A sustainable solution for mitigating environmental corrosion in the construction sector and its socio-economic concern

Abstract

Corrosion in reinforced concrete (RC) structures is a typical occurrence, particularly in coastal locations. Corrosion occurs when steel reinforcement within concrete is exposed to environmental variables such as moisture, oxygen, and chloride ions, resulting in a chemical reaction that deteriorates the steel and degrades the concrete structure's overall function. In order to create effective mitigation techniques, it is critical to evaluate the impact of corrosion on various types of concrete. Chloride ions, often present in marine environments penetrate the concrete cover and reach the steel reinforcement, through pores. The water-cement ratio is a critical factor in concrete mix design. Excess water in the mix can result in the formation of larger and interconnected pores, during the hydration process. Further, improper curing conditions, such as insufficient moisture during the initial stages of hydration, can cause incomplete hydration and the formation of pores. Therefore use of high dense and highly alkaline concrete such as geopolymer concrete (which does not require water curing), can be employed to reduce the impact of corrosion. In the present study an attempt was created to examine the rate of corrosion resistance in three different concrete types: conventional cement concrete (CC), self-compacting concrete (SCC), and geopolymer concrete (GPC). To induce corrosion in the RC (RC) beams, an accelerated corrosion test setup was employed. The main objective of the study is to examine and compare the corrosion resistance of the RC beams by altering the concrete type, which were then exposed to accelerated corrosion to replicate the consequences of long-term exposure to corrosive environments. From the experimental studies it was found that the CC specimens possess a loss (load carrying capacity) of 31.28%, the SCC and GPC specimens possess a loss of 30.08% and 24.95%, respectively. This shows that GPC has higher resistance to salt solution when compared to SCC and CC specimens. Further all the three specimens show similar ductility index (DI), which was found to be in the range between 2.3 and 2.38 with a marginal variation of ± 0.1. GPC shows a 27.41% reduction in carbon emission compared to CC. On the other hand, SCC demonstrates a 12.30% reduction in carbon emission compared to CC. The investigation revealed that the total energy demand for producing 1 m3 of conventional concrete was measured to be 1.88 gigajoules (GJ/m3). On the other hand, the energy demand for the same volume of self-compacting concrete was slightly lower, specifically 1.78 GJ/m3.