Erosion degradation analysis of rice husk ash-rubber-fiber concrete under hygrothermal environment

To study the resistance of rice husk ash-rubber-fiber reinforced concrete (RRFC) to dry-wet cycle/chloride erosion under a hygrothermal environment, the optimal combination was selected by an orthogonal test. The peak strain, residual strain, and fatigue damage strength of the optimal group of RRFC samples under cyclic loading and unloading after dry-wet cycle/chloride erosion under different environments and temperatures were compared and analyzed. After that, microscopic analysis and anti-erosion mechanism analysis were carried out. The results show that the axial peak and residual strain of RRFC specimens increase continuously during the repeated loading-unloading process, and the increase of axial peak and residual strain in the first five cycles is the most obvious. Among them, RRFC has the most significant increase in axial peak strain after 14 dry-wet cycles, which is 11.73%. The rice husk ash reacted with Ca(OH)2 in the specimen to precipitate C-S-H gel, which improved the specimen's corrosion resistance and fatigue resistance. The rubber in the specimen has high elasticity, which reduces the fatigue damage of the specimen during cyclic loading and unloading, thus showing higher fatigue failure strength.