Development of low-carbon engineered cementitious composites incorporating lithium slag: Mechanical properties, microstructure evolution, and life cycle assessment
Meiyan Bai, Long Song, Qinchuan Xiao, Junbo Sun, Haoran Liu
Abstract
The rapid expansion of the global lithium battery industry has led to a significant accumulation of hazardous lithium slag (LS), creating an urgent environmental challenge. This study develops a scalable cleaner production strategy by valorizing LS as a supplementary cementitious material in the fabrication of low-carbon engineered cementitious composites (ECC). The mechanical properties, microstructure evolution, and environmental-economic benefits of ECC mixtures with LS were evaluated. Experimental results indicate that the incorporation of LS significantly enhances the tensile strain of ECC, yielding a 47.57% increase in tensile strain capacity at a 20% replacement ratio. Microstructural analyses via MIP and SEM reveal that LS particles act as hydration nuclei and pore fillers, refining the pore structure (reducing harmful macropores by up to 60%) and optimizing the fiber-matrix interfacial properties. Although a trade-off in compressive strength was observed at higher replacement ratios, the flexural strength increased by 22.1% in the Li30 mixture. Furthermore, life cycle assessment (LCA) and cost-benefit analysis demonstrate that the optimized LS-ECC reduces the carbon intensity index by 8.18% and lowers material costs by 6.9% compared to conventional ECC. A final multi-objective optimization using Pareto frontier analysis identifies the optimal mix designs that balance mechanical resilience with eco-efficiency. This work provides a theoretical basis and practical guidelines for transforming hazardous lithium waste into high-performance, low-carbon construction materials, supporting circular economy goals in both the energy and construction sectors.