An unstable clay soil treated with lime changes its physical properties and is transformed into a stable and durable plate. Lime profoundly modifies the physical characteristics of the soil, decreases the liquid limit and the plasticity index. Increases plastic limit, CBR and compressive strength. Its high index of pozzolanic receptivity makes it possible to transform the inert components, agglomerates the fine particles of clay and transforms a highly plastic soil into another very stable one. Ionic exchange (Ca++ / Na + H+) and the formation of silicates (3CaO. SIO2 ; 2CaO. SiO2) are the fundamental reactions.
Lime hydration also plays an important role:
CaO + H2O –>Ca(OH)2 + 278 Kcal/Kg CaO.
Wet soils dry out when lime is added and this increases their yield strength.
The sub-base and base layers stabilized with lime constitute a barrier resistant to both superficial and capillary water. The floors are resistant to frost and construction delays due to rain are reduced.
A high value of the specific surface area and a percentage of useful CaO above 90% are fundamental for its good behavior next to well-classified granulometries.