Durability of clayey soil stabilized with Potassium additive

Abstract

Plastic clayey soils are characterised by large volume changes associated with moisture variation. These soils must be enhanced to ensure their suitability for the construction of engineering infrastructures. Chemical stabilisation with Potassium ions additives from Potash fertiliser (KNO3) was explored in this research with main emphasis on durability of KNO3 treated soil. Many complementary techniques were used in both micro and macro tests: X ray diffraction, mercury intrusion porosimetry test, full scale water retention curve, shear strength test, and California bearing ratio test were conducted. The results show that the optimum amount of KNO3 required is 5% at 48 hours of curing. The addition of KNO3 causes a reduction in the ability of soil to retain water and a variatabletion in the grain and pore size distributions. Also, the addition of KNO3 to the plastic clayey soil played an important role in the transformation of the soil mineralogical compositions from montmorillonite to illite behaviour. The test results obtained during and after water leaching process on the leachate and leached soils show the ability of soil-KNO3 mixture to resist leaching is weak, and the necessity to protect the potassium stabilized soil against long term water penetration process.