Experimental study on the correlation between mechanical properties of concrete and interface strength of coarse aggregate mortar under freezing-thawing

The frost resistance of concrete is an essential evaluation index in cold areas; however, quantitative analyses of macroscopic mechanical properties and interfacial strength of concrete under freeze-thaw (F-T) action are scarce. Based on rapid F-T cycle tests of concrete, mortar, and interface specimens, with limestone, quartz, and basalt as variables, the internal damage and basic mechanical properties of specimens under F-T action were obtained. Furthermore, the quantitative relationship between the mechanical properties of the specimens, and between the internal damage and the basic mechanical properties of specimens under F-T action was established. The results showed that the properties of a coarse aggregate-mortar interface affected the mechanical properties and frost resistance of concrete specimens to a certain extent. After F-T action, the internal structure of the specimen tended to be loose, and the specimen was in a frozen state. The degree of damage on concrete specimens was more substantial than that on mortar ones. Quantitative analysis also indicated that the F-T erosion of concrete was mainly caused by the damage in the interface transition zone between the coarse aggregate and mortar.