POZZOLANS are materials that provide the finished cementitious products with superior durability, chemical resistance and substantial reduction of unsightly efflorescence.
POZZOLANS react with calcium hydroxide and are used in conjunction with Portland cement to minimise the occurrence of efflorescence.
Portland cement typically has between 8% and 10% free calcium hydroxide (lime) present. This lime can slowly migrate to the surface of the cured concrete through cracks and micropores. When the lime gets to the surface it reacts with carbon dioxide in the air to form calcium carbonate. This is white, crystalline and a somewhat insoluble product. The product is commonly called efflorescence and is undesirable as it’s unsightly.
Trass Floor ®