Foamed concrete

Abstract

The invention relates, inter alia, to a foamed concrete (10), produced from a mixture of cement paste (11) and foam (12), wherein the cement paste comprises at least a) a cement fraction (13), b) a quick-setting cement fraction (14), c) water (15), and d) a plasticizer (16), wherein the foam (12) comprises air (17), water (18) and a foaming agent (19), and wherein the foamed concrete (10) has a dry bulk density of more than 750 kg / m3.

Description

[0001] Applicant: Arccen Ltd.

[0002] - 1 -

[0003] Foam concrete

[0004] The invention relates initially to a foam concrete according to claim 1.

[0005] The applicant has been involved in the development and production of foam concrete for some time.

[0006] Foam concrete is a type of concrete produced by mixing a cement paste, which primarily contains cement and water, with a foam. First, the cement paste is prepared, and the foam is produced separately. The foam and cement paste are then mixed together. The air bubbles contained in the foam remain in the mixed foam concrete and are retained, particularly during the hardening process.

[0007] Foam concrete differs from aerated concrete, which is typically produced by adding a blowing agent (such as aluminum powder) to the cement paste. In the production of aerated concrete, the blowing agent causes the viscous cement paste to foam up. However, unlike in the production of foam concrete, there is no mixing of foam and cement paste.

[0008] The invention relates only to foam concretes or foam concrete mixtures, but not to aerated concretes.

[0009] The incorporation of foam into a cement paste, and thus the known process of producing foam concrete, enables the construction industry to provide novel building components, such as foam concrete insulation panels, which exhibit particularly advantageous properties. Applicant: Arccen Ltd.

[0010] - 2 -

[0011] According to the state of the art, it is also known to add certain additives to the cement paste, which can particularly influence the thermal conductivity or the dry bulk density.

[0012] Even though the well-known foam concrete and the building elements produced from it have proven suitable for the known applications, there is a need to further improve the formula, especially with regard to a higher compressive strength of the foam concrete or the building element produced from it.

[0013] Foam concretes according to the invention, as described for example in EP 3 972 946 A1, typically have dry bulk densities between 10 and 300 kg / m³. 3 on.

[0014] The well-known foam concrete compounds are used, for example, to manufacture insulation boards that have good thermal insulation properties and are non-combustible.

[0015] Based on the described state of the art, the object of the invention is to provide a foam concrete that can replace a conventional precast concrete component.

[0016] The invention solves this problem with the features of claim 1.

[0017] The principle of the invention is to provide a foam concrete which, in terms of its manufacturing method, is produced like conventional foam concrete, namely from a mixture of cement paste and foam. The foam comprises the usual proportions of air, water, and foaming agent. The foam can, for example, have a density of 50-60 g / l. Applicant: Arccen Ltd.

[0018] - 3 -

[0019] The cement paste contains cement, rapid-setting cement, water, and a plasticizer. The special feature of the foam concrete according to the invention is that the foam concrete has a dry density of more than 750 kg / m³. 3The dry density is measured in the hardened state of the foamed concrete. It is significantly lower than the wet density of the still liquid foamed concrete.

[0020] As a result of the drying and curing process, approximately 40% of the water contained in the liquid foam concrete is bound through chemical reaction and crystallization, and approximately 60% of the water evaporates.

[0021] Depending on the water content in the cement paste, a significant reduction in bulk density occurs from the wet state when it is transferred to the dry state.

[0022] The special feature of the foam concrete according to the invention is that it has a very high dry bulk density of more than 750 kg / m³. 3 exhibits. In particular, depending on the intended application, foam concrete masses with dry bulk densities between 800 kg / m³ are produced according to the invention. 3 and 1,600 kg / m² 3 proposed.

[0023] According to the invention, a foam concrete achieves its high dry density through a special microstructure. This is accomplished by including different types of cement in the cement paste, namely at least a proportion of a first type of cement and, independently, a proportion of rapid-setting cement. This allows the foam concrete to harden and begin drying quickly. A shrinkage process, which is unavoidable in precast concrete elements made of normal concrete according to the prior art, is prevented or at least largely prevented according to the invention. Applicant: Arccen Ltd.

[0024] - 4 -

[0025] This shrinkage process is prevented. By preventing this shrinkage process, the desired high compressive strength can be achieved.

[0026] Foam concrete mixes with these high dry densities can completely replace conventional precast concrete elements. The invention thus provides foam concretes that are not intended to provide an insulating layer, e.g., in the form of an insulating board, but rather enable the production of conventional precast concrete elements, such as L-shaped blocks, exterior walls, interior walls, roof elements, balconies, basement walls, stairs, lintels, etc. – i.e., components that are subject to high demands regarding their compressive strength.

[0027] A significant advantage of a precast concrete element made from the foam concrete according to the invention, compared to a precast concrete element made from conventional normal concrete, is its lower thermal conductivity. Those components of the prior art, such as exterior walls, lintels, etc., which form thermal bridges or cold bridges when manufactured from normal concrete and require separate insulation, can, according to the invention, be provided by a precast concrete element made from the foam concrete according to the invention, without the need for additional insulation layers.

[0028] Interior wall elements of conventional buildings, for example, require compressive strengths of at least 7.5 MPa, which are typically achieved with precast concrete elements made of normal-weight concrete. Exterior wall elements, depending on whether it is a bungalow, a two-story house, or a multi-story house, require higher compressive strengths of, for example, 8, 12, or 25 MPa.

[0029] Balconies, roof elements, or similar components require compressive strengths of approximately 35 MPa. Applicant: Arccen Ltd.

[0030] - 5 -

[0031] The foam concrete masses according to the invention can achieve comparable or sufficient compressive strengths.

[0032] For example, foam concrete can have a dry density of approximately 800 kg / m³. 3 achieve or far exceed a compressive strength of 7.5 MPa.

[0033] An exterior wall element made of foam concrete with a dry density of approximately 1,600 kg / m³3 It can achieve a compressive strength far exceeding the legally required 25 MPa.

[0034] According to the invention, a conventional precast concrete element, such as an exterior wall element or an L-shaped block, no longer needs to be made from conventional normal concrete, but can be made from foam concrete.

[0035] Foam concrete is considerably lighter than normal concrete and therefore allows for production with much less material usage and easier transport to the assembly site compared to the production of prefabricated components made of normal concrete.

[0036] A precast concrete element produced with the foam concrete according to the invention is, if it consists of a foam concrete with a dry bulk density of approximately 1,600 kg / m³ 3 still consists of approximately 800 kg / m² 3Lighter than a conventional precast concrete element made of normal concrete. Furthermore, the precast concrete element made of foam concrete according to the invention does not exhibit the shrinkage typical of precast concrete elements made of normal concrete. Applicant: Arccen Ltd.

[0037] - 6 -

[0038] According to the invention, the use of foam concrete masses as high-strength building materials is made possible for the first time ever.

[0039] Furthermore, the building's structural design can be calculated more favorably because the precast concrete elements produced from the foam concrete according to the invention are lighter. This means that, due to their lower weight, several precast foam concrete elements can be transported to a construction site by heavy transport, for example, compared to the transport of precast concrete elements made of normal concrete using conventional methods.

[0040] The foam concrete according to the invention can have a cement content comprising a first type of cement and a second type of cement, wherein each type of cement can in particular have different finenesses of grinding or different degrees of grinding.

[0041] The foam concrete according to the invention also includes a rapid-setting cement component. This constitutes only a fraction of the weight percentage of the cement component.

[0042] Furthermore, the foam concrete according to the invention comprises a superplasticizer, a so-called concrete plasticizer or superplasticizer, which ensures that the foam concrete does not harden in the cement paste, but only after mixing with the foam.

[0043] The flow agent therefore delays the hardening process.

[0044] The use of a rapid-setting cement, i.e., an accelerator, and simultaneously a superplasticizer, i.e., a reaction retarder, appears contradictory at first glance. However, this is precisely where the inventive advantage lies: Arccen Ltd.

[0045] - 7 -

[0046] Special feature: The plasticizer, by liquefying the cement paste, initially delays its hardening. This ensures that no hardening—and therefore no clumping—occurs before a homogeneous mixture with the foam is achieved. The delay can be adjusted to, for example, a few minutes by adding more plasticizer. The rapid-setting cement, on the other hand, ensures a rapid start to the hardening process as soon as the cement paste and foam are fully mixed. At this point, rapid initial hardening is crucial to maintain the structure of the composite during curing, prevent shrinkage, and achieve high compressive strength.

[0047] The quantities are measured so that the foam concrete has a dry density of more than 750 kg / m³. 3 exhibits.

[0048] Exemplary recipes are given in the following character description.

[0049] The foam concretes have dry bulk densities between 750 kg / m³ 3 up to approximately 1,000 kg / m³ 3 exhibiting these properties, can do entirely without sanding agents.

[0050] Foam concretes with higher dry bulk densities, according to the invention, in particular include a sand medium component.

[0051] The sand component within the meaning of the invention is either sand, in particular with a grain size of 0-2 mm, or a sand-like material, such as quartz flour or limestone flour.

[0052] The sand component may, for example, comprise sand, and / or quartz flour, and / or limestone flour. Applicant: Arccen Ltd.

[0053] - 8 -

[0054] The addition of sanding medium can positively influence the microstructure in terms of achieving high compressive strength and high dry bulk density.

[0055] According to the invention, foam concretes with dry bulk densities between 750 kg / m³ can also be used. 3 and 1,000 kg / m² 3 Sand media components are included.

[0056] According to the invention, a complete replacement of a conventional precast concrete element made of normal concrete is proposed by a precast concrete element made of foam concrete.

[0057] Rapid-setting cement, for example, is a so-called CSA cement.

[0058] Rapid-setting cement is also known as quick-setting cement. This is a cement that sets particularly quickly. Mortars made from such cement typically have a working time of only a few minutes. However, cements with a working time of up to one hour can also be considered rapid-setting cement within the meaning of the invention.

[0059] However, because setting occurs far too quickly, rapid-setting cements are actually considered unsuitable for concrete production, as processing times of less than an hour on a large construction site are considered far too short.

[0060] Typically, rapid-setting cements can contain high proportions of aluminum and / or calcium and / or sulfonate.

[0061] The abbreviation CSA in CSA cement stands for calcium sulfoaluminate cement. This example cement is a rapid-setting cement, submitted by Arccen Ltd.

[0062] - 9 -

[0063] Bauxite and / or limestone and / or gypsum are typically used as raw materials.

[0064] In general, rapid-setting cements are characterized by a high gypsum content.

[0065] The aforementioned CSA cement could also be considered a mixture between Portland and alumina cement.

[0066] According to the invention, a mixture of several types of cement is used for the cement paste. The proportion of the first type of cement is much larger than the proportion of rapid-setting cement.

[0067] The foam concrete according to the invention has a special structure due to its composition. This structure is what makes it possible, according to the invention, to produce foam concretes with high compressive strength.

[0068] According to the invention, foam concrete masses can also have dry bulk densities of more than 1,600 kg / m³. 3 can be produced. However, the dry density of a precast concrete element made from foam concrete then approaches the density of a conventional precast concrete element made from normal concrete, so that the weight advantages are lost.

[0069] The manufacturing process for a foam concrete according to the present invention provides, in particular, that the cement paste is produced using water and cement. The proportion of the total solids content of the cement paste provided by cement or the cement mixture is advantageously between 40% and 95%. All percentages in this patent application are to be understood as mass weight values. Applicant: Arccen Ltd.

[0070] - 10 -

[0071] The cement mixture provided for in claim 1 constitutes between 40% and 95% of the total solids used to produce the cement paste. In particular, the proportion of the cement mixture to the total solids content of the cement paste is approximately between 40% and 92%. The exact proportion depends, in particular, on the desired dry density of the hardened foam concrete.

[0072] As already shown above, the invention provides that the proportion of sand also increases with increasing dry bulk density.

[0073] A method for producing the foam concrete according to the invention comprises combining the cement paste with the foam after its respective production.

[0074] Advantageously, it can also be provided that a pre-mixed blend (a so-called "compound") can be added during the production of the cement paste. This compound can include, in particular, the rapid-setting cement component, as well as, if necessary, the superplasticizer and / or a water-repellent agent.

[0075] Due to the completely different manufacturing processes of foam concrete (also known as lightweight aerated concrete or mineral foam) and aerated concrete, different structures arise in the hardened concrete. In aerated concrete components, the pores are interconnected by a capillary system. For this reason, aerated concrete components absorb a considerable amount of water. In contrast, in a foam concrete according to the invention, the individual pores are (at least predominantly) separated from one another and are not interconnected. Applicant: Arccen Ltd.

[0076] - 11 -

[0077] interconnected. Therefore, foam concrete components according to the invention cannot absorb any or almost no water.

[0078] Another key difference between foam concrete and aerated concrete lies in the manufacturing process: aerated concrete is hardened under the influence of heat and pressure. In contrast, the foam concrete according to the invention can harden without the application of heat and / or at atmospheric pressure.

[0079] A method according to the invention for producing a foam concrete according to the invention can therefore advantageously comprise the following step:

[0080] "Allowing the foam concrete to harden without the addition of heat, without the addition of energy, and at atmospheric pressure."

[0081] The manufacturing process according to the invention is carried out, in particular, without the application of heat or pressure, for example in an autoclave. This allows for significant cost savings and a simplification of the manufacturing process compared to prior art methods that use (or require) an autoclave.

[0082] According to the invention, foam concrete is produced by combining or mixing a cement paste with foam. The foam is typically folded into the cement paste, or vice versa. This typically takes place in a mixing station, for example, a mixing station similar to a mixer. The folding in or mixing is generally carried out at a low speed. This allows for gentle mixing. The mixing time can, for example, range from a few seconds to... Applicant: Arccen Ltd.

[0083] - 12 -

[0084] a few minutes, for example between 30 seconds and 5 minutes, and preferably between 1 and 2 minutes.

[0085] The foam required for this process is typically generated in a separate foaming unit and then fed into the mixing station. Alternatively, the foam can be generated directly in the mixing station itself, for example, in a large basin. In both cases, the cement slurry can be added gradually or intermittently to the foam in the mixing station and then incorporated or mixed in using a mixer. The cement slurry is also referred to as "slurry."

[0086] Advantageously, the stirring or folding process occurs with a certain regularity, allowing for the continuous addition of fresh cement paste. This is a well-known procedure, for example, in the production of meringue or Kaiserschmarrn (a type of shredded pancake). Therefore, preferably not all of the cement paste and all of the foam are already present in the mixing station at the beginning of the stirring process.

[0087] According to the invention, the mixing of cement paste with foam can also be carried out in a static mixer. This allows, in particular, the continuous production of foam concrete. For example, the cement paste can be mixed using a mortar pump and conveyed through a delivery line. Foam can be injected into the delivery line, for example, continuously or intermittently, and mix with the cement paste.

[0088] In one example mixing station, one cubic meter of the mixed mass contains, for instance, 750 to 800 liters of foam and 100 to 300 liters of cement paste. However, this is just one applicant: Arccen Ltd.

[0089] - 13 -

[0090] Example value. The stated ratio can also be between 5:1 and 20:1, preferably between 3:1 and 50:1.

[0091] The mass produced in this way, which can also be referred to as (liquid or viscous) foam concrete or foam concrete raw material, is then typically pumped out and further shaped or processed into a finished component.

[0092] The foam, which is mixed with the cement paste to produce foamed concrete, typically consists of a composition of air and a foaming agent containing proteins and / or aluminum salts and / or surfactants and / or water. The foaming agent is therefore typically liquid or at least fluid.

[0093] The foaming agent is aerated with air to produce the foam, preferably by adding the foaming agent to an existing air foam. This can be done using a foam generator, which then either fills the mixing station itself directly with foam or first fills a separate basin or similar container from which the foam is then fed to the mixing station.

[0094] The cement paste is taken, for example, from a colloid mixer, which is also called a colloidal mixer.

[0095] Colloid mixers are used, for example, in the production of suspensions containing minute particles. Besides the uniform distribution of the solid particles in the fluid phase, the focus is on particle disruption, i.e., separating clumps. Particle disruption is achieved, among other things, to increase the reactive surface area of ​​the material. Alternatively, any other suitable mixer can be used, such as a hand mixer or similar device. Applicant: Arccen Ltd.

[0096] - 14 -

[0097] Depending on the application, certain additives are used.

[0098] These additives, in addition to the cement mixture, are of course also components that contribute to the total solids content of the cement paste.

[0099] Examples of suitable additives include metakaolin, microsilica, nanosilica, hydroxylapatite, tricalcium phosphate and / or pyrogenic silica.

[0100] According to a particularly advantageous embodiment of the invention, the cement component comprises a first type of cement, which is provided by Portland cement, in particular Portland cement CEM I 52.5 Portland cement. The first type of cement has in particular a high fineness of grinding, in particular of about 6000 Blaine.

[0101] Advantageously, the cement component also includes a second type of cement, such as Portland cement CEM II 52.5 LL. Alternatively, limestone flour can be used instead of a second type of cement. The second type of cement or the limestone flour has a lower fineness of grinding, particularly around 3000 Blaine.

[0102] The proportion of the second type of cement or limestone flour in relation to the first type of cement can be, for example, between 1:10 and 6:10, preferably about 3:8.

[0103] The cement content may also include recycled cement, so-called R-cement. Applicant: Arccen Ltd.

[0104] - 15 -

[0105] For example, a CSA cement, i.e. a calcium sulfo-aluminate cement, is used as a rapid-setting cement.

[0106] In particular, according to the invention, a mixture of two different CSA cements is used as the rapid-setting cement component.

[0107] Preferably, approximately 10kg to 20kg of rapid-setting cement per m² is used. 3 Foam concrete added.

[0108] According to a particularly advantageous embodiment of the invention, the ratio of the cement content to the rapid-setting cement content is between 100:1 and 2:1. Advantageously, the ratio is approximately between 10:1 and 3:1, and in particular 5:1.

[0109] According to the invention, a concrete plasticizer is added or used in the production of the cement paste. This can be, in particular, a so-called superplasticizer for concrete according to EN 934-2. Such a substance can bring about advantageous properties, especially by reducing the surface tension of the water, such as strong plasticization of the foam concrete without introducing air voids into the concrete.

[0110] According to an advantageous embodiment of the invention, the foam has a density of 40–100 g / l, preferably a density of 50–60 g / l. This embodiment of the invention enables the provision of a foam that allows for optimal mixing with the cement paste. The density of the foam can be adjusted, for example, by adjusting the air supply in the foam generator. Applicant: Arccen Ltd.

[0111] - 16 -

[0112] According to an advantageous embodiment of the invention, the mixture of cement paste and foam comprises approximately 80–120 liters of foam per 100 kg of cement. This embodiment of the invention enables the provision of foam concrete with an optimized mixing ratio between cement paste and foam.

[0113] According to an advantageous embodiment of the invention, the weight fraction of water in the cement paste is 30% to 45% of the weight fraction of cement. This embodiment of the invention enables an optimized composition of the foam concrete.

[0114] According to an advantageous embodiment of the invention, the weight fraction of rapid-setting cement in the cement paste is 1% to 5% of the weight fraction of cement. This embodiment of the invention enables the provision of an inexpensive foam concrete that exhibits the desired high compressive strength properties.

[0115] According to an advantageous embodiment of the invention, the foam concrete has a dry density between 800 and 1600 kg / m³. This embodiment of the invention enables the production of precast concrete elements that can replace conventional precast concrete elements made of normal concrete. For example, with densities between 800 and 1600 kg / m³, an exterior wall element, an interior wall element, a ceiling element, a basement ceiling, a basement wall, or a balcony can be manufactured.

[0116] According to an advantageous embodiment of the invention, the cement paste comprises a sand component. This embodiment of the invention enables the achievement of very high dry bulk densities of a foam concrete according to the invention while achieving high compressive strengths. Applicant: Arccen Ltd.

[0117] - 17 -

[0118] According to an advantageous embodiment of the invention, the sand component comprises sand and / or quartz flour and / or limestone flour. This embodiment of the invention enables the use of inexpensive building materials.

[0119] According to an advantageous embodiment of the invention, the weight fraction of the sand component in the cement paste is 20% - 150% of the weight fraction of the cement component. This embodiment of the invention enables a particularly optimized compressive strength of a foam concrete with a high dry bulk density.

[0120] According to an advantageous embodiment of the invention, the cement component comprises at least one first type of cement and a second type of cement or limestone flour. This embodiment of the invention allows for a mixture of cement types with different degrees of grinding, which leads to the achievement of a particularly high compressive strength.

[0121] According to an advantageous embodiment of the invention, the first type of cement is a Portland cement, in particular of the type CEM I 52.5, and further in particular of CEM I 52.5, with a high fineness of grinding, in particular with a Blaine value of at least 6,000. This embodiment of the invention makes it possible to achieve a particularly high compressive strength.

[0122] According to an advantageous embodiment of the invention, the weight fraction of the second type of cement is approximately 20–80% of the weight fraction of the first type of cement. This embodiment of the invention makes it possible to achieve a particularly high compressive strength.

[0123] According to an advantageous embodiment of the invention, the second type of cement is a cement with a [missing information] compared to the first type of cement. Applicant: Arccen Ltd.

[0124] - 18 -

[0125] A lower Blaine value is provided. This embodiment of the invention enables the achievement of a particularly high compressive strength.

[0126] According to an advantageous embodiment of the invention, the rapid-setting cement comprises at least one CSA cement, in particular two different CSA cements. This embodiment of the invention enables particularly optimized curing and drying.

[0127] According to an advantageous embodiment of the invention, the cement paste comprises a hydrophobing agent, in particular a melamine resin. This embodiment of the invention enables optimized liquid tightness. While foam concretes of the type claimed are inherently liquid tight, since no water can pass through the pores formed, the addition of a hydrophobing agent, e.g., a melamine resin, can further increase the liquid tightness.

[0128] In this embodiment, precast concrete elements made of foam concrete can be manufactured, which are particularly waterproof and, for example, prevent the penetration of salt water, thus preventing the corrosion of precast concrete elements, e.g., L-shaped blocks.

[0129] The invention further relates to a method for manufacturing a precast concrete element according to claim 16.

[0130] Such methods are not known in the prior art.

[0131] This invention aims to provide a method for producing a precast concrete element from foam concrete. Applicant: Arccen Ltd.

[0132] - 19 -

[0133] The invention solves this problem with the features of claim 16.

[0134] According to the invention, a method for producing a precast concrete element from foam concrete is proposed. This comprises process steps A) to E).

[0135] To avoid repetition, reference is made to the above statements regarding the understanding of the features and the explanation of the invention, which apply analogously.

[0136] The invention further relates to a precast concrete element made of foam concrete according to claim 17.

[0137] Such precast concrete elements are not known in the prior art.

[0138] The invention according to claim 17 is based on the objective of providing a precast concrete element that can replace a conventional precast concrete element made of normal concrete according to the prior art.

[0139] The invention solves this problem with the features of claim 17.

[0140] Regarding the understanding of the features of claim 17, reference is made to the above statements.

[0141] According to an advantageous embodiment of the invention, the precast concrete element is provided by an L-shaped block. This embodiment of the invention enables the replacement of a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight. Applicant: Arccen Ltd.

[0142] - 20 -

[0143] According to an advantageous embodiment of the invention, the L-stone comprises a dry bulk density of more than 1,400 kg / m³. 3 . This embodiment of the invention makes it possible to replace a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight.

[0144] According to an advantageous embodiment of the invention, the precast concrete element is provided by an exterior wall element. This embodiment of the invention makes it possible to replace a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight.

[0145] According to an advantageous embodiment of the invention, the outer wall element has a dry bulk density of more than 1,400 kg / m³. 3 This embodiment of the invention enables the replacement of a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight.

[0146] According to an advantageous embodiment of the invention, the precast concrete element is provided by an interior wall element. This embodiment of the invention makes it possible to replace a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight.

[0147] According to an advantageous embodiment of the invention, the inner wall element has a dry bulk density between 800 and 1,000 kg / m³. 3 This embodiment of the invention enables the replacement of one applicant: Arccen Ltd.

[0148] - 21 -

[0149] Conventional precast concrete elements made of normal concrete are replaced by precast concrete elements made of foam concrete, which have comparable compressive strengths but a significantly lower weight.

[0150] According to a further aspect, the invention relates to a precast concrete element according to claim 24. The invention is based on a precast concrete element made of normal concrete of conventional design.

[0151] Based on this, the invention aims to provide a lighter precast concrete element that also meets high requirements for compressive strength.

[0152] The invention solves this problem with the features of claim 24.

[0153] For an understanding of these features of the invention, reference is made to the above explanations.

[0154] According to the invention, the prefabricated component comprises at least one first foam concrete layer and at least one second foam concrete layer, wherein at least one foam concrete layer has a dry bulk density of more than 750 kg / m³. 3 exhibits.

[0155] In particular, at least one of the two foam concrete layers consists of a foam concrete according to any one of claims 1 to 15.

[0156] This embodiment of the invention enables the replacement of a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight. Applicant: Arccen Ltd.

[0157] - 22 -

[0158] According to the invention, a precast concrete component comprising several layers is provided.

[0159] This can, for example, include a first layer of a foam concrete with high dry density, which has high compressive strength and is homogeneously formed, and a thermal insulation layer, whereby the thermal insulation layer can consist of a foam concrete with a lower dry density, for which only very low requirements are placed regarding its compressive strength.

[0160] According to another aspect, the patent application relates to a precast concrete element according to claim 25.

[0161] The invention according to claim 25 is based on the objective of providing a precast concrete element that is particularly pressure-resistant and can replace conventional precast concrete elements.

[0162] The invention solves this problem with the features of claim 25.

[0163] According to the invention, the two layers of foam concrete are bonded together by means of reinforcement. This embodiment of the invention enables the replacement of a conventional precast concrete element made of normal concrete with a precast concrete element made of foam concrete, which has comparable compressive strengths but a significantly lower weight. The incorporation of reinforcement provides a particularly advantageous method for manufacturing this multi-layered precast concrete element. Furthermore, good surface bonding with high adhesive strength is achieved between the different foam concrete layers. In particular, one or more of the foam concrete layers can have a very high dry density of more than 750 kg / m³. 3 exhibit. Applicant: Arccen Ltd.

[0164] - 23 -

[0165] All the described precast concrete components that have multiple layers have a special feature in that the precast concrete component has different foam concrete layers, with at least one foam concrete layer having a dry density of more than 750 kg / m³. 3 The invention encompasses a multi-layered precast concrete element. The two foam concrete layers can be directly bonded to each other. They can also be bonded with the aid of reinforcement. Alternatively, they can be bonded with the aid of an intermediate layer. The invention also includes situations where the precast concrete element has a multi-layered structure with different foam concrete layers comprising different dry densities.

[0166] The invention further relates to a method according to claim 26.

[0167] The invention is based on the objective of specifying a manufacturing process for a precast concrete element made of several layers, wherein the layers are connected to each other over a large area.

[0168] The invention solves this problem with the features of claim 26.

[0169] To avoid repetition, reference is made to the above statements regarding the explanation of the features of claim 26.

[0170] Further advantages of the device according to the invention will become apparent from the uncited dependent claims and from the following description of the exemplary embodiments illustrated in the drawings. Applicant: Arccen Ltd.

[0171] - 24 -

[0172] It shows:

[0173] Fig. 1 is a schematic diagram illustrating the production of a foam concrete according to the invention, comprising providing a cement paste produced in a mixer from several ingredients, and providing a separately produced foam, wherein the cement paste and foam are brought together and mixed in a mixing station and, in the mixed state, provide a foam concrete.

[0174] Fig. 2 shows a perspective, partially cutaway view of a precast concrete element formed as an L-shaped block.

[0175] Fig. 3a shows a first embodiment of a wall in sectional view, which is provided by an external wall element,

[0176] Fig. 3b shows a second embodiment of a wall provided by an interior wall element, applicant: Arccen Ltd.

[0177] - 25 -

[0178] Fig. 4 shows an exemplary embodiment of a wall comprising two layers of foam concrete in a sectional view.

[0179] Fig. 5 shows an embodiment of a wall comprising three layers of foam concrete, which are connected to each other via reinforcement in the form of reinforcing bars.

[0180] Figures 6 to 10 illustrate the production of a building element comprising foam concrete according to the invention, wherein

[0181] Fig. 6 shows a formwork with reinforcement before filling with foam concrete in a sectional view,

[0182] Fig. 7 shows the formwork of Fig. 6 filled with a first layer of foam concrete, wherein only lower sections of the reinforcement are encased by the foam concrete mass,

[0183] Fig. 8 shows the embodiment of Fig. 7, wherein a second layer of foam concrete is poured against the first layer, and middle sections of the reinforcement are embedded.

[0184] Fig. 9 shows the embodiment of Fig. 8, wherein a third layer of foam concrete is added. Applicant: Arccen Ltd.

[0185] - 26 -

[0186] under the encasing of further sections of the reinforcement against the second layer of foam concrete,

[0187] Fig. 10 shows the hardened precast concrete component of Fig. 9 with hardened foam concrete layers,

[0188] Fig. 11 shows a further embodiment of a schematic diagram for the production of foam concrete, in which sand components are provided as a part of the cement paste.

[0189] Fig. 12 in a representation similar to the representation of Fig. 6, a formwork, a reinforcement arranged thereon and a filling device for filling the formwork with foam concrete mass for the production of a further embodiment of a building element according to the invention,

[0190] Fig. 13 in a representation similar to Fig. 12 shows the formwork and the reinforcement, with a first layer of foam concrete poured in.

[0191] Fig. 14 shows the embodiment of Fig. 13, wherein the hardened first layer of foam concrete is combined with the applicant: Arccen Ltd.

[0192] - 27 -

[0193] The reinforcement is inserted inverted into the formwork and the second layer of foam concrete is poured, leaving a cavity between the two layers.

[0194] Fig. 15 in standalone view, the building element taken from the formwork of Fig. 14 in the hardened state of the two foam concrete layers, with an unfilled free space remaining between them, and

[0195] Fig. 16 in a representation according to Fig. 15 shows a further embodiment of a multi-layered building element, in which, unlike the embodiment of Fig. 15, the reinforcing bars do not extend to the outer surfaces of the outer foam concrete layers.

[0196] Exemplary embodiments of the invention are described in the following description of the figures, also with reference to the drawings. For the sake of clarity, identical or comparable parts, elements, or areas are designated with the same reference numerals, sometimes with the addition of lowercase letters, even where different embodiments are concerned. Applicant: Arccen Ltd.

[0197] - 28 -

[0198] Features described only in relation to one embodiment can also be provided in any other embodiment of the invention. Such modified embodiments are included in the invention, even if they are not shown in the drawings.

[0199] All disclosed features are essential to the invention. The disclosure of this application hereby incorporates in full the disclosure content of the associated priority documents (copy of the prior application) as well as the cited publications and the described devices of the prior art, also for the purpose of including one or more features of these documents in one or more claims of the present application.

[0200] An embodiment of a foam concrete according to the invention is designated in its entirety by reference numeral 10 in the drawings.

[0201] Based on the schematic diagram of Figure 1, it will first be explained how the foam concrete 10 according to the invention is composed and how the foam concrete 10 is produced:

[0202] Figure 1 illustrates a mixer 23 used for mixing several components. The cement paste 11 is mixed in the mixer 23.

[0203] Furthermore, Figure 1 indicates a foam mixer 40, which is used to produce foam 12.

[0204] The cement paste 11 and the foam 12 are fed to a mixing station 39 after their production. At the mixing station 39, the applicant is Arccen Ltd.

[0205] - 29 -

[0206] The produced foam 12 is mixed with the cement paste 11. The mixture constitutes the foam concrete 10 according to the invention.

[0207] According to the invention, the cement paste 11 requires various components, namely a cement component 13, a rapid-setting cement component 14, water 15 and a superplasticizer 16.

[0208] The cement component 13 comprises at least a first type of cement 21, preferably also a second type of cement 22. The second type of cement 22 can also be limestone flour.

[0209] The first cement type 21 is preferably finely ground and has a Blaine value of 6,000. In particular, the first cement type is provided by a Portland cement CEM II 52.5 LL with a high degree of fineness of grinding.

[0210] The second cement type 22 can be, for example, a Portland cement CEM II, with a lower grinding fineness, in particular with a lower Blaine value of, for example, 3,000.

[0211] The rapid-setting cement 14 comprises at least one CSA cement 24, preferably two different CSA cements 24 and 25.

[0212] Additionally, a hydrophobizing agent 26 can be provided, which provides an impregnation for the foam concrete 10 and ensures further improved water resistance.

[0213] To produce the foam 12, air 17, water 18 and foaming agent 19 are supplied to the foam mixer 40.

[0214] In the embodiment shown in Figure 1, the sanding agent 20 is, in particular, sand, but alternatively also quartz or limestone flour. Applicant: Arccen Ltd.

[0215] - 30 -

[0216] only optionally provided. To achieve a foam concrete 10 according to the invention with a bulk density of 750-1000 kg / m³ 3 The addition of sanding agent 20 is not absolutely necessary.

[0217] The embodiment of a foam concrete 10 according to Figure 11, however, makes it clear that a sand agent 20 must be supplied to the mixer 23 for the production of the cement paste 11.

[0218] The arrow shown in a solid line from the sanding agent 20 in Figure 11 to the mixer 23 illustrates the mandatory use of sanding agent 20 in this embodiment, in contrast to the arrow shown in dashed lines in Figure 3, which is intended to illustrate the optional supply of sanding agent 20 in this embodiment.

[0219] In a further, particularly preferred embodiment of the invention, a foam concrete 10 has a bulk density of 750 kg / m³. 3 A sand medium component 20 is added, in an amount of, for example, 5 to 15% of the weight fraction of the cement component 13.

[0220] Foam concretes 10 of the type according to the invention with higher dry bulk densities, e.g. 1,200 or 1,600 kg / m³ 3 , generally have a sand content of approximately 20 to 150% of the weight fraction of the cement content 13.

[0221] The embodiment shown in Figure 2 is an embodiment of a precast concrete element 27a, in the form of an L-shaped block 28. The L-shaped block 28 has a width 43, a height 44 and a length 46 and is shown in Figure 2 in perspective, partially cut away.

[0222] The L-shaped concrete block 28 according to the invention has dimensions that correspond to the dimensions of conventional L-shaped concrete blocks made of normal concrete. Applicant: Arccen Ltd.

[0223] - 31 -

[0224] The L-shaped block 27a according to Figure 2 is designed as a substantially homogeneous precast concrete element 27a. According to the invention, the L-shaped block 28 is provided entirely and homogeneously from a foam concrete 10, which has a high dry density of, for example, 1,600 kg / m³. 3 exhibits.

[0225] The L-shaped block 28 can be manufactured in a conventional formwork (not shown). After hardening, the L-shaped block 28 can be removed from the formwork, or the formwork can be removed from the hardened L-shaped block 28.

[0226] The L-stone 28 is designed to be particularly pressure-resistant and can, for example, provide a compressive strength of more than 25 MPa.

[0227] Figure 3 shows a schematic, sectional view of an embodiment of a precast concrete element 27b in the form of an exterior wall element 29. Such an exterior wall element 29 can have a width, height and length that are not shown in Figure 3 and that correspond to the dimensions of conventional exterior wall elements.

[0228] For example, the exterior wall element 29 can have a wall thickness of 5cm to 50cm, a height between 1m and 5m and a length between 1m and 10m.

[0229] For example, a complete building wall with conventional dimensions can be provided for a prefabricated house using the exterior wall element 29. The precast concrete element 27b is also particularly homogeneous. Applicant: Arccen Ltd.

[0230] - 32 -

[0231] Depending on the specific requirements, the outer wall element 29 according to Fig. 3a has a high dry bulk density of, for example, 1600 kg / m³. 3 on.

[0232] The outer wall element 29 also has a very high compressive strength of, for example, more than 25 MPa.

[0233] In contrast, Fig. 3b shows a partially cutaway schematic view of a precast concrete element 27c in the form of an interior wall element 30. Interior wall elements are subject to lower compressive strength requirements. In some cases, a compressive strength of 7.5 MPa may suffice, which can be achieved with a homogeneously formed precast building element 27c made of foam concrete 10 according to the invention, which has a dry density of only 800 kg / m³. 3 exhibits.

[0234] Figure 4 shows an embodiment of a multi-layered precast concrete element 27d according to the invention. This multi-layered precast concrete element 31 has a first foam concrete layer 32 and a second foam concrete layer 33.

[0235] The two foam concrete layers 32, 33 can have different dry densities. At least one of the two foam concrete layers 32, 33 has a dry density of more than 750 kg / m³. 3 on.

[0236] The other of the two foam concrete layers 33, 32 has a lower dry density of, for example, only 130 kg / m³. 3 it and can, for example, act as a thermal insulation layer.

[0237] The embodiments shown in Figures 3a, 3b and 4 have in common that they are large-area wall elements of any dimensions, Applicant: Arccen Ltd.

[0238] - 33 -

[0239] for example, several meters in length, several meters in height and more than 10 cm in thickness, and which can be produced and cast in one go or in one go corresponding to the number of layers.

[0240] The embodiment shown in Figure 5 shows a precast concrete element 27e which has three different layers, namely a first foam concrete layer 32, a second foam concrete layer 33 and a third, intermediate foam concrete layer 41.

[0241] The two outer foam concrete layers 32, 33 can be connected to each other via a reinforcement 34 consisting of several bars 34a, 34b, 34c. This achieves a force-fit, optimized bond between the several layers 32, 33, 41. The individual bars are designated with the reference numerals 34a, 34b, 34c.

[0242] The reinforcing bars 34a, 34b, 34c can be made of a hard, tensile-resistant material, such as steel, or of a tensile-force-transmitting material, such as fiberglass, Kevlar, aramid fibers, etc.

[0243] The reinforcement 34 is cast in during the production of the foamed concrete component 27e. In particular, the middle foamed concrete layer 41 can have a very low dry density, whereas at least one of the two outer foamed concrete layers 32, 33, or even both foamed concrete layers 32, 33, have a high dry density of at least 750 kg / m³. 3 can exhibit.

[0244] Figures 6 to 10 are used to explain the manufacturing process of a precast concrete element 27e: Applicant: Arccen Ltd.

[0245] - 34 -

[0246] Figure 6 illustrates a formwork 36 that is essentially U-shaped in cross-section and has an overall trough-like shape. The reinforcement 34, comprising three reinforcing bars 34a, 34b, and 34c, is positioned within the formwork 36. In the embodiment shown in Figure 6, the reinforcement 34 rests with its lower sections 37 on a base of the formwork 36.

[0247] In further embodiments, a positioning device (not shown) can alternatively be used to achieve a spaced positioning of the bars 34a, 34b, 34c of the reinforcement 34 from the formwork 36.

[0248] Foam concrete 10 can be supplied via a filling device 42 in order to first form a first layer of foam concrete 32.

[0249] This state is shown in Figure 7. The first foam concrete layer 32 can encase the first lower sections 37 of the reinforcement 34 with respect to Fig. 7 and thus firmly attach the reinforcement 34a, 34b, 34c to the first foam concrete layer 32 as soon as it has hardened.

[0250] Then, either after the first foam concrete layer 32 has hardened, or as part of a “wet-on-wet” process, a further, middle, third foam concrete layer 41 can be poured on.

[0251] This situation is shown in Figure 8. The third layer of foam concrete 41 also encases the reinforcing bars 34a, 34b, 34c.

[0252] Finally, Figure 9 shows that a second foam concrete layer 33 can be cast onto the third foam concrete layer 41 to encase the second sections 38 of the reinforcement 34a, 34b, 34c. Applicant: Arccen Ltd.

[0253] - 35 -

[0254] The resulting precast concrete element 27g can be removed from the formwork 36 after peeling, or the formwork 36 can be removed from the precast concrete element 27g after it has hardened.

[0255] In this way, a precast concrete element 27g with a multi-layer structure is provided, wherein at least one of the foam concrete layers 32, 33, 41 consists of a foam concrete 10 with a dry bulk density of more than 750 kg / m³. 3 consists.

[0256] The foam concrete layer 32, 33 has a high dry density of more than 750 kg / m³ 3 can provide the desired load transfer.

[0257] Figures 12 to 15 illustrate the production of a precast concrete part 27h.

[0258] Starting from Figure 6, a modified formwork can be used to manufacture a precast concrete part 27h, which has lower side walls than the formwork of Figure 6.

[0259] As shown in Fig. 12, reinforcement 34 with three reinforcing bars 34a, 34b, 34c is placed in the formwork 36.

[0260] Figure 13 shows that foam concrete 10 is fed via the filling device 42 to pour a first layer of foam concrete 22, which encases the first sections 37 of the reinforcement 34. After the foam concrete layer 32 has hardened, the still unfinished precast concrete element 27h is removed from the formwork 36 and, as shown in Figure 14, inverted, i.e., placed back into the formwork 36 – or another formwork not shown. Applicant: Arccen Ltd.

[0261] - 36 -

[0262] Now, foam concrete 10 can be added via the filling device 42, so that a second foam concrete layer 33 is formed.

[0263] Once it has hardened, the resulting precast concrete element can be removed from the formwork 36 after 27 hours.

[0264] The resulting precast concrete element 27h is shown in isolation in Fig. 15. Here, the reinforcing bars 34a, 34b, 34c extend to the respective outer surface of the two outer foam concrete layers 32, 33.

[0265] An alternative embodiment is shown in Fig. 16 in a representation similar to Fig. 15: Here, the only difference is that the reinforcing bars 34a, 34b, 34c do not extend to the outer surface of the two foam concrete layers 32, 33, but rather that the second sections 38 and also the first sections 37 of the reinforcing bars 34a, 34b, 34c are each covered on their outer surface by foam concrete. This is achieved by spacing the reinforcement 34 from the formwork 36 using a positioning device (not shown) during production, unlike in Fig. 12.

[0266] Subsequently, for example at any later time, the remaining free space 35 between the two foam concrete layers 32, 33 can be filled. This filling can again be done with foam concrete, e.g., with foam concrete of a lower density, for example, on-site at a construction site. Alternatively, it can also be filled with insulating materials, e.g., with a loose fill of polystyrene, cork, etc.

[0267] The precast concrete element 27h can be used in the same way as the previously described precast concrete elements 27b to 27g, an external wall element 29 Applicant: Arccen Ltd.

[0268] - 37 -

[0269] or provide an interior wall element 30 or another building element.

[0270] The invention also includes situations where the precast concrete element provides a basement wall, a ceiling, a balcony floor or another precast concrete element commonly used in building technology.

[0271] Because the precast concrete elements 27a to 27h, 31 produced according to the invention have a dry density that, while significantly higher than that of conventional foam concrete elements, is considerably lower than that of conventional precast concrete elements made of normal concrete, advantages also arise in the design and planning of buildings, particularly with regard to structural integrity. For example, a building ceiling made of precast concrete elements of the type according to the invention can be much lighter, so that the load-bearing capacity requirement of the ceiling is lower than for conventional precast concrete elements made of normal concrete. This, in turn, reduces the requirements, e.g., for compressive strength. It also requires, for example, a smaller amount of steel beams. This makes lightweight building construction possible, with all the associated advantages.

[0272] The following are some examples of compositions and recipes of foam concretes 10 according to the invention:

[0273] First example:

[0274] For the production of a foam concrete 10 according to the invention with a dry bulk density of approximately 800 kg / m³ 3 The following components are mixed together to produce cement paste:

[0275] a) 500kg of a first type of cement Portland cement CEM I 52.5 Applicant: Arccen Ltd.

[0276] - 38 -

[0277] with a Blaine score of 6,000

[0278] b) 100 kg of a second type of cement Portland cement CEM II, 52.5 LL,

[0279] c) 200 liters of water,

[0280] d) 9 kg of a CSA cement,

[0281] e) 0.5 kg of flow agent

[0282] f) 0.3 kg water repellent

[0283] g) 400L foam

[0284] Second example:

[0285] For the production of a foam concrete 10 of the type according to the invention with a bulk density of approximately 800 kg / m³ 3 The following components are mixed together:

[0286] a) 380 kg Portland cement CEM I 52.5, with a Blaine value of 6,000

[0287] b) 100 kg of the second type of cement Portland CEM II, 52, 5 LL c) 200 l water,

[0288] d) 9kg CSA cement,

[0289] e) 0.5 kg of flow agent,

[0290] f) 400L foam,

[0291] g) 160kg sand 0-2.

[0292] Third example:

[0293] For the production of a foam concrete 10 of the type according to the invention with a bulk density of approximately 800 kg / m³ 3 The following components are mixed together:

[0294] a) 450kg of first type of cement, Portland cement CEM I 52.5 with a Blaine value of 6,000. Applicant: Arccen Ltd.

[0295] - 39 -

[0296] b) 130kg of the second type of cement, Portland cement CEM II, 52.5 LL,

[0297] c) 225L water,

[0298] d) 10kg CSA cement,

[0299] e) 0.5 kg of flow agent

[0300] f) 583I Foam,

[0301] g) 130kg sand 0-2

[0302] Fourth example:

[0303] For the production of a foam concrete 10 of the type according to the invention with a bulk density of approximately 1,200 kg / m³ 3 The following components are mixed together:

[0304] a) 450kg of first type of cement, Portland cement CEM I 52.5, with a Blaine value of 6,000

[0305] b) 160 kg of the second type of cement, Portland cement CEM II, 52.5 LL,

[0306] c) 225L water,

[0307] d) 10kg CSA cement,

[0308] e) 0.5 kg of flow agent

[0309] f) 461l foam,

[0310] g) 450kg sand 0-2.

[0311] Fifth example of execution:

[0312] For the production of a foam concrete 10 of the type according to the invention with a bulk density of approximately 1,600 kg / m³ 3 The following components are mixed together: Applicant: Arccen Ltd.

[0313] -40 -

[0314] a) 450kg of first type of cement, Portland cement CEM I 52.5, with a Blaine value of 6,000

[0315] b) 190 kg of the second type of cement, Portland cement CEM II, 52.5 LL,

[0316] c) 225L water,

[0317] d) 10kg CSA cement,

[0318] e) 295I Foam,

[0319] f) 0.5 kg of flow agent,

[0320] g) 870kg Sand 0-2.

Claims

Applicant: Arccen Ltd. Claims 1. Foam concrete (10) produced from a mixture of cement paste (11) and foam (12), wherein the cement paste (11) comprises at least a) a cement content (13) b) a rapid-setting cement component (14), c) Water (15), and d) a flow agent (16) comprises, wherein the foam (12) comprises air (17), water (18) and a foaming agent (19), and wherein the foam concrete (10) has a dry bulk density of more than 750 kg / m³ 3 exhibits.

2. Foam concrete (10) according to claim 1, wherein the foam (12) has a density of 40 to 100 g / l, preferably a density of 50-60 g / l.

3. Foam concrete (10) according to claim 1 or 2, wherein the mixture of cement paste (11) and foam (12) comprises between 70l and 120l of foam (12) per 100 kg of cement content (11).

4. Foam concrete (10) according to any of the preceding claims, wherein the weight fraction of water (15) in the cement paste (11) is between 30% and 45% of the weight fraction of cement (11).

5. Foam concrete (10) according to one of the preceding claims, wherein the weight fraction of rapid cement (14) in the cement paste (11) is 1% to 10%, in particular 1% to 5% of the weight fraction of cement (11). Applicant: Arccen Ltd.

6. Foam concrete (10) according to one of the preceding claims, wherein the foam concrete (10) has a dry bulk density between 800 and 1600 kg / m³ 3 exhibits.

7. Foam concrete (10) according to any of the preceding claims, wherein the cement paste (11) e) comprises a sand medium component (20).

8. Foam concrete (10) according to claim 7, wherein the sand agent portion (20) f) Sand and / or g) Quartz flour and / or h) Limestone flour includes.

9. Foam concrete (10) according to claim 7 or 8, wherein the weight fraction of the sand media fraction (20) in the cement paste (11) is between 1% and 250%, in particular between 1% and 200% of the weight fraction of the cement fraction (11).

10. Foam concrete (10) according to one of the preceding claims, wherein the cement content (11) is at least i) a first type of cement (21 ), and j) a second type of cement (22) or limestone flour, includes. Applicant: Arccen Ltd. -43 - 11. Foam concrete (10) according to claim 10, wherein the first cement type (21) is provided by a Portland cement, in particular of type CEM I 52.5 with a high fineness of grinding, in particular with a Blaine value of at least 6,000, and wherein the second cement type (22) is provided by a cement different from the first cement type (21).

12. Foam concrete (10) according to claim 10 or 11, wherein the weight fraction of the second cement type (22) is between 20 and 80% of the weight fraction of the first cement type (21).

13. Foam concrete (10) according to one of claims 10 to 12, wherein the second cement type (22) is provided by a cement having a lower Blaine value compared to the first cement type (21), in particular by a Portland cement, in particular of the type CEM II 52.5 LL.

14. Foam concrete (10) according to one of the preceding claims, wherein the rapid-setting cement (14) comprises at least one CSA cement (24, 25), in particular comprising two different CSA cements.

15. Foam concrete (10) according to one of the preceding claims, wherein the cement paste (11) comprises a hydrophobizing agent (26), in particular a melamine resin.

16. Method for producing a precast concrete element (31) from foam concrete (10), in particular for producing a precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) from a foam concrete (10) according to any one of claims 1 to 15, comprising the steps: Applicant: Arccen Ltd. - 44 - A) Providing a cement paste (11), wherein the cement paste (11) is at least a) a cement content (13) b) a rapid-setting cement component (14), c) Water (15), and d) a flow agent (16) comprises, B) Providing a foam (12) comprising air, (17) water (18) and a foaming agent (19), C) Mixing the cement paste (11) with the foam (12) to form a foamed concrete (10) comprising the foamed concrete (10) having a dry bulk density of more than 750 kg / m³ 3 exhibits D) Providing a formwork (36) and filling the formwork (36) with the foam concrete (10), E) Allowing the foam concrete (10) to harden and removing the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) formed in this way from the formwork (36) or removing the formwork (36) from the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31).

17. Precast concrete element (27) made of foam concrete (10), in particular of a foam concrete (10) according to one of claims 1 to 15, in particular produced according to a method according to claim 16, wherein the foam concrete (10) is produced from a mixture of cement paste (11) and foam (12), wherein the cement paste (11) comprises at least k) a cement content (13) l) a rapid-setting cement component (14), m) Water (15), and n) a mobile phase (16) comprises, Applicant: Arccen Ltd. -45 - wherein the foam (12) comprises air (17), water (18) and a foaming agent (19), and wherein the foam concrete (10) has a dry bulk density of more than 750 kg / m³3 exhibits.

18. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 17, characterized in that the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) is provided by an L-shaped block (28).

19. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 18, characterized in that the L-block (28) has a dry bulk density of more than 1,400 kg / m³ 3 includes.

20. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 17, characterized in that the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) is provided by an outer wall element (29).

21. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 20, characterized in that the outer wall element (29) has a dry bulk density of more than 1,400 kg / m³ 3 exhibits.

22. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 1, characterized in that the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) is provided by an inner wall element (30).

23. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) according to claim 22, characterized in that the inner wall element (30) has a dry bulk density between 800 kg / m³ 3 and 1,000 kg / m² 3 exhibits. Applicant: Arccen Ltd. -46 - 24. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31), comprising at least one first foam concrete layer (32) and at least one second foam concrete layer (33), wherein at least one foam concrete layer (32, 33) has a dry bulk density of more than 750 kg / m³ 3 comprising and wherein in particular at least one of the two foam concrete layers (32, 33) consists of a foam concrete (10) according to any one of claims 1 to 15.

25. Precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31), in particular according to claim 24, comprising at least one first foam concrete layer (32) and at least one second foam concrete layer (33), characterized in that the two foam concrete layers (32, 33) are connected to each other via a reinforcement (34).

26. Method for producing a precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) from foam concrete (10) with reinforcement (34), comprising the following steps: a) Providing formwork (36), b) Positioning a reinforcement (34) in the formwork (36), c) Pouring a first layer of foam concrete (32) with a first dry bulk density and encasing a first section (37) of the reinforcement (34), d) Pouring a second layer of foam concrete (33), in particular against the first layer of foam concrete (32), and encasing a second section (38) of the reinforcement (34), e) Allowing the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) to harden and removing the precast concrete element (27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 31) from the formwork (36) or removing the formwork (36) from the precast concrete element (27).

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