Lithium silicate is a chemical hardener applied to the concrete surface to improve its strength, durability, longevity, and abrasive resistance. The increased strength of concrete is due to the calcium silicate formed as a result of lithium silicate reaction with calcium hydroxide.
The calcium silicate thus formed precipitates in pores and canals of concrete and consequently increases its surface strength along with other influential properties. Generally, spray operation is used to apply lithium silicate to a newly placed concrete surface.
How Lithium Silicate Chemical Hardener Reacts with Concrete?
Lithium silicate reacts with calcium hydroxide, which is a byproduct of cement hydration, in concrete and produces Calcium Silicate Hydrate (C-S-H). This newly produced calcium silicate hydrate settled mostly in pores and canals close to the concrete surface. Moreover, its effect increases manifold when applied to concrete that is porous.
The chemical reaction between concrete and lithium silicate takes place over a range of two weeks. Also, calcium silicate hydrate is the same substance that is created as a result of blending water with cement and provides concrete with much of its strength and hardness. The extent of penetrability of lithium silicate is about 4 mm to 5 mm on the top surface of normal weight concrete.
Recommendations for Lithium Silicate Applications
When the temperature is too high, the application of lithium silicate would not provide the expected results because the material would begin to evaporate even before it begins to penetrate into concrete.
Whereas if water is used to cool down the concrete surface before the application, it should be allowed to dry properly otherwise low-temperature humidity and high-temperature humidity of air in concrete would make the moisture to migrate to concrete surface. Consequently, the lithium silicate hardener wouldn’t penetrate into concrete.
It is therefore recommended to apply lithium silicate chemical hardener at a time when the concrete surface has a reduced temperature with low relative humidity. This condition is advantageous for the application of lithium silicate concrete hardener.
Finally, lithium silicate chemical hardener shall be applied continuously till the concrete surface is saturated. This allows us to use the full potential of chemical concrete hardener.
Uses of Lithium Silicate in Concrete
Floors in industrial plants and warehouses, storage silos, sewage plants, chemical processing facilities, refineries, and heavy pedestrian floor traffic areas, such as civic centers, sports arenas, stadiums, hospitals, airports, and museums.
- It improves concrete surface strength, abrasive resistance, durability, and longevity.
- It can be applied to the concrete surface easily and quickly.
- Lithium Silicate Densifier is considerably more alkaline, raising the pH of the surface concrete and reducing the possibility of alkali-silica reaction (ASR).
- It used to decorate concrete surfaces.
- It leaves no residue to clean up provided that the correct amount is applied.
- Lithium silicate easily penetrates into concrete because of its low viscosity, and hence harden concrete properly.
- It is highly reactive, so it reacts with concrete easily.
- Improve protection against staining and freeze-thaw cycle damage.
- Reduction and mitigation of alkali-silica reaction at the topical surface.
- As calcium hydroxide migrates to the surface of fresh concrete, it reacts with atmospheric carbon dioxide, producing carbonation which could be detrimental to concrete if reactive aggregates and moisture are present.
- Efflorescence formation due to lithium silicate hardener is probable. Nonetheless, such probability is much in lower in lithium silicate compare with other chemical concrete hardeners.