Quick-drying lightweight fill

Abstract

The invention relates to a single- or two-component mortar composition comprising i) an aluminate binder, ii) a calcium sulfate binder, iii) one or more fillers with a raw density of at least 2.0 g / cm3, and iv) one or more lightweight fillers with a raw density of less than 1.5 g / cm3, wherein the quantity of lightweight filler equals 30 to 70 wt.%, the total quantity of aluminate binder and calcium sulfate binder equals 20 to 65 wt%, and the weight ratio of aluminate binder to calcium sulfate binder ranges from 1:1 to 1:10. When used, the mortar composition hardens quickly and is suitable as a lightweight fill for producing floor structures on substrates with a limited load-bearing capacity.

Description

[0001] QUICK-DRYING LIGHTWEIGHT FILLING

[0002] Technical area

[0003] The present invention relates to a calcium sulfate-based mortar composition suitable for lightweight fill and to a floor construction comprising such lightweight fill.

[0004] State of the art

[0005] Floor constructions are often based on cement-based screeds applied to the existing subfloor. This may involve a subfloor substrate with relatively low load-bearing capacity, for example, during floor renovation.

[0006] Conventional screeds generally have a relatively high dead weight, making them unsuitable for use on substrates with critical load-bearing capacity. In these cases, lightweight fillers are used, whose weight is reduced by the use of lightweight fillers such as Styrofoam.

[0007] The drying of such cement-based systems takes a relatively long time, so that they are only ready for covering after a longer period of time.

[0008] Floor constructions based on lightweight fill also have a relatively complex structure, usually requiring the installation of a reinforcement layer and another leveling screed layer in addition to the lightweight screed before a final floor covering, such as tiles, can be applied. Therefore, several work steps are required.

[0009] Consequently, the following problems exist with conventional state-of-the-art floor constructions based on cement-bound lightweight fill:

[0010] Restrictions on the way of working, e.g. time restrictions for the next work step or spatial restrictions

[0011] Short pot life Long waiting time for walkability

[0012] Long curing time for initial strength (sufficient flexural and compressive strength)

[0013] Long drying time

[0014] The application of the final layer depends on the drying time of the floor construction - different times for different floor coverings (e.g. tiles, PVC, parquet)

[0015] Long waiting time for the next work step or the application of the floor covering

[0016] Many different work steps, for example additional priming

[0017] Not fire-resistant due to polymer-based fillers (additional protective construction may be required)

[0018] So-called binary and ternary binders are increasingly used to formulate building materials, e.g., mortar compositions that can be used as screeds. Binary binders include aluminate cement and calcium sulfate as hydraulic binders. Ternary binders also include Portland cement as a third hydraulic binder. Binary and ternary binders have the

[0019] Advantage of a shortened time until ready for use compared to normal cements.

[0020] For example, WO 2015 / 150319 A1 relates to fast-drying gypsum compositions based on calcium aluminate and calcium sulfate as hydraulic binders.

[0021] Description of the invention

[0022] The object of the present invention is to provide a mortar composition for lightweight fills that cures quickly and is suitable for the construction of floor structures on substrates with relatively low load-bearing capacity. In particular, the mortar composition should also enable accelerated construction of floor structures on subgrades or substrates with limited load-bearing capacity. Furthermore, the system should exhibit good mechanical properties and achieve these quickly.

[0023] The inventors have found that this problem can be solved by using a mortar composition based on aluminate cement and calcium sulfate to which large amounts of a lightweight filler, in particular an inorganic lightweight filler, are added.

[0024] The invention therefore relates to a one- or two-component mortar composition comprising i) an aluminate binder selected from calcium aluminate cement and / or calcium sulfoaluminate cement, ii) a calcium sulfate binder selected from calcium sulfate hemihydrate and / or calcium sulfate anhydrite, iii) one or more fillers having a bulk density of at least 2.0 g / cm 3 and iv) one or more lightweight fillers, in particular inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm 3 , wherein the amount of lightweight filler, in particular inorganic lightweight filler, with a bulk density of less than 1.5 g / cm 330 to 70 wt.% and the total amount of aluminate binder and calcium sulfate binder is 20 to 65 wt.%, wherein the weight ratio of aluminate binder to calcium sulfate binder is in the range of 1:1 to 1:10, wherein the weight data refer to the dry weight of the mortar composition.

[0025] In this application, the dry weight of the mortar composition refers to the dry weight of the mortar composition as a whole, i.e. in the case of a two-component mortar composition, to the combined total weight of both components.

[0026] The mortar composition according to the invention is fast-curing and is particularly suitable as a lightweight fill for the production of

[0027] Floor constructions on substrates with limited load-bearing capacity. Rapid curing offers advantages for walkability and the strength development of the screed, allowing for fewer steps and faster production processes. Furthermore, the lightweight fillers used exhibit relatively high strength. This makes typical screed processing very easy.

[0028] In particular, due to the rapid hydration process of the mortar composition according to the invention when mixed with water, the curing, strength development, and the entire drying process are very rapid. This is the prerequisite for a shorter waiting time for the next work step and the final use of the floor structure.

[0029] With the mortar composition according to the invention, the next work step (final levelling of the floor, ie final levelling) is possible after only a few hours of waiting time and not after more than a day as with the state-of-the-art systems.

[0030] It may be advantageous to use inorganic lightweight fillers that are fire-resistant, unlike the commonly used organic polymer-based materials.

[0031] In summary, the following advantages of the mortar composition according to the invention or of the mortar composition mixed with water and applied to a substrate (screed) can be mentioned:

[0032] • Walkable after a few hours

[0033] • Quick-drying properties

[0034] • High and rapid power development

[0035] • Low density

[0036] • Low pH (due to the gypsum-based technology)

[0037] • Reduction in working hours

[0038] • Only one day of work for floor renovation and leveling of the final floor construction

[0039] • Resistance to fire through the use of mineral material and inorganic lightweight fillers, in particular expanded glass. For the floor construction according to the invention as a whole, which will be explained in detail later, there are further advantages:

[0040] • Ready for the final floor covering (tiles, PVC or parquet) in less than 48 hours after the start of work

[0041] • Reduction of work steps, no primer required (use of materials based on the same basic recipe)

[0042] • High maximum loads are possible, therefore suitable for residential and commercial use

[0043] • very low basis weight

[0044] • low installation height

[0045] • any layer thickness

[0046] • low deformation under load

[0047] Ways to implement the invention

[0048] The invention relates to a one- or two-component mortar composition. In a one-component mortar composition, all ingredients are combined in one component, whereas in a two-component mortar composition, the ingredients are distributed across two components. In a two-component mortar composition according to the invention, it is preferred that one component contains or is formed from the lightweight filler(s), while the other component contains the other ingredients of the mortar composition. In a two-component mortar composition, the component containing the binder is preferably mixed with water before the component containing the lightweight filler is added.

[0049] The one-component mortar composition is preferably a dry mortar. Accordingly, the component of the two-component mortar composition that does not contain the lightweight filler(s) is preferably a dry mortar. The one- or two-component mortar composition according to the invention comprises i) an aluminate binder selected from calcium aluminate cement and / or calcium sulfoaluminate cement, ii) a calcium sulfate binder selected from calcium sulfate hemihydrate and / or calcium sulfate anhydrite, iii) one or more fillers with a bulk density of at least 2.0 g / cm 3 and iv) one or more lightweight fillers, in particular inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm 3 .

[0050] The aluminate binder is calcium aluminate cement and / or calcium sulfoaluminate cement. The aluminate binder is preferably calcium sulfoaluminate cement. The aluminate binder is a hydraulic binder.

[0051] According to one embodiment, the aluminate binder contains at least one calcium aluminate cement (CAC). According to the present invention, a calcium aluminate cement (CAC) is, in particular, a cement comprising a clinker comprising hydraulic calcium aluminates, wherein the main phase is preferably CA (C: CaO; A: Al2O3). Other calcium aluminates, such as C2A, C3A, C12A7, are typically also present. CACs for the present invention may typically also contain other phases selected from gehlenite (C2A5 with C: CaO, A: Al2O3, S: SiO2), perovskite (C2S with C: CaO, T: TiO2), belite (C2S with C: CaO, S: SiO2), tricalcium silicate, ferrites (C2F, C2AF, C4AF with C: CaO; A: Al2O3; F: Fe2O5), ternesite (CsS2$ with C: CaO, S: SiO2; A: SO3), and aluminum oxide. CACs of the present invention may further contain calcium carbonate. In particular, a CAC of the present invention preferably complies with the EN 14647 standard. CACs described in other standards, e.g.ASTM or Chinese standards are equally suitable. Suitable CACs can be purchased commercially, for example, from Royal White Cement.

[0052] According to one embodiment, the aluminate binder contains at least one calcium sulfoaluminate (CSA) cement. A CSA cement according to the present invention is in particular a cement comprising a clinker comprising C4(AS-XFX)$ (C: CaO; A: Al2O3; F: Fe2Os; $: SO3), where x is an integer from 0 to 3. CSA for the present invention can typically contain further phases selected from aluminates (C1A, C3A, C12A7, with C: CaO; A: Al2O3), belite (C2S, with C: CaO, S: SiO2), ferrites (C2F, C2AF, C4AF, with C: CaO; A: Al2O3; F: Fe2Os), ternesite (CsS2$ with C: CaO, S: SiO2; $: SO3), and anhydrite. In certain embodiments of the invention, the CSA contains 15-75 wt% C4As$, 0-10 wt% aluminates, 0-70 wt% belite, 0-35 wt% ferrites, 0-20 wt% ternesite and

[0053] 0-25 wt.% anhydrite, based on the total dry weight of the CSA cement. Any anhydrite present is a component of the CSA cement and is to be attributed to it. Suitable CSAs can be purchased, for example, under the trade name Calumex from Caltra BV.

[0054] The calcium sulfate binder is a hydraulic binder. The calcium sulfate binder is selected from calcium sulfate hemihydrate (CaSO4 ■ 1 H2O) and / or calcium sulfate anhydrite (CaSO4), with calcium sulfate hemihydrate being preferred. Calcium sulfate anhydrite is anhydrous calcium sulfate (no water of crystallization). Calcium sulfate hemihydrate includes alpha-calcium sulfate hemihydrate and beta-calcium sulfate hemihydrate, with alpha-calcium sulfate hemihydrate being preferred.

[0055] With regard to the calcium sulfate binder, it is preferred if it consists essentially or entirely of calcium sulfate hemihydrate, since too high a proportion of anhydrite leads to excessively rapid water absorption by the anhydrite component, which can impair the processability of the composition. Consequently, it is preferred if at least 80 wt.%, preferably at least 90 wt.%, and particularly preferably at least 95 wt.% of the total amount of calcium sulfate binder is calcium sulfate hemihydrate (the remainder being calcium sulfate anhydrite).

[0056] Calcium sulfate dihydrate (CaSO4 ■ 2 H2O) is unable to bind water and therefore does not fall under the category of calcium sulfate binders. However, calcium sulfate dihydrate may also be included in the mortar composition if necessary. Calcium sulfate dihydrate can serve as a nucleating agent and promotes a faster reaction of the calcium sulfate hemihydrate. Therefore, the mortar composition preferably contains calcium sulfate dihydrate.

[0057] The mortar composition according to the invention further contains one or more lightweight fillers with a bulk density of less than 1.5 g / cm 3 . The lightweight fillers are preferably made of an inorganic material, e.g. glass or a mineral material, which usually contains pores or is a hollow body.

[0058] Suitable lightweight fillers can also be organic materials, in particular recycled plastic, rubber powder or bio-based lightweight fillers, in particular based on hemp, rice husks, wood or cork.

[0059] The bulk density of a particulate material, such as fillers, is the ratio between the mass of the particulate material and the volume occupied by the individual particles. This volume includes the pores within the particles (internal pore volume), but not the voids between the particles. In contrast to bulk density, the bulk density does not take into account the spaces between the particles of the material. The bulk densities specified in this application refer to a temperature of 20 °C. Bulk density can be determined according to the EN 1097-6 - 2013 standard.

[0060] The lightweight filler(s), e.g. the examples given below, in particular expanded glass, have a bulk density of less than 1.5 g / cm 3 , preferably less than 1.0 g / cm 3 , preferably less than 0.6 g / cm 3 , particularly preferably less than 0.5 g / cm 3 , In general, the bulk density is preferably at least 0.05 g / cm 3 , preferably at least 0.1 g / cm 3 .

[0061] Examples of suitable inorganic lightweight fillers with the above-mentioned bulk densities are selected from expanded glass, hollow glass spheres, foam glass gravel, aluminum silicate hollow spheres, pumice, expanded clay, expanded slate, expanded perlite, recycled aggregate, e.g. from lightweight concrete or aerated concrete, non-expanded perlite, silicate hollow microspheres or combinations thereof, preferably expanded glass, pumice, expanded perlite, expanded clay, expanded slate or combinations thereof.

[0062] In a preferred embodiment, the lightweight filler(s) has a bulk density of less than 1.5 g / cm 3 expanded glass.

[0063] The lightweight filler(s), e.g., the examples mentioned above, in particular inorganic lightweight fillers, preferably expanded glass, preferably have an average grain size in the range of 0.05 to 16 mm, preferably 0.5 to 10 mm, more preferably 1 to 7 mm, particularly preferably 2 to 4 mm. This applies to all of the aforementioned bulk densities or preferred bulk densities.

[0064] The terms "grain size" and "particle size" are used synonymously here. "Grain size" refers to the average grain size, unless otherwise stated. The average grain size corresponds specifically to the D50 value (50% of the particles are smaller than the specified value, 50% are correspondingly larger).

[0065] The particle size of fine particles with a particle size of up to 3.5 mm can be measured using laser diffraction, as described in ISO 13320:2009. Specifically, a Mastersizer 2000 instrument with a Hydro 2000G dispersing unit and the Mastersizer 2000 software from Malvern Instruments GmbH (Germany) are used. Suitable measurement media include, for example,

[0066] Isopropanol. The particle size of non-spherical or irregular particles is preferably represented by the equivalent spherical diameter of a sphere of the same volume.

[0067] The particle size of coarse particles with a particle size greater than 3.5 mm can be determined by sieve analysis, as described, for example, in the ASTM C136 / C136M standard. In this method, particles of different sizes are separated by sieving the material through a series of sieves with different mesh sizes. The material to be analyzed is shaken through a series of successively decreasing sieves using a single or a combination of horizontal, vertical, or rotating motion. The result is the percentage of particles that pass through a sieve of a specific size. Sieve analysis is also suitable, in principle, for determining the particle size of particles below 3.5 mm.

[0068] It is also possible to obtain grading curves from two or more lightweight fillers, especially inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm 3with different particle size distributions, whereby the lightweight fillers can be of the same or different types. Such mixtures can influence, among other things, the strength of the mortar composition and other processing-related properties.

[0069] The lightweight fillers, especially inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm 3 preferably meet the requirements for lightweight fillers according to DIN EN 13055:2016.

[0070] The particles of lightweight fillers, especially inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm 3may have any spherical and / or non-spherical geometric shape, either uniform or non-uniform. The particles may, for example, be spherical, conical, polygonal, cubic, pentagonal, hexagonal, octagonal, prismatic, and / or polyhedral. Non-uniform particles may, for example, have circular, elliptical, oval, square, rectangular, triangular, or polygonal cross-sections at least partially contained within them. "Non-uniform" and "irregularly" shaped particles refer to three-dimensional particle shapes in which at least two different cross-sections through the particles have different shapes. For the geometric shape of the particles of the fillers described below with a bulk density of at least 2.0 g / cm 3 the same applies.

[0071] The mortar composition also contains one or more fillers with a bulk density of at least 2.0 g / cm 3 , which are also referred to as aggregates, wherein the bulk density of the filler(s) is preferably at least 2.2 g / cm 3 As fillers with a bulk density of at least 2.0 g / cm 3 , preferably at least 2.2 g / cm 3 Materials known to those skilled in the art can be used. Examples include rock, crushed stone, gravel, slag, ground rock, recycled aggregate, recycled concrete, sand such as quartz sand or river sand, ground rock, glass, glass ceramics, porcelain, electrofused or sintered abrasives, kiln furniture, silicon dioxide, carbonates such as ground limestone, ground dolomite, and chalk, and / or ground aluminum oxide.

[0072] Solid materials can be used for which recycling opportunities are being sought. Examples of such fillers or aggregates with a bulk density of at least 2.0 g / cm 3 are the following, provided they have a density of at least 2.0 g / cm 3 have:

[0073] (i) Materials of biological origin, preferably of plant origin, in particular materials of plant origin consisting essentially of cellulose and / or lignin.

[0074] (ii) inorganic aggregates from the demolition of civil engineering structures, preferably selected from concrete waste, mortar, bricks, natural stone, asphalt, tiles, clinker, metal scrap

[0075] (iii) granular materials which are not harmful to health and are normally intended for landfilling, such as used foundry sands, catalyst supports, clinker aggregates, fillers from the treatment of excavated sludge, sewage sludge, liquid manure, paper waste, paper incineration ash, domestic waste incineration ash.

[0076] In a preferred embodiment, the filler(s) comprise or are having a bulk density of at least 2.0 g / cm 3 Sand and / or carbonate, especially in the form of calcium carbonate. Suitable sands are described, for example, in the standards ASTM C778 or EN 196-1.

[0077] Calcium carbonate also includes limestone or limestone flour and chalk. Sand can be quartz sand or river sand, in particular.

[0078] A suitable quartz sand has, for example, a grading curve in the range of approximately 0 to

[0079] 0.5 mm, preferably in the range of about 0.08 to 0.4 mm. Another suitable quartz sand, for example, has a particle size in the range of about 0.1 to 1 mm, preferably about 0.2 to 0.8 mm.

[0080] A suitable calcium carbonate, for example, has an average particle diameter in the range of approximately 3 pm and a residue-free grain size of approximately 40 pm. A suitable limestone powder, for example, has a fineness of < 0.1 mm.

[0081] In the following, weight data relating to the one- or two-component mortar composition according to the invention refer to the dry weight of the mortar composition as a whole, unless otherwise stated.

[0082] The total amount of aluminate binder and calcium sulfate binder in the mortar composition according to the invention is 20 to 65 wt.%, preferably 20 to 60 wt.%, more preferably 35 to 55 wt.%, based on the dry weight of the mortar composition.

[0083] The weight ratio of aluminate binder to calcium sulfate binder in the mortar composition is in the range of 1:1 to 1:10, preferably in the range of 1:1 to 1:5, more preferably 1:1 to 1:3.5.

[0084] The content of lightweight filler, in particular inorganic lightweight filler, with a bulk density of less than 1.5 g / cm 3 , preferably with a bulk density of less than 1.0 g / cm 3 , based on the dry weight of the mortar composition, is 30 to 70 wt%, preferably 35 to 65 wt%, more preferably 40 to 60 wt%.

[0085] The content of filler with a bulk density of at least 2.0 g / cm 3 , preferably at least 2.2 g / cm 3 , based on the dry weight of the mortar composition, may be, for example, 2 to 20 wt.%, preferably 4 to 15 wt.%, based on the dry weight of the mortar composition.

[0086] In a preferred embodiment, the mortar composition according to the invention comprises: i) 8 to 20 wt.% of the aluminate binder, ii) 20 to 50 wt.% of the calcium sulfate binder and iii) 35 to 65 wt.% of the inorganic lightweight filler(s) having a

[0087] Bulk density of less than 1.5 g / cm 3 , preferably less than 1.0 g / cm 3 .

[0088] In a preferred embodiment, the mortar composition may further comprise at least one lithium salt that accelerates the curing of the composition. Suitable lithium salts include, for example, lithium sulfate and lithium halides, especially lithium chloride, and lithium carbonate. Lithium carbonate is most preferred.

[0089] The lithium salt, in particular lithium carbonate or lithium sulfate, is preferably present in the mortar composition in an amount of 0.001 to 0.5 wt.%, more preferably 0.003 to 0.05 wt.%. At less than 0.001%, the concentration is generally too low to provide a noticeable accelerating effect, while an addition of more than 0.5 wt.% may result in the composition curing too quickly and / or exhibit no additional effect, with the additive acting more as a filler.

[0090] In a preferred embodiment, the mortar composition may further contain tartaric acid and / or a tartaric acid salt, preferably an alkali metal salt of tartaric acid, preferably in an amount of 0.15 to 0.005 wt.%, more preferably 0.1 to 0.01 wt.%. Sodium or potassium tartrate or the mixed salt sodium / potassium tartrate is preferred.

[0091] The addition of tartaric acid and / or a tartaric acid salt has a positive effect on the expansion behavior of the mortar composition by suppressing excessive expansion of the material. To achieve this effect, a minimum of 0.005 wt.% is generally used, while more than 0.15 wt.% can lead to excessive setting delay.

[0092] Other suitable retarders that can be added alternatively or in addition to the tartaric acid and / or the tartaric acid salt are gluconates, especially sodium gluconate, or citric acid and / or a citric acid salt, e.g., sodium citrate. In a preferred embodiment, the mortar composition may further contain at least one superplasticizer. The superplasticizers commonly used in the art can be used. Particularly suitable superplasticizers are polycarboxylate ethers (PCEs), also known as "superplasticizers." The polycarboxylate ether preferably has polyethylene glycol side chains.

[0093] The content of flow agent, in particular polycarboxylate ether, in the mortar composition is preferably in the range of 0.005 to 0.5 wt.%, more preferably 0.01 to 0.1 wt.%.

[0094] Thus, in a preferred embodiment, the mortar composition according to the invention may further comprise at least one additive selected from a lithium salt, at least one retarder selected from one of tartaric acid or a tartaric acid salt, a gluconate, in particular sodium gluconate, and citric acid or a citric acid salt, a flow agent, wherein the flow agent is preferably a polycarboxylate ether, or a combination thereof. These additives are described above. In a particularly preferred embodiment, the mortar composition comprises a lithium salt, tartaric acid or a tartaric acid salt, and a flow agent, preferably a polycarboxylate ether.

[0095] In addition to the additives mentioned, the mortar composition may also contain one or more other additives, e.g. thickeners, dyes and / or color pigments, curing retarders, stabilizers, defoamers, shrinkage reducers and / or flexibilizers.

[0096] Examples of suitable flexibilizers are organic polymers, e.g., based on vinyl acetate and ethylene, available from Wacker as Vinnapas®5025 L. A suitable retarder is available from Sika Schweiz AG under the trade name Retardan® P. Examples of suitable color pigments are inorganic or organic pigments, such as metal oxides and mixed metal oxides, e.g., iron oxides.

[0097] Examples of shrinkage reducers are polyols with 2 to 4 hydroxy groups, preferably glycerin and / or erythritol. It has been found that the use of at least one of the aforementioned polyols can lead to a particularly significant reduction in shrinkage.

[0098] The mortar composition may further contain Portland cement, but this is generally not preferred. The mortar composition may, for example, contain up to 5 wt.%, preferably no more than 3 wt.%, more preferably no more than 1 wt.%, especially no more than about 0.1 wt.% of Portland cement. However, the mortar composition is preferably free of Portland cement.

[0099] The amounts of the individual components in the mortar composition can also depend on the type of application and the thickness of the applied layer.

[0100] An advantageous embodiment of the mortar composition according to the invention contains

[0101] 8 to 20 wt.% of the aluminate binder,

[0102] 20 to 50 wt.% of the calcium sulfate binder,

[0103] 35 to 65 wt.% of the inorganic lightweight filler(s) with a bulk density of less than 1.5 g / cm 3 , preferably less than 1.0 g / cm 3, especially expanded glass,

[0104] 4 to 15 wt.% filler with a bulk density of at least 2.0 g / cm 3 , preferably at least 2.2 g / cm 3 , in particular sand, e.g. quartz sand, and / or calcium carbonate, e.g. chalk and / or limestone,

[0105] 0.01 to 0.10 wt.% tartaric acid salt, in particular potassium sodium tartrate, 0.003 to 0.5 wt.% lithium salt, in particular lithium carbonate or lithium sulfate.

[0106] The invention further relates to a method for producing a floor construction on a substrate, comprising a) applying a mixture of the mortar composition according to the invention as described above with water to the substrate to form a first screed layer, b) applying a reinforcing layer to the first screed layer, c) applying a mixture of a leveling compound with water to the reinforcing layer to form a second screed layer and d) optionally applying a floor covering to the second screed layer.

[0107] The above statements regarding the mortar composition according to the invention apply equally to the process according to the invention.

[0108] The method according to the invention relates to the production of a floor construction on a substrate or base. The substrate is not subject to any restrictions. Due to the mortar composition according to the invention used, with which a lightweight fill can be obtained, the method according to the invention is particularly suitable for substrates with limited load-bearing capacity. The method according to the invention is particularly suitable, for example, for soil remediation.

[0109] Examples of suitable substrates include wood, concrete, screed, existing substrates with ceramic coverings, and existing substrates based on screed or concrete. The substrate can be, for example, a cement-based substrate, such as Portland cement, or calcium sulfate-based. The substrate is preferably a wood substrate or a multi-layer substrate comprising a wood layer, e.g., a wood subfloor with an existing substrate on top.

[0110] The substrate can optionally be provided with one or more primers prior to applying the mortar composition mixed with water according to step a). The primer is applied to the substrate, e.g., by brushing. Such pretreatment is known to the person skilled in the art. Common primers can be used, e.g., plastic dispersions or two-component primers based on organic binders, e.g.,

[0111] Epoxy resin binder. Filling primers are also suitable as primers for priming and filling in a single step. Alternatively, the substrate can be provided with a separating layer, e.g., a PE film, if the screed is to be laid as a flowing screed. In the process according to the invention, the mortar composition according to the invention is mixed with water in step a). Since the mortar composition contains hydraulic binders in the form of aluminate binder and calcium sulfate binder, hydration reactions are known to occur upon the addition of water. The mortar composition hardens over time through drying or setting. The mortar is applied to the optionally primed substrate while it is still flowable or pasty.

[0112] The mixing of the two-component mortar composition according to the invention, consisting of component A, which comprises the lightweight filler, and component B, which comprises the remaining components of the mortar composition, can be carried out, for example, in the following manner. Component B is mixed with water, e.g., for approx.

[0113] 60 seconds. Suitable mixing ratios of mortar composition (including lightweight filler) and water are given below. Cold, clean water is preferably used. Component A (lightweight filler) is added to the resulting homogeneous mixture while the mixer is running. Stir for a further period, e.g., approximately 120 seconds, to obtain the ready-to-use mixture. It is also possible to pour component B mixed with water over component A (lightweight filler) and then mix this mixture again.

[0114] The consistency or rheological behavior of the mortar composition can be adjusted not only by the choice of additives used, but also, in particular, by the mixing ratio of mortar composition to water. It is preferred to mix the mortar composition with water in a mass ratio of water to mortar composition in the range of 0.08 to 0.50, preferably 0.10 to 0.40, in particular 0.20 to 0.35. The resulting mortar composition is advantageously pumpable, which facilitates transportation.

[0115] The mortar composition mixed with water is then applied to the substrate, which may have been provided with a primer or a release layer. Application can be carried out using any means known to those skilled in the art, e.g., by trowel, rake, squeegee, or roller, by pouring, or by spraying, preferably using a trowel, squeegee, pouring, or rake. After application, the applied mortar composition can be smoothed, if necessary, e.g., with a smoothing trowel. As a rule, the applied material is leveled over inserted gauges and then smoothed or leveled using a smoothing trowel.

[0116] "condensed".

[0117] After applying the mortar, the first layer is generally waited until it is walkable before applying the reinforcing mesh. The first screed layer is, in particular, a lightweight fill.

[0118] The reinforcement layer can be made from the reinforcements or reinforcements commonly used in the field. The reinforcement layer is preferably or comprises a textile surface carrier, e.g., a woven fabric, a nonwoven, or a nonwoven. Systems other than a nonwoven are preferred, so that the first screed layer and the leveling layer (second screed layer) can interlock with each other. Multi- or three-dimensional woven fabrics or nonwovens, particularly made of glass fibers, are also conceivable. The reinforcement layer is preferably or comprises an armored fabric.

[0119] The reinforcement layer is or particularly preferably comprises a textile surface carrier made of glass fiber, e.g., as a woven fabric, nonwoven fabric, or scrim, in particular a glass fiber fabric or glass fiber scrim. The glass fibers can be plastic-coated. The textile surface carrier, e.g., as a woven fabric, nonwoven fabric, or scrim, can also be formed from another fiber material, e.g., polymer fibers.

[0120] The reinforcement layer is preferably fixed to the first screed layer, e.g., mechanically by means of clamps and / or with a reinforcing mortar. Calcium sulfate leveling compounds based on calcium sulfate binders are particularly suitable as reinforcing mortars. The calcium sulfate binder of the calcium sulfate leveling compound is selected, in particular, from calcium sulfate hemihydrate and / or calcium sulfate anhydrite, corresponding to the calcium sulfate binder of the mortar composition according to the invention. Preference is given to using a stable leveling compound, in particular a stable calcium sulfate leveling compound. Also conceivable is a leveling compound comprising calcium sulfate binders and aluminate binders as binders, the definition of these binders having been described for the mortar composition according to the invention.

[0121] An advantage of the method according to the invention is that the mortar composition according to the invention of the first screed layer dries quickly, so that after a relatively short drying time, e.g. less than 6 hours, preferably less than 4 hours, particularly preferably after no more than 2 hours, waiting time according to step b), the reinforcing mesh can be attached and then after only a further short waiting time, e.g. of approximately 30 minutes, step c) can be continued, the application of the second screed layer.

[0122] According to step c) of the method according to the invention, a mixture of a leveling compound and water is applied to the reinforcement layer to form a second screed layer. Conventional application methods can be used. Examples are given above for the first screed layer. The leveling compound can be self-leveling or, if necessary, smoothed, e.g., with a smoothing trowel.

[0123] Fast-curing systems are particularly used as leveling compounds. The leveling compound is preferably a calcium sulfate leveling compound comprising a calcium sulfate binder, with the calcium sulfate leveling compound preferably comprising a calcium sulfate binder and an aluminate binder. The use of such calcium sulfate leveling compounds is preferred because, on the one hand, they dry quickly and, on the other hand, prior priming of the first screed layer is not required, making the process particularly economical and simple.

[0124] The calcium sulfate binder of the calcium sulfate leveling compound is selected in particular from calcium sulfate hemihydrate and / or calcium sulfate anhydrite, corresponding to the calcium sulfate binder of the mortar composition according to the invention, to which reference is made. The aluminate binder of the calcium sulfate leveling compound, if present, is selected in particular from calcium aluminate cement and / or calcium sulfoaluminate cement, corresponding to the aluminate binder of the mortar composition according to the invention, to which reference is made. The calcium sulfate leveling compound used as a leveling compound generally does not contain lightweight fillers with a bulk density of less than 1.5 g / cm 3 , but a higher proportion of common fillers, e.g. sand and / or calcium carbonate.

[0125] One advantage of the floor construction, which consists of the first screed layer made of the lightweight fill according to the invention, the reinforcement layer, and the second screed layer, is its rapid curing, so that the floor is ready for covering no later than 48 hours after application of the second screed layer, preferably after application of the first layer. This refers to continuous processing, taking into account the necessary waiting times for drying. It is understood that the duration may be extended depending on working hours and practical procedures.

[0126] Once the floor is ready for installation, a floor covering can be applied to the second screed layer, if desired and preferably. Standard floor coverings can be applied. Examples of floor coverings include tiles, laminate, PVC (polyvinyl chloride), linoleum, or carpet. The flooring can be fixed to the second screed layer in the usual way, e.g., by gluing.

[0127] There are no restrictions on the thickness of the screed layers. The following specifications refer to the dried layer.

[0128] The first screed layer can, for example, have a layer thickness of at least 15 mm, whereby the first screed layer preferably has a layer thickness in the range of 15 to 100 mm, more preferably 20 to 100 mm. The layer thickness can also depend on whether the screed is laid as a bonded screed or a flowing screed. When laid as a bonded screed, the layer thickness is preferably at least 15 mm, whereas when laid as a flowing screed, the layer thickness is preferably at least 25 mm. The second screed layer can, for example, have a layer thickness of at least 6 mm, whereby the second screed layer preferably has a layer thickness in the range of 6 to 50 mm, more preferably 8 to 10 mm.

[0129] A preferred embodiment of the method according to the invention for a floor construction with a composite screed comprises

[0130] - Dispersion primer or filling primer on subfloor construction, especially a wooden substrate, e.g. wooden floorboards,

[0131] - Application of the mortar composition according to the invention as the first screed layer (lightweight fill) - preferred layer thickness between 15 and 100 mm, drying time for the application of the reinforcement layer less than 6 hours, e.g. after just 2 hours (corresponds to the time until the first screed layer is walkable),

[0132] - Application of armored fabric or fiberglass fabric, fixed with calcium sulfate filler (e.g. stable calcium sulfate filler),

[0133] - Application of calcium sulphate levelling compound as a levelling compound for the second screed layer (e.g. fast-curing fine levelling compound) - preferred layer thickness between 6 and 50 mm, but especially between 6 and 10 mm; ready for the final floor covering after 48 hours at the latest

[0134] A preferred embodiment of the method according to the invention for a floor construction with a flowing screed comprises

[0135] - Laying of PE film 100 pm on subfloor construction (PE = polyethylene),

[0136] - Application of the mortar composition according to the invention as the first screed layer (lightweight fill) - preferred layer thickness between 25 and 100 mm, drying time for the application of the reinforcement layer less than 6 hours, e.g. already after 2 hours,

[0137] - Application of armored mesh or fiberglass mesh (e.g. Schönox® PZG), fixed with calcium sulfate leveling compound (e.g. stable calcium sulfate leveling compound), - Application of calcium sulfate leveling compound as a leveling compound for the second screed layer (e.g. fast-curing fine leveling compound) - preferred layer thickness between 6 and 50 mm, but especially between 6 and 10 mm; ready for the final floor covering after 48 hours at the latest

[0138] The floor construction according to the invention is preferably a floor construction, in particular for indoor use. The floor construction is particularly suitable for floors in residential areas or retail spaces, or even for commercial use.

[0139] Due to the low weight of the floor construction according to the invention, it is particularly suitable for subfloor constructions or substrates with low load-bearing capacity. Preferred fields of application are soil remediation and / or floor construction on wood substrates or substrates comprising wood layers.

[0140] The invention also relates to the use of the one- or two-component mortar composition according to the invention as described above as screed, in particular as lightweight fill.

[0141] The above statements regarding the mortar composition according to the invention and the method according to the invention apply equally to the use according to the invention, in particular with regard to the design of the mortar composition, the floor construction and the substrate, so that reference is made thereto.

[0142] The use according to the invention is preferably suitable for producing a floor construction on a substrate, comprising in this order a first screed layer made of the one- or two-component mortar composition according to the invention, a reinforcement layer and a second screed layer, wherein optionally a floor covering is arranged over the second screed layer.

[0143] The use according to the invention is particularly suitable for floor renovation or ground restoration, since the weight of fillers or screeds is often limited due to the load-bearing capacity of the subfloor construction. The use according to the invention is particularly suitable for a subfloor construction made of a wood substrate or a multi-layer substrate comprising a wood layer.

[0144] The use according to the invention is particularly suitable in the context of a floor construction according to the invention as described below.

[0145] The invention also relates to a floor construction on a substrate, comprising in this order a first screed layer made of the mortar composition according to the invention as described above, a reinforcement layer and a second screed layer, wherein optionally a floor covering is arranged over the second screed layer.

[0146] The above statements regarding the mortar composition according to the invention, the method according to the invention and the use according to the invention apply equally to the floor construction according to the invention, in particular with regard to the design of the mortar composition, the reinforcement layer, the first and second screed layer, the floor covering and the substrate, so that reference is made thereto.

[0147] The floor construction is preferably obtainable by a process according to the invention as described above.

[0148] The invention is explained in more detail below using exemplary embodiments. These examples are for illustrative purposes and are not intended to limit the present invention in any way.

[0149] Examples of implementation

[0150] Example 1

[0151] Mortar composition

[0152] A two-component mortar composition was prepared from components A and B according to the following formulations. <omponente A

[0153] Component A and component B were mixed in a ratio of 50

[0154] Wt.% component A and 50 wt.% component B were mixed. The resulting mortar composition had the following composition.

[0155] Mortar composition

[0156] Example 2 and Comparative Example 1 A floor construction was produced using the mortar composition of Example 1 on a plasterboard substrate (alternatively a concrete substrate) in the following way (Example 2):

[0157] Mixing of mortar composition of Example 1 with water (ratio 100 kg mortar composition / 16.4 l water) - Applying the mixture to the substrate in the layer thickness specified in Table 1

[0158] Applying an armored mesh (glass fiber mesh) about 2 hours after applying the mixture and fixing with calcium sulfate filler

[0159] Applying a leveling compound (calcium sulfate leveling compound) to the fabric after approximately 2 hours, layer thickness approximately 8 mm. A floor construction was produced using a commercially available cement-based dry mortar for lightweight fill (containing lightweight aggregate made of expanded polystyrene) on a plasterboard substrate in the following way (Comparative Example 1):

[0160] Mixing dry mortar with water (ratio 100 kg dry mortar / 47.6-52.4 l water)

[0161] Apply the mixture to the substrate in the layer thickness specified in Table 1

[0162] Applying a glass fibre fleece approximately 4 hours after applying the mixture

[0163] Apply a cementitious thin screed to the fleece after approx. 48 hours, layer thickness approx. 8 mm

[0164] The properties of the floor constructions according to Example 2 and Comparative Example 1 were tested. The results are shown in Table 1. The tests were carried out on the mortar composition according to the invention ("fill" in Table 1) or on the entire floor construction ("system" in Table 1).

[0165] The following test procedures were used:

[0166] Bulk density: based on DIN EN 1015-10

[0167] Bending tensile / compressive strength: based on DIN EN 13892-2

[0168] Chair castor tester: based on ASTM C627

[0169] Adhesive tensile strength: based on DIN EN 13892-8

[0170] Pot life 2: 20 minutes after mixing the mortar composition of Example 2 or the dry mortar of Comparative Example 1 with water, a small area was created with the mixture every 5 minutes and tested the next day with a hammer blow. If the area crumbles: End of pot life (TZ-End) Table 1

[0171]

[0172] Prisms too soft; SpMa = filler

Claims

Claims 1. One- or two-component mortar composition comprising i) an aluminate binder selected from calcium aluminate cement and / or calcium sulfoaluminate cement, ii) a calcium sulfate binder selected from calcium sulfate hemihydrate and / or calcium sulfate anhydrite, iii) one or more fillers with a bulk density of at least 2.0 g / cm³ 3 and iv) one or more lightweight fillers, in particular inorganic lightweight fillers, with a bulk density of less than 1.5 g / cm³ 3 , wherein the amount of lightweight filler, in particular inorganic lightweight filler, has a bulk density of less than 1.5 g / cm³ 330 to 70 wt.% and the total amount of aluminate binder and calcium sulfate binder is 20 to 65 wt.%, wherein the weight ratio of aluminate binder to calcium sulfate binder is in the range of 1 :1 to 1 :10, the weights referring to the dry weight of the mortar composition.

2. One- or two-component mortar composition according to claim 1, wherein the content of lightweight filler, in particular inorganic lightweight filler, has a bulk density of less than 1.5 g / cm³ 3 35 to 65 wt.%, preferably 40 to 60 wt.%, based on the dry weight of the mortar composition.

3. One- or two-component mortar composition according to one of the preceding claims, wherein the lightweight filler(s) have a bulk density of less than 1.5 g / cm³ 3The selected materials are expanded glass, hollow glass spheres, foamed glass gravel, aluminum silicate hollow spheres, pumice, expanded clay, expanded shale, expanded perlite, recycled aggregate, non-expanded perlite, silicate micro-hollow spheres, recycled plastic, rubber powder, bio-based lightweight fillers, in particular based on hemp, rice hulls, wood or cork, or combinations thereof, wherein Expanded glass, pumice, expanded perlite, expanded clay, expanded shale, or combinations thereof are preferred. A one- or two-component mortar composition according to any one of the preceding claims, wherein the lightweight filler(s) have a bulk density of less than 1.5 g / cm³. 3, in particular expanded glass, having a mean particle size in the range of 0.05 to 16 mm, preferably 0.5 to 10 mm, more preferably 1 to 7 mm, and particularly preferably 2 to 4 mm. One- or two-component mortar composition according to one of the preceding claims, wherein the filler content has a bulk density of at least 2.0 g / cm³. 3 2 to 20 wt.%, preferably 4 to 15 wt.%, based on the dry weight of the mortar composition. One- or two-component mortar composition according to one of the preceding claims, wherein the filler(s) have a bulk density of at least 2.0 g / cm³. 3The mortar composition comprises sand and / or calcium carbonate, wherein the calcium carbonate is preferably chalk and / or limestone flour. A one- or two-component mortar composition according to any of the preceding claims, wherein the total amount of aluminate binder and calcium sulfate binder is 20 to 60 wt.%, preferably 35 to 55 wt.%, based on the dry weight of the mortar composition, and / or the mortar composition further comprises at least one additive selected from a lithium salt, at least one retarder selected from tartaric acid or a tartaric acid salt, a gluconate, in particular sodium gluconate, and citric acid or a citric acid salt, a superplasticizer, preferably a polycarboxylate ether, or a combination thereof.

8. Use of a one- or two-component mortar composition according to any one of claims 1 to 7 as screed, in particular as lightweight fill.

9. Use of a one- or two-component mortar composition according to one of claims 1 to 7 for the production of a floor construction, comprising in this order a first screed layer, in particular a lightweight fill layer, made of the one- or two-component mortar composition according to one of claims 1 to 7, a reinforcement layer and a second screed layer, wherein a floor covering is optionally arranged over the second screed layer.

10. Use of a one- or two-component mortar composition according to any one of claims 1 to 7 in soil remediation and / or on a wood substrate or a multi-layered substrate comprising a wood layer.

11. Method for producing a floor construction on a substrate, comprising a) applying a mixture of the mortar composition according to one of claims 1 to 7 with water to the substrate to form a first screed layer, b) applying a reinforcement layer to the first screed layer, c) applying a mixture of a leveling compound with water to the reinforcement layer to form a second screed layer, and d) optionally applying a floor covering to the second screed layer.

12. Method according to claim 11, wherein the reinforcement layer comprises a textile support, in particular a textile support made of glass fiber, most preferably a glass fiber fabric, and / or The leveling compound is a calcium sulfate leveling compound, wherein the calcium sulfate leveling compound comprises a calcium sulfate binder, preferably a calcium sulfate binder and an aluminate binder.

13. Method according to claim 11 or 12, wherein the first screed layer has a thickness in the range of 15 to 100 mm, preferably 20 to 100 mm, and / or the second screed layer has a thickness in the range of 6 to 50 mm, preferably 6 to 10 mm.

14. Floor construction on a substrate, comprising in this order a first screed layer made of the mortar composition according to one of claims 1 to 7, a reinforcement layer and a second screed layer, wherein a floor covering is optionally arranged over the second screed layer.

15. Floor construction according to claim 14, obtainable by a method according to any one of claims 11 to 13.

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