Improvement of Gypsiferous Soils Properties by Hydrated Lime in the Najaf City, Middle of Iraq

This study includes the effect of lime addition on engineering properties gypseous soil taken from a part Najaf- Karbla plateau (52, 48, 72% gypsum). Also this shows increase in proportion gypsum northwest direction area. Maximum dry density and optimum moisture content (2.065, 2.025 2.003) at 15%, 14% 15% respectively for three samples. The maximum decrease while increases with increasing ratio hydrate lime. results show that gypscous becomes non - plastic when treated by > 3 % hydrated Cohesion Force, percentage 3% to 6%, after which it decreases as reach zero became 9%. reason is cohesion strength between molecules limit adding then 9% added liquid limits are changed more liquidity it's due significantly, clear liquidity. After work separate each other, force decreases. It also noted internal friction angle