineering of the CTM base. In this study, indoor shrinkage tests were conducted on the prepared specimens in ten working conditions, and finite element analysis of the water loss shrinkage of the microcracked CTM was conducted using a cohesive zone model (CZM). The CTM durability after early microcracking was analyzed and evaluated through fatigue tests and freeze–thaw cycle tests. The results showed that the drying shrinkage strain and temperature contraction coefficient of the CTM could be effectively reduced by microcracking. The fatigue life of the CTM decreased with 50% microcracking, but was still within the service requirement. Taking the 104 Chinese road reconstruction project as the research background, microcracking should be conducted 35 d before the freezing period to avoid significantly affecting the frost resistance of the CTM base. This study provides a theoretical basis for the promotion and application of microcracking techniques in practical engineering.