Uniaxial tensile constitutive relations of basalt textile-reinforced concrete with different grid sizes

Abstract

Textile-reinforced concrete (TRC) is a widely used cement-based composite material reinforced with textile that can be utilized effectively in the construction of thin and lightweight structures. However, its mechanical properties are greatly affected by changes in grid size. In this research, four groups of 48 specimens with different grid sizes are subjected to uniaxial tensile tests on basalt TRC (BTRC) sheets to study the effect of grid size on the tensile performance of BTRC and analyze the failure modes of BTRC sheets at macro- and meso-scales. The Aveston–Cooper–Kelly (ACK) model and finite element simulation are combined to verify the applicability of the ACK model to the stress–strain constitutive relationship equation in the pre-fracture stage of the BTRC sheet underuniaxial tensile test. With the triple linear model, the bond–slip constitutive equation of the whole process of the uniaxial tensile test on the BTRC sheets is deduced. Results show that the BTRC sheets exhibit obvious strain-hardening characteristics under tensile load. The failure mode of the BTRC sheets is typical debonding failure, and the smaller the grid size is, the more microcracks are developed by a single crack. The basalt textile cannot significantly improve the cracking strength of the concrete matrix, but it can effectively increase the ultimate tensile strength of the component. A small grid size equates to good tensile strength and bonding behavior and therefore endows the material enhanced ductility. The bond–slip constitutive equation for the whole process of uniaxial stretching of BTRC sheets is established, and the ACK and triple linear models show good applicability to the solution of the constitutive relationship of the BTRC sheets’ uniaxial tension.