The Effect of Wollastonite on Corrosion, Mechanical and Durability Properties of Reinforced Concrete in Chloride Environment

Corrosion of steel rebars is the primary cause of premature damage to reinforced concrete structures. In this study, the simultaneous effect of micro-silica, wollastonite, rebar diameter and cover thickness has been investigated on reinforced concrete's corrosion properties, mechanical and durability in 7.5% NaCl solution. Wollastonite and micro-silica were used as partial replacement of cement, 5 and 10% (optimum amount according to past studies) by weight of cement, respectively. Also, rebars with diameters of 10 and 14 mm and cubic specimens with dimensions of 80, 100, and 120 mm were considered. Experiments of compressive strength, water absorption, half-cell potential, and ultrasonic pulse velocity were performed at 56 and 90 days. In this study, the M5W10 (5% micro-silica and 10% wollastonite) was obtained as the best sample in reducing corrosion. The results show that the simultaneous use of wollastonite with micro-silica instead of cement has a better effect on reducing the possibility of corrosion compared to the separate use of materials. The effect of increasing rebar diameter and cover thickness on corrosion also was investigated. The results show that increasing the rebar diameter increases the probability of corrosion.