The effect of magnesium chloride solution on the engineering properties of clay soil with expansive and dispersive characteristics

Abstract Because expansive and dispersive soils damage engineering structures, extensive studies on using additives to ameliorate the effects of these soils have been conducted. In this study, the effect of magnesium chloride (MgCl 2 ) solution on the engineering properties of clay soils was evaluated. Previous studies on this subject have shown that MgCl 2 is more commonly used as an anti-icing agent on roads than as a soil stabilizer. MgCl 2 is also used to control dust and humidity on roads and to reduce the scattering of coarse particles from road surfaces. However, as the use of MgCl 2 becomes more common, its potential to improve the geotechnical properties of problematic soils will receive increasing attention. To this end, the variation in the engineering properties of expansive and dispersive clay soil samples as functions of the added MgCl 2 content was investigated. First, the physical and chemical properties of the soil sample were determined. Next, the swell percentage, swell pressure, crumb, pinhole and unconsolidated undrained (UU) triaxial compression tests were performed at different curing times on samples with and without the additive by compressing the sample to achieve particular compaction characteristics. Scanning electron microscopy (SEM) analyses were performed to observe the microstructures in the sample without the additive and with the amount of additive that most strongly improved the expansive and dispersive qualities of the clay. The results show that dispersive and expansive clay soils can be effectively improved using an additive MgCl 2 solution.