Mechanical and Durability Properties of Concrete Prepared with Coal Gangue: A Review
Xiaorui Jia, Weitao Li, Dong Xin, Bo Liu, Jiazheng Chen, Jiayue Li, Guowei Ni
Abstract
Coal gangue, an industrial byproduct of coal mining, was traditionally utilized in concrete production as a coarse aggregate. However, recent advancements have expanded its application by processing it into fine powder for use as a supplementary cementitious material (SCM), partially replacing cement. This approach not only enhances the sustainable reuse of coal gangue but also contributes to reducing cement consumption and associated carbon emissions. Nevertheless, the incorporation of coal gangue may adversely affect the mechanical strength and long-term durability of concrete. This review provides a systematic analysis of recent research on coal gangue-modified concrete. It begins by classifying the functional roles of coal gangue in concrete mixtures, followed by a critical evaluation of its impact on mechanical properties and durability—both as an aggregate an as a mineral admixture. When 30% of the aggregate is replaced with activated coal gangue, the average compressive strength of concrete increases by 15%. When coal gangue replaces less than 20% of the cement, the compressive strength of concrete can reach 95% of the reference strength. Second, the review evaluates the modification effects of various mineral admixtures, elucidating their mechanisms for enhancing mechanical properties and durability in coal gangue-based concrete. Finally, it examines the underlying interaction mechanisms between these admixtures and coal gangue, while identifying key future research directions for optimizing admixture formulations. By providing a comprehensive and critical analysis of current research, this paper serves as a valuable reference for developing high-performance coal gangue concrete with increased substitution rates and tailored admixture systems. Ultimately, this work advances the design of sustainable, low-cement concrete using industrial byproducts, enabling performance-driven applications and supporting next-generation green construction materials.