Mechanical and microscopic properties of fiber-reinforced coal gangue-based geopolymer concrete

In order to explore the engineering application potential of coal gangue-based geopolymer concrete (CGGPC), this article formulated the fiber-reinforced coal gangue-based geopolymer concrete (FRCGGPC). The mechanical properties of the specimens were tested to analyze the effects of different types and dosing amounts of fibers on the mechanical properties of CGGPC. The microscopic morphology of the specimens was observed by scanning electron microscopy (SEM) to analyze the strengthening mechanism of fibers on the mechanical properties of the CGGPC. The experimental results show that the splitting tensile strength of FRCGGPC can be improved obviously, but the improvement of compressive strength is not obvious. The control groups containing steel fiber (SF) and polyester fiber (PF) had peaks in their compressive strength. Under the same dosage, the effect of SF and PF on the splitting tensile strength of FRCGGPC is better than basalt fiber. The results of SEM analysis show that within a certain range of dosage, the fiber is closely combined with the matrix, which has a good force transmission effect and strengthens the matrix material. When the fiber dosage is too much, it is easy to agglomerate, which leads to the decrease in the mechanical properties of the specimens.