Influence of basalt fiber on the anti-carbonation performance of recycled aggregate concrete

The rapid carbonization method was used to study the influence of basalt fiber (BF) content and recycled coarse aggregate (RCA) replacement ratio on the anti-carbonization performance of recycled aggregate concrete (RAC). The carbonization depth of 3 days, 7 days, 14 days and 28 days was measured, and the relationship between carbonization depth with BF content and replacement ratio of RCA was analyzed with the increase of carbonization days. The results show that the carbonization of RAC is similar to that of natural aggregate concrete (NAC). The depth of carbonization increases with the increase of carbonization days. As the replacement ratio of RCA increases, the carbonization depth of RAC first decreases and then increases, when the RCA mass replacement ratio is 50%, the carbonization resistance of RAC is the best. Incorporating BF can effectively improve the anti-carbonization performance of RAC. With the increase of BF content, the anti-carbonization performance of RAC increases first and then decreases. In this experiment, the optimal content of RAC is 2 kg/m³. In addition, using scanning electron microscope to observe the microstructure of BF/RAC, combined with diffusion theory, the carbonization damage mechanism was revealed. Using test data for fitting, a carbonization depth model of BF/RAC was established. The research results have reference value for future research and engineering applications.