DE102016123390A1 - Substance mixture for the production of a concrete component, use of such a mixture, concrete component of such a mixture, as well as heat-insulating component with such a concrete component - Google Patents

Abstract

The invention relates to a composition for producing a concrete component with high pressure resistance and low thermal conductivity. For this purpose, a composition according to the invention has a binder and further components. wherein the further components comprise a first additive formed by particles selected from the group of silicate ceramics. Furthermore, the invention relates to the use of such a mixture for the production of a concrete component, in particular prefabricated concrete component. Furthermore, the invention relates to a concrete component, made of such a mixture and a thermally insulating component for connecting a component (3) to a building body (2) with an insulating body (4), with a the insulating body (4) passing through tensile reinforcement (5). and transverse force reinforcement (11), and with at least one of the insulating body (4) passing through the pressure element (8), wherein the at least one pressure elements (8) is formed by such a concrete component.

Description

The invention relates to a mixture for producing a concrete component, the use of such a mixture, a concrete component of such a mixture, and a heat-insulating component with a pressure element of such a concrete component.

In the construction of building structures, especially in building construction, one is often confronted with the problem of having to meet both static and building physics requirements. Such a situation arises, for example, if in the transition region between warm rooms and cold rooms statically supporting and therefore necessary components are arranged, which have only low thermal insulation properties due to their material nature. These components form thermal bridges, which lead to a loss of heat energy. In addition, there is a risk of consequential damage from moisture accumulation in these areas.

When connecting external components such as balconies to a building therefore preferred constructions are used, which in addition to the static load bearing function and the heat protection of a building in the area of the connection. A proven in practice for this purpose device is from the EP 2 824 249 A1 known. The component has an insulating body, which is penetrated by a horizontal in the upper region of the insulator extending tensile reinforcement and a diagonal transverse shear reinforcement. In order to remove horizontal compressive forces occurring in the connection region, rod-shaped pressure elements made of concrete are arranged in the lower region of the insulating body, which in the middle region have a reduced cross-sectional area with respect to their ends. From a building physics point of view, the available for the heat transfer cross-sectional area is thereby reduced and thus reduces the heat flow through the pressure element.

After EP 2 824 249 A1 the printing elements are made of a hardenable mixture of mineral aggregate and cement or polymer-bound matrix as a binder. For example, the pressure elements consist of a high-strength concrete, which allows a slim design and / or a relatively large lateral spacing of the pressure elements in a component due to its compressive strength of over 60 N / mm ² , which further reduces unwanted heat transfer.

Against this background, the present invention seeks to provide a composition and products made therefrom, which are characterized by a high thermal insulation capacity while ensuring high compressive strengths for load transfer.

This object is achieved by a composition according to claim 1, the use of such a composition according to claim 18, a component according to claim 19, and a device according to claim 20.

Advantageous embodiments will be apparent from the dependent claims.

The base components for mixtures for the production of concrete components usually form a hardenable binder and an aggregate, which are mixed together before the curing of the binder. The binder usually consists of a cement-bound matrix which hardens by hydration, or a polymer-bound matrix, in which a chemical reaction of the polymer causes hardening of the mixture. By adding further components to the composition, the properties of the hardened composition and thus the properties of the products produced therefrom can be modified.

It is important in this connection that the chemical reactions of the individual constituents of the substance which are complex during hardening in the substance mixture do not lead to a counterproductive change in the mechanical and physical properties of the substance mixture with regard to their intended use.

The invention therefore aims to limit their thermal conductivity by suitable composition of a hardenable mixture, without affecting the other bächyhsikalischen and mechanical properties, in particular their compressive strength.

It turns out to be a particular difficulty that the densest possible structure leads to high compressive strengths, for a reduced thermal conductivity and thus improved thermal insulation properties of a concrete product, however, a less dense structure is advantageous.

In the context of the present invention, it has now surprisingly been found that the apparently exclusive requirements for high pressure resistance on the one hand and low thermal conductivity on the other hand can be combined if particles of silicate ceramic are admixed to a suitable substance mixture. Thus, tests have shown that the compressive strength and dimensional stability of concrete products according to the invention can be maintained compared to conventional concrete products, while the thermal conductivity has been reduced by 40%. This applies equally to embodiments in which the silicate ceramic replaces the otherwise common aggregate, as well as for embodiments in which the silicate ceramic next to an aggregate is part of a composition of the invention.

Silicate ceramic is a multi-phase material and generally contains clay, kaolin, feldspar and / or soapstone as a silicate carrier. Silicate ceramic is used, for example, for insulators, fuse cartridges and catalysts in heat engineering, measurement and control technology, high and low voltage technology.

Due to the inert properties of silicate ceramics, this substance behaves neutrally during the hardening process and therefore does not cause a chemical change in the reaction product. Unwanted effects of silicate ceramics on the properties of the hardened substance mixture therefore do not occur or only to a non-relevant extent. Also, silicate ceramic is not harmful due to the inert properties, which facilitates their processing.

With regard to fire protection, which is important in structural engineering, it proves to be advantageous that silicate ceramic is thermally resistant and does not absorb water. Silicate ceramic therefore does not increase the fire load and does not actively contribute to the destruction of the building structure due to expanding water vapor in case of fire.

In a first embodiment of the invention, porcelains are preferred as silicate ceramics. This group includes quartz porcelains based on silica and alumina porcelain based on alumina. Quartz porcelains are available inexpensively in sufficient quantities. The advantage of alumina porcelains lies above all in the achievement of consistently high strengths within narrow limits.

Advantageously, the particles of silicate ceramic are present as regrind, so are the product of a grinding process. The grain size of the silicate ceramic particles and thus the fineness of the additive can be controlled by the residence time and / or type of grinding tools. Particles produced in this way favor the processability of a composition according to the invention. However, silicate ceramic particles in the form of fractured material are also suitable, whose numerous corners and edges increase the mechanical properties of the hardened mixture of substances.

For both variants, it is possible to obtain the starting material for the production of silicate ceramic particles from a recyclate, for example, shards of industrial or utility ceramics, which is available everywhere inexpensive and protects environmental resources, but at the same time represents a very high quality material.

In order to achieve the highest possible compressive strength of the hardened substance mixture, it is advantageous if the proportions of different grain fractions are coordinated so that the densest possible grain structure is formed. From this point of view, it is advantageous if the largest grain of the proportion of silicate ceramic has a maximum diameter of 16 mm. The mixture preferably has fractions with a maximum grain size of not more than 2 mm and / or not more than 0.25 mm and / or 0.125 mm.

According to a preferred embodiment of the invention, the particles of silicate ceramic have a bulk density of 2 kg / dm ³ or more, preferably at least 2.2 kg / dm ³ , most preferably at least 2.5 kg / dm ³ , of the hardened mixture to give a density that ensures sufficient compressive strength with minimized thermal conductivity.

In this sense, it has also been found to be advantageous if the proportion of silicate ceramic particles within a mixture according to the invention is at least 20 wt .-%, preferably at least 25% by weight, most preferably at least 30% by weight and / or at least 15% by volume, preferably at least 20% by volume, most preferably at least 30% by volume.

At the same time, it is provided in an advantageous development of the invention to keep the proportion of silicate ceramic particles below certain maximum values. This ensures a good processability of the substance mixture with sufficient strength after the hardening process. Preferred maximum values are at most 50% by weight, preferably at most 40% by weight, most preferably at most 35% by weight and / or at most 40% by volume, preferably at most 30% by volume, most preferably at most 35% by volume. %.

It has proved to be advantageous if the thermal conductivity of the particles of the first additive is 2 W / m / K or less, preferably at most 1.5 W / m / K, most preferably at most 1 W / m / K, which is very efficient for lowering the thermal conductivity of the hardened mixture of substances contributes.

Further preferred is a substance mixture which comprises pozzolanic particles and / or latently hydraulic particles as further component, preferably in superfine grain size, for example microsilica or granulated blastfurnace slag. These proportions cause a filling effect in the grain structure and also interact in the bonding zone between binder and silicate ceramic particles, both of which contribute to increasing the strength of the hardened composition.

A binder suitable for a composition according to the invention can be, for example, a cement-bound binder with which very high compressive strengths can be achieved in an economical manner. By using suitable cements, for example ultrafine cements, a substance mixture according to the invention has, after it has hardened, mechanical properties which are comparable to those of high-strength concretes or ultra-high-strength concretes.

The water cement value of a composition according to the invention is advantageously not more than 0.3, in particular not more than 0.25. As a result, the formation of capillary pores is limited, with the advantage of a further increase in strength of the hardened mixture.

Alternatively, the binder can also be formed from a geopolymer system, with the advantage that the hardened composition has a high chemical resistance. When using a polymer-bound binder, for example based on a reactive resin, the composition is characterized by a comparatively high tensile strength after hardening.

According to a further embodiment of the invention fibers may be added to the composition. Thus, for example, by adding steel fibers in addition to an increase in strength can be additionally achieved that announces a failure of the hardened mixture material failure by disproportionate deformation. By the addition of polymer fibers, however, an improved fire behavior can be achieved because the polymer fibers melt in case of fire and leave in this way channels in the hardened mixture through which strongly expanding water vapor can escape.

Advantageously, additives are added to the composition in order to improve their properties before and after hardening. Thus, by the optional use of a flow agent as an additive, the processability of the composition can be improved. Additives in the form of defoamers counteract pore formation, which in turn increases the strength of the hardened substance mixture.

A composition according to the invention is given in the table below. The composition is suitable for producing a concrete component made of ultra-high-strength concrete, such as those used as pressure elements in heat-insulating components for connecting external parts to a building. component kg / dm ³ l / m3 cement from 100 to 1000 from 30 to 350 Pozzolans and / or latent hydraulic concrete additives from 0 to 300 from 0 to 120 Silicate Ceramics from 300 to 1250 from 120 to 500 microsilica from 50 to 400 from 20 to 180 water from 150 to 350 from 150 to 350 Concrete admixture (plasticizer) from 5 to 50 from 5 to 50 Concrete additive (defoamer) from 0 to 20 from 0 to 20 polymer fibers from 0 to 10 from 0 to 10 steel fibers from 0 to 150 from 0 to 20

The major advantage of using a composition according to the invention for the production of concrete components lies in the fact that without sacrificing the mechanical and / or chemical properties over conventional concrete components and without additional insulation measures results in an improved thermal insulation behavior. Thus, a mixture of substances according to the invention is predestined for the production of components that are used in building construction in a thermal bridges endangered area, such as pressure-transmitting components within heat-insulating components for connecting a balcony or pedestal to a building wall or building ceiling.

The invention will be further explained below with reference to an embodiment shown in the drawings, wherein further features and advantages of the invention will become apparent.

• 1 einen Querschnitt durch den Anschlussbereich zwischen einem Außenteil und einem Gebäude mit einem erfindungsgemäßen Bauelement, und
• 2 eine Schrägansicht auf ein erfindungsgemäßes Druckelement.

It shows

• 1 a cross section through the connection area between an outer part and a building with a device according to the invention, and
• 2 an oblique view of an inventive pressure element.

1 shows a device according to the invention 1 in a cross section from which the intended integration of the device 1 in a building emerges. You can see the corresponding part of a building 2 For example, the floor slab or wall of a building to which a component 3 connects, for example, a cantilever of a balcony, a pedestal or the like. Both in the building 2 as well as component 3 it may be precast concrete or cast-in-place components, or steel or wood structures.

To limit heat loss, which is usually due to a heat flow from the warmer building 2 to the colder part 3 arise is between the building 2 and the component 3 the thermally insulating component 1 inserted, with the first outside 6 of the component 1 a contact surface with the component 3 forms and the opposite second outside 7 a contact surface with the building 2 ,

The component 1 has a substantially rectangular cross-section and extends perpendicular to the plane of representation of 1 over the entire length of the component 3 , The height of the component 1 corresponds to the thickness of the component to be connected 3 , Essential part of the device 1 is a plate-shaped insulating body 4 , which may be made of a foamed material such as polystyrene, polyethylene, polyvinyl chloride or the like. The insulator 4 is in the upper, the Zugzone of the terminal embodying area of a tensile reinforcement 5 interspersed. The tensile reinforcement 5 is formed by steel bars, which are parallel to the axis and in a uniform lateral distance to each other and the existing tensile forces from the component 3 in the building 2 initiate. The tensile reinforcement 5 can already in the manufacture of the device 1 in the insulating body 4 foamed or is subsequently by the insulator 4 inserted, for which sleeve or groove-shaped bushings in the insulating body 4 may be arranged.

In the lower, the pressure zone forming region of the device 1 you can see at regular intervals rod-shaped printing elements 8th , in the 2 are shown in an oblique view on a larger scale.

How out 2 show the pressure elements 8th , apart from the ends thereof, a rectangular cross-section which is constant over the length and has longitudinal sides running essentially plane-parallel 14 , In the end areas of a printing element 8th is one over the top 15 of the printing element 8th protruding bead-like thickening 20 arranged. The bottom 16 however, the plan is flat over the entire length. The front ends 13 a printing element 8th are doubly convexly curved with respect to the cross-sectional main axes, resulting in a spherical bearing surface to the building 2 and component 3 results. On the ends of the pressure elements 8 may optionally be fitted with plastic or metal caps (not shown).

Within the scope of the invention, alternative embodiments are also of different cross-sectional dimensions over the length of a pressure element. For example, the longitudinal sides can have a hollow curvature facing the center line of the pressure element and are thus concave. The same applies to the top and / or bottom, which may also have a concave profile. This results in a shape of the pressure element, in which the cross-section in the region of the end faces is greatest and decreases toward the center in each case. Also conceivable are embodiments of the invention in which only the cross-sectional height or the cross-sectional width of the pressure element is reduced towards the middle. The end faces may also have a cylindrical surface due to a mere simple curvature.

The printing elements 8th enforce the insulating body 4 horizontally and thereby form with their ends in each case a supernatant 9 over the first outer surface 6 or second outer surface 7 out. The supernatants 9 rich in niches 10 placed in the appropriate places of the building 2 or component 3 are provided, on the one hand a toothing for securing the position of the pressure hull 8th to achieve and on the other hand, the absorption and discharge of the component 2 coming shear forces.

The printing elements 8th consist of a high-strength or ultra-high-strength concrete, the formulation of which corresponds to a mixture of substances within the values given in the table.

Furthermore, the reveal 1 and 2 one of U-shaped steel hangers 11 formed shear force reinforcement, the two legs 19 in the area of the building 2 at the level of the tensile reinforcement 5 paraxial and in the lateral distance to this and in the area of their exit from the building 2 are bent downwards by the angle α and the insulating body 4 starting from the second outside 7 in the direction of the pressure element 8th penetrate approximately diagonally. The loop-like lower end 17 a strap 11 the transverse force reinforcement binds each in a pressure element 8th a, so that printing elements 8th and hangers 11 together each a prefabricated unit 12 resulting in the course of the production of the insulating body 4 is foamed into this. For uniform load transfer are the prefabricated units 12 inside the insulating body 4 arranged at a mutual lateral distance between 5 cm and 10 cm.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2824249 A1 [0003, 0004]

Claims (20)

Substance mixture for producing a concrete component with high compressive strength and low thermal conductivity comprising - a binder and - other components, characterized in that the further components comprise a first additive formed by particles selected from the group of silicate ceramics. Mixture after Claim 1 , characterized in that the first additive is formed from particles selected from the group of porcelains, in particular from the group of silicate ceramics based on silica and / or from the group of silicate ceramics based on alumina. Mixture after Claim 1 or 2 , characterized in that the first additive of particles is formed with a grain size of a maximum of 16 mm, preferably a maximum of 2 mm, most preferably a maximum of 0.25 mm, in particular a maximum of 0.125 mm. Substance mixture according to one of Claims 1 to 3 , characterized in that the first additive is formed by particles having a bulk density of at least 2 kg / dm ³ , preferably at least 2.2 kg / dm ³ , most preferably at least 2.5 kg / dm ³ . Substance mixture according to one of Claims 1 to 4 , characterized in that the proportion of the first additive in the composition is at least 20 wt .-%, preferably at least 25 wt .-%, most preferably at least 30 wt .-%. Substance mixture according to one of Claims 1 to 5 , characterized in that the proportion of the first additive in the substance mixture is at most 50 wt .-%, preferably at most 40 wt .-%, most preferably at most 35 wt .-%. Substance mixture according to one of Claims 1 to 4 , characterized in that the proportion of the first additive in the composition is at least 15 vol .-%, preferably at least 20 vol .-%, most preferably at least 30 vol .-%. Substance mixture according to one of Claims 1 to 5 , characterized in that the proportion of the first additive in the substance mixture is at most 40% by volume, preferably at most 30% by volume, most preferably at most 35% by volume. Substance mixture according to one of Claims 1 to 8th , characterized in that the first additive has a maximum thermal conductivity of at most 2 W / m / K, preferably at most 1.5 W / m / K, most preferably of at most 1 W / m / K. Substance mixture according to one of Claims 1 to 9 , characterized in that the particles of the first additive are wholly or partly formed by ground ceramic fragments. Substance mixture according to one of Claims 1 to 10 , characterized in that the further components comprise a second additive formed by particles selected from the group of pozzolans, preferably of the high-purity pozzolans, in particular silica fume. Substance mixture according to one of Claims 1 to 11 , characterized in that the further components comprise a third additive formed by particles selected from the group of latent hydraulic substances, in particular granulated blastfurnace slag. Substance mixture according to one of Claims 1 to 12 , characterized in that the binder is selected from the group of cement-bound or polymer-bound binders or geopolymer systems. Substance mixture according to one of Claims 1 to 12 , characterized in that the binder is a cement-bound binder and the maximum water-cement value is 0.3, preferably at most 0.25. Substance mixture according to one of Claims 1 to 14 , characterized in that the further components comprise at least one additive selected from the group of flow agents and / or defoamers. Substance mixture according to one of Claims 1 to 15 , characterized in that the further components comprise an aggregate. Substance mixture according to one of Claims 1 to 16 , characterized in that the further components comprise fibers, preferably steel fibers and / or polymer fibers. Use of a composition according to one of the Claims 1 to 17 for producing a concrete component, in particular prefabricated concrete component. Concrete component made from a mixture of substances according to one of Claims 1 to 17 , Thermally insulating component for connecting a component (3) to a building body (2) with an insulating body (4), with a tensile reinforcement (5) and transverse force reinforcement (11) passing through the insulating body (4), and with at least one insulating body (4) ) passing through pressure element (8), characterized in that the at least one pressure elements (8) of a concrete component after Claim 19 is formed.

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