Experimental Study on Stabilized Expansive Soil by Blending Parts of the Soil Kilned and Powdered Glass Wastes

This experimental study explores the utilization of glass wastes mixed with kilned soil for weak soil improvement. Expansive soil remains a reason for a lot of road and building damage through settlement and cyclic volume change. Replacing or stabilizing the soil can minimize the risks associated with the soil type. Cement and lime have been the major stabilizers. However, the cost of these materials is raised. Among many stabilizing materials, parts of the expansive soil burned and mixed with glass powder are investigated to fulfill the major requirements. It is proved that the soil sample taken requires improvement. Parts of the soil kilned and mixed with powdered glass waste have 75% of expansive soil kilned and 25% of glass waste powder, which are then added in expansive soil with percentages of 5%, 15%, and 25% to test the change that occurred on liquid limit, plastic limit, free swell, unconfined compression, compaction, California bearing ratio (CBR), and mineral composition. Maximum dry density (MDD) improved from 1.33 g/cm³ to 1.61 g/cm³, optimum moisture content (OMC) reduced from 40% to 21.3%, plastic index reduced from 58.79% to 19.91%, California bearing ratio (CBR) increased from 0.95% to 12.08%, and unconfined compressive strength (UCS) changed from 216 kPa to 910 kPa on 14 days of curing period. Similarly, the addition of 15% and 25% of the stabilizer improved the free swell of expansive soil to 36% and 14%, respectively. CBR swell values significantly improved from 7.16% to 0.22%. Changes in mineral contents from X-ray diffraction (XRD) test are observed: montmorillonite and illite minerals disappeared, and the nonexpansive minerals are observed abundantly in stabilized soil. The addition of 15% to 25% of the stabilizer in expansive soil improved the physical and chemical properties as to be in the appropriate range for road subgrade construction use.

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