Experimental Study and Mechanism Analysis of Cemented Soil under Magnesium Chloride Solution

The Mg²⁺ and Cl^– in the surrounding environment of cement-soil piles may affect the mechanical properties of cemented soil, which may cause some serious damage to structures. In order to simulate and study the erosion effect process, a series of unconfined compressive tests were conducted on the cemented soil blocks which were cured in the MgCl₂ solutions with various concentrations and ages. For comparison purposes, photos of the blocks were taken and the Mg²⁺ and Cl^– concentration of the MgCl₂ solution were recorded after the curing process. The testing results show that the MgCl₂ solution does make out-looks of the cement-soil samples change, but not seriously, mainly represent crystallization adhering to the surface. The unconfined compressive strength of cemented soil block is decreased with the increasing of solution concentration, increased with the curing time. A coefficient α is put forward to predict the modification of the compressive strength of cemented soil in various concentration of MgCl₂ solution. The Mg²⁺ concentration is increasing with the erosion time increasing, Cl^– concentration is increasing before first 7 days, then decreased after 7 days. Chemical analysis indicates that the corrosion of MgCl₂ solution to cemented soil is a composite action including resolving and crystallizing corrosions.