Investigation on compressive strength of fiber reinforced concrete subjected to the coupling effects of freeze-thaw cycling and loading utilizing fractal theory

This study explores the correlation between the compressive attributes of the fiber reinforced concrete and the fractal dimension value under the combined influence of continuous loading and freeze-thaw cycling. Freeze-thaw cycling tests were conducted on the fiber reinforced concrete with varying compressive stress levels (0, 0.3, 0.5). The fractal characteristics of the concrete cracks pre and post freeze-thaw were examined, and the alteration in the compressive strength of the samples under different coupling effects was analyzed using the fractal theory. An evolution equation was established between the fractal dimension of the cracks and the compressive strength. Findings indicate that as the number of freeze-thaw cycles increases, the compressive strength of the sample progressively decreases. When the number of freeze-thaw cycles increases to 160, the loss rates in the compressive strength of the specimens under different coupling stresses exhibit the significant differences, the smallest loss rate of 21.59% is observed at a coupling stress of 0.3, while the maximum of 33.58% is noted at a coupling stress of 0.5. A clear linear relationship is found between the fractal dimension of the cracks and the coupling effect, quantitatively reflecting the deterioration pattern of the fiber reinforced concrete. A larger fractal dimension value of the cracks indicates greater freeze-thaw damage to the fiber reinforced concrete and a lower compressive strength.