Method for connecting two mineral building blocks having substantially planar placement surfaces

Abstract

The invention relates to a method for connecting two mineral building blocks (1) which have substantially planar placement surfaces (3) and which comprise silicon and / or silicon compounds and / or aluminium and / or aluminium compounds. Advantageous connection conditions result from the fact that an activator solution for geopolymer synthesis is applied to the placement surface (3) of a first building block (1) and then a second building block (1) is placed at least in sections on the placement surface (3) of the first building block (1).

Description

[0001] Method for joining two mineral building blocks with essentially flat set surfaces

[0002] Technical area

[0003] The invention relates to a method for joining two mineral building blocks comprising silicon, silicon compounds, and / or aluminum, and / or aluminum compounds, having substantially planar seating surfaces. The invention also relates to a set for forming a building block assembly, comprising at least two stackable mineral building blocks comprising silicon, silicon compounds, aluminum, and / or aluminum compounds, having substantially planar seating surfaces.

[0004] State of the art

[0005] Typically, mortar or other adhesives applied to the flat seating surfaces of building blocks are used to connect them. For example, EP3174939B1 discloses the use of geopolymer foam as an adhesive. However, the required adhesives, as an additional intermediate layer, require additional resources during production and, on the other hand, usually create a bonding force between the building blocks that is not actually necessary for construction requirements. Subsequent separation of the building blocks is therefore only possible by destroying or damaging them. Consequently, after their use in a masonry structure, for example, they can only be disposed of as construction waste or recycled.

[0006] Further methods for connecting building blocks with flat setting surfaces, in which several building blocks are placed directly or offset on top of one another and connected to one another by means of adhesives or foams as connecting means, are shown in EP 2549026 A2, AT 414333 B, CN 104790678 A and US 8196370 B2.

[0007] To reuse interconnected building blocks, US20150259910A1, for example, proposes connecting several building blocks with form-fitting connectors, which allows for a residue-free building block to be obtained after the connecting elements have been removed. However, due to the necessary form-fitting, such building blocks require complex manufacturing and assembly conditions, making them impractical for mass applications.

[0008] Description of the invention

[0009] The invention is therefore based on the object of proposing a method for joining two mineral building blocks which, with low use of resources, enables simple assembly conditions on the one hand and reuse of the building blocks on the other.

[0010] The invention solves the stated problem by applying an activator solution for geopolymer synthesis to the setting surface of a first building block and then placing a second building block, at least in sections, onto the setting surface of the first building block. The invention is based on the idea that the connection between the building blocks is created during the laying of the preferably aluminosilicate building blocks on site by applying an activator solution for geopolymer synthesis to the setting surface of a first building block. This makes it possible to dispense with the need for an additional adhesive or mortar to be produced beforehand, since the geopolymer is formed when the activator solution comes into contact with the building block. By adding the activator solution, the solid components are initially dissolved from the building block, which enables the formation of silicon-oxygen aluminates.Polymerization occurs through rearrangement and condensation, forming a three-dimensional aluminosilicate polymer network that hardens the geopolymer. According to the features of the invention, a reaction occurs between the activator solution, which is initially geopolymer-free, and the reactive silicon and / or aluminum components present in the building block, resulting in the formation of geopolymers. The resulting polymer chains of the geopolymer serve as a crosslinking bond between the building blocks. Since the activator solution is liquid, it can diffuse into the building block, so that the polymer chains do not merely run between the settling surfaces on the respective surfaces, but also penetrate into the building block.However, since the amount of activator solution diffused into the building block decreases with penetration depth, excessive bond strength is prevented. So that while the activator solution can generate the bonding force required for typical construction applications, a type of smooth predetermined breaking point is still provided in the area of ​​the setting surfaces. Along this predetermined breaking point, the building blocks can be separated from one another if they are intended for another use. Because the activator is a liquid solution, handling conditions are simple during transport and when applied to the building blocks, so that in particular the layer thickness of the adhesive does not have to be taken into account. In contrast to conventional mortar or foam adhesives, the activator solution takes up a much smaller volume, so that no visible joints or barely visible joints arise between overlapping building blocks.The activator solution is particularly suitable for ceramic bricks, as these usually contain silicon, aluminum, or their compounds. Therefore, building blocks are required that contain silicon, and / or silicon compounds, and / or aluminum, and / or aluminum compounds. A typical silicon compound is SiO2. A typical aluminum compound is aluminum oxide. An example of a silicon-aluminum compound is clay minerals such as kaolinite. Within the scope of the invention, the horizontal base and top surface of a building block, preferably a flat brick, is considered the setting surface of the building block. The setting surfaces are essentially flat, which means that the setting surfaces can deviate from a completely flat design within standardized limits.While it is fundamentally possible to carry out geopolymer synthesis on the building block under acidic reaction conditions, it has proven particularly practical for the present application in the construction sector if the activator solution is alkaline, preferably with a pH value greater than or equal to 10. An alkali hydroxide, an alkali silicate, alkali aluminate, alkali carbonate, or alkali sulfate, for example, can be used as an activator solution for geopolymer formation. Sodium and / or potassium hydroxide and / or water glass are preferred activator solutions. Water glass is an amorphous, i.e., glassy, ​​water-soluble sodium, potassium, and / or lithium silicate, or its aqueous solutions, that has solidified from a melt. Depending on whether sodium, potassium, or lithium silicates are predominantly present, the term sodium water glass, potassium water glass, or lithium water glass is used.

[0011] It has been found that the flatter the building blocks, the stronger the bonding force generated by the activator solution. To generate bonding forces suitable for construction, it is recommended that the maximum deviation of the set surfaces from flatness be 1 mm, preferably 0.5 mm. Particularly strong bonds are created on surfaces with deviations from flatness of less than or equal to 0.1 mm. The preferred deviation from flatness of the set surfaces is 0.05 mm to 0.5 mm, as this range generates a sufficiently high bonding force while still allowing non-destructive separation of the building blocks if they are to be reused for other purposes.

[0012] To further increase the bonding strength, it is proposed that the activator solution for geopolymer synthesis be applied separately to the facing surfaces of both building blocks before they are bonded together. This allows the activator solution to diffuse sufficiently deep into both building blocks.

[0013] The method can be carried out using a set for forming a building block assembly. This set comprises at least two mineral building blocks comprising silicon and / or silicon compounds and / or aluminum and / or aluminum compounds, which can be stacked on top of one another and have essentially flat seating surfaces. In addition, an activator solution for geopolymer synthesis is provided for application to the seating surfaces of the building blocks. The activator solution is preferably alkaline and in particular has a pH value greater than or equal to 10. Water glass, for example, is suitable as an activator solution. The maximum deviation of the seating surfaces from flatness can be 1 mm, preferably 0.5 mm, more preferably 0.1 mm.

[0014] Brief description of the invention

[0015] The figure shows an example of the subject matter of the invention, wherein the figure shows a schematic front view of two modules connected with the method according to the invention.

[0016] Ways to implement the invention

[0017] A method according to the invention can be used to connect two building blocks 1 to form a building block composite 2. For this purpose, an activator solution for geopolymer synthesis is applied to the seating surface 3 of a first building block 1. Since the building blocks 1 contain silicon and / or aluminum or their compounds, the reaction of the activator solution with the building block 1 produces a geopolymer 4 that acts as an adhesive and connects the building blocks 1 to one another. Geopolymers 4 are mineral systems with a high content of silicon (as SiO2) and aluminum (as Al2O3), during whose reaction the formation of alumino-silicate networks predominates.

[0018] The building blocks 1 are essentially planar. Preferably, the maximum deviation of the seating surfaces 3 from flatness is 1 mm.

[0019] The bonding force generated by the resulting geopolymers 4 between the building blocks 1 depends on the type and quantity of the activator solution used, as well as on the proportion of activatable substances and the size of the contacting surfaces of the building blocks 1. With a mass fraction of activatable substances in ceramic bricks of at least 50% and when using sodium water glass, the required quantity of activator solution is 100 to 200 mL per m 2 touching settling surface 3 of the building blocks 1. Likewise, the time until geopolymer formation is completed depends on the influencing factors listed above and can take from a few hours to a few days in the case of ceramic bricks.

Claims

Patent claims 1. A method for joining two mineral building blocks (1) having substantially planar set surfaces (3) which comprise silicon, and / or silicon compounds, and / or aluminum, and / or aluminum compounds, characterized in that an activator solution for geopolymer synthesis is applied to the set surface (3) of a first building block (1) and then a second building block (1) is placed at least in sections onto the set surface (3) of the first building block (1).

2. Process according to claim 1, characterized in that the activator solution is alkaline, preferably has a pH value greater than or equal to 10.

3. Method according to claim 1 or 2, characterized in that the maximum deviation of the setting surfaces (3) from the flatness is less than or equal to 1 mm, preferably less than or equal to 0.5 mm, more preferably less than or equal to 0.1 mm.

4. Method according to one of claims 1 to 3, characterized in that the activator solution for geopolymer synthesis is applied separately to the mutually facing setting surfaces (3) of both building blocks (1) before they are connected to one another.

5. Set for forming a building block assembly (2), comprising at least two mineral building blocks (1) which can be stacked one above the other and have substantially planar set surfaces (3), which comprise silicon, and / or silicon compounds, and / or aluminum, and / or aluminum compounds, characterized by an activator solution for geopolymer synthesis for application to the set surfaces (3) of the building blocks (1).

Images