Effect of polyvinyl alcohol powder on the impermeability, frost resistance and pore structure of calcium sulfoaluminate cement concrete

The pore structure has close tie with the performances of concrete, especially the impermeability and frost resistance. In this paper, Polyvinyl alcohol (PVA) powder was added into calcium sulfoaluminate cement (CSA) concrete to improve the pore structure. The effect of PVA on the impermeability, frost resistance and pore structure of CSA concrete were studied, and the relationship between impermeability and pore structure was revealed. The results show that PVA significantly improves the impermeability and frost resistance of CSA concrete. The seepage height reduces from 3.06 mm to 1.43 mm, the relative permeability coefficient reduces from 4.82 x 10-6 mm & sdot;h- 1 to 1.05 x 10-6 mm & sdot;h- 1, and the frost resistance increases from F100 to F150. PVA can reduce the porosity of CSA concrete, and the critical pore size and pore connectivity also gradually decrease, while the fractal dimension gradually increases. The relative permeability coefficient of CSA concrete has a good linear relationship with porosity and capillary porosity, an exponential relationship with critical pore size, a negative linear relationship with fractal dimension, and a logarithmic relationship with pore connectivity. Therefore, the addition of PVA reduces the porosity of CSA concrete and improves the impermeability and frost resistance.