Value-added utilization of pulverized fuel ash as construction materials: State-of-the-art technologies and future prospects

Pulverized fuel ash (PFA) is a by-product from coal-fired power plants. The generation of PFA is huge and increases yearly. A large amount of untreated PFA is harmful to the environment, and it is also a waste of resources. Recycling PFA as construction materials would improve resource utilization efficiency, reduce environmental risks, conform to the demand for high-efficient and low-carbon utilization of solid waste and help to achieve the national strategy goals of carbon peak and carbon neutrality. The utilization efficiency of PFA as construction materials could be improved by optimizing production processes and developing new technologies, which would promote its large-scale and high-value utilization. In this paper, the general situation and physical and chemical properties of PFA are summarized. Various value-added utilization technologies of PFA as construction materials, including raw materials for cement production, supplementary cementitious materials, bricks and blocks, artificial aggregates, glass-ceramic materials, fire-resistant insulation materials, and new intelligent construction materials are comprehensively reviewed. This paper also introduces the research status of the utilization of PFA in construction materials, analyzes the applicability of different technologies, summarizes the latest technologies for preparing the PFA-based green construction materials and challenges faced in future research, provides detailed introductions to the mechanism of PFA application, and proposes thoughts on the problems existing in the utilization of PFA as construction materials. Finally, the further perspectives of the development of the PFA-derived low-carbon construction materials are highlighted. The study suggests that the “traditional large-scale consumption of PFA” and “high-value utilization of PFA” should be researched in parallel, and theoretical research and engineering practice should support each other, which would provide some scientific references for the sustainable management of PFA.