Permeability of cement-treated soil with the addition of magnesium sulfate

In the control of contaminated soil, cut-off walls are often used beneath existing structures or in areas where contaminated soils are widespread, created by mixing soil in situ with cement. These cut-off walls are designed to limit the spread of contaminants into the groundwater and therefore require low permeability. Recently, the permeability of cement-treated soil subjected to the flow of a magnesium solution was investigated. As a result, it was shown that the permeability decreased significantly with increasing flow rate of the magnesium solution, suggesting that magnesium salts contribute to the reduction of permeability in cement-treated soil. In this study, cement-treated soil with added magnesium sulfate was investigated to develop a low-permeability material. As a result, it was confirmed that the permeability of the cement-treated soil decreased as the magnesium sulfate content increased. Instrumental analysis showed that the amount of ettringite formation increased with higher magnesium sulfate content. The reduction in the permeability of the specimens with magnesium sulfate was attributed to the filling of the pores and the increased complexity of the pore structure caused by the formation of ettringite.