Experimental study on strength of cement soil under Mg²⁺and SO₄^2- interaction influence

The Mg2+ and SO42-in the surrounding environment of soil-cement piles may affect the mechanical properties of cement soil in turn to cause some serious damage to structures.In order to simulate and study the erosion effect process such as the changes of corrosive degree of surface,compression strength of cement soil samples and Mg2+ concentration and SO42-concentration of corrosive solutions,a series of tests are conducted on the cement soil blocks cured in different concentrations of MgSO4 solutions,including taking photos,compressive strength tests,and measuring Mg2+ and SO42-concentrations.The test results show that the corrosive degree of the sample surface increases while the compression strength decreases with the increase of the corrosive solution concentration at the same erosion time,and that the corrosive degree increases with the corrosive time.Chemical analysis of corrosive environment indicates that the Mg2+ concentration decreases and the SO42-concentration shows a parabolic trend with the corrosive time.So it is concluded that the compressive strength is closely related with the Mg2+ concentration and SO42-concentration of MgSO4 corrosive environment.Finally,a strength model of cement soil is set up based on the relationship of compressive strength and Mg2+ concentration and SO42-concentration.The predicted and measured values agree well so that the accuracy of the formula is rather high and the model may be used in practical design.