Life cycle assessment of sustainable air-cured alkali-activated concrete for permeable pavements using agro-industrial wastes

Abstract

Abstract This study evaluates the environmental performance of air-cured alkali-activated permeable concrete (PAC) developed using agro-industrial by-products, including sugarcane bagasse ash (SBA), recycled concrete aggregates (RCA), waste foundry waste sand (WFS), and ground granulated blast furnace slag (GGBS). A cradle-to-gate life cycle assessment (LCA) was conducted to quantify reductions in equivalent carbon dioxide emissions (ECO2e) and embodied energy (EE) relative to conventional OPC-based permeable concretes (OPCC). The results reveal that optimized PAC mixes achieve up to 57% lower EE and 77% lower ECO2e, confirming their environmental superiority. These improvements are attributed to the complete substitution of OPC with low-impact binders and the replacement of virgin aggregates with recycled counterparts. In addition to its environmental advantages, PAC demonstrated notable cost reductions of up to 60%, enhancing its viability for real-world infrastructure applications. The study further highlights the functional advantages of PAC including enhanced permeability, structural resilience, and suitability for stormwater management which make it an effective solution for sustainable pavement infrastructure. By integrating agro-industrial waste streams into concrete-composite production, the research advances the principles of resource-efficient engineering and circular economy. The findings establish a strong foundation for future studies on life cycle cost analysis, activator optimization, and implementation strategies, thereby promoting the adoption of PAC as a low-carbon alternative in urban infrastructural practices.