Laboratory investigation of cracking resistance performance of the cold-mixed epoxy resin

Cold-mix epoxy resin (CER) is an excellent binder material but with weak crack resistance and brittle failure risk. Therefore, it is of significance to find a feasible parameter to constrain the failure potential. To this end, the dynamic mechanical test, tensile test, volume shrinkage test, fracture test, and scanning electron microscopy (SEM) were used to analyze and evaluate mechanical properties, curing shrinkage, and fracture toughness of the CER. Subsequently, the bivariate correlation analysis was used to feature the relationship among different indicators. The results indicated that the amount of curing agent has a significant influence on the tensile strength, elongation at break, volume shrinkage, fracture toughness, and plastic radius of CER. Meanwhile, there is a close correlation between tensile strength, elongation at break, and fracture toughness. Fracture toughness can be used as an evaluation index to represent the crack resistance of CER, and tensile test can be used as a confirmatory parameter. However, the volume shrinkage of CER cannot be ignored. Small voids distributed on the fracture surface of the CER can increase the toughness and then improve the crack resistance of the CER through SEM analysis.