Soil Stabilisation
Improving weak soil's strength/durability by additives or mechanical means
Soil stabilisation is the process of improving the engineering properties — strength, stiffness, volume stability and durability — of an in-situ or borrow soil so it can serve as subgrade, sub-base or fill instead of being excavated and replaced. Mechanical stabilisation regrades the particle size by blending soils/aggregate and compacting; chemical stabilisation adds binders — lime (effective on plastic clays, reducing PI and swelling), cement (granular and low-plasticity soils), bitumen, fly ash, or proprietary enzymes/geopolymers.
It is central to economical road and embankment construction, governed for pavements by IRC 37 and IRC SP 89 and tested per IS 4332 (methods of test for stabilised soils) and IS 2720. Lime stabilisation of expansive/black-cotton soils both raises strength and curbs the swell-shrink that destroys pavements; cement-stabilised sub-bases (CTSB/CTB) provide stiff load-spreading layers. Design fixes binder type and dosage by trial mixes against target UCS/CBR, with field control of pulverisation, mixing uniformity, moisture and compaction.
- Pavement subgrade + sub-base improvement (IRC 37)
- Expansive/black-cotton soil treatment
- Cement-treated sub-base/base (CTSB/CTB)
- Embankment + fill from marginal borrow soils
- Reducing excavation + import of select fill