Effect of Carbonation on the Collapse Potential of Magnesium Oxide Treated Gypseous Soil

Collapsible soils are soils susceptible to large volumetric strains when they become saturated. Numerous soil types fall in the general category of collapsible soils, including gypseous soil which is characterized by relatively low density, appreciable strength and stiffness in the dry state, but is susceptible to significant deformations as a result of wetting. The aim of this study is to investigate the effectiveness of curing period time of carbonation on magnesium oxide stabilization of gypseous soil. In this research, magnesium oxide is used to improve a collapsible gypseous soil by using (۰, ۵, ۱۰ and ۱۵%) with two relative densities (۳۵ and ۷۵%) and carbonation at different carbonation periods (۰, ۱, ۳ and ۲۴ hours). Conventional collapse tests, single oedometer and double odeometer and modified collapse test are used in this research to investigate the effect of carbonation periods on the improvement of the soil. The modified collapse test apparatus is used. The results illustrated that the collapse potential decreased more than ۶۵% and ۵۵% for the carbonated soil without treatment for conventional tests and modified collapse test, respectively. A decreased about ۵۵% for treated soil with ۱۰% magnesium oxide and carbonated for ۳ hours for both of conventional tests and modified collapse test. The carbonation period time is used to accelerate the improvement of the soil as well as decreased the collapse potential and the results showed that no clear change in collapse potential for the period time more than ۳ hours.

Keywords:

Collapsible Soil , Gypseous soil , Magnesium oxide , carbonation