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    • 专利摘要:
    A method for producing a foam concrete mixture for the production of highly deformable foam concrete products with providing a foam concrete mixture comprising binders (212), foaming agents (232) and granules, with: establishing a required minimum compressive strength (110); Establishing a required minimum deformability (120); Determining (130) depending on the required minimum compressive strength and the required minimum deformability percentage of at least the following substances: binding agent (212), foaming agent (232) and grain groups of the granulate according to a grading curve (214), and providing and mixing the determined percentage of at least the Binder (212), the foaming agent (232) and the grain groups of the granulate according to a grading curve (214) as a foam concrete mixture (140).
    公开号:CH716186A2
    申请号:CH00548/20
    申请日:2020-05-07
    公开日:2020-11-13
    发明作者:Steiner Patrick；stolz Markus
    申请人:Solexperts Ag；
    IPC主号:
    专利说明:

    Field of invention
    The invention relates to a method for producing a foam concrete mixture for the production of highly deformable foam concrete products, highly deformable foam concrete products and their use.
    State of the art
    Deformable components and their various applications are known in tunnel construction. In particular, deformable components are used in tunnel construction for temporary expansion in order to reduce loads that can arise from pressure-sensitive or swellable rock by means of deformation. Deformable components can have different geometries and properties. Beam-shaped components or flat systems are used in tunnel construction. Deformable components and systems that are used can consist of different materials or material combinations, for example steel, concrete or mortar.
    [0003] For example, hiDCon® elements are available from Solexperts AG, Switzerland, which are deformable. However, in some applications, even more extensive deformability or even more extensive predictability of the deformation behavior may be desirable.
    Disclosure of the invention
    The object of the invention is to provide a method for producing the foam concrete mixture for the production of improved highly deformable foam concrete products and improved highly deformable foam concrete products, wherein said foam concrete products or their uses should in particular have improved deformation properties.
    The object is achieved with a method according to claim 1 and devices according to independent claims. Advantageous developments and embodiments emerged from the subclaims and from this description.
    One aspect of the invention relates to a method for producing a foam concrete mixture for the production of highly deformable foam concrete products with providing a foam concrete mixture comprising binders, foaming agents and granules, with: setting a required minimum compressive strength, setting a required minimum deformability, determining percentage proportions of at least the following substances : Binder, foaming agent and grain groups of the granulate according to a grading curve depending on the required minimum compressive strength and the required minimum deformability, and providing and mixing the determined percentage of at least the binding agent, the foaming agent and the grain groups of the granulate as a foam concrete mixture.
    Typical embodiments of the highly deformable foam concrete products described here have largely predictable or definable deformation properties after overcoming their elastic deformation range over a comparatively large plastic deformation range.
    In embodiments, the method comprises setting a required minimum compressive strength, in particular setting a minimum compressive strength under the action of tension. In the context of this application, the term “tension” encompasses mechanical tension, in particular mechanical compressive tension. For example, stress in the foam concrete product can be caused by rock stress of a pressing rock.
    Typically, the minimum compressive strength of a foam concrete is defined herein according to DIN EN 12390-3, in particular defined in a compression test analogous to DIN EN 12390-3, so for example tested in compression tests on cylinders, cubes or drill cores of the foam concrete at the age of 7 days , 21 days or 28 days. In particular, the minimum compressive strength of a foam concrete according to DIN EN 12390-3, in particular in a pressure test analogous to DIN EN 12390-3, is tested on a cube with at least 100 mm, for example 200 mm edge length. For this purpose, the minimum compressive strength of a foam concrete under a uniaxial stress state or a multidimensional stress state, for example under a three-dimensional stress state, can be tested. Typically the minimum compressive strength is 0.5 MPa, 5 MPa or 10 MPa. In the present disclosure, the term “uniaxial” refers to a compression test without lateral support of the specimen. The terms “three-dimensional” or “multi-dimensional” refer to a pressure test with lateral support of the specimen on all sides.
    [0010] Typically, the method includes establishing a required minimum deformability. For example, the deformability or deformation of a material can be measured in a compression test analogous to DIN EN 12390-3. According to DIN EN 12390-3, only the minimum compressive strength is tested; the standard test then typically ends after the first break. The term “first break” is typically used to describe a first stress maximum after which a stress drop can be observed in the test due to plastic deformation processes or breaks in the material. A minimum deformability is not dealt with in this standard. To measure the minimum deformability, the test is typically continued over the range specified by the standard. The term “minimum deformability” can refer to a plastic deformation range that lies between the elastic limit and the breaking limit of the foam concrete product. In the case of typical foam concrete in accordance with aspects of the invention, a different behavior compared to standard concrete with regard to the fracture behavior can be observed. After the first break, the force or tension does not drop to a massively low value, but remains at a high level, typically at least 50%, at least 60% or at least 70% of the tension at the first break.
    Conventional concrete, which is described in the standards, reaches the maximum compressive strength, in the uniaxial compression test, after a very small deformation or expansion of the test specimen. The elongation is in the per thousand range, according to the standard at around 2 ‰. After reaching the maximum compressive strength, the stress or force that can be absorbed in the test specimen drops sharply with further deformation, typically a drop of> 50% in compressive strength. In the case of the foam concrete described here, the behavior is different. In the uniaxial compression test, a maximum of compressive strength is achieved after a slight deformation, analogous to conventional concrete technology. In contrast to conventional concrete, the subsequently absorbable tension does not drop to a comparable extent (e.g. between 5 - 40%), but the tension can be maintained through permanent forced deformation. The tension is at least substantially maintained if the forced deformation is continued or maintained. The lowest value reached here defines the minimum compressive strength. The minimum compressive strength described herein for typical embodiments is significantly lower than that of a foam concrete with comparable cement, foam and aggregate proportions. This can be explained by the fact that additional pore volume is introduced in particular through the porous aggregate. Aggregates such as sand usually do not contain this pore volume. By using a grading curve optimized as described herein, the additional proportion of pores can be further maximized.
    The minimum deformability describes the range in which, with increasing deformation, the absorbable stress of the test specimen is below the maximum compressive strength but above the minimum compressive strength. Deformability is not defined in conventional concrete technology in connection with pressure loads, since the expansion that occurs should always be in the elastic range. With increasing deformation, the stress increases continuously and exceeds the maximum compressive strength that was reached at the beginning of the deformation. This behavior can be described with an elastic, plastic, bi-linear material model, where ET is not constant.
    Typical methods include determining percentages of at least the following substances for the foam concrete mixture: binders, foaming agents and granules, in particular grain groups of the granules according to a grading curve, depending on the required minimum compressive strength and the required minimum deformability. The minimum deformability can be adjusted via the composition of the grading curve and the pore volume it contains. A high proportion of a small fraction increases the minimum compressive strength and reduces the deformability.
    [0014] Typically, highly deformable foam concrete, in particular highly deformable foam concrete products, are produced with one of the typical foam concrete mixtures described herein. Typical foam concrete products have an increased air void content, in particular of generally more than 20% by volume or more than 30% by volume. Typical foam concrete products described here do not correspond to concrete according to DIN EN 206-1 / DIN 1045-2. Typical foamed concrete products according to aspects of this invention also correspond to non-typical conventional foamed concrete which conventionally has no grain groups. Typical foamed concrete products according to the invention comprise groups of grains with at least a proportion which has larger grains than sand.
    Typically, the term "highly deformable" in relation to a foam concrete product means that the foam concrete product in the compression test according to DIN EN 12390-3, in particular analogously to DIN EN 12390-3, without lateral support of the specimen, in particular after overcoming an elastic limit 50% deformation shows a compressive stress of less than 200% of the minimum compressive strength, preferably at 55% deformation a compressive stress of less than 250% of the minimum compressive strength and more preferably at 60% deformation a compressive stress of less than 350% of the minimum compressive strength. In the compression test, in typical embodiments, the compressive strength measured in the same test or in a further test on the same foam concrete product can be used instead of the minimum compressive strength.
    The term "highly deformable" typically means in relation to a foam concrete product that a typical foam concrete product described herein with 35% deformation in a compression test according to DIN EN 12390-3, in particular analogously to DIN EN 12390-3, without or with lateral support lateral support of the specimen shows a compressive stress of less than 200% of the minimum compressive strength on all sides, preferably at 40% deformation a stress of less than 300% of the minimum compressive strength and more preferably a stress of less than 500% of the minimum compressive strength at 45% deformation. In the compression test, in typical embodiments, the compressive strength measured in the same test or in a further test on the same foam concrete product can be used instead of the minimum compressive strength.
    The binder is typically cement or suitable synthetic resin mortar, typically fire-safe or fire-retardant synthetic resin mortar. Typically, drinking water or naturally occurring water is used as the added water.
    Typically, cement or a cement paste is used as the basis for the preparation of a foam concrete mix. Typically, cement paste comprises a binding agent, in particular cement, added water and possibly additives. Thus, a foam concrete mixture can be produced with the further addition of a separately prefabricated foam made of foaming agent, in particular with the further addition of a separately prefabricated foam made of a mixture of foaming agent and water for foam formation and possibly additives. The water for the foam formation can be taken from the added water or measured in addition to the added water, i.e. not counted towards the amount of the added water. Typically, the physical foaming used to produce the foam concrete or foam concrete mixture does not require any blowing agent or the production is typically carried out without blowing agent. Typical processes are thus in contrast to other processes with chemical foaming, for example with the addition of substances that react with the release of gases in or with the cement paste and thus form pores. Alternative typical methods for producing the foam concrete or foam concrete mix additionally use chemical blowing agents.
    Typicherweise a foam concrete mixture is formed by the introduction of foam filled with air or with other gases from foaming agent or from a mixture of foaming agent and water, for example in a cement paste. Typically, only inert gases are used for foam formation or are introduced into a mixture of foaming agent and water, for example nitrogen, argon or helium. This can be advantageous in particular when used in connection with final storage sites for nuclear waste or in applications which are sensitive to oxygen. The pressure of the air or other gases introduced is typically a maximum of 5 bar, typically a maximum of 3 bar, or typically a maximum of 1.5 bar or typically at least 0.3 bar.
    The gas bubbles generated with the foaming agent can in physical foams, similar to chemical foams, only temporarily serve as a support body until a solid structure of the foam concrete mixture has formed during curing or drying.
    Typically, cement is an inorganic, finely ground hydraulic building material. For example, cement is made by burning the starting materials limestone, sand or clay or mixtures of these materials at the sintering limit of around 1,450 ° C. In the context of the present disclosure, a hydraulic building material is a building material which, after the addition of water, independently solidifies and hardens as a result of chemical reactions with the added water and, after hardening, remains solid and stable under water. From a chemical point of view, cement can mainly contain calcium silicate with proportions of aluminum and iron compounds.
    In the context of the present disclosure, Portland cement (CEM I), Portland composite cement (CEM II), blast furnace cement (CEM III or VLH III), pozzolan cement (CEM IV or VLH IV), or composite cement (CEM V or VLH V), in particular according to the cement types according to DIN EN 197-1 or DIN EN 14216, be suitable as a binder. Portland cement is typically made by grinding clinker and gypsum or anhydrite. For example, a Portland cement with approx. 58 to 66% calcium oxide (CaO), 18 to 26% silicon dioxide (SiO2), 4 to 10% aluminum oxide (Al2O3) and 2 to 5% iron oxide (Fe2O3) can be used for the typical processes described here.
    [0023] The foaming agent is typically a surfactant, proteins or enzymes or mixtures thereof. Protein-based foaming agents typically have a high level of stability. The choice of surfactant or proteins can influence the cement chemistry and the rheological properties of the cement paste or foam concrete mixture. In particular, the high ion concentration and the high pH value in a foam concrete mixture can reduce or suppress the foaming effect of many surfactants or proteins.
    In the context of the present disclosure, suitable proteins are typically those that have negative charges in the alkaline cement paste. In typical processes, such proteins are used to create a close connection between the loosened protein strands, so that the foam stability is increased. For example, the foaming agent can have a protein, in particular a hydrolyzed protein or protein fractions, which are in particular 50% by mass, 70% by mass or 90% by mass of the amino acids A (alanine), E (glutamic acid), G (glycine ), I (isoleucine), L (leucine), M (methionine), P (proline), Q (glutamine) and V (valine) with a molar mass between 20,000 and 120,000 Daltons. The remaining 10% by mass, 30% by mass or 50% by mass can be other amino acids, in particular other anionic amino acids.
    In principle, particularly highly foaming alkali-stable or even alkaline-reacting surfactants are suitable as surfactants. A high foaming power is typically important here. Anionic surfactants and in particular sulfonates, alkyl sulfonates, in particular alkali alkyl sulfonates, alkylene sulfates or alkyl ether sulfonates are preferred. The alkyl chains or alkylene chains of the sulfonates and sulfates are in particular long-chain and more preferably unbranched. Chain lengths greater than or equal to C8 and in particular between C10 and C20 can be regarded as typical.
    Preferred surfactants include i.a. linear alkylate sulfonates, alpha olefin sulfonates, beta olefin sulfonates, alkyl ether sulfates, ethoxylated alkyl phenols. Typical surfactants that are used are alpha olefin sulfonates, e.g. B. sodium C14-16 olefin sulfonate, among the alkyl sulfates SDS and SLS and / or certain alkali, ammonium or ethanolamine salts of sulfuric acid esters of alkoxylated alcohols.
    Other anionic surfactants that can be used are acylamino acids and their salts, including acyl glutamates, such as sodium acyl glutamate, di-TEApalmitoyl aspartate, sodium caprylic / capric glutamate or sodium cocoyl glutamate, acyl peptides, sarcosinates, glycine, alcinates, taurates, acylinates, valcinates, acyl lactylates , Aspartates, propionates, lactylates, and amide carboxylates. Typically, phosphates / phosphonates can be considered. Further examples are sulfosuccinates, sodium cocomonoglyceride sulfate, sodium lauryl sulfoacetate or magnesium PEG-n-cocoamide sulfate, alkylarylsulfonates and acyl isethionates, ether and ester carboxylic acids, preferably fatty acids, and other known foaming anionic surfactants such as are commercially available.
    In typical embodiments it is provided that the ionic foam-forming surfactant contains or consists of at least one anionic surfactant or consists exclusively of anionic surfactants or exclusively anionic surfactants are used. A single surfactant or a mixture of several surfactants can be used. In a mixture of further typical embodiments, in addition to at least one anionic surfactant, at least one other, in particular nonionic surfactant can be included. In particular, in typical embodiments, Sika® Lightcrete-400 with a density of 1.07 kg / L can be used as a foaming agent.
    In typical embodiments of the invention, a foam concrete mixture contains at least 10 g, at least 30 g, at least 50 g, at least 75 g or at least 100 g or a maximum of 3 kg, a maximum of 2 kg or a maximum of 1 kg of the foaming agent based on 1 m <3 > the foam concrete mix.
    In the context of the present disclosure, the term “aggregates” can encompass granules, fibers or mixtures thereof. The term "additives" can include limestone powder, pigments, or mixtures thereof. The term “additive” can include concrete plasticizers, retarders, setting accelerators, hardening accelerators, flow agents, sealants, organic and inorganic stabilizers or mixtures thereof. For this purpose, an additive can be added to a foam concrete mixture or a cement paste, a binder or a foaming agent.
    Typical granules, which are used in the context of embodiments, consist of a natural granulate from mineral deposits, an artificial granulate or a combination of these two. For example, granules comprise or consist of natural granules such as pumice, tuff, lava sand, lava gravel, kieselguhr, vermiculite or mixtures thereof. A typical granulate consists of or comprises artificial granulate such as expanded slate, expanded clay, expanded glass, expanded mica, expanded perlite, coal fly ash, brick chippings, slag pumice (slag pumice), ceramic, plastic and boiler sand or mixtures thereof. In the context of the present disclosure, a granulate made of expanded glass can be a foam glass granulate.
    In typical embodiments of the invention, a granulate comprises or consists of foam glass granulate, expanded clay granulate, clay granulate, vermiculite granulate or mixtures thereof. Typical granules used in embodiments are porous. Typically, a foam glass granulate can be a mineral lightweight building material, which is made in particular from pure waste glass. In particular, the foam glass granulate consists of closed-pore foam glass granulate, which typically has an essentially spherical grain shape. Alternatively, broken foam glass is used. For this purpose, foam glass can be the name for a solidified expanded glass with air-tight closed cells which are in particular filled with gas. Typically, the gas composition in the pores or honeycombs can depend on the manufacturing process. In particular, in typical embodiments, Poraver <®> Liaver <®> or mixtures of these two are used exclusively or at least partially as granules.
    In typical embodiments, the granules are at least substantially spherical. “Essentially spherical” typically means a grain shape with an average diameter ratio of largest to smallest diameter, in particular average largest diameter to average smallest diameter, of less than 9: 1, less than 6: 1, less than 3: 1, less than 2 : 1 or less than 1.5: 1, in particular less than 1.3: 1. Typically, the term “granules” refers to granular solids. The term "substantially spherical" can mean that more than 50%, more than 75%, or more than 90%, or all of the grains correspond to a specific maximum average diameter ratio.
    Typical grains have an average diameter in the range of at least 0.02 mm, at least 0.03 mm or at least 0.04 mm or up to 10 mm, up to 8 mm or up to 4 mm. An average diameter of the spherical grains of the present disclosure can typically be determined by applying a laser diffraction method according to ISO 13320: 2009, a SEM (scanning electron microscopy) image analysis method according to ISO 13322-1: 2014, or a sieve analysis device according to ISO 6274: 1982.
    The granules are typically divided into grain groups. In particular, the grain groups can be defined by specifying two limiting sieves (dmin and dmax).
    In the context of the present disclosure, dminals can be defined in mm as the sieve size of the lower limiting sieve or the diameter of the smallest grain of a grain group or a grain mixture or granulate. For this purpose, dmax can be defined as the mesh size of the upper limiting sieve or the diameter of the largest grain of a grain group or a grain mixture or granulate in mm. Typically, the grain groups of the granulate can be at least one of the grain groups with the limiting sieve (dmin / dmax) 0.25 / 0.5 mm, 0.5 / 1 mm, 1/2 mm, 2/4 mm, 4/6 mm and 4 / 8 mm. In particular, the ratio of the screen widths of the lower and upper limiting sieves of the grain groups is not less than 1.4.
    Typically, sieving to test the grain composition according to DIN EN 933 Part 1 and Part 2 can be carried out. Grain groups which are used in embodiments typically have a grain group minimum compressive strength, in particular an average grain group minimum compressive strength of 0.5 MPa, preferably 1.0 MPa and more preferably 1.5 MPa. A grain group minimum compressive strength, in particular an average grain group minimum compressive strength, can typically be determined in accordance with DIN EN 13055-1. In particular, the percentage of the grain groups in the granulate is determined as a function of the required minimum compressive strength and the required minimum deformability by selecting grain groups with a certain grain group minimum compressive strength or certain limiting sieves. In typical embodiments, the required minimum compressive strength and the required minimum deformability in a foam concrete or foam concrete product produced with the foam concrete mixture are achieved in this way.
    In typical embodiments, the percentage of at least the grain groups of the granules are determined as a function of the required minimum compressive strength, taking into account the respective average compressive strength of the respective grain group. In typical exemplary embodiments, the minimum compressive strength of a foam concrete product produced later can be calculated or estimated when determining the percentage of the grain groups by weighting the compressive strengths of the respective grain groups according to their percentage shares, in particular volume shares, and thus calculating an overall compressive strength becomes. This calculation can include the compressive strength and the volume of the binder in the foam concrete product, as well as the volume of the voids formed with the foaming agent (compressive strength zero).
    For production, the volume fractions are typically converted into weight fractions to make the fractions easier to provide. The calculation of the grain pattern is based on the volume proportions, since typically the mechanical properties such as strength or yield strength can be estimated according to the area and thus the volume proportions in the finished product. The binder is typically included in an initial calculation and may not be included in subsequent calculations.
    Typically, the percentages of the binder, the foaming agent and the grain groups of the granulate are determined iteratively according to a grading curve. In the context of the present disclosure, the term "iterative" stands for step-by-step and repeated calculations to determine the percentage of at least the following substances: binders, foaming agents and grain groups of the granules up to the required minimum compressive strength through the weighted, in particular volume-weighted average of the compressive strengths of the respective percentage shares is achieved.
    The minimum deformability can be estimated on the basis of the volume of the foamed foam. Typically, the minimum deformability corresponds to 0.8 to 0.9 times the volume fraction of the foamed foam or the volume fraction of the pores in the finished product.
    Typically, the percentage proportions of the binder, the foaming agent and the grain groups of the granules are determined according to the equation, where:V cement paste is the volume of cement pasteV total is the volume of the foam concrete mix with foamed foam,Vgranulate is the volume of the granulate,VSofoam is the volume of the foamed foamD foam concrete is the required minimum compressive strength of foam concrete,Dcement paste is the compressive strength of the cement paste, andDGranulate is the compressive strength of the granulate.
    If the granulate comprises several grain groups with different compressive strength, the compressive strengths are typically weighted according to the volume fractions of the grain groups in the above equation in the term of the compressive strength of the granulate. Typically, a calculated or determined compressive strength of the granulate is a weighted average of the typical compressive strengths of all grain groups of the granulate in a foam concrete mixture, for example specified by the manufacturer.
    Typically, determining the percentage of the grain groups of the granulate according to a grading curve as a function of the required minimum compressive strength and the required minimum deformability includes stipulating the number of grain groups in the granulate. Typically, the granulate consists at least essentially of percentages of a plurality of grain groups. The granules typically consist of percentages of at least two or at least three different grain groups.
    For example, in order to achieve a desired packing density of the granulate in the foam concrete mixture, the percentages of the grain groups are calculated using a grading curve. The grading curve used typically deviates from a Fuller grading curve. For example, in order to achieve a high degree of deformability, in embodiments the aim is for the granulate to be as dense as possible. In order to achieve as dense a grain structure as possible from several selected grain groups of a granulate, percentages of a plurality of grain groups of a granulate are compiled using a grading curve.
    Typically, a grading curve is a straight or cumulative curve, by means of which the grain size distribution or grain composition of a granulate is graphically represented. The grain sizes can be plotted on the horizontal axis (abscissa) of a grading curve diagram, and the percentage of the respective sieve passes or grain sizes on the vertical axis (ordinate).
    Typical methods use a grading curve, which is referred to in technical jargon as the ideal grading line or which ensures a dense grain structure in which the amount of glue required to fill the gaps between the grains is low. With grading curves typically used, the surface area of the grains is minimized in relation to the volume of the grains in order to minimize the cement required to coat the grains.
    A grading curve used by typical methods can be a Fuller grading curve. Typical Fuller grading curves correspond to the equation where:A is the sieve passage in mass% (mass fraction) that passes through the sieve with the diameter d,d is the diameter or average diameter with a value between 0 and dmax, for which the percentage in a grain mixture, granulate is to be calculated,dmax is the diameter of the largest grain of the grading curve to be calculated, andn is the exponent for taking into account the grain shape.
    Typically, the method according to the invention is based on a sphere as the grain shape. Typically, the exponent n is set at at least 0.3, at least 0.35 or in particular at least 0.4 and at most 0.47, at most 4.5 or in particular at most 0.43.
    In typical embodiments of the invention, the percentages are calculated using a non-Fuller grading curve. Typical embodiments use a grading curve which, compared with a Fuller grading curve, has a reduced proportion of small grain sizes. A typical grading curve that is used in embodiments is a Funk-Dinger grading curve. A Funk-Dinger grading curve shows a reduced proportion of small grain sizes compared to a comparable Fuller grading curve. However, other grading curves with a proportion of small grains that is reduced compared to a Fuller grading curve can also be used in typical embodiments.
    The term “reduced proportion of small grain sizes” typically means that in the grain groups of the granulate less than 10%, typically less than 5%, typically less than 2%, typically less than 1% or typically at least essentially 0% grains are less than 250 µm, less than 100 µm or less than 50 µm in diameter. The expression “essentially 0% grains” typically means that only unavoidable residues of grains with a diameter of less than 250 μm, less than 100 μm or less than 50 μm are present. Unavoidable residues can arise, for example, during production or typically be present in material supplied by a manufacturer.
    In typical embodiments of the invention, the percentages of a plurality of grain groups are calculated using a grading curve at least essentially according to the Funk-Dinger grading curve.
    A Funk-Dinger grading curve is typically a curve that can be plotted according to the equation, where:A is the sieve passage in mass% (mass fraction) that passes through the sieve with the diameter d,d is the diameter or average diameter with a value between dmin and dmax, for which the percentage in a grain mixture, granulate is to be calculated,dmax is the diameter of the largest grain, the grading curve to be calculated,d is the diameter of the smallest grain, the grading curve to be calculated, andn is the exponent for taking into account the grain shape.
    Typically, a Funk-Dinger grading curve takes an ideal sphere into account as the grain shape. In particular, the corresponding exponent n for this grain shape for the Funk-Dinger grading curve is 0.37.
    Typically, the determination of the percentage of the grain groups of the granulate according to a grading curve comprises a calculation of the bulk volume and the grain volume of the grain groups of the granulate on the basis of the bulk density and bulk density. The bulk density of the grain groups used is typically between 125 kg / m 3 and 500 kg / m 3, typically between 150 kg / m 3 and 475 kg / m 3, typically between 170 kg / m 3 > and 450 kg / m <3>. Typical grain densities of grain groups are between 250 kg / m 3 and 1100 kg / m 3, typically between 275 kg / m 3 and 1050 kg / m 3, typically between 300 kg / m 3 and 1000 kg / m <3>.
    Typically, the determination of the percentage of the grain groups of the granulate according to a grading curve comprises a calculation of the pore space, a calculation of a water-binding agent value, in particular a calculation of a water-cement value, a calculation of a binding agent amount, in particular a calculation of a cement amount, a calculation of an additional water amount or a Calculation of a glue density of the foam concrete mixture.
    For example, the pore space of a foam concrete mixture can be calculated by using the bulk volume and grain volume of the percentage of the several selected grain groups of the granulate. The term pore space refers to the space that is present in the foam concrete mixture without the addition of foaming agents.
    In typical embodiments, the mixing of the proportions in order to obtain the foam concrete mixture takes place by means of a compulsory mixer, a free-fall mixer, a truck mixer or a planetary mixer with or without a vortex. For example, the mixing of the proportions of the binding agent, the foaming agent and the grain groups of the granulate can comprise a mixing-in process or a foaming process or can be carried out exclusively by means of a mixing-in process or a foaming process. In the mixing process, the foam concrete mix is typically produced in a compulsory mixer with the addition of a foaming agent. In the foam process, a prefabricated foam is mixed into the binder and the grain groups, for example on the construction site or in a concrete plant.
    In embodiments, the foam is generated with the aid of a foaming device such as a foam generator and a foaming agent. Typically, all proportions except for the foaming agent, for example binding agent, grain groups of the granulate and added water, are premixed and the prefabricated foam or foaming agent is added last. In further embodiments, the foam is generated and added to the binding agent or a mixture of binding agent and added water, with the addition of, for example, the grain groups only then.
    In further embodiments of the invention, the foam concrete mixture can be provided and mixed with fibers. The deformation behavior of foam concrete can be influenced with fibers. In embodiments, fibers can produce the effect of improved tensile strength. Typically, the term “fibers” includes at least one of the following fibers: vegetable fibers, plastic fibers, glass fibers, carbon fibers and steel fibers. The fibers, in particular plastic fibers, can, for example, have a minimum length of 1 mm, 5 mm, 10 mm, or 30 mm. The fibers, in particular plastic fibers, typically have a maximum length of 80 mm, 90 mm, and 120 mm.
    Typically, glass fibers with a minimum length of 0.5 mm, 1 mm, or 3 mm and / or with a maximum length of 60 mm, 80 mm, 100 mm or a maximum of 120 mm are used. Typically, the fibers comprise monocomponent fibers or bicomponent fibers or a mixture thereof or consist of one of these fibers or a mixture thereof. In embodiments, the fibers are used as fiber bundles or individual fibers. The foam concrete mixture typically contains less than 100 kg of fibers based on 1 m 3 of the foam concrete mixture, typically less than 50 kg of fibers based on 1 m 3 of the foam concrete mixture, in particular less than 20 kg of fibers based on 1 m 3 of the foam concrete mixture or typically less than 5 kg of fibers per 1 m 3 of the foam concrete mixture. In particular, Concrix <®>, Dramix 2D or Dramix 3D, 4D or 5D are used as fibers - exclusively or in a mixture with other fibers.
    A typical highly deformable foam concrete or a typical highly deformable foam concrete product is made with one of the foam concrete mixes described herein. In particular, the typical highly deformable foam concrete products described herein are used underground. In particular, the typical highly deformable foam concrete products described herein will be used in tunnel construction or mining or in a protective structure. For this purpose, highly deformable foam concrete products can be bar-shaped or plate-shaped compression elements or tubbing elements. For example, the bar-shaped or plate-shaped compression elements or tubbing elements can be used in compressive or swellable mountains.
    Typical advantages of embodiments according to the invention are high deformability with comparatively low forces, so that rock movements underground can be absorbed without complete failure of the shell constructed with the embodiments. This offers a wide range of uses, particularly in tunnel construction or underground structures.
    Brief description of the drawings
    The invention is explained in more detail below with reference to the accompanying drawings, the figures showing: FIG. 1 schematically shows a sequence of a typical embodiment of a method according to the invention; FIG. 2 schematically shows another sequence of a typical embodiment of a method according to the invention; FIG. 3 shows schematically the results of uniaxial stress tests on cubes made from different foam concrete mixes; FIG. 4 shows schematically the results of three-dimensional tension tests on cubes made from different foam concrete mixes.
    Description of exemplary embodiments
    Typical embodiments of the invention are described below with reference to the figures, the invention not being restricted to the exemplary embodiments, rather the scope of the invention is determined by the claims. In the description of the embodiment, the same reference symbols may be used for the same or similar parts in different figures and for different embodiments in order to make the description clearer. However, this does not mean that corresponding parts of the invention are limited to the variants shown in the embodiments.
    FIG. 1 shows a schematic overview of a sequence 100 of a typical method for producing a foam concrete mixture for the production of highly deformable foam concrete products.
    The method comprises setting a required minimum compressive strength 110, setting a required minimum deformability 120, determining depending on the required minimum compressive strength and the required minimum deformability percentage of at least the following substances: binders, foaming agents and grain groups of the granulate according to a grading curve 130, and providing and mixing the determined percentage proportions of at least the binder, the foaming agent and the grain groups of the granules as foamed concrete mixture 140.
    In the exemplary embodiment shown in FIG. 1, the determination, as a function of the required minimum compressive strength and the required minimum deformability, comprises percentage proportions of at least the following substances: Binding agents, foaming agents and grain groups of the granulate according to a grading curve 130, the blocks 132 included in the overlapping block 130 - 139. The percentage proportions of the binder, the foaming agent and the grain groups of the granules according to a grading curve are typically carried out iteratively in blocks 132 to 138.
    In block 132, as a function of the required minimum compressive strength and the required minimum deformability, percentage proportions of the grain groups of the granulate are determined or estimated according to a grading curve. Typically, several grain groups of the granulate are selected, for example in order to achieve a dense grain structure.
    For example, in a first calculation, percentages of the grain groups of the granulate are calculated or estimated by means of a weighted, in particular volume-weighted average of the compressive strengths of the percentages of selected grain groups of the granulate. Furthermore, the corresponding percentage of the binder and possibly also of the foaming agent (compressive strength of the voids created with the foaming agent equal to zero) can be determined in order to estimate or determine the total compressive strength of the later foam concrete product (blocks 134 and 136).
    In block 138 it is checked whether the percentage of at least the following substances: binder, volume of the foam foamed by means of the foaming agent and grain groups of the granules according to a grading curve, the required minimum compressive strength and the required minimum deformability result. If this check is positive, the process continues in block 140. If the test ends in the negative, the method continues with block 139 for executing an iterative loop.
    In block 139, at least one portion of the percentage proportions is estimated and adjusted: binders, foaming agents and grain groups of the granulate according to a grading curve. For example, if the desired minimum compressive strength is not reached, a different binder can be used, fewer foaming agents can be used or other grain groups can be selected. If the minimum deformability is not achieved, for example the proportion of foaming agent and thus the voids created by the foaming agent can be increased. The method then jumps back to block 132.
    In block 140, after a positive outcome of the check in block 138, the determined percentages of at least the binder, the foaming agent and the grain groups of the granules are prepared and mixed as a foam concrete mixture.
    FIG. 2 shows a schematic overview of a typical process for providing and mixing the percentages of the following substances: binders, foaming agents and grain groups of the granules according to a grading curve and for producing a foam concrete mixture for the production of highly deformable foam concrete products 200 shown.
    In a first mixer 210, cement as a binder 212 is mixed with grain groups of the granulate according to a grading curve 214. For this purpose, added water 220 is mixed in the first mixer 210 to form cement paste. The binder 212 is typically premixed with added water 220 up to a W / C value of a maximum of 0.6, typically a maximum of 0.55, typically a maximum of 0.50, in particular a maximum of or approximately 0.47. Optionally, one or more additives 216, such as concrete plasticizers or setting accelerators, are added to the cement paste. Furthermore, one or more additives 218, which can influence the workability of the fresh concrete or the strength of the hardened concrete, are optionally added to the mixture. In contrast to the additives 216, they are taken into account in the calculation of the material space in typical exemplary embodiments.
    In addition, water 222 is typically mixed in a foam generator 230 with a foamer 232 and air 234 or at least one other gas, for example nitrogen, to form a foam. For example, the foaming agent is mixed with the water for foaming in a storage tank of a foam generator. The foam produced is typically weighed. The foam density is typically checked. The foam generator 230 preferably operates at an operating pressure of a maximum of 4 bar. In typical embodiments, additives can optionally be added to the cement paste or the foaming agent.
    In typical embodiments, the water mixed with the foaming agent can be taken from the added water or all of the added water is mixed with the binder and an additional amount of water is provided for the foaming agent to be mixed with the foaming agent. Typically, the amounts of water required for foam formation are small, so that they do not necessarily have to be taken into account when calculating the mixture.
    In a second mixer 240, the cement paste from the first mixer 210 is mixed with the foam formed in the foam generator 230 and a flowable and pumpable foam concrete mixture is formed. A foam concrete mixture can also be formed by mixing the foam formed in the foam generator 230 in the first mixer 210 with a cement paste.
    From the second mixer 240, the foam concrete mixture is discharged at the place of use with a feed pump 250 or a transport means for pouring out or discharged in a casting mold in which it can set and produce a highly deformable foam concrete product 260.
    The method according to the invention is further explained in more detail using the following exemplary embodiments:
    Embodiment 1
    A cubic meter of a typical foam concrete mixture for the production of typical highly deformable foam concrete products can for example consist of or comprise: Poraver 0.5-1 mm 44.97 kg Poraver 1-2 mm 45.95 kg Poraver 2-4 mm 55.90 kg Poraver 4-6 mm 69.97 kg Foaming agent (total mass with water for foaming) 10.67 kg of which: foaming agent (Sika Lightcrete 400) 0.27 kg binder (cement) 245.96 kg added water 103.30 kg synthetic fibers (Concrix) 3.00 kg
    In the exemplary embodiment, the water for mixing with the foaming agent is not taken from the added water. Specifically, 10.67 kg of foam are used per cubic meter of foam concrete mixture in the exemplary embodiment. The Sika Lightcrete 400 foaming agent is premixed with water. The 10.67 kg of foam contain 0.27 kg of Sika Lightcrete 400 foaming agent (equivalent to a 2.5-3% solution of Sika Lightcrete 400 in water). The foaming agent is mixed with the water for foaming (here: 10.67 kg - 0.27 kg = 10.40 kg of water for foaming) in a storage tank of a foam generator and then the foam produced is weighed and the foam density produced is checked. By checking the foam density, it can be achieved that the required voids are also present in the foam concrete mixture according to the calculation. Sika Lightcrete 400 is available from Sika Schweiz AG, Tueffenwies 16, CH 8048 Zurich.
    The percentage of the grain groups in the granulate corresponds to a Funk-Dinger grading curve.
    A cubic meter of a comparable example with the same glue density as the glue density of the foam concrete mixture of embodiment 1 comprises or consists of: foaming agent (total mass with water for foam formation) 10.67 kg of which: foaming agent (Sika Lightcrete 400) 0.27 kg binding agent (cement) 683.40 kg added water 287.00 kg synthetic fibers (Concrix) 3.00 kg
    In FIGS. 3 and 4, the results of the corresponding uniaxial and three-dimensional printing tests on cubes are shown in a schematic overview. The cubes are made from foam concrete mixes with grain groups of the granulate according to a grading curve and from foam concrete mix without grain groups. The foam concrete mixes are made with identical glue density values.
    In Figures 3 and 4 it can be clearly seen that a typical highly deformable foam concrete product 310, after overcoming the elastic deformation range, has a smaller ratio between the minimum compressive strength and the stress in the plastic range of the highly deformable foam concrete product 310 than a corresponding typical foam concrete product 320 shows, which, however, was produced without grain groups of the granulate according to a grading curve.
    For example, the results of the uniaxial compression test in FIG. 3 for a highly deformable foam concrete product 310 according to the invention show a minimum compressive strength with a value of 0.9 MPa and a uniaxial stress with a value of 2.7 MPa with a deformability of 60% . In comparison, the results for a typical foam concrete product 320 without granules in FIG. 3 show a minimum compressive strength with a value of 3 MPa and a uniaxial stress with a value of 12 MPa with a deformability of 60%. Thus, the ratio between the minimum compressive strength and the uniaxial stress with a deformability of 60% has a value of 3 in the case of a highly deformable foam concrete product 310 with typical grain groups. The corresponding value is 4 for a typical foam concrete product 320 without typical grain groups of the granulate corresponding to a grading curve.
    In addition, the results of the three-dimensional compression test in FIG. 4 for a typical highly deformable foam concrete product 410 show a minimum compressive strength with a value of 1.5 MPa and a stress between 1.5 MPa and 4.0 MPa in the deformation range between 0% and 40%. This means that the ratio between the minimum compressive strength and the stress in the plastic range of the highly deformable foam concrete product 410 is between 1.0 and 2.7 with 2.7 at 40% deformation.
    In comparison, a typical foam concrete product 420 without typical grain groups of the granulate shows a minimum compressive strength of 4 MPa and a stress between 4 MPa and 13.5 MPa in the area of deformation between 0% and 40% according to a grading curve in the three-dimensional compression test (FIG 4). The ratio between the minimum compressive strength and the stress in the plastic range of the foamed concrete product 420 is between 1.0 and 3.4 with 3.4 at 40% deformation.
    The ratio of the maximum stress to the minimum stress in the range of up to 40% deformation in typical highly deformable foam concrete products 410 in the three-dimensional compression test is thus lower.
    List of reference symbols
    210 first mixer 212 binder 214 grain groups of the granulate corresponding to a grading curve 216.236 additives 220 water addition 230 foam generator 232 foaming agent 234 air 240 second mixer 250 feed pump 260, 310, 410 highly deformable foam concrete product 320, 420 typical foam concrete product
    权利要求:
    Claims (17)
    [1]
    1. A method for producing a foam concrete mixture for the production of highly deformable foam concrete products (260, 310, 410) with providing a foam concrete mixture comprising binders (212), foaming agents (232) and granules, with:- Establishing a required minimum compressive strength (110);- Establishing a required minimum deformability (120);- Determine (130) depending on the required minimum compressive strength and the required minimum deformability percentage of at least the following substances:o binding agent (212),o Foaming agent (232) ando Grain groups of the granulate according to a grading curve (214),and- Provision and mixing of the determined percentages of at least the binder (212), the foaming agent (232) and the grain groups of the granulate according to a grading curve (214) as a foam concrete mixture (140).
    [2]
    2. The method according to claim 1, wherein the percentages of the grain groups of the granules are determined according to a grading curve (214) using a grading curve which deviates from a Fuller's grading curve.
    [3]
    3. The method according to claim 1 or 2, wherein the grading curve has a reduced proportion of small grain sizes compared to a Fuller grading curve.
    [4]
    4. The method according to any one of the preceding claims, wherein the foam concrete mixture contains at least 10 g and / or a maximum of 3 kg of the foaming agent (232) based on 1 m 3 of the foam concrete mixture.
    [5]
    5. The method according to any one of the preceding claims, wherein the granules comprise foam glass granules.
    [6]
    6. The method according to any one of the preceding claims, wherein the granulate consists of at least 50% spherical grains which have a grain shape with a diameter ratio of the largest to the smallest average diameter of less than 3: 1.
    [7]
    7. The method according to any one of the preceding claims, wherein the foam concrete mixture is provided with fibers and mixed.
    [8]
    8. The method according to any one of the preceding claims, wherein the fibers comprise at least one of the following fibers: vegetable fibers, plastic fibers, glass fibers, carbon fibers and steel fibers.
    [9]
    9. The method according to any one of the preceding claims, wherein the foam concrete mixture contains less than 100 kg of fibers based on 1 m 3 of the foam concrete mixture.
    [10]
    10. The method according to any one of the preceding claims, wherein the grain groups of the granulate according to a grading curve at least one of the grain groups with the limiting sieve (dmin / dmax) 0.25 / 0.5 mm, 0.5 / 1 mm, 1/2 mm, 2/4 mm, 4/6 mm, and 4/8 mm.
    [11]
    11. The method according to any one of the preceding claims, with determining the percentage of the grain groups of the granulate according to a grading curve depending on the required minimum compressive strength and the required minimum deformability (132) by selecting grain groups with a certain grain group compressive strength and / or a certain size range in order to achieve the required minimum compressive strength and the required minimum deformability in a foam concrete made with the mixture.
    [12]
    12. The method according to any one of the preceding claims, wherein the determination is carried out iteratively.
    [13]
    13. The method according to any one of the preceding claims, wherein the foamed concrete mixture comprises so much added water (220), foaming agent (232) and binder (212) that the grain groups of the granulate form a dense grain structure according to a grading curve (214).
    [14]
    14. Highly deformable foam concrete product (260, 310, 410), in particular intended for use underground, produced with a foam concrete mixture which is produced using a method according to one of claims 1 to 13.
    [15]
    15. The highly deformable foam concrete product (260, 310, 410) according to claim 14, wherein the highly deformable foam concrete product (260, 310, 410) shows a corresponding compressive stress of less than 350% of the minimum compressive strength at 60% deformation.
    [16]
    16. Use of a highly deformable foam concrete product (260, 310, 410) according to claim 14 or 15 in tunnel construction or mining or in a protective structure.
    [17]
    17. Use according to claim 16, wherein the highly deformable foam concrete product (260, 310, 410) is a bar-shaped or plate-shaped compression element or a tubbing element.
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    同族专利:
    公开号 | 公开日
    DE102020112292A1|2020-11-12|
    FR3095815A1|2020-11-13|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
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    优先权:
    申请号 | 申请日 | 专利标题
    DE102019111999|2019-05-08|
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