Experimental and theoretical investigation on compression-shear properties of high-strength engineered cementitious composites (HS-ECC)

Abstract

High-strength engineered cementitious composites (HS-ECC) has broad application prospects due to its excellent mechanical performance and durability. Construction materials in structural members are susceptible to combined compression-shear stress. Therefore, the mechanical properties of HS-ECC under the combined stress are experimentally investigated by a servo-controlled biaxial testing machine. The effects of normal stress ratio on the compression-shear properties are systematically studied, and mortar specimens serve as control group. The experimental results show that the shear stress versus shear displacement curves of HS-ECC are able to be divided into four stages, namely linear ascending, non-linear ascending, rapid descending and stable stages. Compared with mortar specimens, the shear strength and residual shear strength of HS-ECC increase by 5–21% and decrease by 33–42% respectively. HS-ECC has a friction coefficient of 0.53, which is smaller than that of mortar specimens and concrete. When the normal stress ratio increases, the dilation angle of HS-ECC decreases at first and then remains basically unchanged. The damage evolution of HS-ECC is delayed when compared with that of the mortar specimen. Finally, a damage constitutive model is proposed to describe the compression-shear properties of HS-ECC. It is found that the predicted results agree well with the experimental results. This study is of great significance to understand the compression-shear properties of HS-ECC and promote its structural applications.