Cellular concrete - from fly ash by product of combustion of provence coal

摘要

Cellular concrete whose main constituent is calcium-containing fly ash from the combustion of Provence basin coal and which is formed from a mixture of fly ash, sand, water and aluminium powder. Up to 10% Portland cement may be added. Free chalk in the flash reacts with Al to evolve H2. The reactivity is controlled by dry grinding the fly ash, with or without part or all of the sand to a specific surface of 2500 cm 2/g. After mixing the concrete is allowed to "rise" then heated in a steam autoclave. The product has a density 0.65 and dimensional changes 0.1 mm/metre after 120 hours in water.