Chloride-induced corrosion of reinforcement in low-calcium fly ash-based geopolymer concrete

Geopolymer concrete (GPC) has significant potential as a more sustainable alternative for ordinary Portland cement concrete (PCC). However; as a rather new engineering material, there are some concerns over the durability aspects of geopolymer-based binders. In this study, the performance of chloride-contaminated reinforced GPC specimens manufactured using a blended low-calcium fly ash and slag cement is investigated by long-term monitoring of corrosion parameters such as open circuit corrosion potential, polarization resistance and Tafel slopes. The electrochemical results are validated by contrasting the electrochemical mass losses with the mass losses obtained from the gravimetric measurements. The investigated low-calcium fly ash-based GPC exhibit a comparable electrochemical performance to a similar strength PCC during the propagation phase of corrosion. Additionally, some of the conventional classifications which are commonly used to assess the severity of corrosion in Portland cement-based corroding systems might need some recalibration to be used for low-calcium fly ash-based corroding systems.