Coal bottom ash as supplementary material for sustainable construction: A comprehensive review

The world is facing considerable challenges with managing wastes and by-products, mainly hazardous materials. On the other hand, the construction sector still needs to source sustainable solutions to address its negative impact on the ecosystem. Coal bottom ash (CBA) is one of the by-product materials resulting from coal combustion in coal-fired power plants. The open disposal of CBA poses serious environmental pollution, in addition to occupying a large area of valuable land. The use of CBA in concrete production is one of the effective ways to circumvent the direct disposal of CBA, as this material can be a feasible supplementary material for cement and aggregates in concrete. This study provides a comprehensive review of the influence of CBA incorporation (as cement and aggregate replacement) on the workability, mechanical, durability, leaching, and alkali-silica reactivity of cementitious composites. A bibliometric analysis demonstrating the distribution pattern of previous studies on concrete containing CBA has also been included in this paper. Most of the research has indicated that CBA utilization reduces the workability and mechanical properties of concrete. Overall, the optimal utilization of CBA as a cement replacement or fine aggregate substitution demonstrates the feasibility of attaining the required performance of concrete.