Study on the relationship between the double-sided shear strength of ECC and the critical fracture toughness of mode II

Abstract

To avoid the risk of Type II fracture failure in building structures under pure shear forces, which involves complex experimental elements and is difficult to effectively control. Therefore, studying the relationship between shear strength and type II critical fracture toughness has become particularly crucial. This article studied the uniaxial ultimate tensile strength, cubic compressive strength, double-sided shear strength, and type II critical fracture toughness of ECC using different mix proportions. The results showed that the initiation strength σfti and ultimate tensile strength σftu of ECC with different ratios were found to be M10 > M1 > M2 > M8 > M3 through tensile tests; The compressive strength of ECC cubes with different mix ratios was obtained as M10 > M1 > M8 > M2 > M3, and compared with Nissan fibers, it was found that the influence of fiber types on the compressive strength of ECC was not significant; Linear fitting was performed on the tensile strength, cubic compressive strength, and double-sided shear strength of ECC, and strong correlations were found. The linear fitting coefficient R2 between shear strength and critical fracture toughness is as high as 0.98, indicating that this fitting relationship curve can further understand the mutual influence between shear strength and critical fracture toughness of ECC at different stress levels, and estimate complex Type II fracture toughness through relatively simple shear strength fs, which helps predict the bearing capacity of the structure and provides theoretical support for the improvement and optimization design of ECC.