Abstract: A blended hydraulic cement composition, curable at low temperatures, including temperatures below the freezing point of water, is composed of portland cement, slag, pozzolans including metakaolin, and admixtures including potassium carbonate and water reducing compositions. The cement is particularly useful in producing concrete compositions which achieve high strength in a brief period of time, and continue curing at ambient temperatures, and temperatures below the freezing point of water.

Abstract: An early high-strength mineral polymer composition is formed of a polysialatesiloxo material obtained by adding a reactant mixture consisting of alumino-silicate oxide (Si.sub.2 O.sub.5,Al.sub.2 O.sub.2) with the aluminum cation in a four-fold coordination, strong alkalis such as sodium hydroxide and/or potassium hydroxide, water, and a sodium/potassium polysilicate solution; and from 15 to 26 parts, by weight, based upon the reactive mixture of the polysialatesiloxo polymer of ground blast furnace slag. Sufficient hardening for demolding is obtained in about 1 hour with this composition.