Studies on Strength and Flexural Behaviour of Reinforced Concrete Beams with the Corroded Steel Reinforcements as a result of Sodium Chloride (NaCl)

Abstract

Corrosion on embedded reinforcement is a serious structural failure which its deterioration are rarely concerned. Reinforcing steel are frequently found left unattended on corrosive environment where potential corroding substances might expose surface of rebar resulting in corrosion initiation. This paper reports result of a study conducted to investigate the impact of a rebar corrosion on flexural strength of reinforced concrete beam induced by 10.5% NaCl. Tensile test was conducted in this study to determine the degradation of tensile strength on rebar and was later utilized to analyse the reduction of maximum load bearing capacity on reinforced concrete beam. Both flexural rebar and tensile rebar were corroded using manual basting method which is carried out every day from 08.00 A.M-10 P.M (every 2 hours step). The corrosion area on flexural steel samples is at the maximum flexural strength area (400 mm in the middle of the span) and is later used on flexural testing purposes after casting with concrete, the tensile steel samples which is 600 mm span of rebar is later utilized for tensile testing purposes and is corroded in the middle of the span (185 mm in the middle of the span). Based on test results, it was observed that steel bar suffered significant loss of weights due to corrosion induced by 10.5% NaCl with respect to its corroding duration three and four months are 1.85% and 3.34% reduction of weight from its normal form and its tensile strength degraded, respectively, 6.78 % and 9.86%. Meanwhile, the reinforced concrete beam with corroded steel bars happened to experience degradation of maximum load capacity which are, respectively, 10% and 15% reduction for three and 4 months of corroding duration.