Hydraulic binder and hydraulic composition comprising same
A hydraulic binder which includes a clinker with a specific shape, the clinker including as main phases, given as weight percentages relative to the total weight of the clinker: (i) 70 to 95% of a belite phase having a particle size such that the Dv50 ranges from 5 to 15 μm; (ii) 5 to 30% of a calcium aluminoferrite phase; and (iii) less than 5% of minor phases; the clinker having an Al 2 O 3 /Fe 2 O 3 weight ratio of less than 1.5; and the clinker including less than 5% of alite phase and less than 5% of calcium sulphoaluminate phase; and at least 0.5% dry weight of an activator made of calcium sulphate, as a weight percentage relative to the total weight of phases (i) to (iii).
1. A hydraulic binder which comprises
a particulate-shaped clinker, the clinker comprising as main phases, in % expressed in mass relative to the total mass of the clinker:
(i) from 70 to 95% of a belite phase having a particle size such that Dv50 ranges
from 5 to 15 μm;
(ii) from 5 to 30% of a calcium alumino-ferrite phase; and
(iii) less than 5% of minor phases;
the clinker having an Al 2 O 3 /Fe 2 O 3 mass ratio lower than 1.5; and
the clinker comprising less than 5% of alite phase and less than 5% of calcium sulpho-alminate phase
and at least 0.5% dry mass of a calcium sulphate-based activator, in mass percent relative to the total mass of the phases (i) to (iii).
2. The hydraulic binder according to claim 1 , comprising a setting accelerator.
3. The hydraulic binder according to claim 1 , wherein the clinker comprises less than 5% of water-soluble alkaline salts.
4. The hydraulic binder according to claim 1 , wherein the clinker is prepared by a process which comprises:
decarbonating a raw mix having a particle size such that the maximum diameter is lower than 100 μm;
clinkering the decarbonated raw mix for 5 to 30 minutes at a temperature ranging from 1 150 to 1 400° C. of calcium, silicon, alumina, magnesium, iron sources and capable, by clinkering, of providing the belite phase and the calcium alumino-ferrite phase, to obtain the clinker comprising as main phases, in % expressed in mass relative to the total mass of the clinker:
(i) from 70 to 95% of said belite phase;
(ii) from 5 to 30% of said calcium alumino-ferrite phase; and
(iii) less than 5% of minor phases;
the clinker having an Al 2 O 3 /Fe 2 O 3 mass ratio lower than 1.5; and
the clinker comprising less than 5% of alite phase and less than 5% of calcium sulpho-alminate phase; and
cooling by quenching the clinker obtained.
5. The hydraulic binder according to claim 1 , comprising a Portland clinker.
6. A process for preparing a hydraulic binder according to claim 1 , which comprises a step of grinding the clinker and a step of adding calcium sulphate.
7. A hydraulic composition which comprises a hydraulic binder according to claims 1 and water.
8. A process for preparing a hydraulic composition according to claim 7 , comprising a step of mixing water and the hydraulic binder.
9. A shaped object for the construction field comprising a hydraulic composition according to claim 7 .