Geotechnical Properties of Expansive Soil Treated With Silica Fume


Problematic soils such as expansive soil are those clay soils which exhibitedsignificant volume changes as results of soil moisture variation, when a dry mass ofclay is allowed to absorb water, the effective size of particles increases and thereforethe clay mass swells. This type of soil, upon wetting and drying, causes sever damageto structures built on such soil.A treatment of swelling/shrinkage using silica fume was studied in this work. Thesoil selected for the present investigation classified as (CH) according to unified soilclassification system with liquid limit = 51% and plastic limit = 27%. Soil specimenswere mixed with various percentages of silica fume contents (10%, 20%, 25%, 30%and 50%) to determine their effects on geotechnical properties such as Atterberge’slimits, compaction, unconfined compression and swelling properties.The results show that the silica fume played an important role in improving theproblem of swelling behavior in expansive soil. The silica fume decrease liquid limitand changed compaction parameters of expansive soils the moisture content valuesincreased and the maximum dry unit weight values decrease. Also the silica fumeincreased unconfined compressive strength, decreased the compressibility and thevertical swelling percentages of clayey soil-silica fume mixtures.