Inorganic binder system comprising blast furnace slag and solid alkali metal silicate

1. An inorganic binder system comprising

(i) blast furnace slag, wherein the blast furnace slag comprises from 30 to 45% by weight of CaO, 4 to 17% by weight of MgO, 30 to 45% by weight of SiO 2 , and 5 to 15% by weight of Al 2 O 3 , and

(ii) at least one solid alkali metal silicate having the empirical formula m SiO·n M 2 O,

wherein M is selected from the group consisting of Li, Na, K and mixtures thereof, and wherein the inorganic binder system is obtained by co-grinding a mixture comprising the blast furnace slag and the at least one solid alkali metal silicate.

2. The inorganic binder system according to claim 1 , wherein the molar ratio of m:n is ≤4.0.

3. The inorganic binder system according to claim 1 , wherein the weight ratio of the blast furnace slag and the at least one solid alkali metal silicate is in the range from 500:1 to 1:5.

4. The inorganic binder system according to claim 1 , having a Blaine value in the range from 200 to 1000 m 2 /kg, as determined according to DIN EN 196-6.

5. The inorganic binder system according to claim 1 , wherein co-grinding is performed using a ball mill, a planetary mill, a disc mill, a rotor mill, a vertical mill or a mortar grinder.

6. The inorganic binder system according to claim 1 , wherein the blast furnace slag is granulated blast furnace slag or ground granulated blast furnace slag.

7. The inorganic binder system according to claim 1 , further comprising at least one additional inorganic binder selected from the group consisting of hydraulic binders, latent hydraulic binders, pozzolanic binders and mixtures thereof.

8. The inorganic binder system according to claim 7 , wherein the pozzolanic binder is selected from the group consisting of precipitated silica, pyrogenic silica, microsilica, ground glass, brown coal fly ash, mineral coal fly ash, metakaolin, pozzolana, tuff, trass, volcanic ash, natural and synthetic zeolites and mixtures thereof.

9. The inorganic binder system according to claim 1 , wherein the inorganic binder system further comprises at least one additive.

10. The inorganic binder system according to claim 2 , wherein the molar ratio of m:n is ≤3.8.

11. The inorganic binder system according to claim 3 , wherein the weight ratio of the blast furnace slag and the at least one solid alkali metal silicate is in the range from 30:1 to 1:1.

12. The inorganic binder system according to claim 9 , wherein the at least one additive is selected from the group consisting of grinding aids, fillers, accelerators, retarders, rheology modifiers, plasticizers, fibers, alkaline activators, surfactants and mixtures thereof.

13. A process for the manufacture of the inorganic binder system as defined in claim 1 , comprising co-grinding a mixture comprising

(i) the blast furnace slag, wherein the blast furnace slag comprises from 30 to 45% by weight of CaO, 4 to 17% by weight of MgO, 30 to 45% by weight of SiO 2 , and 5 to 15% by weight of Al 2 O 3 , and

(ii) the at least one solid alkali metal silicate,

and optionally mixing the obtained co-ground mixture with at least one additional inorganic binder and/or at least one additive, to obtain the inorganic binder system.

14. The process according to claim 13 , wherein the co-grinding is performed using a ball mill, a planetary mill, a disc mill, a rotor mill, a vertical mill or a mortar grinder.

15. The process according to claim 13 , wherein co-grinding is performed until the co-ground mixture has a Blaine value in the range from 200 to 1000 m 2 /kg, as determined according to DIN EN 196-6.

16. An inorganic binder system, obtained according to the process according to claim 1 .

17. A construction material formulation and/or building product comprising the inorganic binder system as defined in claim 1 .

18. The construction material formulation and/or building product of claim 17 wherein the construction material formulation and/or building product is selected from the group consisting of concrete, finished concrete parts, concrete goods, concrete blocks, on-site concrete, sprayed concrete, ready-mixed concrete, building adhesives and thermal insulation composite system adhesives, concrete repair systems, one-component and two-component sealing slurries, screeds, knifing fillers and self-levelling compositions, tile adhesives, plasters and renders, adhesives and sealants, coating systems, dry mortars, joint grouts, drainage mortars, repair mortars and mixtures thereof.

19. A cement, mortar or concrete containing the inorganic binder system as defined in claim 1 .