Evaluating the corrosion resistance and LCA of lightweight geopolymer concrete integrating sintered fly ash aggregate as coarse aggregate

The current study examined the corrosion resistance of lightweight geopolymer concrete (LWGPC) incorporating sintered fly ash aggregate (SFA) as the coarse aggregate. The LWGPC was developed from a mixture of ground granulated blast furnace slag (GGBS) and fly ash (FA). The geopolymer binder is composed of 70 % FA and 30 % GGBS. The study is also directed towards understanding the means by which, LWGPC can contribute to the development of a sustainable environment. Since the alkaline content to binder (AC/B) ratio substantially impacts the performance of LWGPC, corrosion studies were performed on a broad spectrum of AC/B ratio ranges from 0.3 to 0.8 at an interval of 0.1. To assess the corrosion performance of various developed concretes, the coarse aggregates were completely substituted with coarse SFA. The assessment was conducted using several tests, including accelerated carbonation test, half-cell potential, surface resistivity test, pH test, and corrosion rate test with Tafel plots analysis. The results demonstrate that an inverse relationship exists between the AC/B ratio and all the corrosion parameters of LWGPC samples investigated. The highest level of corrosion resistance is achieved at the lowest AC/B ratio. The air dry density of LWGPC varied from 1850 to 1908 kg/m 3 after 28 days of ambient curing, fulfilling the different codal guidelines to be designated as lightweight concrete. The LWGPC samples had carbonation depths of 5–44 mm, corrosion rates of 0.0209–0.222 mils per year (mpy), surface resistivity of 22.5–45.5 kΩ-cm, and pH between 11.5 and 12.5. The above results demonstrate satisfactory performance for structural applications, particularly for samples with a low AC/B ratio. SEM findings also strongly correlate with corrosion parameter information. The LCA of LWGPC has achieved lower values of Embodied energy (EE) and Global Warming Potential (GWP) than the OPC based lightweight concrete, with 57 % and 55 % reductions respectively. • The corrosion behaviour was observed with various AC/B ratios over time. • LWGPC's carbonation attributes differ significantly from OPC's. • The GP binder with SFA showed distinct microstructural and corrosion resistant behaviour. • After one year, corrosion rates fall into the negligible to moderate category.