5 Methods of Soil Stabilization
Following are the 5 Methods of Soil Stabilization:
1. Mechanical soil Stabilization.
2. Soil-Cement Stabilization.
3. Soil-lime Stabilization.
4. Soil-Bitumen Stabilization.
5. Chemical Stabilization.
Methods of Soil Stabilization Are Described Below
1. Mechanical Soil Stabilization
⇰ In this method, the stability of the soil is increased by blending the available soil with imported soil or aggregates so as to obtain a desired particle size distribution and by compaction of the mixture to achieve the desired density.
⇰ This method is generally adopted for the construction of sub-base and base course. It is also useful for the construction of a surface course of low-cost roads such as village roads when the traffic and rainfall are low.
2. Soil-Cement Stabilization
⇰ Soil-cement is an intimate mixture of soil, cement and water which is well compacted to form a strong base course. The addition of cement in small proportion to soil improves its strength and modifies the properties of soil.
⇰ Soil-cement stabilization can be used as a sub-base or base course for all types of pavements. However, this method can not be used as a surface course due to its poor resistance to abrasion and impact.
⇰ This method is costly and needs a high degree of quality control as compared to soil-lime stabilization.
3. Soil-lime Stabilization
⇰ Soil-lime is widely used either as a modifier for clayey soil or as a binder. When clayey soil with high plasticity is treated with lime, the plasticity index is decreased and the soil becomes brittle and easy to be pulverized having less attraction with water. Lime also imparts some binding action.
In fine-grained soil, lime imparts pozzolanic action which increases its strength. All these modifications are considered desirable for stabilization work.
⇰ Soil lime is quite suitable as a sub-base course for the high type of pavements with low traffic. However, this method can not be used as a surface course due to its poor resistance to abrasion and impact. This method is quite suitable in warm regions, but not very suitable under freezing temperatures.
4. Soil-Bitumen Stabilization
⇰ The basic principles in bituminous stabilization are waterproofing and binding. Generally, both the binding and waterproofing actions are provided to the soil by adding bituminous material. The most commonly used bituminous materials are cutback and emulsion.
⇰ Bituminous stabilized layer can be used as a sub-base or base course of ordinary roads and even as a surface course for roads with low traffic in low rainfall regions.
5. Chemical Stabilization
⇰ Granular soils lack stability when they are too dry. If their moisture content is stabilized by the addition of some chemicals, then these soils can be used successfully.
Chlorides of calcium and sodium are the most popular salts used for this purpose. A number of other chemical materials such as sodium silicate, lignin, resins, molasses etc., are used for the chemical stabilization of soils.
⇰ The addition of chemicals with the soil helps to retain moisture & to impart some cohesion and thus retain stability. These chemicals also reduce the dust nuisance in un-surfaced roads.
Consolidation Settlement Analysis – Soil