Slag-based hydraulic binder, dry mortar composition comprising same and system for activating a slag-based binder

1 . A hydraulic binder comprising, in % by dry weight:

A. at least 50 of at least one ground and granulated blast-furnace slag;

B. more than 5 of at least one calcium aluminate cement and/or of at least one calcium sulfoaluminate cement;

C. between 6 and 30 of at least one source of sulfate ions selected from the group consisting of natural or synthetic gypsum, calcium sulfate hemihydrate, bassanite, anhydrite, selenite, alabaster, fibrous gypsum, saccharoidal gypsum, marine gypsum, gypsum flower, phosphogypsum, desulfurization gypsum, titanogypsum, citrogypsum, tartarogypsum, borogypsum, lactogypsum and mixtures thereof;

D. between 1 and 5 of Ca(OH) 2 and/or of Portland cement;

E. between 0.01 and 1 of at least one alkali metal carbonate;

F. and at least one alkalifying reagent consisting of at least one alkali metal carbonate and/or bicarbonate, different from E;

 subject to the following conditions:

(i) an amount of C is sufficient to allow the sulfate ions of C to react with B and with A;

(ii) the amount of F is sufficient so that its reaction with component D in a presence of water brings the pH of a resulting wet formulation to a value of not less than 12, for a water-to-binder mixing rate of between 10 and 35% by weight,

wherein 1≤[C]/[B]≤3; and

wherein the hydraulic binder is free from any polyvinyl alcohol.

2 . The hydraulic binder according to claim 1 , wherein

0.1<[C]/[A].

3 . The hydraulic binder according to claim 1 , comprising, in % by dry weight:

A. 55 to 90 of at least one ground and granulated blast-furnace slag;

B. 5.5 to 30 of at least one calcium aluminate cement and/or of at least one calcium sulfoaluminate cement;

C. 6 to 30 of at least one source of sulfate ions with 1≤[C]/[B]≤3;

D. 1 to 5 of Ca(OH) 2 and/or of Portland cement;

E. 0.01 to 1 of Li 2 CO 3 ;

F. and at least one alkalifying reagent consisting of at least one alkali metal carbonate and/or bicarbonate, different from E;

G. 0 to 10 of at least one binder different from A, B and D, comprising: silica or silica-alumina binders, fly ashes, advantageously silica-alumina fly ashes, silica-calcium-alumina fly ashes, expanded or calcined clay dusts and/or metakaolins.

4 . A dry mortar composition comprising a binder according to claim 1 .

5 . The dry mortar composition according to claim 4 , wherein the dry mortar composition is an adhesive mortar and in that it comprises, in % by dry weight:

A. 10 to 50 of at least one ground and granulated blast-furnace slag;

B. 0.5 to 20 of at least one calcium aluminate cement and/or of at least one calcium sulfoaluminate cement;

C. between 2 and 15 of at least one source of sulfate ions with 1≤[C]/[B]≤3, wherein the at least one source of sulfate ions is selected from the group consisting of natural or synthetic gypsum, calcium sulfate hemihydrate, bassanite, anhydrite, selenite, alabaster, fibrous gypsum, saccharoidal gypsum, marine gypsum, gypsum flower, phosphogypsum, desulfurization gypsum, titanogypsum, citrogypsum, tartarogypsum, borogypsum, lactogypsum and mixtures thereof;

D. 0.05 to 5 of Ca(OH) 2 and/or of Portland cement;

E. 0.02 to 0.8 of Li 2 CO 3 ;

F. and at least one alkalifying reagent consisting of at least one alkali metal carbonate and/or bicarbonate, different from E;

G. 30 to 80 of at least one type of aggregates;

H. 1 to 10 of at least one redispersible polymer;

I. 0.01 to 5 of at least one thickener;

J. 0.01 to 0.5 of at least retarder.

6 . The dry mortar composition according to claim 4 , wherein the dry mortar composition is a screed or a render and in that it comprises, in % by dry weight:

A. 3 to 50 of at least one ground and granulated blast-furnace slag;

B. 0.5 to 20 of at least one calcium aluminate cement and/or of at least one calcium sulfoaluminate cement;

C. between 2 and 15 of at least one source of sulfate ions with 1≤[C]/[B]≤3, wherein the at least one source of sulfate ions is selected from the group consisting of natural or synthetic gypsum, calcium sulfate hemihydrate, bassanite, anhydrite, selenite, alabaster, fibrous gypsum, saccharoidal gypsum, marine gypsum, gypsum flower, phosphogypsum, desulfurization gypsum, titanogypsum, citrogypsum, tartarogypsum, borogypsum, lactogypsum and mixtures thereof;

D. 0.05 to 5 of Ca(OH) 2 and/or of Portland cement;

E. 0.02 to 0.8 of Li 2 CO 3 ;

F. and at least one alkalifying reagent consisting of at least one alkali metal carbonate and/or bicarbonate, different from E;

G. 30 to 80 of at least one type of aggregates;

H. 1 to 10 of at least one redispersible polymer;

I. 0.01 to 5 of at least one thickener;

J. 0.01 to 0.5 of at least retarder.