Anhydrite-free foam concrete and its use

Abstract

Anhydrite-free foamed concrete comprising a cement paste mixture, additives for accelerating setting and / or adjusting the setting time and / or for hydrophobing, and fillers as a dry mass, the dry mass being mixed with a foaming agent and water, characterized in that the foamed concrete comprises 50–90 wt.% of a cement paste mixture comprising 20–70 wt.% Portland cement and 8–50 wt.% calcium aluminate (SCA cement), 0.01–3 wt.% aluminum hydroxide as an additive for accelerating setting, 0.5–5 wt.% aluminum stearate as an additive for hydrophobing, 0.01–3 wt.% polyacrylic acid derivatives as a plasticizer, 0.01–5 wt.% lithium carbonate as a reaction accelerator, 1–30 wt.% mineral fillers, and 10–50 wt.% of the mixture of foaming agent and water. which contains 0.01 - 2 wt.% of a liquid additive, and foamed liquid foaming agent.

Description

[0001] The invention relates to an anhydrite-free foam concrete, the term “foam concrete” being understood as a hydrothermally hardened, porous mineral material whose composition contains at least water, cement and foaming agent, as well as its use and a building block filled therewith.

[0002] Foam concretes, with their various compositions, are known in many different forms. Foam concrete is a collective term for flowable fresh concretes that contain binders, fillers, and water, as well as foam or a foaming agent. Traditional binders are cement and lime. Due to the grain size of the filler – often gravel, limestone, or quartz – of less than 2 mm, it is technically foam mortar by definition, but since it is used outdoors and for load-bearing elements, it is referred to as foam concrete. The use of the foam or foaming agent creates a lightweight, porous material with excellent thermal insulation properties. This makes it ideal for use, for example, as a filler for cavities or for lightweight, thermally insulating, yet load-bearing leveling layers.

[0003] For example, DE 10 2023 109 513 A1 discloses a porous mineral building material in the form of a foam concrete with the composition of a cement paste mixture as dry mass, comprising Portland cement, calcium sulfo-aluminate (CSA cement) and calcium aluminate (SCA cement), additives for accelerating the hardening and / or for adjusting the setting time and / or for hydrophobization and optionally consisting of fillers, and a foaming agent comprising a mixture of a rhamnolipid-alginate polymer complex, sodium lauryl sulfoacetate, decyl glycoside, polyoxyethylene(20) sorbitan monolaurate, alkyl polyglycosides, tetrasodium N,N-bis(carboxylatomethyl)-L-glutamate and water.

[0004] Building blocks in the form of thermal insulation bricks made of fired brick material or sand-lime brick material with a plurality of vertical holes are well known. These must meet a variety of requirements, for example, with regard to thermal insulation, sound insulation, stability, fire protection, etc., which are sometimes contradictory. The increasing demands for good thermal insulation have increasingly led to the design of conventional thermal insulation bricks with increasingly delicate designs in order to minimize the heat transfer surfaces and thus the heat transfer. However, this not only compromises the load-bearing capacity but also the sound insulation level, making such bricks unsuitable for all applications.

[0005] The air chambers created by the cavities increase the thermal insulation capacity of the building block. Recently, efforts have been made to further optimize the thermal insulation capacity of building materials for energy-saving reasons. In this context, perforated blocks are already known, whose cavities are filled with highly insulating fillings, such as polystyrene moldings. The direct filling of mineral foam concrete into the cavities is also known, which represents a desirable solution due to lower material costs and more efficient production methods.

[0006] Known from DE 10 2007 031 365 B4 is a building block and a method for its production, which allows the hole pattern to be filled with a highly porous foam concrete filling to form a highly thermally insulating building block. After providing a structurally load-bearing base body for the building block with a hole pattern consisting of cavities, a water-repellent barrier layer is applied to the walls of the base body bordering the cavities, and then a highly porous foam concrete material is introduced into the cavities.

[0007] DE 198 07 040 C5 comprises a thermal insulation filling brick with butt joint teeth arranged on opposite abutting surfaces and a perforation, the transverse and longitudinal webs of which form filling channels into which a lightweight brick foam is filled as insulation material.

[0008] From DE 20 2006 012 748 U1 a thermal insulation brick is known which consists of a fired brick material and has a plurality of vertical hollow holes, wherein some of the hollow bodies are completely or partially filled with a thermal insulation material, for example a perlite lightweight aggregate or another suitable thermal insulation material.

[0009] DE 20 2010 017 852 U1 discloses a device for constructing a structure, in particular a masonry structure, comprising at least one brick section and at least one aerated concrete section. The brick section and the aerated concrete section are joined together in such a way that the aerated concrete section is on the inside and the brick section is essentially on the outside.

[0010] DE 94 00 103 U discloses a rectangular masonry block, particularly made of concrete, ceramic, clay, or similar materials, with holes and ribs arranged transversely to the block. According to a special design, the oblong holes can be filled with any insulating material.

[0011] DE 197 08 779 A1 relates to a binder-bound lightweight brick foam, which comprises, as essential components, brick dust, one or more binders, and one or more foaming agents, as well as optionally one or more setting accelerators and / or other additives, as well as a process for its production. The described binder-bound lightweight brick foam can be used for the production of thermally insulating devices and / or components, such as foam-filled double- or multi-leaf walls, sanitary vents, gable slopes, ceiling linings, chimney casings, window and door reveals, wall elements, molded parts, or thermally insulating screed.

[0012] Anhydrite-based building materials or insulation materials do not tolerate moisture, so they cannot be installed in damp areas of the house. Their strength is also somewhat lower than that of traditional cement-based building materials, which must be taken into account during construction planning. The insulation material collapses within a few days, destroying its insulating effect. Mold can develop within a short time, which is difficult to remove.

[0013] The invention is based on the object of providing an improved mineral anhydrite-free foam concrete for filling cavities, the composition of which contains at least water, cement, and foaming agents, and which is characterized by both low thermal conductivity and high mechanical strength. The porous mineral building material in the sense of the present application is a hydrothermally cured, porous mineral material, the production of which uses at least water, cement, and foaming agents, preferably based on surfactants or proteins.

[0014] According to the invention, the object is achieved by an anhydrite-free foam concrete which comprises a cement paste mixture, additives for accelerating the hardening and / or for adjusting the setting time and / or for hydrophobization and fillers as a dry mass and which is mixed with a foaming agent and water. The foam concrete contains 50-90 wt.% of a cement paste mixture comprising 20-70 wt.% Portland cement and 8-50 wt.% calcium aluminate (SCA cement), 0.01-3 wt.% aluminum hydroxide as an additive to accelerate hardening, 0.5-3 wt.% aluminum stearate as an additive for hydrophobization, 0.01-3 wt.% polyacrylic acid derivatives as a plasticizer, 0.01-5 wt.% lithium carbonate as a reaction accelerator, 1-30 wt.% mineral fillers and 10 to 50 wt.% of the liquid foaming agent foamed from foaming agent and water to which 0.01-2 wt.% of a liquid aggregate is added.The liquid aggregate consists of a mixture of 30 - 85 wt.% demineralized water, 5 - 35 wt.% olefin sulfonates and 10 - 35 wt.% butyldiglycol.

[0015] A rhamnolipid-alginate polymer complex is used as the foaming agent. The foaming agent may be provided with additional components and foamed with water in a ratio of 1:5 to 1:80 to form a liquid foaming agent with a foam density of 50 to 100 g / l. The foaming agent may contain sodium lauryl sulfoacetate, decyl glycoside, polyoxyethylene(20) sorbitan monolaurate, alkyl polyglycosides, and tetrasodium N,N-bis(carboxylatomethyl)-L-glutamate as additional components.

[0016] The anhydrite-free foam concrete has a dry bulk density of 45 to 110 kg / m after curing. 3 and a thermal conductivity in the range of 28 to 44 mW / mK.

[0017] Mineral powders and / or mineral dusts are added to the anhydrite-free foam concrete as fillers. Minerals that can be added include ground clay and / or loam powder, pumice powder, ground brick powder, and / or ground powder from a recycled mineral building material. Brick grinding dust and / or concrete block grinding dust generated during the manufacture and processing of building blocks, for example, during the production of flat bricks.

[0018] The anhydrite-free foam composition can be used to fill cavities in building blocks or multi-layer concrete components.

[0019] Building blocks made of fired clay or clay material or of concrete have a perforation pattern. To improve thermal insulation, at least one hole, a hollow geometry, or a row of holes in the building block is filled with the foam concrete composition.

[0020] A device for producing anhydrite-free foam concrete can comprise a mixing section, which is preferably modular and designed as a continuous mixer, and a conveying section. The conveying module is connected to the outlet of the mixing section and can be designed either as a free outlet for filling various formwork or molds or as a free outlet into a mortar pump. The conveying module can also be directly connected to a number of nozzle lances or injectors, which are arranged according to the number of cavities to be filled. Instead of the nozzle lances or injectors, a filling mold can also be used, which is placed on the building block to be filled, whereby the foam concrete introduced into the filling mold is introduced into the cavities by gravity or under pressure.

[0021] The invention will be described in more detail using an embodiment.

[0022] The anhydrite-free foam concrete according to the invention comprises, as a dry mass, a cement paste containing a first type of cement, in particular a standard cement (Portland cement), and a second type of cement, in particular an SCA cement. Additives to accelerate curing, in particular aluminum hydroxide, can be added to the cement paste. Furthermore, additives such as polyacrylic acid derivatives as plasticizers and / or lithium carbonate as a reaction accelerator to adjust the setting time, and aluminum stearate for hydrophobicity, mineral fillers, and a liquid foamed foaming agent can be added.

[0023] In a preferred embodiment, the mineral anhydrite-free foam concrete according to the invention is further explained using the following exemplary embodiment.

[0024] The anhydrite-free foam concrete comprises 80 wt.% of a dry mass and 20 wt.% of a liquid foaming agent.

[0025] The dry mass consists of 50 wt.% of a cement paste mixture composed of 65 wt.% Portland cement and 35 wt.% amorphous calcium aluminate (SCA cement), 1.5 wt.% aluminum hydroxide, 2.3 wt.% aluminum stearate, 1.0 wt.% of a polyacrylic acid derivative, 0.2 wt.% lithium carbonate, and 25 wt.% of a mixture of mineral fillers. The mixture of mineral fillers preferably consists of 20 wt.% ground brick powder and 5 wt.% brick grinding dust.

[0026] The total dry mass is mixed with 20 wt.% of a foamed liquid foaming agent to form a foam concrete, wherein the foaming agent is formed from 2.0 wt.% of a rhamnolipid-alginate polymer complex as foaming agent and 18 wt.% water, to which 0.5 wt.% of an aqueous solution of 30 - 85 wt.% demineralized water, 15 wt.% olefin sulfonate and 20 wt.% butyldiglycol is added.

[0027] The foaming agent and water are mixed in a ratio of 1 to 20 using local continuous or batch mixing technology. In a foam generator, a foam is generated from the aqueous solution, foaming agent, and air via a foam pipe. The foam has a foam density of 60 g / l.

[0028] This allows for the production of very stable foam concrete mixtures with pleasingly low thermal conductivities. Thermal conductivities of the building elements of between 28 and 44 mW / mK can be achieved.

[0029] Using a device comprising a mixing section and a conveying section, the foam concrete according to the invention can be produced from the individual components. A filling mold is preferably used to fill the building blocks, which are provided with a perforated pattern. This is placed on the open side of the building block to be filled, and the foam concrete introduced into the filling mold is forced into the cavities under pressure. The cavities are thus completely filled with the foam concrete. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] DE 10 2023 109 513 A1

[0003] DE 10 2007 031 365 B4

[0006] DE 198 07 040 C5

[0007] DE 20 2006 012 748 U1

[0008] DE 20 2010 017 852 U1

[0009] DE 94 00 103 U

[0010] DE 197 08 779 A1

[0011]

Claims

[1] Anhydrite-free foam concrete, which comprises a cement paste mixture, additives to accelerate hardening and / or to adjust the setting time and / or to provide water repellency and fillers as dry mass, and the dry mass is mixed with a foaming agent and water, characterized by that the foam concrete contains 50 - 90 wt.% of a cement paste mixture comprising 20 - 70 wt.% Portland cement and 8 - 50 wt.% calcium aluminate (SCA cement), 0.01 - 3 wt.% aluminum hydroxide as an additive to accelerate hardening, 0.5 - 5 wt.% aluminum stearate as an additive for hydrophobization, 0.01 - 3 wt.% polyacrylic acid derivatives as a plasticizer, 0.01 - 5 wt.% lithium carbonate as a reaction accelerator, 1 - 30 wt.% mineral fillers and 10 to 50 wt.% of the liquid foaming agent foamed from foaming agent and water to which 0.01 - 2 wt.% of a liquid aggregate is added. [2] Anhydrite-free foam concrete according to claim 1, characterized bythat the liquid additive consists of a mixture of 30 - 85 wt.% demineralized water, 5 - 35 wt.% olefin sulfonates and 10 - 35 wt.% butyldiglycol. [3] Anhydrite-free foam concrete according to claim 1, characterized by that a rhamnolipid-alginate polymer complex is used as the foaming agent and the foaming agent is foamed with the aqueous solution in a ratio of 1 to 5 to 1 to 80 to form a liquid foaming agent with a foam density of 50 to 100 g / l. [4] Anhydrite-free foam concrete according to claim 1, characterized by that the foam concrete composition after hardening has a dry bulk density of 45 to 110 kg / m 3 and has a thermal conductivity in the range of 28 to 44 mW / mK. [5] Anhydrite-free foam concrete according to claim 1, characterized by that the foam concrete contains mineral substances in powder form and / or mineral dust as fillers. [6] Anhydrite-free foam concrete according to claim 5, characterized by that a ground clay or loam powder is added as a mineral substance. [7] Anhydrite-free foam concrete according to claim 5, characterized by that ground brick powder and / or pumice powder is added as a mineral substance. [8] Anhydrite-free foam concrete according to claim 5, characterized by that a ground powder from a recycled mineral building material is added as a mineral substance. [9] Anhydrite-free foam concrete according to claim 5, characterized by that brick grinding dust is added as mineral dust. [10] Anhydrite-free foam concrete according to claim 5, characterized by that concrete stone grinding dust is added as mineral dust. [11] Use of the anhydrite-free foam concrete according to claim 1 and at least one of claims 2 to 10 for filling cavities in building blocks. [12] Use of the anhydrite-free foam concrete according to claim 1 and at least one of claims 2 to 10 for filling multi-layer concrete or brick components. [13] Building block with a filling of a foam concrete according to claim 1 and at least one of claims 2 to 10, characterized by that at least one row of the hole pattern of the building block is filled with foam concrete. [14] Module according to claim 13, characterized by that the filled row runs parallel to the longitudinal wall of the building block.