SMITH, Thomas, Frederick (34 Gloversfield, Kelvedon Hatch, Brentwood CM15 0BD, GB)
HOWARD, Ian, David (Westwood, Heronway, Shenfield CM13 2LX, GB)
SMITH, Thomas, Frederick (34 Gloversfield, Kelvedon Hatch, Brentwood CM15 0BD, GB)
HOWARD, Ian, David (Westwood, Heronway, Shenfield CM13 2LX, GB)
| CLAIMS 1 . A method of forming a concrete body with a smooth surface, comprising pouring a concrete mix into a mould or frame, and then, while the mix is still liquid, spraying on to the surface thereof an aqueous finishing composition containing powdered stone, mica, and a cement binder, and allowing the mix and the finishing composition to harden. 2. A method forming a floor surface, comprising applying to a base floor surface a self-levelling screed composition and then, while the said composition is still liquid, spraying on to the surface of the screed an aqueous finishing composition containing powdered stone, mica, and a cement binder, and allowing the screed composition and the finishing composition to harden. 3. A method according to Claim 2, comprising cutting a pattern of grooves in the hardened surface to define simulated discrete floor tiles, and then filling the grooves with grout. 4. A method according to Claim 1 , 2 or 3, wherein the dry components of the finishing composition before addition of water contain, by volume, a major proportion of powdered stone and minor proportions of mica and cement binder. 5. A method according to any preceding claim, wherein the powdered stone is powdered limestone. 6. A method according to any preceding claim, wherein the dry components of the finishing composition before addition of water contain 70% powdered limestone by volume, with the balance being equal volumes of mica and white cement. 7. A method according to Claim 6, wherein the powdered limestone has particle sizes below 0.25mm with 30% of the powder below 0.06mm. 8. A method according to Claim 6 or 7, wherein mica has a particle size of 0.42mm or less, with 50% being 0.25mm or smaller. 9. A method according to any preceding claim, comprising incorporating into the finishing composition a pigment and/or a dye. 10. A method according to any preceding claim, comprising applying to the hardened surface a stone hardening compound. 1 1 . A method according to any preceding claim, comprising applying to the hardened surface a sealing compound. |
AND OF FORMING A FLOOR SURFACE
Field of the Invention
[0001] This invention relates to a method of forming a concrete body with a smooth surface and to a method of forming a floor surface.
Background to the Invention
[0002] In a commonly used method of making floors, a rough concrete base is provided with a smooth finish by application of a self-levelling screed composition, which is a cementitious liquid slurry poured on the surface to find its own level across the surface before hardening. However, such a surface is generally not suitable as a working floor because its appearance is unappealing, and it is difficult to keep clean. Accordingly, it is usual to apply a flooring surface to the screed, for example ceramic tiles. While these provide an attractive and durable floor surface which is more easily cleaned, the application of flooring tiles is a skilled job which is relatively time-consuming and therefore costly.
[0003] EP0749404 discloses a mortar composition comprising powdered stone, mica and a cement binder, such as white Portland cement, which can be cast to form floor tiles or for floor surfaces. When applied to the surface of an article, the water content is minimised, and so application is by conventional plastering techniques.
[0004] WO2004/009375 discloses spraying a similar composition on to a substrate bearing a suitable mask, in order to produce a finish simulating the appearance of brick. The object of the disclosed method is thus to achieve a suitably textured finish on existing hardened surfaces.
[0005] It has now surprisingly been found that when the composition is sprayed in liquid form on to a liquid surface, for example newly cast concrete, or a liquid self-levelling screed, the composition does not sink into the liquid, but instead remains on the surface to form a smooth, hard, decorative layer which can serve as a finished floor, or as a wall panel, for example. Summary of the Invention
[0006] Accordingly, the present invention provides a method of forming a concrete body with a smooth surface, comprising pouring a concrete mix into a mould or frame, and then, while the mix is still liquid, spraying on to the surface thereof an aqueous finishing composition containing powdered stone, mica, and a cement binder, and allowing the mix and the finishing composition to harden.
[0007] The invention also provides a method of forming a floor surface, comprising applying to a base floor surface a self-levelling screed composition and then, while the said composition is still liquid, spraying on to the surface of the screed an aqueous finishing composition containing powdered stone, mica, and a cement binder, and allowing the screed composition and the finishing composition to harden.
[0008] The flooring method preferably also comprises the steps of cutting a pattern of grooves in the hardened surface to define simulated discrete floor tiles, and then filling the grooves with grout.
[0009] Preferably, the finishing composition comprises, excluding the water, a major proportion, by volume, of the powdered stone and minor proportions of the mica and cement. The powdered stone is suitably powdered limestone.
[0010] A preferred method of the invention comprises using a finishing composition in which the dry components before addition of water contain 70% powdered limestone by volume, with the balance being equal volumes of mica and white cement. The mica suitably has a particle size of 0.42mm or less, with 50% being 0.25mm or smaller.
[0011] While the preferred method mentioned uses powdered limestone, other powdered stone can be used, for example sandstone, marble, or mixtures of these.
[0012] The finishing composition may incorporate a pigment and/or a dye to achieve the desired decorative appearance. A stone hardening compound such as an acid crystallizer for marble or terrazzo floors may be applied to the hardened surface of the finishing composition. A sealing compound, for example a co-polymer acrylic- based liquid sealant, may also be applied to forma protective coating on the floor, in conventional manner
Example
[0013] A finishing composition was made up of 70% limestone powder having a particle size below 0.25mm, and with 30% of the powder below 0.06mm particle size, 15% white Portland cement (Dragon® cement), and 15% mica having a particle size of 0.42mm or below, with 50% being 0.25mm or less in particle size. 20kg of the composition was mixed with 6 litres of water to produce a mixture of putty-like consistency which can be sprayed using a gravity feed spray gun (e.g. Meiji sgs-2) or, for large volumes, a mixer pump spray machine (for example a Powerspray PS1000 electric worm pump). A commercially-available self-levelling screed composition was prepared in the conventional way and was poured on to a concrete floor base. While the screed composition was still liquid, the finishing composition was sprayed on to the wet surface to form a layer 1 -4mm thick. It was observed that the slurry remained on the surface of the liquid screed, rather than sinking into it. The screed and the slurry composition were allowed to harden overnight.
[0014] On the next day, the floor had hardened sufficiently to be walked on, and to permit grooves to be cut into the surface using a diamond-tipped saw, the grooves being cut in a grid pattern simulating floor tiles. The grooves were then grouted in conventional manner to give the appearance and functionality of a tiled floor. The surface can be polished smooth using abrasive discs, if necessary, and sealed using a resin-, wax- or silicone-based sealing composition.
[0015] While the invention has been particularly described in relation to floors, it will be appreciated that the method can be applied to other structural panels such as wall panels cast in a horizontal mould. Additionally, the underlying substrate can be of materials other than concrete, provided that a thin ce- mentitious liquid screed is applied prior to the spraying of the stone-based composition in accordance with the invention.