Impermeability performance and corrosion resistance mechanism of basalt fiber recycled concrete under the coastal tidal environment

The application of Recycled Aggregate Concrete (RAC) can effectively reduce resource consumption and mitigate environmental pollution. Under the coastal tidal environments, the performance of concrete is significantly impacted by environmental degradation. Incorporating fibers into RAC can enhance its performance in such special conditions. This study investigates the variations in properties of RAC with different Basalt Fiber (BF) volume ratios (0%, 0.5%, 1.0%, 1.5%) under composite salt dry-wet cyclic erosion cycles (0 d, 30 d, 60 d, 90 d). The results from apparent corrosion morphology analysis, internal microstructure examination, and impermeability testing demonstrate that BF can effectively inhibit the expansion of micro cracks and micropores within the test block while improving the overall compactness of the internal structure of RAC. When the BF content reaches 1.0%, it exhibits an optimal toughening effect on RAC with significantly improved impermeability and corrosion resistance properties. Furthermore, this paper comprehensively summarizes and verifies the corrosion damage mechanism of Basalt Fiber Recycled Aggregate Concrete (BFRAC) under composite salt dry-wet cycles through chemical reaction principles. A salt solution erosion model for BFRAC is proposed to elucidate fiber crack resistance mechanisms and explain accelerated corrosion caused by ion crack channels within salt solutions. This proposed model provides theoretical support for understanding salt erosion damage in fiber-reinforced concrete. •The variation of impermeability of BFRAC in coastal tidal environment was discussed.•The deterioration mechanism was analyzed from macro and micro perspectives.•The BFRAC damage deterioration model was established.•The damage mechanism of BFRAC was analyzed by chemical reaction principle.•The mechanism of ' ion crack channel ' accelerating corrosion was proposed.