Local Bond Stress-Slip Models for Reinforcing Bars and Prestressing Strands in High-Peformance Fiber- Reinforced Cement Composites

Abstract

This paper discusses previous studies that use pullout-type tests comprising monotonic, unidirectional cyclic, and reversed cyclic loads have shown that bond between reinforcing bars/prestressing strands and concrete can be significantly enhanced by replacing the conventional concrete with high-performance fiber-reinforced cement composites (HPFRCCs). This can be attributed to the fact that, compared to plain concrete and conventional fiber-reinforced concrete (FRC), HPFRCCs exhibit a strain-hardening response under tension up to large strains, thereby preventing the concrete from deterioration under bond action. Pullout test results provide the bond stress versus slip relationship that can be considered the constitutive property of the steel-to-HPFRCC interface. Since the post-cracking tensile stress and strain of fiber-reinforced cement composites are the fundamental characteristics that distinguish them from conventional concrete, the HPFRC tensile stress-strain response obtained from direct tensile tests was used to derive the local bond stress-slip models presented in this paper. This paper shows that the proposed models are more concise than previous models suggested for FRC and give good agreement with test results.