Soil Stabilization and Modification Treatments

Soil Modification is sometimes referred to as "mud drying" however, soil modification is much more than that. Often, subgrade soils have high moisture content, giving them poor workability and lacking sufficient strength to support construction equipment. Chemical additives such as lime, fly ash, and cement can be added to these soils to dry and improve the soil’s workability.

Soil modification refers to the process of adding and mixing the above chemical agents into the soil to dry it, improve its workability, reduce the plasticity index (PI), and shrink swell potential. These improvements often result in slight strength gains for the soil.

There are two types of Soil Stabilization, chemical and bituminous. Chemical stabilization is the process of adding and mixing additional amounts of the same chemical agents used in soil modification into the soil to allow a significant increase in the strength of the soil. This improves the load-bearing capacity and physical properties of a subgrade to support pavements and foundations.

The soil property results from soil stabilization and modification treatments are the same. Bituminous soil stabilization results in an improvement in soil strength but is not generally recommended for clay soils; therefore, it is not used to modify soils. Many agencies require a specified increase in unconfined compressive strength before a soil can be considered a stabilized layer.