Size effect on tensile strength of interface between coarse aggregate and mortar under freeze-thaw cycle

Abstract

Through the cleavage tensile test and freeze-thaw cycle experiment, the variation of tensile strength of mortar and interfacial bond-splitting tensile strength of coarse aggregate-mortar interface with different specimen sizes under freeze-thaw cycle was studied. The results indicate that the splitting tensile strength of the mortar specimen and the interfacial bond-splitting tensile strength of the coarse aggregate-interface specimen have a significant size effect, and the splitting tensile strength of the coarse aggregate-mortar interfacial specimen is significantly lower than that of the mortar specimen. At the same time, it is found that the statistical size effect model, the multifractal size effect model, and the fracture mechanics size effect model all can well describe the size effect of the split tensile strength of mortar specimens. Finally, considering the splitting tensile strength of standard mortar and the number of freeze-thaw cycles, a two-parameter size effect calculation model for the interfacial bond-splitting tensile strength of the coarse aggregate-mortar interface was established, basing on the Bažant-Xi statistical theory size effect correction formula, which was verified to be universal by experimental data.