Concrete with a low clinker content
A process for the preparation of a wet concrete composition, including mixing Portland clinker in the form of grains having a Dv97 from 10 to 30 μm or having a Blaine specific surface greater than or equal to 5300 cm 2 /g; slag; calcium sulphate; complementary materials, having a Dv90 less than or equal to 200 μm; from 1500 to 2200 kg/m 3 of aggregates; a plasticizer; optionally an accelerator and/or an air-entraining agent and/or a thickening agent and/or a retarder and/or a clay-inerting agent; with 140 to 220 l/m 3 of effective water, the total quantity of clinker in the wet concrete being less than or equal to 200 kg/m 3 .
1. A process for the preparation of a wet concrete composition, comprising a stage of mixing of:
Portland clinker in the form of grains having a Dv97 from 10 to 30 μm or having a Blaine specific surface greater than or equal to 5300 cm 2 /g, the minimum quantity of the clinker in kg/m 3 being determined according to formula (V) for a clinker having a Dv97 from 10 to 30 μm, or according to formula (VI) for a clinker having a Blaine specific surface greater than or equal to 5300 cm 2 /g:
[(90×ln(Dv97 k ))−150]×(W eff ÷140) Formula (V)
in which Dv97 k is the DV97 of the clinker given in μm,
W eff is the quantity of effective water in l/m 3 ;
[(−0.021×BSS k )+263]×(W eff ÷140) Formula (VI)
in which BSS k is the Blaine specific surface of the clinker given in cm 2 /g,
W eff is the quantity of effective water in l/m 3 ;
slag, of which the minimum quantity in kg/m 3 is determined according to formula (VII) in the case of a mixture with clinker having a Dv97 from 10 to 30 μm, or according to formula (VIII) in the case of a mixture with clinker having a Blaine specific surface greater than or equal to 5300 cm 2 /g:
(3500÷BSS S )×[−90×ln(Dv97 k )+310]×(W eff ÷140) Formula (VII)
in which Dv97 k is the Dv97 of the clinker given in μm,
BSS S is the Blaine specific surface of the slag given in cm 2 /g,
W eff is the quantity of effective water in l/m 3 ;
(3500÷BSS S )×[0.021×BSS k −103]×(W eff ÷140) Formula (VIII)
in which BSS k and BSS S are respectively the Blaine specific surface of the clinker and the slag given in cm 2 /g,
W eff is the quantity of effective water in l/m 3 ;
calcium sulphate;
complementary materials, having a Dv90 less than or equal to 200 μm, of which the minimum quantity in kg/m 3 is determined according to the following formula (IX):
220−(quantity of slag)−(quantity of clinker)−(quantity of calcium sulphate) Formula (IX);
from 1500 to 2200 kg/m 3 of aggregates;
a plasticizer;
optionally an accelerator and/or an air-entraining agent and/or a thickening agent and/or a retarder and/or a clay-inerting agent; with
140 to 220 l/m 3 of effective water,
the total quantity of clinker in the wet concrete being less than or equal to 200 kg/m 3 .
2. The process for preparation of a wet concrete composition according to claim 1 , wherein the grains of the Portland clinker have a Blaine specific surface greater than or equal to 5500 cm 2 /g.
3. The process for preparation of a wet concrete composition according to claim 1 , wherein the quantity of effective water used varies from 140 to 200 l/m 3 .
4. The process for preparation of a wet concrete composition according to claim 3 , wherein the quantity of effective water used varies from 150 to 180 l/m 3 .
5. A wet concrete composition obtained by the process according to claim 1 .
6. A hardened concrete object obtained from the wet concrete composition according to claim 5 .
7. The process for preparation of a wet concrete composition according to claim 1 , comprising from 1700 to 2000 kg/m 3 of said aggregates.
8. The process for preparation of a wet concrete composition according to claim 1 , wherein the complementary materials are selected from the group consisting of fly ash, limestone powder, calcined shale, metakaolin, siliceous filler, silica powder, pozzolan, slag, or clinker and a mixture thereof.