Review of the bond behavior between reinforcing steel and Engineered cementitious Composites

The bond between reinforcing steel and concrete is critical for the optimal performance of reinforced concrete (RC) structures. The same applies to structures incorporating short, randomly-distributed fibers in the cementitious matrix, such as Fiber Reinforced Concrete (FRC) and Engineering Cementitious Composites (ECC). Several studies have investigated the bond strength between steel and ECC because of the high ductility, energy absorption capacity, and damage tolerance of the latter. The present article reviewed several studies that investigated the steel/ECC bond strength. The studies showed that the steel/ECC bond outperformed conventional RC under both monotonic and cyclic loading conditions. The review revealed that more research was conducted using ECC mixes containing 2% Polyvinyl Alcohol (PVA) fibers than other types of fibers. Data from numerous papers discussing the steel/ECC bond with ECC mixes containing 2% PVA fibers were collected, and a bond strength predictive model was proposed. Majority of studies yielded consistent results about the correlation between bond strength and critical specimen parameters. It was found that increasing the ECC compressive strength, cover thickness, reducing the rebar diameter and shortening the embedment length all led to an improvement in bond strength. Based on the results of the literature review several recommendations for future research on the steel/ECC bond behavior are proposed.