Strength improvement of expansive soil by utilizing waste glass powder

Abstract

Expansive soils expand and lose their strength when wetted and shrink when dried, and this makes a considerable volume change. Construction on expansive soils has made problems around the world for different civil engineering projects such as highways, railways, embankments, and foundations. Therefore, the improvement of expansive soils is crucial, especially for road construction. The strength improvement of these types of soils can be gain by adding another material, and waste glass powder (WGP) was selected for this study. The WGP was crushed and mixed with the soil sample with various percentages: 2.5 %, 5%, 10 %, 15 %, and 25 % by the dry weight of the soil. Various laboratory tests were conducted for the treated and untreated expansive soil with the different percentages of the WGP, including Atterberg limits, compaction, free swelling, unconfined compressive strength (UCS), direct shear strength, and California bearing ratio (CBR) tests. According to the test results, adding WGP to the expansive soils has a significant impact on the consistency and shear strength of the soil sample. In addition, improving subgrade expansive soil with 15 % of WGP decreases the thickness of the sub-base by about 63 %. The optimum percentage of the WGP for enhancement this type of soil is around 15 %.