Experimental Investigation on the Effect of Reinforcement Bar Corrosion on Steel Fiber Reinforced Concrete Beam

Abstract

Reinforcement bar corrosion is one of the problems that affect the strength of RC structure. When the reinforcement bar is corroded, it will lose its strength and then the overall design strength of RC structure will be reduced. Currently, this is a major construction industries problem throughout the world. The same is true in Ethiopia; the country lost about 15million ETB for the maintenance of corrosion damaged RC bridges per year. Therefore, it is necessary to investigate the effect of reinforcement bar corrosion in RC structures and the influence of steel fiber addition. The aim of this study is to investigate the effect of reinforcement bar corrosion on SFRC beam. The concrete with an average compressive strength of 25MPa and the reinforcement bar with steel grade S-300 are used. The total of eighteen RC beam specimens with/without steel fiber have taken with 5% and 10% bar corrosion, six cubic specimens for compressive strength test such as 3 plain concrete and 3 SFRC and six cylindrical specimens for splitting tensile test such as 3 plain concrete and 3 SFRC. Data was collected by carefully observing the experimental results. The experimental results shows that, the corrosion of the reinforcement bar which embedded into concrete affects not only the strength of the embedded steel bar but also it affects the strength of concrete which the bar embedded in and the mutual strength that the steel and the concrete which have in common. The experimental result analysis of this study revealed that SFRC beams carry more flexural loads before failure than plain RC beam with similar exposure of corrosion environments. Steel fiber reinforcement which used in this study has an obvious impact on the load capacity, which increased by approximately 14% for the reference beams and, even for those subjected to chloride exposure; all fiber reinforced beams exhibited a greater load at yielding than the reference beams of the plain series such that 35% for 5% corrosion and 15% for 10% corrosion than the reference (plain RC) beams. Therefore, the addition of the steel fiber extracted from used tire into concrete matrix improves the residual flexural strength of the corroded RC beam. In this study only the effect of corrosion of the reinforcement bar on flexural strength of RC beam was considered, but still the corrosion of steel bar has effects on the shear strength of the RC beam, therefore it is recommended to study the effects of corrosion on the shear strength of the RC beam by including shear reinforcement/stirrups in addition to the longitudinal bar.