Geopolymer concrete represents the radical alternative to the traditional cement industry. By replacing Portland clinker with a cold alkaline reaction, it transforms the waste of heavy industry into a synthetic rock of unrivalled performance.
The binder does not derive from the calcination of limestone, but from geopolymerisation. Two ingredients are required: precursors (powders rich in aluminium and silicon, such as fly ash or blast-furnace slag) and a liquid alkaline activator. Mixed together, they trigger an exothermic polycondensation that creates an amorphous, ultra-compact three-dimensional network. Producing 1 tonne of Portland cement generates about 850 kg of CO2; the geopolymer uses already-calcined materials as by-products of other industries.
The geopolymer matrix contains no free calcium hydroxide (portlandite). This absence solves the two great Achilles' heels of classic concrete: sulphate/acid attack and thermal vulnerability. Geopolymers withstand temperatures above 1000 degrees C without surface spalling, matching refractory ceramic materials.
Standards
European and international references applicable.
Physical properties
Usage environment
Flash setting risk: the alkaline reaction is fast — specific retarders are mandatory for ready-mix use. Preferred in prefabrication or 3D printing where the rapid setting is an advantage.