Research on the performance of high-strength lightweight concrete incorporating lithium slag-based artificial aggregate and TMA fiber

This study investigates the feasibility of replacing manufactured sand with lithium slag-based artificial aggregate (LSAA) in the production of high-strength lightweight concrete (HSLC) and the enhancement of its properties through the addition of tri-modal amorphous (TMA) fibers. Eight HSLC mixtures were prepared with LSAA replacement levels of 0%, 25%, 50%, 75%, and 100% by volume, and TMA fiber dosages of 1.0%, 1.5%, and 2.0% by volume were incorporated at 100% LSAA replacement. Flowability, bulk density, water absorption, compressive strength, flexural strength, drying shrinkage, and microstructural characteristics such as SEM, XRD, and pore structure analysis were systematically evaluated. Results indicated that the increasing LSAA content improved flowability but reduced bulk density and mechanical strength due to porous structure and high water absorption of LSAA. The incorporation of TMA fibers enhanced both compressive and flexural strengths up to an optimal dosage of 1.5%, which increased 28-day compressive and flexural strengths by 14.24% and 21.78%, respectively, compared to fiber-free LSAA concrete. Excessive fiber content caused fiber agglomeration, leading to strength reduction. Microstructural analysis revealed that LSAA increased pore size and total porosity, whereas TMA fibers refined pore structure, reduced large pores, and improved the interfacial transition zone. The proposed approach demonstrates the potential of LSAA and TMA fiber synergy in producing sustainable HSLC.