Corrosion Resistance of High Calcium Fly Ash Based Reinforced Geopolymer Concrete in Marine Environment

The performance of reinforced concrete elements is affected by its corrosion resistance. Chloride attacks on reinforced concrete elements in a marine environment is caused by chloride seeping into the concrete thereby damaging the passive layer and causing corrosion of the steel reinforcement. This study evaluated the mechanical properties, permeability, and corrosion resistance of Geopolymer Concrete (GPC) in a marine environment which was compared with Ordinary Cement Concrete (OCC). In this instance, the compressive strength and splitting tensile strength were used to determine the strength of the OCC and GPC. Meanwhile, the concrete's permeability coefficient was assessed in accordance with DIN 104. In addition, measurements were made of the density, absorbance, and volume of permeable voids. The corrosion performance of steel reinforcement in reinforced concrete was assessed using an accelerated corrosion test where the specimens were submerged in a 3% NaCl solution and coupled to a continuous DC voltage of 6V. The test results revealed that the compressive strength and splitting tensile strength of GPC could be greater than the values suggested by Gomaa et al. and Ryu et al (2018) and were nearly as high as the projected value recommended by ACI. The permeability coefficient of GPC is less than that of OCC while the corrosion resistance properties of GPC showed better results than OCC. Microstructural analysis showed that the structure of GPC is more stable when corrosion occurs, compared to OCC.