Water glass is referred to as an "air-hardening cementitious material" because:



It meets the definition of a cementitious material: It can harden from a liquid paste into a solid state and bind other materials together.



Its hardening process is essentially a physico-chemical process, the core of which is the precipitation and coagulation of silica gel.



This hardening process strongly relies on carbon dioxide (CO₂) in the air to trigger and complete the key chemical reaction.



It can only harden and gain strength in air. It cannot harden effectively or achieves very low strength in water or environments isolated from airaira

Water glass, commonly known as soluble alkali metal silicate (or "paohuajian" in Chinese), is a material typically composed of a mixture of alkaline metal oxides (e.g., sodium or potassium oxide) and silicon dioxide. It is widely used in construction and industrial applications.

I. Properties of Water Glass



Chemical Properties



Water glass is alkaline and can react with acids to form silica gel and corresponding salts.



It possesses good adhesion and viscosity.



It decomposes into silicon dioxide and sodium carbonate at high temperatures.



Water glass solutions dry in air to form a hard, glass-like film.





Physical Properties



Water glass typically appears as a colorless or slightly yellow transparent liquid.



It has high viscosity and density.



It is soluble in water but insoluble in alcoholic solvents.