The process of maintaining or improving the performance of a soil as a constructional material, usually by the use of admixtures, is known as:
Try it first: pick an option, then read the explanation.
Correct answer: B. Soil stabilisation
Asked in SSC JE 2015
Detailed Explanation
Natural soils are often too weak, too plastic or too sensitive to water to be used directly in roads, embankments and foundations. Their properties can be improved before use.
Why “Soil stabilisation” Is Correct
Soil stabilisation is any process that improves or maintains the strength, durability and stability of a soil as a construction material. It is usually done by adding admixtures — other soils (mechanical stabilisation), cement, lime, bitumen or chemicals — followed by compaction.
| Method | How it works | Best for |
|---|---|---|
| Mechanical | Blend soils to a good grading and compact | Granular bases and sub-bases |
| Cement | Cement hydrates and binds particles | Sandy and low-plasticity soils |
| Lime | Cation exchange and pozzolanic reaction cut plasticity and swelling | Clays, black cotton soil |
| Bitumen | Coats grains, waterproofs and binds | Sandy soils |
| Chemical / other | Calcium chloride, sodium silicate, geotextiles, heat | Special cases |
Why the Other Options Are Wrong
- A. Soil exploration: Soil exploration is investigating subsurface conditions (boring, sampling, testing).
- C. Soil compaction: Compaction densifies soil by mechanical energy; it does not involve admixtures, though it is part of most stabilisation.
- D. Consolidation: Consolidation is the slow volume decrease of saturated clay as water drains out under load.
Key Point
Stabilisation = improving soil as a construction material, usually with admixtures.
Key Concepts for Students
- Mechanical stabilisation blends coarse and fine soils for good grading.
- Stabilised soils are common in road bases and sub-bases.
- Good stabilised mixes balance friction (granular part) and cohesion (clay binder).
Practice more: this is question 2 in Soil Stabilization MCQs – Part 1. Try the whole set and check every answer instantly.