Fracture Behavior of Semiflexible Pavement Containing Cement Asphalt Emulsion Paste

Abstract

Semiflexible pavement (SFP) is gradually gaining more attention for its excellent rutting resistance and high load-bearing capacity. However, cracking damage is one of the most challenging distresses in SFP due to the brittle behavior of cement paste (CP) and insufficient adhesion between porous asphalt matrix (PAM) and hardened CP. In this study, the cement asphalt emulsion paste (CAEP) was introduced as a grouting material for SFP to overcome the shortcomings of CP. Therefore, the effect of CAEP on the cracking resistance of the SFP was studied by conducting a semicircular bending test and obtaining the full-field displacement and strain of the specimen during the whole loading process through digital image correlation (DIC). The maximum average value of full-field tensile strain was proposed to accurately determine the specimens’ fracture failure point for calculating fracture parameters. Results indicated that DIC data could identify the three fracture phases of SFP materials (i.e., crack initiation, crack propagation, and failure) precisely. In addition, incorporating the asphalt emulsion in the cement grout significantly improved the SFP material’s fracture performance by increasing the fracture energy, J-integral (Jc), and cracking resistance index (CRI) values on average by 48%, 76.1%, and 43% in SFP with CAEP20 and by 13.4%, 45.7%, and 87% in SFP with CAEP40, respectively. Overall, CAEP with an asphalt emulsion content between 20% and 40% by weight of cement is recommended as the best grout in SFP to obtain the best cracking resistance.