Corrosion performance and sustainability of high-strength lightweight geopolymer concrete incorporating sintered fly ash aggregate as the coarse aggregate

Implementing eco-friendly practices is essential to mitigate the environmental impact of the construction sector. A potential solution is to develop concrete with binders and aggregates from industrial wastes such as ground granulated blast furnace slag (GGBS) and fly ash (FA), utilising geopolymer (GP) technology to reduce reliance on cement and natural aggregates. This study explores the development of high-strength lightweight geopolymer concrete (HSLWGC); for this, metakaolin (MK) incorporation with 10 and 15 % replacement levels for all alkaline content to binder ratios (AC/B) has taken place using 100 % synthetic sintered fly ash aggregates (SFA) as coarse aggregate. Incorporation of MK was employed to enhance the mechanical and corrosion performance of the developed samples. The corrosion performance of the developed HSLWGC samples was thoroughly investigated in this investigation. Experimental investigations assessed mechanical properties, corrosion performance through several tests, including the alkalinity test, surface resistivity, half-cell potential, and corrosion rate, using the Tafel plot study and the accelerated carbonation study, which is also supported by microstructural analysis (SEM). Results indicate that HSLWGC achieves significant density reduction, excellent corrosion resistance, and improved microstructure after incorporating MK in the mixes. Life cycle assessment (LCA) further confirmed its lower global warming potential and energy demand, demonstrating the material’s potential as a sustainable alternative for construction applications.