Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1996-08-28
1998-03-24
Marcheschi, Michael
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
106738, 106814, 106817, 106 3827, 106 389, C04B 1420
Patent
active
057307970
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of International application No. PCT/GB95/00407, filed Feb. 27, 1995.
1. Field of the Invention
This invention relates to a mortar composition for use in producing a simulated stone material. The composition can be used for moulding or casting, and as an external plaster.
2. Background to the Invention
Conventional cement mortars and concrete mixes containing sand and other relatively coarse aggregates have two principal disadvantages. Firstly, the surface finish is rough and it is difficult to achieve fine moulding in the surface. Secondly, as the surface weathers and the cement binder is eroded, the aggregate particles become raised relative to the remainder of the surface, leading to further toughening of the surface and an unsatisfactory appearance.
A finer surface finish can be achieved by the use of gypsum plasters, but these are unsuitable for exterior use as they are readily and rapidly eroded by rainwater. Replacing coarse aggregates in cement-based mixes with finer materials gives rise to shrinkage as the mixes harden, which in turn leads to cracking. In addition, such materials generally have a low mechanical strength.
GB-A-1 447 591 discloses an insulating material containing expanded mica with masonry cement, high alumina cement and sodium disilicate. The mixture contains a high proportion, by volume, of mica, approximately twice the volume of the masonry cement, and is intended for insulation purposes, rather than as a surface finish itself.
GB-A-1 091 766 discloses a brick formed of a hardened mixture of a granular aggregate and a bonding material which can contain silica flour and a small proportion of finely ground mica to improve the appearance, imparting lustre and sparkle to the brick.
GB-A-874 280 discloses a finishing plaster based on gypsum and hydrated lime, and with finely ground chalk, limestone or dolomite, together with aggregates, which may include perlite or vermiculite and which are intended to alter the texture or density of the final plaster. The aggregates are usually coarser that the finely ground materials, or of fibrous character.
SUMMARY OF THE INVENTION
The invention provides a mortar composition comprising: and a minor proportion of particulate mica, and a binder therefor.
Preferably, the mixture contains 1 part by volume of mica to 1.5 to 8 parts, more preferably 2 to 6 parts, still more preferably 2.5 to 4 parts, of powdered stone. The stone is suitably sand grade or finer, preferably in the form of a dust or flour grade in order to give a very smooth finish when hardened. 100 .mu.m grains or smaller may, for example, be used. The mica is suitably a 20-100 mesh powder, preferably formed from expanded mica. A 60 mesh powder is particularly useful.
The mortar composition suitably contains up to 70% by weight of powdered stone.
The binder is preferably a hydraulic cement, and the composition preferably contains approximately one part by volume of a hydraulic cement powder to 1 to 5 parts, preferably at least 2.5 parts, of the mixture. More preferably, the composition contains up to 2 parts, suitably about 1 part, by volume of hydraulic cement to each part of mica. The hydraulic cement powder is suitably a Portland cement and is more preferably a white Portland cement, such as that sold under the trade mark "SNOWCRETE" in the UK by Blue Circle Cement Ltd, since this permits the true colour of the stone to be seen in the hardened material.
Alternatively, other binders such as polymeric binders may be used, alone or in combination, and mixtures of polymeric materials with cementitious binders may also be used.
It is preferred that excess water is not present, and it has been found that when casting wet, the addition of 1% calcium chloride to the mortar is beneficial.
Plasticisers known for cementitious mortars may be added. The hardened composition may be treated with silicone to reduce permeability.
The mixture can be used for dry packing. When dry packing, delamination of the layers must be avoided by scuffing each layer after compaction.
T
REFERENCES:
patent: 766938 (1904-08-01), Diefendorf
patent: 1317525 (1919-09-01), Romano
patent: 2032071 (1936-02-01), Scholz
CA 86:110477, Ohta, "Cement mortar for decorative use", corresponds to JP 51,145,525., Dec. 1976
Parrish John Anthony
Smith Robert John
Smith Thomas Frederick
Marcheschi Michael
Stonelight Systems Ltd.
LandOfFree
Mortar composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mortar composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mortar composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2285706