Bond Performance of Steel-Reinforced Polymer (SRP) Subjected to Environmental Conditioning and Sustained Stress

Abstract

Concrete beams reinforced with a steel-reinforced polymer (SRP) strengthening system were subjected to environmental conditioning with and without stress. They were subjected to environmental cycling in an environmental chamber that simulated the exterior weather of the Midwest United States. Two types of steel fibers (galvanized and brass-coated steel fibers) were investigated in this study. These SRP specimens experienced a series of freeze-thaw, varying temperature, and humidity cycles to experimentally investigate the influence of the accelerated aging environmental conditioning on bond performance between SRP strengthening system and concrete substrate. Flexural bending tests and direct pull-off bond tests were performed to evaluate the long-term bond performance of SRP-to-concrete interfaces. The flexural bending test results illustrated that the bond behavior between SRP and concrete was affected by the environmental cycling. The results of pull-off tests were scattered. This high variability was related to several issues including the nonhomogeneous characteristic of the concrete, applied load rate using a hand applied loading method, and the variable test method. The direct pull-off test was deemed to be a less reliable methodology to capture bond degradation than the flexural bending test.