DE29717541U1 - Building element - Google Patents

Description

Andrejewski, Honke & Partners Patent attorneys

European Patent Attorneys European Trademark Attorneys

Graduate Physicist Dr. Waiter Andrejewski (-1996) Graduate engineer Dr. Manfred Honke * Graduate Physicist Dr. Karl Gerhard Masch * Graduate engineer Dr.-lng. Rainer Albrecht * Graduate Physicist Dr. Jörg Nunnenkamp * Graduate Chemist Dr. Michael Rohmann Attorney file:

87 017/WO& D 45127 Essen, Theaterplatz 3 D 45002 Essen, PO Box IO 02 54

22 September 1997

Utility model application

Hans Peter Böe Speldorfer Strasse 17 - 19 46049 Oberhausen

Building element

Andrejewski, Honke & Sozien, patent attorneys in Essen

Description:

The invention relates to a building element made of a concrete body and a glass body placed in front of it, the glass body having a coating of composite mortar on the building side, the composite mortar consisting of a finely divided aggregate and cement and mixed with an aqueous dispersion of a polyacrylic acid derivative, the polyacrylic acid derivative having a logarithmic decrement, determined according to DIN 53445, which has a maximum at Celsius temperatures of below 0° C, the composite mortar on the glass body being hardened with a lack of hydration water and the hardened coating being bonded to the concrete body. - Building element within the scope of the invention means a wall element or the like and in particular a roof element.

In known building elements of the aforementioned type (EP 0 700 776 Art 2), the glass body consists of a glass pane, in particular a tempered glass pane or a float glass pane, which is produced by contact of the hardened coating with the mixed and hardening concrete of the concrete body. Such building elements have proven themselves in practice because they are characterized by an excellent bond between the glass pane and the concrete body that remains constant even over longer periods of time, even when they are subjected to thermal cycling over a wide temperature range.

0 The invention is based on the object of expanding the application area of the above-mentioned building elements.

Andrejewski, Honke & Sozien, patent attorneys in Essen

To this end, the invention teaches that the glass body is designed as a solar element in the form of a solar glass pane. In this context, solar glass pane means in particular amorphous, monocrystalline or polycrystalline solar cells, which are embedded between two hardened glass plates using a highly transparent casting resin.

The invention is based on the knowledge that the building elements mentioned at the beginning can easily be made with solar glass panes as glass bodies and then enable roofs and the like to be built in a simple and cost-effective manner. This has not been considered so far; in the prior art, solar elements have always been attached to building bodies using mechanical means, which is very complex.

In a further embodiment, the bond between the hardened coating and the concrete body can be created not only by contact 0 of the hardened coating with the mixed and hardening concrete of the concrete body, but also by bonding the hardened coating to the already hardened concrete body using a so-called tile adhesive or other concrete adhesive.

In the context of the invention, mortar means a binding material for the bond between the glass pane and concrete. The coating of the mortar can be applied to the glass pane using a spray, roller, spatula or similar method. Hardening of the mortar means "sufficient" hardening. The layer of composite mortar must not be too stiff

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Andrejewski, Honke & Sozien, patent attorneys in Essen

or too rigid. In this way, the applied layer of mortar remains able to bond with fresh, not yet hardened concrete over long periods of time. The added polyacrylic acid derivative also contributes to an optimal bond with the concrete. According to the preferred embodiment, the composite mortar layer has a layer thickness of 2 to 7 mm, preferably 4 to 6 mm.

The composite mortar preferably has a finely divided neutral additive with a grain size of 0.1 to 1 mm, preferably 0.2 to 0.7 mm. Quartz sand or glass powder is expediently used as a finely divided neutral additive. According to a preferred embodiment, the cement is Portland cement. In the context of the invention, polyacrylic acid derivatives means in particular polymers based on acrylates, i.e. acrylic acid esters and their derivatives, acrylic acid or acrylonitrile as the characteristic chain building block. The polyacrylic acid derivative can also be designed as a copolymer in which in particular acrylates, acrylic acid 0 or acrylonitrile are used as comonomers. Methacrylic acid and its derivatives are also possible as comonomers. It is also within the scope of the invention that the polyacrylic acid derivative is designed as a polymer mixture of various polyacrylic acid derivatives. According to a preferred embodiment, the polyacrylic acid derivative is a polyacrylate, preferably an acrylic resin. It is within the scope of the invention that polyacrylate adhesives are mixed into the composite mortar. According to a preferred embodiment, the polyacrylic acid derivative, preferably polyacrylate, is a copolymer with 0 acrylonitrile as a comonomer. The proportion of the acrylonitrile comonomer based on the

Andrejewski, Honke & Sozien, patent attorneys in Essen

Polyacrylic acid derivative, preferably polyacrylate, at least

2 wt.%. The composite mortar is mixed with an aqueous emulsion of the polyacrylic acid derivative.

According to the invention, the polyacrylic acid derivative has a logarithmic decrement, determined according to DIN 53445, which has a maximum at Celsius temperatures below 0°. This is the logarithmic decrement of the torsional vibration damping in the torsional vibration test according to DIN 53445 with the polyacrylic acid derivative as a test specimen. Preferably, a polyacrylic acid derivative is used whose logarithmic decrement has a maximum at Celsius temperatures above -8° C. A polyacrylic acid derivative, whose logarithmic decrement according to DIN 53445 has a maximum at Celsius temperatures of below 0° C, surprisingly acts not only in the temperature range of below 0° C, but especially in the range of -50° C to +200° C as an effective bonding agent within the framework of the composite mortar according to the invention 0 between the glass pane and the composite coating on the one hand and between the concrete body and the composite coating on the other. Even at a temperature of

3 00° C, a gradual loss of the adhesive effect can only be observed after a temperature exposure period of more than 30 minutes. Surprisingly, even relatively high temperatures, such as those that occur in strong sunlight or in the event of a fire, do not affect the firm adhesion of the glass panes to the concrete body. In this respect, the effective adhesion is insensitive to climatic changes and thermal expansion of the glass pane. However, the expert could not have expected that on the one hand

Andrejewski, Honke & Sozien, patent attorneys in Essen

a bond between the coating and the glass pane that is so strong and heat-sensitive is achieved, but that on the other hand the glass pane can also expand due to heat without cracking. Surprisingly, the same applies if the bond is made by gluing the hardened coating to the already hardened concrete body using a so-called fly glue or other concrete adhesive.

The strong bond between the coating and the solar glass pane is apparently achieved by a molecular interaction between the polyacrylic acid derivative and the glass. It is assumed that the cement in the composite mortar, in particular the alkaline components of the cement, roughens the glass surface microscopically, so that a larger surface is created for interaction with the molecular components of the polyacrylic acid derivative. During this roughening, free silanol groups can form in the glass surface, which are capable of chemical and/or physical interactions with the functional groups of the acrylic acid monomer units. Relatively strong hydrogen bonds are probably formed here between these functional groups and the silanol groups of the glass surface. However, the expert could not have expected that such effective physicochemical interactions between an organic polyacrylic polymer and the inorganic glass material were possible and that such a strong adhesion of the glass pane could be achieved as a result.

0 Despite this strong bond between the glass pane and the coating, the composite mortar grips the glass pane

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Surprisingly, this is not visible. Of particular importance within the scope of the invention is an embodiment in which the composite mortar contains Portland cement as cement and is mixed with an aqueous dispersion of a polyacrylate, which polyacrylate is a copolymer with acrylonitrile as a comonomer. It is assumed that the alkaline components of the Portland cement etch the surface of the glass pane and thus roughen it microscopically particularly effectively, so that a very pronounced interaction can take place between the glass surface or the silanol groups formed therein and the carboxyl and/or nitrile groups of the polyacrylate copolymer. Particularly good results are achieved with glass panes made of float glass.

The solar glass pane can be connected to the concrete on the coating side before the concrete hardens, whereby the concrete bonds monolithically with the coating of the glass pane. The feature "bonds monolithically" means that the bond is not created with the help of an additional adhesive that is applied to the surface of the concrete body to be covered with the glass pane or to the glass pane or to the coating of the glass pane made of composite mortar. The monolithic bond is created when the glass pane is connected to the concrete that has not yet hardened. The bond is monolithic because the crystallites of the concrete grow into the composite mortar that forms the coating during hydration and bond with the crystallites in the coating, especially since hydration can still take place there, which is based on the fact that the composite mortar on the glass pane lacks hydration-capable properties.

Andrejewski, Honke & Sozien, patent attorneys in Essen

It is understood that the hydration water for the composite mortar comes from the aqueous dispersion of the polyacrylic acid derivative. However, it is also within the scope of the invention that additional hydration water can be added when mixing the composite mortar, always with the proviso that the composite mortar hardens on the glass pane with a lack of hydration water and is therefore still capable of hydration. In this respect, hydration water from the not yet hardened concrete can also diffuse into the composite mortar coating and thus a subsequent hardening of the composite coating can take place. The polymeric plastic in the composite mortar does not contribute to the monolithic bond, although it probably supports the growth of the crystallites of the concrete into the coating.

The polyacrylic acid derivative allows the composite mortar to be adjusted by its proportion of the polyacrylic acid derivative and the thickness of the coating so that it can accommodate thermal expansion of the solar glass pane without cracking when hardened. The polyacrylic acid derivative gives the composite mortar of the coating the elasticity that is required so that the coating can accommodate thermal expansion without cracking. According to a preferred embodiment of the invention, the aqueous dispersion of the polyacrylic acid derivative contains 50 - 65% by weight, preferably 55 - 50% by weight of the polyacrylic acid derivative and 35 - 50% by weight, preferably 40 to 45% by weight of water. If a polyacrylate is used in the context of the invention, the structure produced according to the invention is characterized by particularly good long-term behavior. According to a preferred embodiment of the invention,

Andrejewski, Honke & Sozien, patent attorneys in Essen

A composite mortar has proven to be effective, which is mixed with the following ratio:

Finely divided neutral additives: 10 to 40 wt.%

Cement: 10 to 40 wt.%
aqueous dispersion of

Polyacrylic acid derivative: 10 to 40 wt.%

It is understood that the weight percentages in a mixture according to the invention each add up to 100 wt.%.

Preferably, the composite mortar is made up of a mixture ratio of 25 to 35% by weight of finely divided neutral aggregate, 25 to 35% by weight of cement and 25 to 35% by weight of the aqueous dispersion of the polyacrylic acid derivative. As already mentioned, the amount of hydration water is hardened. It is understood that the coating of the glass panes has such a thickness that sufficient stress relief occurs towards the concrete body when the glass panes experience considerable thermal expansion, but the thermal expansion of the concrete body itself is low. With regard to the thickness of the coating to be set, an embodiment of the invention has proven to be successful in which the composite mortar layer has a visible thickness of 2 to 7 mm, preferably 4 to 6 mm.

The invention is based on the knowledge that in a 0 glass pane a coating of a composite mortar of the described structure on the one hand with the surface of the

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Andrejewski, Honke & Sozien, patent attorneys in Essen

The glass pane can be bonded effectively and permanently, while on the other hand the coating can follow the thermal expansion of the glass panes through elastic deformation and thus without cracking. The invention is also based on the finding that, surprisingly, a coating made of such a composite mortar bonds to the concrete in a monolithic manner, thereby achieving an unexpectedly strong bond between the coating and the concrete body. In this way, the glass pane can remain attached to the concrete body for a long time and without mechanical constraints that impair its durability.

The invention is explained in more detail below using a drawing that merely shows an exemplary embodiment. It shows a schematic representation

Fig. 1 a plan view of a building element and

Fig. 2 is a section A-A through the object of Fig. 1 in an enlarged view.

The basic structure of the building element 1 shown in the figures consists of a concrete body 2 and a glass body 3 placed in front of it. The glass body 3 has a coating 4 of composite mortar on the building side, which consists of a fine-particle aggregate and cement and is mixed with an aqueous dispersion of a polyacrylic acid derivative, whereby the polyacrylic acid derivative has a logarithmic decrement, determined 0 according to DIN 53445, which has a maximum at Celsius temperatures of below 0°. The composite mortar is

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Andrejewski, Honke & Sozien, patent attorneys in Essen

hardened on the glass body 3 with a lack of hydration water. The hardened coating 4 is bonded by contact of the hardened coating 4 with the mixed and hardening concrete of the concrete body 2. Not shown is the variant in which this bond is made by gluing the hardened coating 4 to the already hardened concrete body 2 with the help of a so-called tile adhesive or other concrete adhesive.

In any case, the glass body 3 is designed as a solar element in the form of a solar glass pane. This consists of amorphous, monocrystalline or polycrystalline solar cells 5, which are embedded between two glass plates 6, 7 with the aid of a highly transparent casting resin 8.

Claims (2)

AndVejewski, Honke & Sozien, patent attorneys in Essen Protection claims: 1. Building element made of a concrete body and a glass body placed in front of it, the glass body having a coating of composite mortar on the building side, the composite mortar consisting of a finely divided aggregate and cement and having a logarithmic decrement, determined according to DIN 53445, with an aqueous dispersion of a polyacrylic acid derivative, which has a maximum at Celsius temperatures of below 0°, the composite mortar on the glass body being hardened with a lack of hydration water and the hardened coating being bonded to the concrete body, characterized in that the glass body is designed as a solar element in the form of a solar glass pane. 2. Building element according to claim 1, characterized in that the bond is produced by contact of the hardened coating (4) with the mixed and hardened concrete of the concrete body (2) or by bonding the hardened coating (4) with the hardened concrete body (2) with the aid of a so-called tile adhesive or other concrete adhesive.