Experimental study on the mechanical properties of reinforced engineered cementitious composites

The bond between fiber-reinforced composites and concrete plays a critical role in reinforcing concrete structures and composite constructions. The study conducts a comprehensive investigation on the uniaxial tensile behavior of steel-reinforced engineered cementitious composites (ECC) and the bond behavior of reinforced ECC-concrete interface. Fifteen steel reinforced ECC specimens were tested under uniaxial load to experimentally evaluate the effect of reinforcement ratio on tensile behavior. Twenty-seven specimens were tested under double-shear conditions to experimentally evaluate the bond behavior of the reinforced ECC-concrete interface. The experimental results demonstrated that the steel reinforcement can significantly improve the ultimate tensile load of ECC and effectively inhibit the generation and propagation of cracks. Furthermore, a simplified model was proposed to predict the uniaxial tensile behavior of steel reinforced ECC. As the reinforcement ratio, width and thickness increased, the bond strength increased, in which the width and thickness serve as the main contributor to the bond strength. Based on the experimental results, a simplified bond-slip constitutive model for the reinforced ECC-concrete interface was proposed by modifying the existing bond-slip constitutive model, which is shown to be able to accurately describe the bond-slip relationship between reinforced ECC and concrete in ascending stage.