EP2113352A1 - Component made out of porous concrete and method for its manufacture - Google Patents

Abstract

The component (1) has two layers (2, 3) that are separated from each other along a layer border (4), where the layers are made of aerated concrete of different characteristics. The aerated concrete in the layer (2) exhibits bulk density which is different from the bulk density of the aerated concrete in the layer (3). The layer (2) contains characteristic-determining and/or characteristic-changing additives. A boundary line runs in the layer border between the layers in a wave-shape or a zig-zag shape. An independent claim is also included for a method for manufacturing a single piece component from aerated concrete.

Description

The invention relates to a component made of cellular concrete and a method for its production.

Autoclaved aerated concrete is a material that has been known for many decades and, because of its favorable properties in the construction industry, is highly valued not only for the construction of external walls, but also for interior work.

Made of aerated concrete components can be made by the specific choice of formulations with different properties, in particular, for example, the porosity and thus the bulk density or compressive strength can be variably adjusted. A low bulk density and thus a high proportion of pores due to the high degree of air inclusions a particularly good thermal insulation or thermal insulation, a lower porosity and thus higher bulk density gives the component a higher pressure resistance and thus stability. It is therefore particularly better suited to take loads, and has moreover, for example also compared to aerated concrete lower density better soundproofing properties.

Aerated concrete is nowadays often produced in processes in which initially the raw material for the concrete is introduced into a mold, ferment the aerated concrete blank in the mold to form the pores, which are formed by a corresponding pore-forming agent in the starting formulation is left and sets to obtain the so-called green strength, the so-called green cake formed, then cut into the components and finally these precut components are cured in the presence of hot water vapor and pressure.

In this production, depending on the initial formulation, components of cellular concrete with a homogeneous property that is continuous throughout the component, such as, for example, are produced. a predetermined and adjustable due to the recipe compressive strength. It is also known to add property-modifying additives to aerated concrete, such as e.g. encapsulated phase change materials to alter the heat storage properties of the cellular concrete. Again, a uniform casting is made to a coherent green cake, so that the properties set for the entire component of cellular concrete are homogeneous.

When using the aerated concrete components thus obtained is now turned off on the given by the architecture and construction of the building to be erected conditions. So load-bearing outer walls are regularly built with aerated concrete components higher compressive strength, since here the pressure resistance and thus the load capacity is more important to evaluate than a loss of thermal insulation properties, which would be cheaper in aerated concrete with lower pressure resistance.

The e.g. For the construction of exterior walls used aerated concrete components have due to the customary desired and desired wall depths often larger dimensions than would be required to form the actual support function. In other words, a narrower aerated concrete component of the same compressive strength class often suffices for the construction of an outer masonry work that is as stable as it is capable of bearing, as the component actually used.

In principle, it would be possible to improve the heat protection properties behind a first wall made of aerated concrete with higher pressure resistance and higher bulk density, to construct a second wall with aerated concrete elements with a lower density and thus better thermal insulation properties. However, this means a loss of space in enclosed space and above all significantly higher costs due to the additional material to be applied and the increased workload.

Based on these observations, the inventors have set themselves the task of creating a structural element made of cellular concrete, which is more flexible in use and combines in particular in one element more favorable properties of the material or with appropriate additives to be achieved favorable properties in itself.

This object is achieved by a structural element made of cellular concrete with the features of claim 1, furthermore, a solution according to the invention of the object is to be seen in a method having the features of claim 6. Advantageous developments of the device according to the invention are given in claims 2 to 5, those of the method according to the invention in claims 7 to 10.

The invention is based on the recognition that a flexible structural element of aerated concrete can be designed by integrally forming it with at least two layers, each layer of which contains aerated concrete which has properties differing from the aerated concrete of the respective other layer. For example, the layers of a cellular concrete element may be designed with different bulk densities, e.g. when installing in an outer wall or other load-bearing wall on the one hand to find the good static properties and compressive strength of aerated concrete of high density, on the other hand, but also the good heat insulating properties of aerated concrete with lower density.

The one-piece design of the component ensures that this does not have a weak point at the boundary between the layers and threatens to break apart here. In this case, a one-piece design can be achieved in principle by further raw mass applied to an already cured aerated concrete component for forming an aerated concrete with properties deviating from the properties of the cured component and allowed to harden. The inventors have found that even with such a subsequent "growth" of another aerated concrete layer an intimate and one-piece compound is created, which meets high strength and stability requirements.

More favorable in the production, however, is a method in which the layers of aerated concrete of different properties are brought together before a final curing step, in particular before curing in an autoclave, since the energy-intensive curing only once has to be completed and the production can take place more quickly.

In the layers, as an alternative to the different bulk density, aerated concrete can be used with properties that are set differently due to specific additives; this can also be done in combination with aerated concrete of different bulk densities. Such property-determining additives are, for example, the encapsulated phase-change materials already described above, but other additives which have a property-altering effect also come into consideration.

In order for later use in such cases where, in use of the device, alignment of the differently formed layers e.g. is relevant to an outside of an external wall to be constructed and the inside, to facilitate identification of the layers, the aerated concrete in at least one layer, a dye, e.g. in the form of color pigments or other distinguishing features. Likewise, the aerated concrete for differentiation in different layers of different dyes or the like can be added.

Even if a good and intimate connection of the layers is already given by the one-piece design of the component according to the invention made of cellular concrete, the strength of this compound can be further improved by a wavy or jagged boundary line between the layers or a correspondingly structured interface. Such a configuration of the boundary lines or the interface increases the contact area between the layers and thus improves the one-piece and intimate connection.

As already stated, a method in which the layers are applied to one another prior to the actual final curing and the cured layer material is then cured, in particular in an autoclave, is preferred for the production of a structural element according to the invention from cellular concrete in at least two layers.

In principle, two approaches are conceivable:

On the one hand, an upper layer to be applied to an existing base layer can take place only after a first hardening of the lower layer, in particular only after reaching the green rigidity, on the other hand, the layer structure can be created by a "wet-on-wet" method, in which the further Layer is applied to a still liquid or viscous and not yet solidified to a green rigidity lower layer.

While with the former method usually achieved sharper boundary lines and diffusion in the borderline area can be better avoided, the second-mentioned method can contribute to a reduction of production times, since the waiting time to reach the green stiffness of a first layer before pouring a further layer is eliminated ,

In order to achieve an intimate connection between the layers, the boundary region, as already mentioned above, can be formed jagged or wavy. For this, e.g. With a comb-like tool, the surface of a first layer are "roughened", in particular in two different directions, before the further layer is applied.

Since usually the green rigid porous concrete cake, the process according to the invention at least two different For example, in this cutting process, care must be taken to ensure that the boundary line between the layers in the finished component runs in the desired direction. This will often be a transverse direction of the component, so its width, since the length is usually installed in the wall escape and different properties in a substantially vertical direction lying to the wall plane most likely to be required.

• Fig. 1 in schematischer Darstellung eine Aufsicht auf ein erfindungsgemäßes Bauelement aus zwei Schichten Porenbeton mit unterschiedlichen Eigenschaften und
• Fig. 2 eine vergleichbare schematische Aufsicht auf ein Bauelement aus Porenbeton mit anders ausgebildetem Verlauf der Grenzschicht.

Further advantages and features of the invention will become apparent from the following description of an embodiment with reference to the accompanying figures. Showing:

• Fig. 1 in a schematic representation of a plan view of an inventive component of two layers of cellular concrete with different properties and
• Fig. 2 a comparable schematic plan view of a component made of cellular concrete with differently designed course of the boundary layer.

In the figures, two possible embodiments of an inventive component 1 made of cellular concrete are each shown in a plan view in a highly simplified and schematic representation. The component 1, which here is a simple block-shaped aerated concrete block, is composed of two layers 2, 3, which are separated from one another by a layer boundary 4. Both layers 2, 3 are integrally connected to one another along the layer boundary and thus form the one-piece component 1.

Both layers are made of cellular concrete, but with different properties. Thus, the cellular concrete in the layer 2 is equipped with different properties than the Cellular concrete in the layer 3. For example, in the layer 2, a high bulk density aerated concrete, eg a porous concrete material of the classification P6 may be arranged, while the aerated concrete in the layer 3 is one of a lower density, eg one of the classification P2.

However, it can also occur in both layers 2, 3 aerated concrete of a single density, the layers may differ by addition of property-modifying additives in only one of the layers or in both layers, but in different concentrations, it can also in both layers additives, however, they may be different for different property changes. Such aggregates may e.g. encapsulated chamfering materials for improving the heat storage properties or the like.

Of course, both in the layers 2, 3 both different densities of the respective aerated concrete material can be realized and also also, if necessary, different additives may be included. Also, one of the layers 2 and 3 may be colored, or it may be added to both layers different colors.

In one application, e.g. For building an outer wall, the layer 2 could serve as the outer layer of the stone and have a high bulk density and thus good static properties and structural strength. The layer 3, which then lies on the inside of the wall, may be made of a porous concrete with a low bulk density in order to improve the thermal insulation properties of the stone as a whole.

This in FIG. 2 shown component 1 is basically the same structure as the device 1 according to FIG. 1 , differs only in the course of the layer boundary 4. While this layer boundary 4 in the first shown example runs straight or forms a plane in three dimensions, this runs in FIG. 2 structured, especially wavy. This formation of the layer boundary brings an enlarged contact surface between the two layers 2, 3 and can thus contribute to an improved connection and adhesion or expression of the one-piece connection between the layers 2 and 3.

The components of cellular concrete shown in the figures can in principle be produced in different ways. So it is e.g. possible on an already completely, cured, in particular hardened in the autoclave, first layer 2 of cellular concrete to pour another layer 3 and then cure this composite component again. In this renewed curing process, as the inventors have found, intimate and one-piece connections, which form a one-piece component 1, are formed.

However, preference is given to another production method, which is more favorable in terms of production time and also for energy reasons. Here, the layer 3 is applied to the layer 2 before curing, either in the process "wet-on-wet", ie on a still liquid or viscous layer 2, be it in a green stage of the layer 2. The latter Variant offers a sharper interface and in particular allows a very good training of a selected layer boundary structure, but it lasts longer in the process.

Not least from the description of the embodiment has been made clear to a person skilled in the art, which considerable advantages the novel aerated concrete component according to the invention entails and which enormous design variety opens up.

LIST OF REFERENCE NUMBERS

• 1 component
• 2 layer
• 3 layer
• 4 layer boundary

Claims (10)

Component of aerated concrete, which is integrally formed and at least two along a layer boundary (4) separate layers (2, 3), which consist of aerated concrete of different properties. Component according to claim 1, characterized in that the cellular concrete in a first layer (2) of the component (1) has a bulk density which is different from the bulk density of the cellular concrete in a second layer (3) of the component (2). Component according to one of the preceding claims, characterized in that the aerated concrete in at least one first layer (2) contains property-determining or property-changing additives that the aerated concrete in at least one second layer (3) or not in a different concentration. Component according to one of the preceding claims, characterized in that the one boundary line in layer boundary (4) between at least two layers (2, 3) is wavy or serrated. Component according to one of the preceding claims, characterized in that the cellular concrete in at least one of the layers (2, 3) for the distinctness of the layers (2, 3) contains color pigments or comparable distinguishing features. A method for producing a one-piece construction element made of cellular concrete with at least two respective aerated concrete each having different properties layers, wherein in a form first a layer of a first raw material mixture in a first, aerated concrete with first properties forming formulation introduced and prior to a final curing step, in particular an autoclaving, on the first layer at least a second layer of a second raw material mixture in a second, aerated concrete with second, deviating from the first properties properties forming formulation is applied and the finished layered starting material of a curing reaction to reach the final strength, in particular in an autoclave is subjected. A method according to claim 6, characterized in that the second layer is applied to the first layer, after the latter has achieved by a first solidification process, a certain basic strength, in particular a green rigidity. A method according to claim 6, characterized in that the second layer is applied to the first layer, while the former is still liquid or viscous. Method according to one of claims 6 to 8, characterized in that prior to the application of the second or another layer, the previously introduced into the mold layer is provided on its surface with wave or jagged structures. Method according to one of claims 6 to 9, characterized in that the layered raw mass is fermented or ripened to a green strength in all layers, the raw mass is formed and cut and then cured, in particular in an autoclave, the raw mass cut so becomes, that the resulting components each contain the individual layers in a transverse extension.

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