The Effect of Sugarcane Bagasse Fiber on the Fatigue Performance of Recycled Aggregate Concrete

This study tested the mechanical properties of sugarcane bagasse fiber-reinforced recycled aggregate concrete (SFRAC) with sugarcane bagasse fiber (SF) volume fractions of 0.5%, 1.5%, and 3%, and recycled coarse aggregate (RCA) replacement rates of 20%, 40%, and 60% by the mass of coarse aggregate. Evaluated parameters included compressive strength and flexural strength. Based on the mechanical performance test results, seven specimens with superior performance were selected for further flexural fatigue testing. This identified the optimal SF and RCA replacement ratios that balance mechanical performance, fatigue resistance, and economic/environmental considerations. The study concluded that sugarcane bagasse fiber significantly enhances the mechanical properties of recycled aggregate concrete (RAC). At a fiber volume concentration of 1.5%, compressive strength increased by up to 15.1%, while flexural strength improved by up to 24.6%. Regarding fatigue performance, the flexural fatigue life of SFRAC increased synchronously with rising SF content, with test results highly consistent with the three-parameter Weibull distribution. Based on this, the P-lgS-lgN equation and the S-λf-N equation incorporating failure probability and fiber parameters were derived. A fatigue strain-based damage evolution model was established to predict damage levels and remaining life of SFRAC. SEM experiments confirmed SF’s reinforcing effect on SFRAC at the microstructural level. These studies demonstrate that SFRAC with a 1.5% SF content and 40% RCA substitution offers optimal performance and environmental sustainability.