关键词: 初始缝高比, 楔入劈拉试验, 双K断裂韧度, 有效裂缝长度, 混凝土断裂性能

Abstract:

The effect of initial seam-height ratio on concrete’s fracture performance was researched through wedge splitting test. Four groups including 32 specimens with different initial seam-height ratio were tested. The eigenvalues of parameters and the corresponding process curves of complete load, crack opening displacement and concrete surface strain were determined. Fracture parameters inclusive of effective crack length a_c, initial fracture toughness Kⁱⁿⁱ_IC and unstable fracture toughness K^un_IC were calculated based on double-K fracture theory. Results indicate that along with the increase of seam-height ratio, the effective crack length a_c increassd and the subcritical crack propagation length Δa_c reduces; Kⁱⁿⁱ_IC is not affected by the initial seam-height ratio, and K^un_IC increases with the reduction of seam-height ratio, but when a₀/D≥0.5, it can be considered as a constant.

Key words: initial seam-height ratio, wedge splitting test, double-K fracture toughness, effective crack length, concrete’s fracture performance