Microcrack Propagation of Basalt Fiber Reinforced Pavement Concrete under Wheel Load and Freeze-Thaw Cycles Coupling

To quantitatively evaluate the crack resistance effect of basalt fiber in pavement concrete, the propagation behavior of microcrack under the coupling of wheel load and freeze-thaw cycles was investigated. The effect of basalt fiber contents, stress levels, and coupling environments on microcrack parameters was studied, and the micromorphology of basalt fiber reinforced pavement concrete (BFRPC) after double fields coupling was analyzed. The results show that the change slope of crack density increases after loading 150,000 times, whereas the slope of width reduces. Basalt fiber reduces the crack connectivity, resulting in an "extending-fracturing" pattern of crack maximum length. The difference of crack width between BFRPC (0.08 %) and ordinary concrete gradually increases with the coupling stage, and the crack resistance effect of basalt fiber is more significant in the later coupling stage. Compared with the single field action of wheel load, the freeze-thaw cycles mainly promote crack expansion in the width direction and change the propagation mode of crack length in BFRPC. The microcracks in BFRPC are distributed dispersedly rather than penetrating owing to the anticrack effect of basalt fiber.