DE10226176A1 - Components made of lightweight concrete, in particular for building construction, and methods for increasing the pressure resistance of a component made of lightweight concrete - Google Patents

Abstract

A component made of lightweight concrete, especially for building construction, which is formed from an aqueous mixture of cement and a lightweight aggregate, is characterized in that the aqueous mixture further contains a polymer in such an amount that its solids content, based on the amount of cement, is in the range of 0.01-20% by weight.

Description

The invention relates to a component made of lightweight concrete, in particular for building construction, and a method for increasing the compressive strength of such a component, according to the preamble of claims 1 and 13.

Nowadays, in the construction of buildings and masonry, are known Wise components made of lightweight concrete or lightweight building blocks used.

The use of lightweight concrete as a starting material for the following generally as Component designated molded parts or components offers here compared to the heavier Building blocks not only have the advantage that the lower weight means greater volume can be transported and also processed, but that it is also beyond has excellent thermal insulation properties. Because of the constantly tightening thermal protection regulation is the use of components Nowadays, lightweight concrete in building construction is indispensable.

This reduces the density of the lightweight concrete components achieved that the starting material for the component from an aqueous cement Mortar mix exists, which is mixed with a light aggregate. The Light aggregate is, for example, pumice, cottage pumice, perlite, expanded clay, expanded glass or Expandable slate, etc., and has a normal concrete made of sand, gravel and cement significantly reduced density.

From AT 406 877 B, for example, a lightweight concrete building block is known which is known as Light aggregate contains expanded glass or expanded clay and to improve the Provide thermal insulation with corrugated tongue and groove depressions is.

For the production of the components from lightweight concrete, an aqueous and preferred just spreadable mixture of cement and the light aggregate Stirring produced in a suitable processing facility. The mixture is pressed under pressure into appropriate molds, and the finished components then removed from the mold after curing. Here the curing process if necessary be accelerated by increasing the temperature.

By adding the lightweight aggregates, the compressive strength of the hardened lightweight concrete is reduced, whereby the bulk density for lightweight materials can be in the range of 0.15 to 2.0 t / m ³ .

The reduction in pressure resistance has the consequence that the manufactured components Made of lightweight concrete can only be used to a limited extent in building construction.

Gross density and compressive strength are generally d. Usually in a fixed relationship to each other. A Increasing the compressive strength of the lightweight concrete material for components with a given bulk density class can be added by adding the ones listed below Polymer additives can be achieved.

Accordingly, it is an object of the invention to provide a component made of lightweight concrete, especially for building construction, with which there is a higher compressive strength can be achieved with the same bulk density class of the lightweight concrete, as well as a method To provide with which the compressive strength of components made of lightweight concrete same bulk density class of lightweight concrete.

This object is achieved by the features of claims 1 and 13 solved.

Further features of the invention are described in the subclaims.

The lightweight concrete component according to the invention has the advantage that compared to conventional components with the same bulk density - due to the increased pressure resistance are used in the construction of buildings can, that also means that a reduction in wall thickness with the same thermal insulation leads to an enlargement of the enclosed space with the same footprint of the building.

Another advantage is that the increased in the inventive manner The compressive strength of the lightweight concrete material does not affect the thermal conductivity of the material changed. The hollow chambers z. B. in a hollow block, can thus be a larger one Have volume and the material thickness of the lightweight building blocks of walls and walkways can accordingly be chosen thinner. The heat flow z. B. by such Hollow block is therefore lower overall. As a result, the requirements according to new thermal insulation regulation more easily met. It doesn't matter if that Component according to the invention as a full block, hollow block or other cement-bound molded part is produced because the improved thermal insulation too can be achieved by a lower bulk density class.

The inventive method also has the advantage that the Compressive strength of the lightweight concrete in a simple process simple mixing in of those described in more detail below Substances can be increased when preparing the aqueous mixture.

The component according to the invention made of lightweight concrete, which consists of an aqueous This is a mixture of cement and a lightweight aggregate characterized in that the aqueous mixture further contains a polymer in such Amount contains that its solids content, based on the amount of cement, in the range of 0.01 to 20% by weight. The polymer has within usual Processing temperatures also have the property that it form a polymer film can, or has a liquefying effect.

The polymer can be used both in the form of an aqueous polymer dispersion and in Form of a polymeric flow agent can be used in the component according to the invention. If the polymer is used in the form of an aqueous polymer dispersion, it is advantageous that the polymer dispersion is present in such an amount that its Solids content, based on the amount of cement, in the range from 0.5 to 15% by weight, is particularly preferably in the range from 1.0 to 10% by weight.

The polymer dispersions suitable for this are aqueous dispersions of polymers, in addition to homopolymers in particular also copolymers can be used from different monomers.

The solids content of these polymer dispersions is preferably 30 to 80, particularly preferably 45 to 75% by weight. For example, high polymer solids levels can decrease Methods which are described in EP-A 37923 can be set.

• - 80 bis 100 Gew.-%, bevorzugt 85 bis 99,9 Gew.-%, bezogen, auf das Gesamtgewicht der Monomere für das Polymerisat, wenigstens eines ethylenisch ungestättigten Hauptmonmeren sowie
• - 0 bis 20 Gew.-%, bevorzugt 0,1 bis 15 Gew.-%, bezogen auf das Gesamtgewicht der Monomere für das Polymerisat, wenigstens eines ethylenisch ungesättigten Comonomeren.

The polymer is a radical emulsion polymer. All monomers polymerizable by radical polymerization can be used to produce it. The polymer is generally composed of

• 80 to 100% by weight, preferably 85 to 99.9% by weight, based on the total weight of the monomers for the polymer, at least one ethylenically unsaturated main monomer and
• 0 to 20% by weight, preferably 0.1 to 15% by weight, based on the total weight of the monomers for the polymer, of at least one ethylenically unsaturated comonomer.

Of course, several main monomers or Comonomers can be used.

• - Estern aus vorzugsweise 3 bis 6 C-Atomen aufweisenden α,β-monoethylenisch ungestättigten Mono- oder Dicarbonsäuren, wie Acrylsäure, Methacrylsäure, Maleinsäure, Fumarsäure und Itaconsäure mit C₁-C₁₂-, vorzugsweise C₁-C₈- Alkanolen. Derartige Ester sind insbesondere Methyl-, Ethyl-, n-Butyl-, Isobutyl-, tert-Butyl-, n-Pentyl-, iso-Pentyl- und 2-Ethylhexylacrylat und/oder -methacrylat;
• - vinylaromatischen Verbindungen, bevorzugt Styrol, α-Methylstyrol, o-Chlorstyrol, Vinyltoluolen und Mischungen davon;
• - Vinylestern von C₁-C₁₈-Mono oder Dicarbonsäuren, wie Vinylacetat, Vinylpropionat, Vinyl-n-butyrat, Vinyllaurat und/oder Vinylstearat;
• - Butadien;
• - linearen 1-Olefinen, verzweigtkettigen 1-Olefinen oder cyclischen Olefinen, wie z. B. Ethen, Propen, Buten, Isobuten, Penten, Cyclopenten, Hexen oder Cyclohexen. Des Weiteren sind auch Metallocen-katalysiert hergestellte Oligoolefine mit endständiger Doppelbindung, wie z. B. Oligopropen oder Oligohexen geeignet;
• - Acrylnitril, Methacrylnitril;
• - Vinyl- und Allylalkylethern mit 1 bis 40 Kohlenstoffatomen im Alkyrest, wobei der Alkylrest noch weitere Subsituenten, wie eine oder mehrere Hydroxylgruppen, eine oder mehrere Amino- oder Diaminogruppen oder eine, bzw. mehrere Alkoxylatgruppen tragen kann, wie z. B. Methylvinylether, Ethylvinylether, Propylvinylether und 2-Ethylhexylvinylether, Isobutylvinylether, Vinylcyclohexylether, Vinyl-4-hydroxybutylether, Decylvinylether, Dodecylvinylether, Octadecylvinylether, 2-(Diethylamino)ethylvinylether, 2-(Di-n-butyl-amino)ethylvinylether, Methyldiglykolvinylether sowie die entsprechenden Allylether, bzw. deren Mischungen.

The main monomer is preferably selected from

• Esters of α, β-monoethylenically unsaturated mono- or dicarboxylic acids, preferably 3 to 6 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid with C ₁ -C ₁₂ -, preferably C ₁ -C ₈ - alkanols. Such esters are in particular methyl, ethyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl and 2-ethylhexyl acrylate and / or methacrylate;
• vinyl aromatic compounds, preferably styrene, α-methylstyrene, o-chlorostyrene, vinyltoluenes and mixtures thereof;
• - Vinyl esters of C ₁ -C ₁₈ mono or dicarboxylic acids, such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and / or vinyl stearate;
• - butadiene;
• - Linear 1-olefins, branched-chain 1-olefins or cyclic olefins, such as. B. ethene, propene, butene, isobutene, pentene, cyclopentene, hexene or cyclohexene. Furthermore, metallocene-catalyzed oligoolefins with a terminal double bond, such as. B. oligopropene or oligohexene suitable;
• - acrylonitrile, methacrylonitrile;
• - Vinyl and allyl alkyl ethers having 1 to 40 carbon atoms in the alkyl radical, where the alkyl radical can also carry further substituents, such as one or more hydroxyl groups, one or more amino or diamino groups or one or more alkoxylate groups, such as, for. B. methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether and 2-ethylhexyl vinyl ether, isobutyl vinyl ether, vinyl cyclohexyl ether, vinyl 4-hydroxybutyl ether, decyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, 2- (diethylamino) ethyl vinyl ether, 2- (di-n-butylamino) ethyl vinyl ether, and methyl digly the corresponding allyl ethers or mixtures thereof.

Particularly preferred main monomers are styrene, methyl methacrylate, n-butyl acrylate, Ethyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, ethene and butadiene and mixtures of these main monomers.

• - ethylenisch ungestättigten Mono- oder Dicarbonsäuren oder deren Anhydriden, vorzugsweise Acrylsäure, Methacrylsäure, Methacrylsäureanhydrid, Maleinsäure, Maleinsäureanhydrid, Fumarsäure und/oder Itaconsäure;
• - Acrylamiden und alkylsubstituierten Acrylamiden, wie z. B. Acrylamid, Methacrylamid, N,N-Dimethylacrylamid, N-Methylolmethacrylamid, N-tert.- Butylacrylamid, N-Methymethacrylamid und Mischungen davon;
• - sulfogruppenhaltigen Monomeren, wie z. B. Allysulfonsäure, Methallylsulfonsäure, Styrolsulfonsäure, Vinylsulfonsäure, 2-Acrylamido-2- methylpropansulfonsäure, Allyloxybenzolsulfonsäure, deren entsprechenden Alkali- oder Ammoniumsalzen bzw. deren Mischungen sowie Sulfopropylacrylat und/oder Sulfopropylmethacrylat;
• - C₁-C₄-Hydroxyalkylestern von C₃-C₆-Mono- oder Dicarbonsäuren, insbesondere der Acrylsäure, Methacrylsäure oder Maleinsäure, oder deren mit 2 bis 50 Mol Ethylenoxid, Propylenoxid, Butylenoxid oder Mischungen davon alkoxylierten Derviate oder Estern von mit 2 bis 50 Mol Ethylenoxid, Propylenoxid, Butylenoxid oder Mischungen davon alkoxylierten C₁-C₁₈-Alkoholen mit den erwähnten Säuren, wie z. B. Hydroxyethylacrylat, Hydroxyethylmethacrylat, Hydroxypropylacrylat, Hydroxypropylmethacrylat, Butandiol-1,4-monoacrylat, Ethyldiglykolacrylat, Methylpolyglykolacrylat (11 EO), (Meth)acrylsäureester von mit 3, 5, 7, 10 oder 30 Mol Ethylenoxid umgesetzten C₁₃/C₁₅-Oxoalkohol bzw. deren Mischungen;
• - Vinylphoshonsäuren und deren Salzen, Vinylphosphonsäuredimethylester und anderen phosphorhaltigen Monomeren;
• - Alkylaminoalkyl (meth) acrylaten oder Alkylaminoalkyl (meth) acrylamiden oder deren Quarternisierungsprodukten, wie z. B. 2-(N,N-Dimethylamino)-ethyl (meth) acrylat oder 2-(N,N,N-Trimethylammonium)-ethylmethacrylat-chlorid, 3-(N,N-Dimenthyl-amino)-propyl(meth)acrylat, 2-Dimethylamino-ethyl (meth) acrylamid, 3-Dimethylaminopropyl(meth)acrylamid, 3- Trimethylammoniumpropyl(meth)acrylamid-chlorid und Mischungen davon;
• - Allylestern von C₁-C₃₀-Monocarbonsäuren;
• - N-Vinylverbindungen, wie N-Vinylformamid, N-Vinyl-N-methylformamid, N- Vinylpyrrolidon, N-Vinylimidazol, 1-Vinyl-2-methyl-imidazol, 1-Vinyl-2- methylimidazolin, 2-Vinylpyridin, 4-Vinylpyridin, N-Vinylcarbazol und/oder N- Vinylcaprolactam;
• - Diallyldimethylammoniumchlorid, Vinylidenchlorid, Vinylchlorid, Acrolein, Methacolein;
• - 1,3-Diketogruppen enthaltenen Monomeren, wie z. B. Acetoacetoxyethyl(meth)acrylat oder Diacetonacrylamid, harnstoffgruppenhaltigen Monomeren, wie Ureidoethyl(meth)acrylat, Acrylamidoglykolsäure, Methacrylamidoglykolatmethylether;
• - Silylgruppen enthaltenden Monomeren, wie z. B. Trimethoxysilylpropylmethacrylat;
• - Glycidylgruppen enthaltenen Monomeren, wie z. B. Glycidylmethacrylat.

The comonomer is preferably selected from

• - Ethylenically unsaturated mono- or dicarboxylic acids or their anhydrides, preferably acrylic acid, methacrylic acid, methacrylic anhydride, maleic acid, maleic anhydride, fumaric acid and / or itaconic acid;
• - Acrylamides and alkyl-substituted acrylamides, such as. B. acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylol methacrylamide, N-tert-butylacrylamide, N-methymethacrylamide and mixtures thereof;
• - Monomers containing sulfo groups, such as. B. allysulfonic acid, methallylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, allyloxybenzenesulfonic acid, their corresponding alkali metal or ammonium salts or mixtures thereof, and sulfopropyl acrylate and / or sulfopropyl methacrylate;
• - C ₁ -C ₄ hydroxyalkyl esters of C ₃ -C ₆ mono- or dicarboxylic acids, in particular acrylic acid, methacrylic acid or maleic acid, or their derivatives alkoxylated with 2 to 50 moles of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof or with 2 up to 50 moles of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof alkoxylated C ₁ -C ₁₈ alcohols with the acids mentioned, such as. B. hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, butanediol-1,4-monoacrylate, ethyl diglycol acrylate, methyl polyglycol acrylate (11 EO), (meth) acrylic acid ester of C ₁₃ / C ₁₅ - reacted with 3, 5, 7, 10 or 30 mol ethylene oxide Oxo alcohol or mixtures thereof;
• - vinylphosphonic acids and their salts, dimethyl vinylphosphonate and other phosphorus-containing monomers;
• - Alkylaminoalkyl (meth) acrylates or alkylaminoalkyl (meth) acrylamides or their quaternization products, such as. B. 2- (N, N-dimethylamino) ethyl (meth) acrylate or 2- (N, N, N-trimethylammonium) ethyl methacrylate chloride, 3- (N, N-dimenthylamino) propyl (meth) acrylate, 2-dimethylamino-ethyl (meth) acrylamide, 3-dimethylaminopropyl (meth) acrylamide, 3-trimethylammonium propyl (meth) acrylamide chloride and mixtures thereof;
• - Allyl esters of C ₁ -C ₃₀ monocarboxylic acids;
• - N-vinyl compounds, such as N-vinylformamide, N-vinyl-N-methylformamide, N- vinylpyrrolidone, N-vinylimidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-methylimidazoline, 2-vinylpyridine, 4- Vinyl pyridine, N-vinyl carbazole and / or N-vinyl caprolactam;
• - diallyldimethylammonium chloride, vinylidene chloride, vinyl chloride, acrolein, methacolein;
• - Monomers containing 1,3-diketo groups, such as. B. acetoacetoxyethyl (meth) acrylate or diacetone acrylamide, monomers containing urea groups, such as ureidoethyl (meth) acrylate, acrylamidoglycolic acid, methacrylamidoglycolate methyl ether;
• - Monomers containing silyl groups, such as. B. trimethoxysilylpropyl methacrylate;
• - Monomers containing glycidyl groups, such as. B. Glycidyl methacrylate.

Particularly preferred comonomers are hydroxyethyl acrylate, hydroxypropyl acrylate, Hydroxybutyl acrylate, hydroxyethyl methacrylate, ethylenically unsaturated mono- or Dicarboxylic acids, such as. B. acrylic acid, methacrylic acid, maleic acid, fumaric acid, Itaconic acid and acrylamides such as e.g. B. acrylamide, methacrylamide, N-tert. Butylacrylamide. The comonomers can also be used as mixtures of various such Comonomers can be used.

Particularly suitable polymers contain acrylates as main monomers (acrylate Dispersions), mixtures of acrylates and styrene (styrene-acrylate dispersions), Mixtures of styrene and butadiene (styrene-butadiene dispersions) and vinyl acetate (Vinylacetatdisperionen).

The polymer is preferably produced by radical polymerization. Suitable polymerization methods, such as substance, solution, suspension or Emulsion polymerization are known to the person skilled in the art.

The copolymer is preferably obtained by solution polymerization with subsequent Dispersion in water or particularly preferably by emulsion polymerization produced so that aqueous copolymer dispersions are formed.

The emulsion polymerization can be carried out batchwise, with or without the use of Seed latices, with presentation of all or individual components of the reaction mixture, or preferably with partial submission and replenishment of the or individual components of the Reaction mixture, or carried out according to the dosing process without submission.

The monomers can be used in the emulsion polymerization as usual in the presence of a water-soluble initiator and an emulsifier at preferably 30 to 95 ° C. be polymerized.

Suitable initiators are e.g. B. sodium, potassium and ammonium persulfate, tert-butyl hydroperoxides, water-soluble azo compounds or redox initiators such as H ₂ O ₂ / ascorbic acid.

As emulsifiers z. B. alkali salts of longer-chain fatty acids, alkyl sulfates, Alkyl sulfonates, alkylated aryl sulfonates or alkylated biphenyl ether sulfonates. Of others come as emulsifiers, reaction products of alkylene oxides, in particular Ethylene or propylene oxide with fatty alcohols, acids or phenol, or alkylphenols into consideration.

In the case of aqueous secondary dispersions, the copolymer is first passed through Solution polymerization prepared in an organic solvent and then with the addition of salt images, e.g. B. of ammonia to carboxylic acid groups Copolymers, in water without the use of an emulsifier or Dispersing aid dispersed. The organic solvent can be distilled off. The preparation of aqueous secondary dispersions is known to the skilled worker and z. B. described in DE-A-37 20 860.

Regulators can be used in the polymerization to adjust the molecular weight become. Are suitable for. B. -SH containing compounds such as mercaptoethanol, Mercaptopropanol, thiophenol, and thioglycolic acid esters.

The gel content of such radical polymers is preferably below 40% by weight. preferably below 30% by weight, particularly preferably below 20% by weight, based on the Polymer. The gel content should preferably be above 5% by weight. The gel content is the Content of insoluble components.

The gel content is determined and defined by the following method: The Dispersion is dried at 21 ° C. to a film with a thickness of approx. 1 mm. One gram Polymer film is placed in 100 ml of tetrahydrofuran and left at 21 ° C for one week calmly. Thereafter, the solution or mixture obtained with the aid of a fabric filter (Mesh size 125 µm) filtered. The residue (swollen film) is at 21 ° C for 2 days dried in a vacuum drying cabinet and then weighed. The gel content is that Mass of the weighed residue divided by the mass of the used Polymer film.

The monomer composition is generally chosen so that a glass transition temperature Tg in the range from -60 ° C. to + 150 ° C., in particular in the range from -50 ° C. to + 100 ° C., results for the polymer. The glass transition temperature Tg of the polymers can in a known manner, for. B. can be determined by means of differential scanning calorimetry (DSC). The Tg can also be calculated approximately using the Fox equation. According to Fox TG, Bull. Am. Physics Soc. 1, 3, page 123 (1956) applies: 1 / Tg = x ₁ / TG ₁ + x ₂ / Tg ₂ +. , , + x _n / Tg _n , where x _{n stands} for the mass fraction (% by weight / 100) of the monomer n, and Tg _{n is} the glass transition temperature in Kelvin of the homopolymer of the monomer n. Tg values for homopolymers are listed in Polymer Handbook 3rd Edition, J. Wiley% Sons, New York (1989).

Instead of the aqueous polymer dispersions, those described herein can be used Polymers also in the form of dried polymer powder from the aqueous mixture Cement and the light aggregate are added.

If the polymer is used in the form of a polymeric superplasticizer, it is advantageous that the polymeric flow agent is present in such an amount that its Solids content, based on the amount of cement, in the range from 0.01 to 5% by weight, is in particular in the range from 0.1 to 2% by weight.

Suitable polymeric flow agents are u. a. Condensation products from Naphthalenesulfonic acid and formaldehyde as well as condensation products from Melamine sulfonic acids and formaldehyde, also polycarboxylates, lignin sulfonates, Oxycarboxylates and glucosaccharides.

• a) mindestens einer monoethylenisch ungesättigten Carbonsäure oder deren Salzen

erhalten wurden. Further suitable polymeric flow agents are derived from water-soluble polymers with polyalkylene glycol ether side chains which are obtained by copolymerizing a) esters of the formula (I)


in the
R ¹ , R ^{2 are the} same or different and are H or CH ₃
A is an alkylene group with 2 to 4 carbon atoms or -CH ₂ -CH ₂ -CH ₂ -CH ₂ ,
R ^{3 represents} C ₁ to C ₅₀ alkyl or C ₁ to C ₁₈ alkylphenyl and
n is a number from 2 to 300,
With

• a) at least one monoethylenically unsaturated carboxylic acid or its salts

were obtained.

Such polymeric flow agents preferably have molar masses (M _W = weight average) of 15,000-650,000 and are, inter alia, by solution polymerization of the monomers a) and b), optionally in the presence of initiators such as B. organic peroxides and azo initiators available. The solution polymerization can also be carried out in the presence of suitable entraining agents and regulators.

Such flow agents are widely used in the concrete industry.

Examples

Model systems were mixed in the laboratory and the compressive strength and the bending tensile strength of the lightweight materials were tested. Two systems are given here as examples. It was found that in a cement / pumice mixture, the addition of 10% of a carboxylated styrene-butadiene polymer, based on the cement content, increased the compressive strength by 251% and the bending tensile strength by 219%. The addition of a styrene-acrylate dispersion consisting of butyl acrylate and styrene showed a similar tendency.
Styrofan® D 750 aqueous dispersion made from a carboxylated styrene-butadiene copolymer (registered trademark of BASF Aktiengesellschaft)
Acronal® S 702 aqueous dispersion, containing a copolymer of n-butyl acrylate and styrene (registered trademark of BASF Aktiengesellschaft)
W / Z: ratio (weight) water / cement
K / Z: ratio (weight) plastic (polymer) / cement

composition

When developing such a lightweight material, it is important to ensure that sensible quantitative or volume ratios are preferably maintained. in this connection it can be assumed that the lightweight aggregate is preferably in the packing is as tight as possible and the cement paste or cement mortar Fills cavities in between. If too little light aggregate is used, the specific mass or bulk density unnecessarily increased and thus the heat-insulating effect lower. If too much light aggregate is used, voids will result in the cement matrix, which weakens the overall structure and thus the surprising counteracts strengthening effect of the polymer additives.

Furthermore, the residual water content and the absorbency of the used is preferably Light aggregate must be observed because it is part of the total water content of the system to consider.

The following weight ratios were established in test series:

The density of the cement mortar is approximately 2.2 g / cm ³ .

The measured values are exemplary of the light aggregates used in the experiment or fillers. Depending on the quality and location, the bulk densities, Residual water content and grain composition vary widely. The optimal ratio is preferably determined by experiment.

Claims (14)

1. Component made of lightweight concrete, in particular for building construction, which is formed from an aqueous mixture of cement and a light aggregate, characterized in that the aqueous mixture further contains a polymer in such an amount that its solids content, based on the amount of cement in the range of 0.01-20% by weight. 2. Component according to claim 1, characterized, that the polymer is a polymer dispersion, which in a such an amount is present that its solids content, based on the amount of cement, in Range is 1.0-10 wt .-%. 3. Component according to claim 2, characterized, that the polymer dispersion is a styrene-butadiene dispersion. 4. The component according to claim 2, characterized, that the polymer dispersion is an acrylate dispersion. 5. The component according to claim 1, characterized, that the polymer is a polymeric superplasticizer, which in such an amount is present that its solids content, based on the Amount of cement, is in the range of 0.1-2 wt .-%. 6. The component according to claim 5, characterized, that the polymeric superplasticizer is a polymer made from esters of (Meth) acrylic acid with polyalkylene glycol ether side chains. 7. The component according to one of the preceding claims, characterized, that weight ratio of cement to light aggregate in the mixture 1: 4 to 1: 5. 8. The component according to claim 1, characterized, that the lightweight aggregate is expanded clay or contains such. 9. The component according to claim 1, characterized, that the light aggregate is or contains pumice and / or cottage pumice. 10. The component according to claim 1, characterized, that the lightweight aggregate is expanded slate or contains such. 11. The component according to claim 1, characterized, that the lightweight aggregate is or contains perlite. 12. The component according to claim 1, characterized, that the lightweight aggregate is expanded glass. 13. Method for increasing the compressive strength of a component made of lightweight concrete, which consists of an aqueous mixture of cement and a light aggregate is shaped characterized, that the aqueous mixture before setting with a polymer in a such an amount is added that its solids content, based on the The amount of cement is in the range of 0.01-20% by weight. 14. Use an aqueous mixture of cement and a light aggregate as lightweight concrete for building elements, the aqueous mixture still being a Contains polymer in such an amount that its solids content, based on the amount of cement is in the range of 0.01-20% by weight.