Concrete compositions
View Patent ↗A concrete obtained through mixing a composition comprising the following constituents: a) 21 to 27% of a hydraulic binder, b) 52 to 68% of aggregate particles having a size of between 0.02 mm and 5 mm, c) 2 to 6% of pozzolanic reaction particles having a particle size of between 0.1 and 1 micron, d) up to 10% of filler having a particle size between 10 and 200 microns, e) 0.32 to 1.6% of a dispersant, f) 0.1 to 1.2% of fibres, g) 0.02 to 0.1% of a defoamer agent, and h) 7 to 10% of water, each percentage being the percentage by weight of the respective constituent relative to the sum of the weights of constituents a) to h). The concrete obtained is particularly suitable for polished flooring overlay.
1. A concrete obtained through mixing a composition comprising the following constituents:
a) 21 to 27% of a hydraulic binder,
b) 52 to 68% of aggregate particles having a size of between 0.02 mm and 5 mm,
c) 2 to 6% of pozzolanic reaction particles having a size of between 0.1 and 3 microns,
d) up to 10% of filler having a particle size between 10 and 200 microns,
e) 0.32 to 1.6% of a dispersant,
f) a weight of fibres such that the volume of fibres in the composition is 0.1 to 1.2% of the total volume of the composition,
g) 0.02 to 0.1% of a defoamer agent, and
h) 7 to 14% of water,
each percentage being the percentage by weight of the respective constituent relative to the sum of the weights of constituents a) to h).
2. A concrete according to claim 1 , wherein said filler comprises partially or wholly pozzolanic reactive particles, which react on mixing with said hydraulic binder.
3. A concrete according to claim 2 wherein the pozzolanic reactive particles include microsilicas.
4. A concrete according to claim 2 wherein the pozzolanic reactive particles include metakaolin.
5. A concrete according to claim 1 , wherein said filler is partially or wholly an inert filler.
6. A concrete composition according to claim 1 wherein said dispersant comprises one or more superplasticizers.
7. A concrete composition according to claim 1 wherein said dispersant includes a superplasticizer based on modified phosphonates.
8. A concrete composition according to claim 1 , wherein said dispersant includes a superplasticiser based on polycarboxylates.
9. A concrete according to claim 1 and further including an anti-shrinkage agent.
10. A concrete composition according to claim 9 wherein the anti-shrinkage agent is present in 0.5% to 5% of the mix weight.
11. A concrete according to claim 1 , wherein the fibres are made of polyvinylalcohol.
12. A concrete according to claim 1 , wherein said fibres have a length of between 2 mm and 14 mm.
13. A concrete according to claim 1 , wherein said fibres are selected from cut lengths of 4, 6, 8, and 12 mm.
14. A concrete according to claim 1 , wherein said fibres are less than 0.01 mm in diameter.
15. A concrete according to claim 1 wherein said aggregate particles comprise particles selected from at least one of the following particle size/ranges: 2 mm to 5 mm, 1 mm to 2 mm, 0.25 mm to 0.75 mm, 0.1 mm to 0.3 mm, and 0.01 mm to 0.2 mm.
16. A concrete according to claim 15 , wherein said particles are selected from particles having at least two of said particle size ranges.
17. A concrete according to claim 15 , wherein said particles are selected from particles having at least three of said three particle size ranges.
18. A concrete according to claim 1 and including a decolourant.
19. A prefabricated element for machining made of a concrete according to claim 1 .
20. A method for producing the concrete according to claim 1 through mixing a composition comprising the constituents a) to h).
21. A method according to claim 20 , wherein the hydraulic binder, aggregate particles, the pozzolanic reaction particles, the filler, the foam control agent, and at least a portion of the fibres are dry mixed together, then a combination of the water and the dispersant are added and mixed, and then the composition is decanted.
22. A method according to claim 21 wherein further fibres are added after the combination of water and the dispersant, and before decanting.
23. A method according to claim 19 and including the step of applying a partial vacuum to the composition to remove entrained and entrapped air within the composition.