Study on Sulfate Migration Behavior of Potassium Magnesium Phosphate Cement Slurry Based on Electro-Pulse-Accelerated Corrosion

By accelerating the migration of sulfate ions in potassium magnesium phosphate cement (PMPC) paste through an electric field, its sulfate resistance can be quickly evaluated, thereby making up for the defect of long test cycles in existing evaluation methods. Through sulfate concentration analysis, strength tests, microanalysis and theoretical analysis, this paper investigated the SO₄^2- migration behavior of PMPC specimens subjected to electro-pulse-accelerated corrosion. The conclusions are as follows: the distribution of SO₄^2- concentration c (x, t) in PMPC specimens followed a polynomial pattern with corrosion period t. The surface SO₄^2- concentration c (0, t), measured SO₄^2- migration depth h₀, and c (x, t) of specimens increased with the t. After 56 days, the c (0, 56 days) and h₀ of the PN containing nickel slag powder and the PS containing silica fume were lower than that of the reference P0. Their calculated SO₄^2- migration depth h₀₀ and SO₄^2- migration coefficient D were smaller than that of P0. The h₀₀ and D could be estimated based on t due to a logarithmic relationship between t and h₀₀, D. The strength of specimens at the pulse cathode end gradually improved with t. The 56-day strength for P0, PN, and PS specimens increased by 7.14%, 7.94%, and 8.42%, respectively. The research findings provided a theoretical foundation for the application and quality evaluation of PMPC-based material.