Influence of Chloride Salt-Freeze-Thaw Coupling Effect on Corrosion Resistance of Hybrid Fibers Reinforced RPC

Abstract:

To investigate the improvement mechanism of hybrid fibers on the corrosion resistance of reactive powder concrete （RPC） subjected to the coupling effect of chloride salt-freeze-thaw， reinforced RPC samples with different types（steel fibers（SFs）， polypropylene fibers（PPFs）， rice straw fibers（RSFs））and contents of fiber were prepared. The effect of SFs， PPFs， and RSFs on the corrosion resistance of RPC were systematically studied through mass loss rate， relative dynamic elastic modulus， Tafel polarization curves， and electrochemical corrosion rate. The results show that hybrid fibers significantly enhance the corrosion resistance of RPC. After respectively selecting the optimal mixture from single-fiber， double-fiber， and triple-fiber hybrid schemes， the performance can be ordered as follows： 2% SFs+1% PPFs+1% RSFs>3% SFs+1% PPFs>3% SFs. With the optimal hybrid fiber mixture， the mass loss rate of the specimen decreases by 85.33% compared to the control group， the relative dynamic elastic modulus increases by 61.25%， and reduction rate of the reinforcement corrosion rate decreases by 59.19%. The incorporation of rice straw fiber not only improves the compactness of the matrix but also exerts a synergistic effect of fiber hybridization， effectively delaying the process of chloride attack and freeze-thaw damage.