An experimental study on bond behaviors of reinforced concrete under fatigue loading and corrosion

Abstract

Corrosion and fatigue loading would inevitably degrade bond between rebar and concrete. However, there were only a few related test results available, and confinement of rebar was different from case to case. An experimental study was conducted to investigate the combined effects of corrosion and fatigue loading on bond behaviors between strong confined rebar and concrete.A total of 72 cube specimens with 13 target corrosion levels from 0% to 30% with a step of 2.5% were made and tested. Seven specimens were tested with monotonic pull-out load. Sixty-five specimens were tested with fatigue loads and divided into two groups according to corrosion level with two different loaded upper limits. Bond strength, corresponding slip value, residual slip value, and residual bond stress of tested specimens with different corrosion levels and stress levels are studied. Three typical failure modes were observed during fatigue loading processes: rebar fracture, bond fatigue failure, and pullout splitting failure, respectively. Test results indicated the residual slip continued to accumulate under fatigue load, and corrosion further increased the residual slip value. Specimens began to show bond fatigue failure when the actual stress level was >50%. The results of this study can provide reference for service life evaluation of reinforced concrete structures in coastal area under repeated loading.