Experimental Study of Wollastonite Powder Effects on Dispersive Potential and Mechanical Properties of Clay

Document Type : Original Article

Authors

Department of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran.

Abstract

As it is well-known, dispersive clay soils pose challenges in construction projects, so thus it requires modification and improvement. The main issue in this article is studying the effects of wollastonite powder on the geotechnical properties of dispersive clay soil. Wollastonite, a mineral substance is derived from natural limestone deposits, is used in various forms, such as fibers, tufts, or powders, which is used in multiple industries. Several tests such as pinhole, compaction, Atterberg limits, unconfined compressive strength, and CBR tests, are conducted on clay samples, which are containing different percentages (2, 4, 6, 8, and 10 percent) of wollastonite powder. The curing times of 3 and 7 days are also considered. The obtained results reveal that wollastonite powder not only increases the resistance parameters, but also can reduce dispersive potential. Added wollastonite powder to dispersive clay soil reduced the optimum moisture content to 8.89%. It increases the specific gravity to 1.62%, and the plasticity index decreased to 30.76%. Saturated soil samples had lower CBR strength than dry samples. Reaching up to 10% wollastonite content in The CBR test improves the strength of both saturated and dry samples significantly up to the enhancement of 89% (saturated) and 141% (dry) in comparison with original soil. Using 8% wollastonite powder, the compressive strength of the unconfined specimen is enhanced by 181% in 7 days as a result it has better performance than other samples. Also, it is noted that curing time is crucial item in stabilizing clay soils.

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