Altering natural soil to serve an engineering objective is known as soil stabilisation. Improvements to reinforce road pavements include raising the tensile strength, weight-bearing capacity, and general performance of in-situ subsoils, sands, and waste materials.
Several novel soil stabilising approaches provide hydrophobic surfaces and bulk that shield roads from severe frosts or water intrusion by preventing water from penetrating the treated layer. However, modern technology has led to a rise in the amount of conventional chemicals used to stabilise soil.
The best soil stabilisation technique is chosen based on several factors, including the kind of soil accessible, the amount of time and money required, etc.
Different methods of stabilising soil
Soil stabilisation may be classified into three main categories: chemical, physical, and biological.
- Biological soil stabilisation
Using afforestation or planting, it controls erosion. Architectural, morphological, physiological, and biotic root features help soils evolve physically and chemically, ensuring structural stability. This strategy works on water- and wind-exposed terrain not suited for development. However, planting requires further soil stability from when seeds or seedlings are placed until they are robust. Otherwise, water or wind would carry seeds or young plants away with the surface layer.
- Physical soil stabilisation
Soil stabilisation involves altering soil particle size distribution and plasticity, while mechanical stabilisation alters soil porosity and interlock. Five methods include compaction, pre-wetting, reinforcement, wetting-drying cycles, and solid wastes. Compaction expels air gaps, pre-wetting reduces soil swelling, wetting-drying cycles stabilise soil, and reinforcement uses geosynthetics or fibres. Solid wastes like plastic, glass, wood, and e-waste are primary components. Recent efforts to promote a circular economy include soil stabilisation using waste solids, with drainage and compaction systems being two systems. Compaction makes soil denser, less compressible, and more water-resistant, supplementing chemical stabilisation.
- Chemical soil stabilisation
Both conventional and non-traditional agents may be used to accomplish this. In contrast to the most recently discovered agents, the two classes differ according to the pre-existing and well-established additions. Traditional chemical stabilising agents are often calcium-based and include fly ash, cement, lime, and bitumen. They experience short- and long-term chemical changes when exposed to water, improving the soil matrix’s overall properties, including reduced swelling, increased shear strength, and resistance to wetting and drying. Cation exchange, agglomeration, flocculation, pozzolanic reaction, and carbonate cementation are the stabilising processes for conventional chemical stabilisers.
When there is enough moisture in the soil, non-traditional substances react chemically with the soil to create physicochemical interactions. Blasting emulsions, pulverised coal bottom ash, steel slag, polymers, sulfonated oils, bitumen emulsions, cement kiln dust, and powdered granulated blast furnace slag are a few examples. They are accomplished using different materials that serve as binders, water repellents, and/or compaction aids. Naturally, the stabiliser with all three qualities is the most effective. These chemicals are often sprayed into soil after being diluted with water and mixed or compacted.
Soil stabilisation is an important procedure in building projects that improves the engineering qualities of soil. To improve soil’s stability, strength, and load-bearing capacity, mechanical, chemical, and biological techniques may be used alone or in combination. Construction projects may get superior outcomes, enhanced durability, and long-term cost savings using efficient soil stabilisation with high-quality soil stabilisation products.
