Improvement of Gypseous Soil by Compaction and Addition of Cement

Abstract

The engineering problems faces by a civil engineer in building and construction, is almost foundation problems resulting from the properties of the beneath soil. One of the affected problems is the presence of gypseous soil. The presence of gypsum in some regions reaches up to 70%. Gypsum salts are one of the highly dissolved salts in water. The solubility depends on temperature degree, atmospheric pressure, and PH of the dissolved liquid. There are many treatments for such soils, some of them are physical like earth reinforcement, and compaction. The others are chemicals like the addition of lime, asphalt emulsion, oil products…etc(1). The aim of this study is to investigate the ability to improve gypseous soil by reducing the collapsibility during wetting with water, by the addition of Portland cement with different percentages:( 1.5%, 4%, 6%,7.5%, 10%), to gypseous soil with at different densities14 kN/m³ and 11 kN/m³. A laboratory model test consists of a cylindrical plastic container of 250 mm in diameter and 400mm in height. The soil was artificially prepared by mixing natural soil brought from a location near the Civil Engineering Department building in Diyala University and mixed with 70% gypsum. The density of the soil was controlled by placing the required weight inside the container of known volume, to the required height. A rectangular footing 25mm*40mm made from steel was used. The stress was applied from a fixed loading system designed especially for model tests and.......