Experimental study and mechanics model of ECC-to-concrete bond interface under tensile loading

Abstract

This work aims to investigate the effects of construction method and compressive strength of engineered cementitious composite (ECC), PVA fiber type, and interface roughness on the tensile performance of ECC-to-concrete interface with both experimental study and mechanical model. Two failure modes (i.e., interface debonding and concrete fracture) were observed in the experiment. The failure modes were significantly affected by interface roughness and ECC compressive strength, but the failure modes were slightly affected by PVA fiber types and construction methods. All load–displacement curves were similar, which means the change of curves were almost unaffected by the four studied parameters. The interface roughness value was defined and utilized to quantify interface roughness. With the increase of interface roughness value and ECC compressive strengths, interface bond strength increased significantly. While the types of PVA fiber had no effect on interfacial tensile strengths. An interface mechanical model was proposed to predict interface tensile strength, and a failure criteria of the interface was established to determine the failure modes based on the interface roughness value. The experimental results were in good agreement with the analysis results, indicating that the proposed model can be used to predict the interface bond strength and determine the failure modes.