MODIFIED SULFOALUMINATE CEMENT CONCRETE TO THE CHLORIDE ION PERMEABILITY

The transport rate of chloride ions (Cl-) in sulfoaluminate cement (SAC) is lower than that in ordinary Portland cement (OPC). However, after long-term service, the steel rebar in the SAC still suffers erosion. To improve the chlorine ion erosion resistance of SAC concrete, this study incorporated a polyvinyl alcohol (PVA) powder into the SAC concrete. The effects of the PVA powder on the capillary absorption coefficient (S) and chloride ion erosion resistance of the specimen were evaluated. The results show that, after adding the PVA powder, the total porosity, macropores and capillary pores reduce. Meanwhile, the pore structure connectivity decreases and the pore complexity increases. The PVA powder decreases the capillary water absorption coefficient of the specimens (reduction rate ˃ 21.84%). Additionally, the electric flux and unsteady state chloride diffusion coefficient decrease by 16.32% and 18.09%, respectively, indicating that the transport rate of chloride ions inside the SAC concrete decreases and the chloride erosion resistance is improved. Therefore, the PVA powder-modified SAC concrete exhibits excellent resistance to chloride ion erosion, which becomes a good material for buildings with long service life requirements in marine engineering.