Experimental study on the effect of corrosion on shear strength of fibre-reinforced concrete beams

Abstract

In the present study, nineteen beam specimens with a dimension of 10 × 15 × 130 cm were prepared to investigate the shear behaviour of steel fibre-reinforced concrete (SFRC) beams exposed to corrosion. The tensile reinforcements of the specimens were subjected to 7% and 20% corrosion rates. Steel fibres in volume fractions of 0.8%, 1.2%, and 1.8% were added to concrete matrices. Six of the beam specimens were mixed with pre-corroded steel fibres at a corrosion level of 50% to study the hybrid effect of their corrosion and the longitudinal reinforcement on shear performance. The test results showed that adding the fibres improved the shear capacity, and reduced crack initiation and propagation due to corrosion, mode of failure, and deflection. The shear capacity of the non-corroded SFRC beams increased by about 68%, 72%, and 82% for the 0.8%, 1.2%, and 1.8% volume fractions of steel fibre, respectively, compared to RC beams without fibre. Also, the mode of failure changed from brittle shear failure to ductile flexure failure for SFRC beams. A 1.8% volumetric ratio of steel fibres was very useful in terms of enhancing shear behaviour. The corrosion in the tensile reinforcement of the beams reduced the shear strength by 6%–8% for the corrosion rates of 7% and 20%, respectively; however, the corrosion also reduced the maximum loading by 10%–22%. Furthermore, the corroded both steel fibres and corroded rebars reduced loading by 6%–37%. As a result, it was concluded that the steel fibres can enhance the performance of the beams for shear even in a harsh environment. Finally, the results of some models obtained from the literature to compute the shear strength of RC and SFRC beams with and without corrosion effect were compared with the experimental results of this study.