Delithiated β-spodumene as a partial cement replacement in waste-based concrete with recycled aggregates and sugarcane fiber

Delithiated β-Spodumene (DβS), a lithium-mining by-product rich in reactive alumina and silica, is a promising supplementary cementitious material (SCM). This study, for the first time, investigates the fresh and mechanical properties of concrete incorporating DβS as a partial cement replacement, lead smelter slag (LSS) as a sand substitute, recycled coarse aggregate (RCA) as a coarse aggregate replacement, and sugarcane fiber as reinforcement. The research evaluates the effects of using DβS at various levels (10%, 20%, 30%, 40%, and 50%) on key concrete properties, with a focus on workability, compressive strength, splitting tensile strength, and surface hardness. Results indicate that incorporating DβS reduces workability, with a 35% decrease observed at 50% replacement. Notably, a 20% replacement of DβS yields optimal mechanical performance, with the compressive strength increasing by 22%, the splitting tensile strength improving by 14%, and surface hardness, as measured by rebound number, enhanced by 3.5% after 28 days. However, increasing DβS content to 50% results in reductions of 32% in the compressive strength, 16% in the splitting tensile strength, and 10% in the surface hardness. This study offers valuable insights into the potential of integrating industrial by-products and recycled materials into concrete, thereby improving performance and reducing environmental impacts.