Geopolymer is an inorganic binder created by the alkaline activation of aluminosilicates, such as fly ash or blast furnace slag, and forms a sustainable alternative to Portland cement with a significantly lower CO₂ footprint.
Whereas traditional cement requires a lot of energy and emissions, geopolymer makes use of industrial by-products. This gives it a growing role in sustainable construction.
How geopolymer works
Geopolymer forms when aluminosilicates react with an alkaline activator (for example sodium silicate or caustic soda). A three-dimensional network develops that hardens into a strong, stone-like material.
Important raw materials:
- Fly ash: a residual product from coal-fired power plants.
- Blast furnace slag: a by-product of steel production.
- Metakaolin: calcined clay.
Application
Geopolymer is used for:
- Sustainable concrete with a low CO₂ footprint.
- Fire-resistant and chemically resistant applications.
- Repair mortars and precast elements.
| Property | Geopolymer | Portland cement |
|---|---|---|
| CO₂ emissions | Low | High |
| Chemical resistance | High | Moderate |
| Curing speed | Fast | Medium |
Advantages include low environmental impact, high strength and good resistance to acids and high temperatures. Points of attention are the availability of suitable raw materials and the precise dosing of the activator.
Related terms
- Concrete
- Cement
- Binder
- Sustainability
- Mortar
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