Durability performance of reinforced waste-based geopolymer foam concrete under exposure to various corrosive environments

The construction of conventional concrete structures produces a significant quantity of CO2 released into the environment which can directly impact human health and contribute to global warming. Geopolymer foam concrete is a low carbon eco-friendly concrete in which CO2 releasing cement is replaced with industrial waste materials. However, the durability of geopolymer foam concrete under needs to be investigated over a range of corrosive environments to enable application as a construction material. Therefore, determining the influence of these corrosive factors on the reinforcing steel in geopolymer foam concrete is the objective of the current research. A detailed multi-variable experimental programme was conducted, and models were derived to quantifying the factors influencing the corrosion and mechanical behaviour of reinforced geopolymer foam concrete (RGFC) under exposure to varying chloride, temperature and humidity. Specimens were cast with three chloride percentages, i.e., 1%, 3% and 5% for accelerated corrosion, and exposed to temperatures of 35 and 24 Celsius, and humidity levels of 50% and 90%, respectively. Gravimetric weight loss measurements of the corroded reinforcing steel were undertaken at three designated time intervals. Following corrosion monitoring, the corroded reinforcing steel was tested under tension to observe the influence of the environmental exposure on their mechanical properties, specifically ductility and strength. Utilizing the test results, analytical expression and Multilayer Perception (MLP) neural network computations were executed to accurately quantify the influence of the various environmental exposure conditions on corrosion in RGFC. The findings of the modelling suggested temperature as the most dominant factor in inducing corrosion followed by humidity. Furthermore, the relationships for the prediction of loss of ductility and tensile strength of the reinforcing steel in RGFC as the function of chloride, temperature and humidity were derived. Finally, to conclude, the outcomes of the current research enhance the knowledge on the durability of GFC as a construction material and practically contribute to its service life determination.