Enhancement Mechanism of the Mechanical and Shrinkage Properties of Red Clay Solidified Using the Consolid System

Abstract

As a typical special soil, red clay found in Guizhou Province, China, must be improved before it can be used for projects owing to its high plasticity. As a soil curing agent, the Consolid system is applicable to a wide range of soils, has good improvement effects and a simple operation, and is environmentally friendly. The effects of the dosage and curing age of the Consolid system on the unconfined compressive strength and shrinkage properties of the cured red clay–gravel mixture are studied. The results showed that both these properties of the red clay–gravel mixture were significantly improved by the Consolid System, and the higher the dosage of the Consolid system, the better the improvement effect. The thermal methods of thermogravimetric analysis and differential scanning calorimetry were used to determine that the bound water content was related to the amount of Consolid system admixture. With the increase in the dosage of the Consolid system, the weakly bound water content of red clay appeared to be reduced to different degrees, while the strongly bound water content was reduced to a lesser extent. The reduction in the weakly bound water led to an increase in the molecular gravitational force between the soil particles. This promoted the agglomeration of the soil particles to form a stronger agglomerate structure, thereby enhancing its mechanical properties. The physical phase analysis of cured soils with different amounts of Consolid system admixture was carried out by X-ray diffraction analysis. No chemical reaction occurred during improvement, but the crystal spacing was reduced. This phenomenon could be a factor improving the shrinkage properties. In addition, the shrinkage properties of the soil improved because of the low number of exchangeable cations on the mineral surface, allowing the cured soil to enter a charge equilibrium state quickly.