Research Status of Mechanical Properties and Frost Resistance of Fly Ash Concrete

Abstract

With the continuous advancement of sustainable construction materials, fly ash concrete (FAC) has garnered significant attention due to its environmental benefits and mechanical performance. FAC is a novel concrete material in which fly ash, a byproduct of coal combustion in power plants, is used to partially replace cement. Research on its mechanical properties primarily focuses on compressive strength, tensile strength, flexural strength, and elastic modulus. Numerous studies have shown that the incorporation of fly ash may reduce the early-age strength of concrete; however, its later-age strength—particularly after 28 days—tends to increase markedly. The spherical morphology and pozzolanic activity of fly ash contribute to the refinement of the concrete’s microstructure, thereby improving deformability and toughness. In recent years, various constitutive models have been developed to better describe the mechanical behavior of FAC, including linear elastic models, plastic damage models, and nonlinear constitutive models that account for volumetric deformation. These models take into account the influence of fly ash on cement hydration, the interfacial transition zone, and stress–strain response, providing a more accurate prediction of the material’s load-bearing and failure processes. Overall, fly ash concrete exhibits favorable long-term mechanical performance, and its constitutive behavior has been theoretically well-characterized, laying a solid foundation for its further application and performance optimization in engineering practice.