Effect of Adding Cement Dust Waste on the Geotechnical Properties Behavior of Selected Gypseous Soil in Al-Najaf City

Abstract

The Gypseous soils are soils that cause major engineering problems such as collapse or settlement in several cities in Iraq, and the world. For these reasons, several methods were used to get rid of these engineering problems, including, using additives. This study utilized cement dust waste as an additive in the form of cement dust to improve some of the physical and engineering properties of gypseous soils collected from two sites in Al-Najaf city, with various content of gypsum. Cement dust waste was used in different percentages of %5, 10%, and 15%. Results showed a slight improvement in some properties, where the percentage of the liquid limit increased with the increase in the percentage of additives. Values of the specific gravity decreased in all the added percentages of cement dust. The values of the maximal weight were little decreased, while the optimal moisture percentage increased by increasing the percentage of the additive. Results of the direct shear tests, utilized a percentage of 15 % of cement dust waste, were used in two cases for dry soil and soaked soil for curing 1 day and 7 days. The results showed increasing the quantity of additives by 15% increased the cohesion value which is due to the action of cement dust particles forming bonding bonds with gypseous soil grains. The internal friction angle of cement dust was lower than the internal friction angle of gypseous soil, resulting in a small decrease in the internal friction angle.