Determining the properties of expansive soils, under different environmental conditions

DETERMINING THE PROPERTIES OF EXPANSIVE SOILS, UNDER DIFFERENT ENVIRONMENTAL CONDITIONS Murat ÇETİN Civil Engineering, Master Thesis, 2003 Supervisor: Assist. Prof. Yücel GÜNEY SUMMARY In civil engineering, soils which have considerable potential of volume change by the changes in water content are named as expansive soils. Expansive soils cause significant damages in many parts of the world. The problem of expansive soil is more dangerous to structures particularly light buildings and pavements, than any other natural hazards including earthquakes and floods. Generally, stabilization with chemical admixtures, prewetting, compaction control, surcharge loading, moisture control systems are used to solve the expansive soil problems. Because of the effective and economical advantages, lime stabilization is the most commonly used method. These soils are subjected to many environmental conditions such as wetting-drying, temparature, curing period, freeze-thaw, variations of water content, pollution etc. before and after stabilization. In this study, natural and different bentonite-kaolinite mixtures which have swelling potential were used. The effects of water content, applied compaction energy, admixtures, curing period, cure tempruture, freeze-thaw cycles, wetting-drying cycles, on swelling characteristics were investigated on the natural and lime-cement stabilized specimens. It was determined that the swelling potential is increased by the reduction of water content and increase in applied compaction energy. Additionally it was seen that the swelling potential decreased with the increase of admixture and curing temperature and period. On natural soils wetting and drying cycles reduced the swelling potential where as, on stabilized soils it was determined that it caused small increase in the swelling potential. Keywords: Curing Conditions, Expansive Soils, Stabilization, Wetting-Drying