DE1954013A1 - Plastic-coated concrete units with smooth - weather proof surface - Google Patents

Abstract

Concrete units for wall facing plates, slabs, building plates and purlins resistant to rain water and temps below freezing, are made by (a) casting concrete, if necessary with vibration, in a mould with a smooth surface using a comparatively rich mixture and fine-grained additives (a) at least in area near the smooth surface, (b) leaving concrete unit in mould for 1-5 (2-4) days so that the surface layers of the unit lying by the smooth mould wall are hardened to an extent such that they can be lifted from mould surface without leaving marks and (c) coating the concrete unit surface cast near the smooth mould wall with a hard, vitreous, weatherproof plastic layer. Pref. mould surface is made of glass, plastic such as polyvinyl chloride, silicone rubber, acrylic, polyester, polystyrene or polyethylene plastic or a polished metal inert to cement. Pref. plastic coating consists of epoxy resin, silicone polyester, acrylic or polyurethane plastic, more pref. admixed with a pigment or metal powder such as Cu, Al or alloy, such as Cu bronze.

Description

Process for the production of concrete elements with smooth, weatherproof Surface In the production of concrete elements for automotive engineering such as facade panels, Concrete slabs, and elements, roof slabs and the like has long been sought, a more aesthetically pleasing one in a simple and economically acceptable way and also to achieve a more weatherproof surface q Often a completely smooth and shiny Surface desired that be of different colors or a metal-like appearance may have. It is already known to apply a surface coating to a concrete part to give a comparatively smooth, shiny surface with an epoxy resin. With conventionally manufactured concrete parts becomes consumption on the rather expensive plastic material but because of the porous structure of the concrete surface so great that this approach is not economically viable. Even the one with this one The surface obtained by the process is unsatisfactory from an aesthetic point of view, since it is not completely smooth and shiny, nor is it completely uniform looks like. It is also already known that when pouring concrete elements a comparatively smooth and almost glossy surface can be achieved without the cast Concrete part still needs further treatment. However, it is not yet sufficient stable method has been developed, such a smooth and shiny surface on a concrete element, and it has also been shown that the surface is not water resistant but under the influence of rain and moisture quickly loses its smooth and shiny property.

The object of the invention is therefore a simple and economical one to create a portable and permanent process for the production of concrete elements, which have a smooth and shiny, weather-resistant surface, which are also available in different Colors and also with a metal-like character is to be established. The 'method according to the invention is characterized in that the concrete element is first eaten in a mold, preferably using vibration, which has a smooth and shiny inner surface, the concrete mix being comparatively is set in fat and a fine-grained filler material at least in the part of the Concrete element uses @ird, which is adjacent to the surface of the form, that the concrete element not out of shape before the lapse of one to five days and preferably between two and four days it is taken that the surface layer of the concrete element, which has been located on the smooth, shiny surface of the mold, has hardened to the extent that they can be lifted from the surface of the mold, leaving no traces behind, and that the surface of the concrete element, which was located on the smooth surface of the mold, finally with a coating of hard, glassy and weather-resistant plastic material is covered.

It has been shown that when using the method according to the invention it is possible to obtain a concrete product in which the surface exposed to, the smooth, shiny surface of the mold, almost as smooth and shiny was as was the mold surface itself. It was also found that this was not porous and glossy The surface of the poured concrete element was very weatherproof and its shiny Appearance retained when covered with a thin layer of tough, glassy and weatherproof Plastic material has been coated. Since the surface of the concrete element according to deni Pouring is already very dense and shiny, so is the VelX use of plastic material for coating the surface only very little, whereby the inventive Process is economically acceptable.

A smooth glass plate can preferably be used for the mold. However, it is also possible to use a plastic material as the smooth mold wall to use, for which e.g. polyvinyl chloride, silicone rubber, acrylic plastic, polystyrene, Polyester plastic or polyethylene plastic are suitable. It is also possible to have a polished one Use metal plate or a metal sheet metal panel that does not contain any cement Response received.

If necessary, the molding surface can be filled with a suitable release fluid. Such a release liquid is not necessary if a glass plate or a plastic layer is used will. Be it nor noticed that it is not necessary that the smooth, shiny surface is completely flat, it can e.g. be wavy or otherwise have a non-planar shape, if only it is smooth and shiny.

The concrete mix should be at least in the area that is immediately adjoins the smooth and shiny surface of the mold, a comparatively rich mixture and contain at least as much cement per unit of space as is desired Corresponds to hardness class, as well as an additional material, the largest parts of which are fine-grained Sand are. at least 10 to 20 5 of the additive material should have a grain size of less than 0.25mm, and the rest of the additive should also be comparative fine-grained and preferably not coarser than 1 mm.

As a plastic surface coating for the shiny surface of the cast Epoxy resin is particularly suitable for the concrete product, but other plastic materials can also be used Like eta silicone plastic, polyester plastic, acrylic plastic and polyurethane plastic materials are used.

It turned out that the surface of a concrete element, which is produced by the method according to the invention, completely smooth, dense and is shiny and also very hard and weatherproof.

The smooth, shiny surface of the concrete element can be very easy way to be designed in different colors by adding color cement or a any other suitable lsarb powder to the plastic material used for the surface coating is used, is added. This pigment powder can be a metal powder, for example such as copper or aluminum powder, being the surface of the concrete product has the appearance of a polished copper or aluminum surface. It goes without saying also possible to use powdered metal alloys or metal mixtures, e.g. a so-called copper bronze to give the surface a metal-like appearance of the concrete product.

For the part of the concrete element that is not directly adjacent to the smooth and a glossy surface is adjacent, a concrete mix of a different composition can be used can be chosen as for the part immediately adjacent to the surface. So ht needs e.g. the remaining part of having a not-so-fat mixture and may also contain coarser additive material should required reinforcement elements. The method according to the invention is intended to be further illustrated by the following examples will.

Example concrete assembly- pouring- curing- epoxy- addition for plastic setting driving time layer coating 1.2kg sand, 0-3mm vibration on 3 days 0.3-0.4mm- (15% <0.25mm) hard plastic 1 0.5 kg standard cement 0.23 kg water 1.5 kg sand 0-3mm Vibration for 2 days 0.3-0.4mm 5g aluminum powder (1.5% <0.25mm) glass ver per m² 2 0.5 kg standard cement 0.24 kg water 1.8 kg sand 0-3mm vibration for 4 days 0.3-0.4mm- (15% <0.25mm) a plastic film 3 0.5 kg standard cement 0.28 kg water 1.6 kg sand 0-4mm vibration for 2 days 0.3-0.4mm- (20% <0.25mm) a plastic film 4 0.5 kg Standard cement 0.25 kg of water When using after the According to the method according to the invention, concrete elements produced outdoors in a cold climate e.g. for roofs or facade panels, the elements are washed through the surface with water saturated through it, which is not closed with an impermeable plastic layer and when these elements are then exposed to freezing temperatures Difficulties arose as they showed frost damage. After repeated freezing and thawing alternately, more or more occurred in the elements less fine cracks, so that the concrete breaks down into individual flakes or flakes split off while the plastic coating was unaffected by it on the concrete material stuck.

This difficulty can be overcome by a modified embodiment of the method according to the invention can be completely eliminated. Then the concrete element manufactured in such a way that the concrete of the element does not have a water absorption factor of has more than 7 ß and preferably less than 5. This required low Water absorption factor can be achieved that a very dense and not porous concrete is produced, which is when using very fine-grained sand as an additive, if there is so little more in the production of the concrete pore-forming as possible Liquids are used. It will preferably no pore-forming additional liquids added at all, if this is possible with regard to the manufacturing method used.

The fine-grained sand used as an additive should be used with this Embodiment of the invention contain at least 90 grains of sand whose grain size is less than 2mm, where 50, «a grain size of less than 0.5mm and at least 23% has a grain size that is smaller than 0.25mm. The conditions for a concrete product of this type that is safe from spelling is therefore in Any relationship is comparable to the conditions that are required to create a Achieve a product with a smooth, shiny and weather-resistant surface.

The frost resistance of concrete products, which after the modified Earth method according to the invention has been used in a large number of Tried and tested, with the test pieces having a smooth and shiny surface an epoxy resin coating according to the method according to the invention sen, while in the production of fine-grain sand according to the above composition was used as an additive. The porosity of such test pieces was determined by different addition of pore-forming liquids, which are commercially available under the Names "Zackamin" available varies. At first it was Dry weight of the test pieces, after which they are then placed in boiling water for 5 hours and then weighed again. The percentage increase in weight between The two weighings are designated as the water absorption factor of the various test pieces. These test pieces were then alternately frozen and thawed again and thereby determines how many such freeze-thaw cycles each test piece can withstand could without cracks and cracks appearing. The result of this test is in in the following table: Water absorption number of Freeze Result Thaw Cycles 5.5 50 Flawless 4.0 30 "4.5 30" 4.7 30 "7.0 30" 7.0 15 Cracks and fissures 7.5 10 "7.5 11" -8.4 10 lt 8.5 15 10.0 10 li 11.0 13 From the table it can be seen that test pieces with an absorption factor be able to withstand at least 50 such freeze-thaw cycles of less than 7%, without damaging them, whereas test pieces with a higher water absorption content showed cracks and fissures even before the 50 freeze-thaw cycles were reached.

Test pieces with a water absorption factor less than 5, have shown that they have a significantly greater number of freeze-thaw cycles than 30 could withstand without damage.

Corresponding tests with test pieces made in the same way but not the impermeable plastic surface coating showed that regardless of the degree of water absorption, these test pieces Able to withstand at least 50 freeze-thaw cycles without cracks or cracks occurred. This now shows that there is the presence of the impermeable surface layer is made of a plastic material which can overcome the difficulty of frost resistance of the concrete elements produced when such an element is used, which by those surfaces that are not covered with liner plastic surface layer sirid, can enrich with water, and the element then an interplay of frost and Is exposed to thawing. Claims

Claims (1)

P A T E N T A N S P R Ü C H E Process for the production of concrete elements such as facade panels, concrete panels, wall panels, roof panels or the like a smooth, impermeable, weatherproof upper. surface, characterized. That the concrete element may initially using vibration in a shape with a smooth surface underneath Use of a comparatively rich mixture and fine-grain additives is cast at least in the area near the smooth surface, the element at least is left in the form for one to 5 days, preferably two to four days, so that the surface layers of the concrete element resting against the smooth wall of the mold are cured to such an extent that they are lifted from the mold surface without leaving any marks can, and then the cast surface of the concrete element on the smooth mold surface is covered with a hard, glassy and weather-resistant plastic layer. 2. The method according to claim 1, characterized in that the smooth, shiny mold surface made of glass, a plastic material such as polyvinyl chloride, Silicone rubber, acrylic plastic, polyester plastic, polystyrene plastic, polyethylene plastic or a polished metal that is insensitive to cement. 5. The method according to claim 1 or 2, characterized in that the Concrete mix contains an additive material in which at least 10, 0 a grain size of less than 0.25mm and the remaining part has a grain size of less than 4mm, this concrete mixture, at least in that immediately adjacent to the smooth, shiny Form surface adjacent part of the concrete element is used. 4. The method according to any one of claims ~ 1 to 3, characterized in that that as plastic surface coating epoxy resin, silicone plastic, polyester plastic, Acrylic plastic or polyurethane plastic is used. 5. The method according to any one of the preceding claims, characterized in, that the plastic coating material is a pigment powder or a metal powder, e.g. a Copper powder or aluminum powder or a metal alloy powder or metal mixture such as copper bronze is added. A method according to any one of claims 1 to 5 for the manufacture of concrete elements for use in the outside air such as roof panels or facade panels, which saturated by rainwater and exposed to sub-freezing temperatures, characterized in that such fine-grained material is selected as the additive and such a small amount of pore-forming liquid added to the concrete mix will require the finished concrete product to have a water absorption factor of less than 7 ffi and preferably less than 5%. 7. The method according to claim 6, characterized in that as an additive a sand is used in which 90 g0 has a particle size of less than 2 mm, at least 50% a grain size below 0.5 mm and at least 25 a grain size below 0.25 mm having. 8. The method according to claim 6, characterized in that no pore-forming Liquid-added to the concrete mix. 9. Concrete element, e.g. facade panel, roof panel, concrete panel, wall element or the like, characterized in that one of its surfaces is smooth and shiny is and a surface coating made of hard, glass-like and weather-resistant Has plastic material. 10. Concrete element according to claim 9, characterized in that the Plastic coating made of epoxy resin, silicone plastic, polyester plastic, acrylic plastic or polyurethane plastic. 11. Concrete element according to claim 9 or 10, characterized in that that the plastic coating is a pigment powder or a metal powder, e.g. a copper powder or aluminum powder or a powder of a metal alloy or metal mixture, e.g. Copper bronze. 12, concrete element according to one of claims 9 to 11, characterized in that that at least the part directly adjoining the smooth, shiny surface is made from a raw material with an additional material that is at least 10 ß from a grain size of less than 0.25 mm and otherwise from a grain size is less than 4 mm, 15. Concrete element according to one of the claims 9 to 12, characterized in that it has a water absorption factor of less than 7.%, preferably below 5%. 14. Concrete element according to claim 13, characterized in that the The additive material used in its manufacture is sand, the grain size of which is 90 ß below 2 mm, at least 50% below about 0.5 mm and at least 25% below 0.25 mm.