Experimental study on effect of corrosion-induced cracking on bond property between deformed steel bar and concrete

In order to investigate the influences of cover cracking due to corrosion expansion on the bond behaviour between the reinforcing bar and concrete, the pullout test on the bonding specimens with deformed steel bar was designed. The strain gauges were fixed in the interior of deformed steel bars. The accelerated corrosion tests by applying a constant electrical current to the bars by a power supply were used to compare the results that experienced in real RC structures. The reinforcement strains at various positions in bonding specimens with various corrosion-induced cracking widths are obtained. The present study analyzes the effect of corrosion cracking width on strain of reinforcement at different positions. As a result, the bonding stresses at various positions between the reinforcement and concrete are obtained. This paper also develops the relationship between the corrosion cracking width and bonding stress between reinforcement and concrete. The experimental results show that for the specimens with the narrow crack the peak bond stress mainly appears near region of the loading end，however for the specimens with the wide crack the peak bond stress is close to the free end.