Abstract: The design variables of the experiment were water cement ratio, recycled aggregate replacement ratio, waste fiber length and volume content.The fractal characteristics of pore structure and carbonation performance of waste fiber recycled concrete were investigated by mercury injection test and rapid carbonation test.The results indicate that waste fiber recycled concrete pore structure has a prominent fractal characteristic, the addition of waste fiber can prevent the formation of harmful pore structure, and improve the waste fiber recycled concrete pore structure inside.The waste fiber can improve the carbonation resistance of recycled concrete and the optimal volume content is 0.12%, the smaller fractal dimension of the carbide boundary contour, the greater carbonation depth.There is a correlation between the depth of carbonation and pore volume fractal dimension of recycled concrete waste fiber.As the pore volume fractal dimension decreases and carbonation depth increases, it is feasible to evaluate different design variables of waste fiber recycled concrete carbonation depth according to the pore volume fractal dimension.

Key words: recycled concrete;waste fiber;fractal dimension;pore structure;carbonization