Abstract
The idea of this research is to improve the properties of expansive soil, such as, liquid limit, plastic limit and shrinkage limit by adding different amount of Ordinary Portland Cement to expansive soil. All variable which effect on soil properties, such as: amount of water, the ratio of compacting, time of mixing and the time for testing should be constant, to determine the differences in liquid limit, plastic limit and shrinkage limit for expansive soil with and without different amount of Ordinary Portland Cement. Four different percentages of Ordinary Portland Cement were used in those experiments, 2.5, 5.0, 10, and 15% by dry weight, these amounts were added to the expansive soil, mix each ratio with an amount of expansive soil and then samples were compacted by a steel rod. After that, the samples were cured for 7 days by covering them with a damp cloth. The samples were weighted and the dimension was measured on the first day; then on the seventh day; and finally on the 28th day to see the differences in weight and volume for each sample. The results were compared to find out which percentage indicated more effect on expansive durability in 7 and 28 days.
Liquid limit and plastic limit were reduced when the amount of cement is equal to 5%, and also the ratio of shrinkage, reduced when the amount of cement was equal to 5%. While the liquid limit, plastic limit and ratio of shrinkage seem to be constant when the amount of cement is more than 5%. So the ratio of 5% cement seems to be more suitable and more economical to use to improve the expansive soil properties.
