Evaluation of Corrosion Resistance of Steel Reinforced Concrete Containing Ordinary Portland Cement Blended with Wheat Ash and Blast Furnace Slags as Mineral Admixture Under Simulated Marine Condition

Abstract

Current study was conducted on the evaluation of corrosion resistance of reinforced concrete containing ordinary Portland cement (OPC) blended with wheat ash (WA) and wheat stalk ash (BFS) as mineral admixtures under simulated marine conditions using electrochemical techniques. WA and BFS admixtures were used to partially replace the OPC including OPC0 as control sample (400 kg/m3 OPC), OPC+BFS60 (340 kg/m3 OPC+60 kg/m3 BFS), OPC+WA60 (340 kg/m3 OPC + 60 kg/m3 WA) and OPC+WA30+BFS30 (340 kg/m3 OPC+30 kg/m3 WA + 30 kg/m3 BFS). Results of potentiodynamic polarization, cyclic voltammetry and electrochemical impedance spectroscopy analyses indicated that OPC+WA30+BFS30 sample showed higher corrosion resistance and potential than the other samples because of the synergetic effect BFS and WA in concrete which enhanced the steel rebar corrosion resistance in 3.5 wt% NaCl solution. Moreover, the SEM studies showed that the OPC+WA30+BFS30 had lower corrosion products and lower density of narrow pits on steel surface than that OPC0 specimen which confirmed the electrochemical studies. These results demonstrated that WA and BFS can used as appropriate mineral admixtures to decrease hydroxide ion concentrations and enhance the passivation of the reinforcement steel rebar in marine environments.