Hydraulically-bonded multilayer panel

1 . A method for producing a hydraulically-bonded multilayer panel with at least one face layer and at least one core layer, wherein the method comprises the following steps:

a. introducing a flowable face mixture into a mold, wherein the face mixture contains at least the following components:

i. face paste containing at least

1. hydraulic binder and

2. water; and

ii. aggregate, wherein the aggregate has a mean diameter d50 determined according to ISO 13320:2009 and/or according to EN 12620 of greater than 100.0 μm;

whereby a face mixture layer is formed;

b. introducing a dry to earth-moist core mixture into the mold, wherein the core mixture contains at least the following components:

i. core paste containing at least

1. hydraulic binder,

2. fines having a mean diameter d50 determined according to ISO 13320:2009 of

1.0 to 30.0 μm, in particular 1.0 to 5.0 μm, and fines having a mean diameter d50 according to ISO 13320:2009 of 30.1 to 100.0 μm in an amount of 0 to 45 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste, and

3. water; and

ii. aggregate, wherein the aggregate has a mean diameter d50 determined according to ISO 13320:2009 and/or according to EN 12620 of greater than 100.0 μm;

whereby a core mixture layer is formed, and

c. pressing the face mixture layer with the core mixture layer into the mold to form a hydraulically-bonded, directly strippable multilayer panel with at least one face layer and at least one core layer, wherein water contained in the face mixture layer is partially or completely pressed into the core mixture layer.

2 . The method according to claim 1 , wherein the core paste contains fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 100.0 μm in an amount of 5 to 45 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste.

3 . The method according to claim 1 , wherein the core paste contains fines having a mean diameter d50, determined according to ISO 13320:2009, that is less than the mean diameter d50 determined according to ISO 13320:2009 of the hydraulic binder contained in the core paste.

4 . The method according to claim 1 , wherein the core paste contains fines having a mean diameter d50 determined according to ISO 13320:2009 of 30.1 to 100.0 μm in an amount of 0 to 25 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste.

5 . The method according to claim 1 , wherein the core paste contains fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 30.0 μm in an amount of 5 to 45 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste.

6 . The method according to claim 1 , wherein the core paste contains fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 5.0 μm in an amount of 5 to 20 vol %, and in particular of 8 to 15 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste.

7 . The method according to claim 1 , wherein the face paste contains, as a further component, fines, and in particular fines having a mean diameter d50 determined according to ISO 13320:2009 of up to 100.0 μm.

8 . The method according to claim 1 , wherein the face paste contains fines having a mean diameter d50, determined according to ISO 13320:2009, that is less than the mean diameter d50 determined according to ISO 13320:2009 of the hydraulic binder.

9 . The method according to claim 1 , wherein the face paste contains fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 30.0 μm, and in particular 1.0 to 5.0 μm.

10 . The method according to claim 1 , wherein the fines in step a. and/or step b. contain at least one inert rock flour-preferably an inert rock flour selected from the group consisting of limestone, dolomite, and quartz, or a combination thereof.

11 . The method according to claim 1 , wherein the fines in step a. and/or b. contain at least one hydraulically-active substance, and in particular a hydraulically-active, natural, or synthetically-produced substance.

12 . The method according to claim 11 , wherein the hydraulically-active substance is selected from the group consisting of granulated slag, microsilica, and fly ash, or a combination thereof.

13 . The method according to claim 1 , wherein the core paste contains 350 to 1,000 kg/m 3 , and in particular 500 to 1,000 kg/m 3 , of hydraulic binder, relative to the total dry weight of the core mixture.

14 . The method according to claim 1 , wherein the face paste contains 350 to 1,000 kg/m 3 , and in particular 500 to 1,000 kg/m 3 , of hydraulic binder, relative to the total dry weight of the face mixture.

15 . The method according to claim 1 , wherein the hydraulic binder in step a. and/or step b. is selected from the group consisting of cement, hydraulically-active additives, latent hydraulic or pozzolanic additives, siliceous binders, or a combination thereof.

16 . The method according to claim 1 , wherein the hydraulic binder in step a. and/or step b. is selected from the group consisting of cement, fly ash, microsilica, granulated slag, natural or artificial pozzolanas, geopolymers, metakaolin, calcined clays, or a combination thereof.

17 . The method according to claim 1 , wherein the hydraulic binder in step a. and/or step b. is cement, and in particular a cement selected from the group consisting of the CEM I and CEM II/A classes according to EN 197-1, or a combination thereof.

18 . The method according to claim 1 , wherein the core paste contains hydraulic binder—in particular, cement—in an amount of 60 to 95 vol %, and in particular of 65 to 80 vol %, relative to the total volume of hydraulic binder and fines contained in the core paste.

19 . The method according to claim 1 , wherein the core mixture contains 450 to 1,250 kg/m 3 , and in particular 600 to 1,250 kg/m 3 , of core paste, relative to the total dry weight of the core mixture.

20 . The method according to claim 1 , wherein the amount of core paste contained in the core mixture is calculated such that a paste saturation degree for the core mixture, calculated according to formula 1 specified in the description, is 1.0 to 1.5, and in particular 1.1 to 1.4.

21 . The method according to claim 1 , wherein the amount of core paste contained in the core mixture is calculated such that a paste layer thickness, calculated according to formula 2 specified in the description, for the core paste layer is at most 30.0 μm, and in particular at most 20.0 μm or 3.0 to 20.0 μm.

22 . The method according to claim 1 , wherein the face mixture contains 450 to 1,250 kg/m 3 , and in particular 600 to 1,250 kg/m 3 , of face paste, relative to the total dry weight of the face mixture.

23 . The method according to claim 1 , wherein, prior to pressing according to step c., the core mixture introduced into the mold has a water binder mean value (W/B) of 0.10 to 0.40, and preferably 0.12 to 0.20, based upon the ratio of water to the sum of hydraulic binder and fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 100.0 μm, and in particular of 1.0 to 30.0 μm.

24 . The method according to claim 1 , wherein, after pressing according to step c., the core mixture introduced into the mold has a water binder mean value of 0.20 to 0.45, and in particular of 0.21 to 0.28 or 0.22 to 0.24, based upon the ratio of water to the sum of hydraulic binder and fines having a mean diameter d50 determined according to ISO 13320:2009 of 1.0 to 100.0 μm, and in particular of 1.0 to 30.0 μm.

25 . The method according to claim 1 , wherein, after pressing according to step c., the face mixture layer has a consistency of at least consistency class F5 according to DIN 1045-2 and/or EN 206.

26 . The method according to claim 1 , wherein, prior to pressing according to step c., the core mixture layer has a consistency of at most consistency class F1 according to DIN 1045-2 and/or EN 206.

27 . The method according to claim 1 , wherein the core mixture and/or the face mixture contains, as a further constituent, 0.01 to 3.0 wt %, relative to the total dry weight of the hydraulic binder, admixture according to EN 934, wherein the admixture is optionally selected from the group consisting of concrete plasticizers, superplasticizers, stabilizers, air entraining agents, accelerators, retarders, and sealants, or a combination thereof.

28 . The method according to claim 27 , wherein the admixture according to EN 934 is a superplasticizer, and in particular a superplasticizer selected from the group consisting of surface-active substances, in particular naphthalene sulfonates and/or lignosulfonates, and dispersing substances, in particular melamine resins, polycarboxylates, and polycarboxylate ethers, or a combination thereof, and in particular polycarboxylate, polyacrylic ether, and polycarboxylate ethers.

29 . The method according to claim 1 , wherein the aggregate contained in the core mixture and/or face mixture is a mixture containing organic and/or inorganic substances, wherein the organic and/or inorganic substances are optionally selected from the group consisting of coarse rock flours, mineral aggregate including rock granules according to EN 12620, ceramic, glass, synthetic fibers, natural fibers, and biological constituents—in particular, grass—or a combination thereof.

30 . The method according to claim 1 , wherein the aggregate and/or fines contained in the core mixture and/or the face mixture are rock granules according to EN 12620.

31 . The method according to claim 30 , wherein the aggregate and/or fines contained in the core mixture and/or the face mixture are rock granules according to EN 12620 based upon quartz, basalt, granite, lime, lime grit, or mixtures thereof.

32 . The method according to claim 30 , wherein the aggregate contained in the core mixture and/or face mixture is rock granules according to EN 12620 that have a mean diameter d50 determined according to ISO 13320:2009 of 0.101 mm to 5.000 mm, and in particular of 0.125 mm to 5.000 mm.

33 . The method according to claim 1 , wherein the aggregate contained in the core mixture and/or face mixture is a mixture that is optimized in its composition by means of methods for determining the optimal grading curve, such that a minimal cavity for aggregate mixtures with a smallest grain is greater than the mean diameter d50 determined according to ISO 13320:2009 of the hydraulic binder.

34 . The method according to claim 1 , wherein introducing the core mixture into the mold according to step b. takes place by applying the core mixture to the flowable face mixture layer formed according to step a.

35 . The method according to claim 1 , wherein the pressure during pressing according to step c. is at least 0.5 N/mm 2 , and in particular at least 10 N/mm 2 or at least 15 N/mm 2 .

36 . The method according to claim 1 , wherein the pressing according to step c. takes place with a pressing time of 5 to 60 seconds, and in particular of 5 to 40 seconds or 5 to 15 seconds.

37 . The method according to claim 1 , wherein the pressing according to step c. takes place in at least two successive pressing processes at the same or different intensity.

38 . A hydraulically-bonded multilayer panel producible by a method according to claim 1 , wherein the core mixture layer has a degree of compaction, determined according to the formula 3 specified in the description, of 0.93 to 0.99, and in particular of 0.97 to 0.99 and/or wherein the core mixture layer has a packing density, determined according to the formula 4 specified in the description, of 0.75 to 0.85, and in particular of 0.78 to 0.83.

39 . The hydraulically-bonded multilayer panel according to claim 38 , wherein the hydraulically-bonded multilayer panel has a length of at least 300, 400, 500, 600, 700, or 800 mm, and in particular of 800 to 1,200 mm.

40 . The hydraulically-bonded multilayer panel according to claim 38 , wherein the hydraulically-bonded multilayer panel has a surface area of at least 0.16 m 2 , and in particular of 0.18 to 1.44 m 2, 0.32 to 1.44 m 2 , 0.18 to 0.83 m 2 , or 0.32 to 0.83 m 2 .

41 . The hydraulically-bonded multilayer panel according to claim 38 , wherein the hydraulically-bonded multilayer panel has a thickness of at most 40.0 mm, and in particular of 15.0 to 40.0 mm.

42 . The hydraulically-bonded multilayer panel according to claim 38 , wherein the multilayer panel has a characteristic bending tensile strength, ascertained according to DIN EN 1339, after 7 days of hardening, of more than 7.5 N/mm 2 , and in particular of at least 8.5 N/mm 2 .