Corrosion Durability and Structural Response of RC Beams Containing Supplementary Cementing Materials

Abstract

This paper reports the results of an experimental program on the effect of fly ash, slag and silica fume used as partial replacement of ordinary Portland cement (OPC) in retarding the corrosion of steel in medium-scale reinforced concrete beams. Eight reinforce concrete beams measuring 2.5 meters in length and 210 x 300 mm in cross-section were cast, four of which were subjected to accelerated corrosion. It was found that concrete containing fly ash, slag and silica fume showed better corrosion protection of steel in RC beams than OPC concrete. Among these, fly ash concrete showed the best performance in terms of lowest corrosion current (hence lowest steel loss), least visual damage and lowest tendency for delamination as measured by a concrete-embeddable fibre optic strain sensor. Corroded and un-corroded RC beams were tested under four point bending in order to evaluate the effect of corrosion damage on flexural behaviour of the beams. The results showed that corroded RC beam containing fly ash lost only 3% of its ultimate load capacity compared to 13% strength loss observed in the corroded OPC concrete beam.