Investigating the Use of Calcined Dolomite to Stabilize Expansive Soils

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Soils which possess high amounts of clay content are more susceptible to shrink and swell behaviors due to varying moisture contents. This makes it hard for such soils to be suitable for engineering structures to be constructed on them for example roads, foundations and buildings. For a long time, soil stabilization has been used as a technique to modify such soils in order to change their properties so that they can favor construction of different structures. Cement and lime have been the most common stabilizers that aid chemical stabilization of soil. However, these two are so much competitive on market hence necessary to find other alternative materials that can perform the same purpose of stabilizing soil. This study explored using calcined dolomite to improve expansive soil. Various lab tests like sieve analysis, hydrometer tests, plasticity tests, compaction tests, strength tests, and swelling tests were performed. The untreated soil was a highly plastic clay of PI 38.9 and LL 61% and therefore unsuitable for subgrade road construction. The soil was mixed with different amounts of calcined dolomite (5%, 10%, 15%, and 20%). A 10% mix showed the best results, significantly reducing fine particles and plasticity that is from a PI of 38.9% to 12.2%. While density increased slightly, water content also decreased. Importantly, swelling and shrinkage of the soil were greatly reduced. Strength also increased considerably as CBR increased from 6.4% to 31.7%. These findings suggest calcined dolomite could be a promising and effective method for stabilizing expansive soils.