The present invention is directed to a two-component (2K) anhydrous composition comprising a first component (1) comprising calcium aluminate cement; Ground Granulated Blast Furnace Slag (GGBS); and fumed silica; and a second component (2) comprising calcined bauxite; and fused zirconia mullite.

Binders for geopolymers, which include: a) not less than 30 w % of a mixture of at least two chemically different aluminosilicates, b) not less than 20 w % of Ordinary Portland cement, and c) 8-20 w % of a mixture of calcium sulfoaluminate cement or calcium aluminate cement with a source of calcium sulfate, wherein in the mixture the weight ratio of calcium sulfate to calcium sulfoaluminate and/or calcium aluminate is between 0.08-1.5, preferably 0.3-1.1, more preferably 0.6-1.1. Also, geopolymers using such binders as well as their use in various construction methods.