Evaluation of Sand Glass Powder to Enhance Some Geotechnical Properties of Expansive Clay Soils.

Expansive soil is mostly considered a problematic soil due to its potential for changes in geotechnical characteristics such as heave, differential settlement, expansion and shrinkage. This soil has a low bearing capacity and it is very sensitive to moisturizing, drying and other factors. Consequently, these soils need suitable improvement before any construction. The waste glass (WG) has been used to improve and stabilize the weak soils. In this study, an investigation into the influence of sand glass powder (SGP) addition to the expansive soil is conducted. SGP is a natural material abundantly available in western Iraq. It is characterized by a high content of silicate minerals, aluminum, iron and other elements that are effective in reducing the risks of the expansive soils. Although, WG has similar properties, it is present to a lesser extent. Moreover, recycling waste glass requires labor, as well as crushing and grinding processes, making it significantly more expensive compared to raw materials such as SGP. The expansive clay soil and natural sand glass are taken from the western Iraq. SGP was mixed with the dry expansive clay soil by different intensities (0%, 5%, 10%, 15%, and 20%). The result showed an enhancement in the expansive clay soil, where the geotechnical properties such as liquid limit, plastic limit, and plastic index (L.L., P.L. and P.I) were declined at about 14.5%, 24.1% and 35.8% by increasing SGP at 20%. Also, the free swelling and swelling pressure were reduced by 18.7% and 32.9% with an increase of SGP at 20%. Moreover, the unconfined tests showed that the treated samples increased the value from 90.12 kPa to 151.8 kPa after the addition of 20% of SGP. This improvement is particularly important because of the availability of the SGP as a natural material with a very low cost. The study is sustainable and environment friendly because of the high reduction for swelling potential. [ABSTRACT FROM AUTHOR]