Bond behaviour of steel rebar in polyethylene engineered cementitious composites under various load conditions

Abstract

Engineered Cementitious Composites (ECC) are a special type of ultra-ductile fiber-reinforced concrete that uses microfibers. The bond strength of Polyethylene ECC with steel reinforcement was found to be not well investigated in the literature under both monotonic loading and cyclic loading conditions. This study aims to investigate the bond strength properties of Polyethylene ECC with steel reinforcement under monotonic and cyclic loading conditions and to evaluate the effect of embedment length, loading rate, and the cover on bond strength experimentally. The beam-end test was selected for this experiment since it is a relatively simple test, yet it produces a realistic stress field. The results indicated that ECC's main failure mode is splitting-pullout, with high slippages occurring. Furthermore, increasing the cover thickness from 3db to 4db enhanced the bond strength by 91%, while raising the anchorage length from 5db to 7db improved it by 105%. Increasing the load rate from 0.01 mm/s to 32 mm/s resulted in a significant 63% improvement in bond strength. Moreover, ECC performed exceptionally well under cyclic loading, displaying increased peak loads by an average of 76.8% compared to monotonic loading. The study findings are expected to guide the formulation of development length equations and finite element models incorporating ECC.