Geopolymer concrete is made from fly ash and an alkaline solution, combining waste products into a useful material. Its setting mechanism depends on polymerization and it cures between 60-90 degrees Celsius. It is made by mixing fly ash aggregates with an alkaline activator solution of sodium or potassium hydroxide and silicate. The fresh concrete can be worked with for up to 120 minutes before setting and does not lose strength. It offers advantages over traditional concrete like lower carbon emissions, better strength and fire resistance, and excellent properties in acid and salt environments.