A Laboratory Evaluation of Stabilization of Silty Clay Soil by Using Chloride Compounds


Large areas of Iraq consist of soils with high clay contents which have lowstrengths and bearing capacity.This problem has an influence on construction ofroad and highway, if adequate support does not exist, the road will rapidlydeteriorate. The solution to these construction problems is by soil treatment withchemical additives. The main objective of this study is to investigate effectivenessof salts used as an additive in stabilization of silty clay soil. Three types of saltsused which are sodium chloride (NaCl), magnisum chloride (MgCl2) and calciumchloride (CaCl2). Various amounts of salts (2%, 4%, and 8%) were added to thesoil to study the effect of salts on the consistency limits, compaction characteristicsand CBR value.The test results indicated that the liquid limit, plastic limit andplasticity index decreased as the salts content increased. The addition of salts to thesoil increased the maximum dry density and reduced the optimum moisturecontent. The addition of (2 %) salt to the soil causes increases the CBR valuebetween (8 to 28 %), while, in samples containing large amount of salt (4 and 8 %)the increase was between (55 to 80%).The CBR value increased as the salt contentincreases for different type of salt and the greatest value is found in the soil treatedwith (4%) calcium chloride which was equal to (80 %).