The portland cement is mixed with three expansion agents, viz. (a) 2-8% pentahydroxy-chloride, Al2(OH)5Cl, 2H2O (APC); (B) 4-15% gypsum; and (c) =7% lime. Mixing is carried out in the dry state. The mixt. is used for filling joints, e.g. in floors, between planks, in roads, or in other coatings. The expanding cements possess high strength and a stable vol. which does not alter with time. The APC is used as a source of aluminate ions, necessary for the formation of a large amt. of ettringite.

Simeonov Yordan Todorov

Papers

Expanding mortars based on Portland cement - which is mixed with aluminium penta:hydroxy-chloride, gypsum and lime