Experimental Study on the Compressive Behavior of Fiber-Reinforced Ceramsite Concrete

Ceramsite concrete is a kind of green building material with advantages such as low weight, heat insulation, and fire resistance. However, it has low strength, high brittleness, and the problem of aggregate floating. In this study, by adding polypropylene fibers and optimizing the preparation process, the mechanical properties of ceramsite concrete have been significantly improved, which is of great significance for promoting the application of this material in the engineering field. Through uniaxial compressive tests on 54 specimens in six groups (divided into three strength grades), the failure characteristics and stress-strain relationships of each group of specimens were analyzed, and the effects of strength grades and fiber contents on parameters such as peak stress, peak strain, ultimate strain, and elastic modulus were studied. The results show that the addition of polypropylene fibers can improve the strength of ceramsite concrete, effectively improve the deformation performance and ductility of specimens before failure, and reduce brittleness. Specifically, as the fiber content increases, the peak stress first increases and then decreases, reaching its peak at a content of 0.05%, with an increase of 8.98%. At the same time, as the fiber content increases, the peak strain and ultimate strain increase significantly, reaching their peaks at a content of 0.075%, with increases of 21.3% and 25.2%, respectively. In addition, this paper proposes a piecewise correction model for the uniaxial compressive stress-strain curve of fiber-reinforced ceramsite concrete. This model has a good fit with the full experimental curve, providing an accurate theoretical reference for the application and development of this material in engineering.