Influence of untreated and treated recycled coarse aggregates on engineering properties of slag dolomite geopolymer concrete

Abstract In search of sustainable construction material as an alternative to existing ordinary cement concrete, the use of recycled aggregates in geopolymer concrete has garnered significant attention. Using industrial by-products such as dolomite and ground granulated blast furnace slag (GGBS), combined with alkali activators like sodium silicate and sodium hydroxide to prepare geopolymer concrete, offers a promising substitute to traditional Portland cement concrete. This study explores the potential of incorporating recycled aggregates, specifically focusing on the benefits of treated recycled-aggregates (TRCA) into the concrete for improving sustainability of geopolymer concrete. Mechanical grinding treatment is found to be effective in removing adhered mortar from recycled-aggregates, and thus improving aggregate quality and reducing porosity and micro-cracks. By systematically analyzing the effects of untreated and treated recycled aggregates on concrete properties, this research provides a comprehensive understanding of how treatment processes can mitigate the limitations of RCA and optimize the material’s performance. Incorporating treated recycled aggregates enables the construction industry to adopt more sustainable building practices, thus helping global efforts to minimise damages to the environment. The experimental results demonstrated that treating recycled aggregates showed key engineering properties of geopolymer concrete similar to normal geopolymer concrete with reduction less than 5% at 100% replacement level. Geopolymer concrete, made from GGBS and dolomite with treated recycled aggregates, provides a sustainable substitute for conventional concrete, offering environmental and structural advantages. This paper promotes the use of treated recycled aggregates to decrease the dependency on natural resources, therefore promoting the circular economy within the building industry. The findings of this study are expected to advance the knowledge of recycled aggregate utilization in geopolymer concrete, offering practical insights for construction professionals and researchers. The research seeks to develop novel, sustainable, and high-performance construction materials that meet environmental and structural requirements.