Method for producing a clinker substitute, use thereof, cement mixtures, method for producing the cement mixtures, and dry concrete mixture, dry mortar mixture, fresh concrete mass, and fresh mortar mass, each of which comprises a cement mixture

Abstract

The invention relates to dry, pourable, powdery cement mixtures, to methods for producing the cement mixtures, and to a dry concrete mixture, a dry mortar mixture, a fresh concrete mass, and a fresh mortar mass, each of which contains a cement mixture. The invention additionally relates to the production of a clinker substitute and to the use thereof in a cement mixture.

Description

[0001] Methods for producing a clinker substitute and its use, cement mixtures, methods for producing the cement mixtures, dry concrete mixture, dry mortar mixture, fresh concrete mixture and fresh mortar mixture, each with a cement mixture

[0002] The present invention relates to dry, pourable, flour-like cement mixtures, methods for producing the cement mixtures, as well as a dry concrete mixture, a dry mortar mixture, a fresh concrete mix, and a fresh mortar mix, each containing a cement mixture. Furthermore, the invention relates to the production of a clinker substitute and its use in a cement mixture.

[0003] Cement is a well-known hydraulic, inorganic binder that solidifies and hardens through a chemical reaction with water (hydration) and remains stable even underwater after hardening. Cement is finely ground or powdery. It is a bulk material.

[0004] In the context of the invention, "flour-like" means a grain size of < 200 pm.

[0005] Unless otherwise specified, the determination of grain sizes within the scope of the invention is carried out by means of laser light diffraction in accordance with ISO 13320:2020-01.

[0006] Cements are classified according to their composition as defined in DIN EN 197-1:2011-11 and DIN EN 197-5:2021-07 into different cement types or normal cements CEM I-VI. All cement types contain at least 95% by mass of main constituents and at most 5% by mass of minor constituents, based on the sum of main and minor constituents. The main constituents include Portland cement clinker (K), granulated blast furnace slag (S), silica fume (D), natural pozzolans (P), natural tempered pozzolans (Q), silica-rich fly ash (V), lime-rich fly ash (W), burnt shale (T), and limestone (L or LL). Each main constituent must be present at a minimum of 5% by mass, based on the sum of main and minor constituents.

[0007] Portland cement clinker is known to consist essentially of four clinker phases: tricalcium silicate (alite) C3S, dicalcium silicate (belite) C2S, tricalcium aluminate C3A, and tetracalcium aluminate ferrite C4AF. Portland cement clinker may also contain free CaO (calcium oxide). The clinker phases are known to react primarily with hydration to form calcium silicate hydrate phases (CSH phases). Furthermore, the hydration of C3S and C2S is known to form portlandite (calcium hydroxide (Ca(OH)2)).

[0008] Pozzolans are, according to DIN EN 197-1 :2011-11, natural substances with a silicic or aluminosilicate composition or a combination thereof.

[0009] Pozzolans do not harden on their own after being mixed with water, but react, finely ground and in the presence of water, at normal ambient temperature with the dissolved calcium hydroxide (Ca(OH)2) to form strength-forming calcium silicate calcium aluminate hydrate phases.

[0010] Pozzolans contain reactive silicon dioxide (SiO₂) and possibly aluminum oxide (Al₂O₃) and inert minerals, which may have varying iron content. The proportion of reactive calcium oxide (CaO) in pozzolans is low. The mass fraction of reactive silicon dioxide (SiO₂) must be at least 25.0 wt.% according to standards.

[0011] Natural pozzolans (P) are generally substances of volcanic origin or sedimentary rock with a suitable chemical-mineralogical composition and must meet the requirements of 5.2.3.1 of DIN EN 197-1 :2011- 11.

[0012] Natural tempered pozzolans (Q) are thermally activated materials of volcanic origin, clays, shales, or sedimentary rocks and must comply with the requirements of section 5.2.3.1 of DIN EN 197-1:2011-11. The minor constituents are specially selected inorganic natural minerals, inorganic minerals derived from clinker production, or constituents as described in section 5.2 of DIN EN 197-1:2011-11, unless they are already present as major constituents in the cement.

[0013] In addition to its main and minor constituents, cement also contains calcium sulfate to regulate its setting behavior. Calcium sulfate can be present in the form of gypsum, hemihydrate, anhydrite, or a mixture thereof. The proportion of calcium sulfate carrier is calculated as a percentage of the total main and minor constituents.

[0014] Hardened concrete is a hydraulically hardened mixture produced from a fresh concrete mix containing a hydraulic binder, at least one aggregate, in particular a rock aggregate, and mixing water. Concrete is standardized, among others, in DIN EN 206-1:2013+A2:2021 / DIN 1045-2:2008-08.

[0015] In contrast to concrete, which has at least a coarse aggregate with a grain size > 4 mm, the aggregate in mortar has a grain size of at most 4 mm.

[0016] Dry concrete mixes or dry mortar mixes (factory-mixed dry mortar or factory-mixed mortar) are frequently used for the production of fresh concrete or fresh mortar. These are prefabricated dry mixes containing at least one mineral binder and at least one aggregate, which only need to be mixed with water on the construction site to create fresh concrete or fresh mortar, and are then ready for use.

[0017] The cement industry is increasingly striving to reduce CO2 emissions during cement production. One way to achieve this is by producing more cements containing supplementary cementitious material (SCM). In these cements, Portland cement clinker is partially replaced by reactive clinker substitutes, thereby reducing CO2 emissions.

[0018] For example, calcined or tempered clays are used as clinker substitutes. Within the framework of AiF research project no. 16566 N, "Use of natural tempered clays as a main cement component," various natural clays from bentonite, kaolinitic, and kaolinitic-illitic deposits were tempered and used as a main cement component in quantities of 20% and 40% by mass.

[0019] Clays are known to be sedimentary rocks consisting of fine-grained (predominantly < 2 pm), crystalline, hydrous aluminosilicates with a platy layered structure (clay minerals). Clay minerals are therefore phyllosilicates that occur predominantly in a size < 2 pm.

[0020] Clay minerals consist of two characteristic structural elements: a tetrahedral layer and an octahedral layer. The tetrahedral layer contains corner-sharing SiO₄ tetrahedra, in some of which Si is substituted by Al. The octahedral layer contains edge-sharing Al(OH)e octahedra, in some of which Al is substituted by Mg. Depending on the arrangement of these layers, a distinction is made between 1:1 clay minerals (two-layer clay minerals), 2:1 clay minerals (three-layer clay minerals), and 2:1:1 clay minerals (four-layer clay minerals). The 1:1 clay minerals have one tetrahedral layer and one octahedral layer (TO). Examples of such clay minerals are kaolinite and halloysite. The 2:1 clay minerals have a three-layered structure (tetrahedral layer-octahedral layer-tetrahedral layer (TOT)). Examples include illite, smectite, especially montmorillonite, and vermiculite.The 2:1:1 clay minerals have a four-layered structure (tetrahedral layer-octahedral layer-tetrahedral layer-octahedral layer (TOTO)). Examples include the clay minerals of the chlorite group, such as clinochlore. Clays release their water of crystallization when heated at approximately 500 to 700 °C, forming intermediate phases. The clay mineral kaolinite, for instance, releases its water when heated at approximately 500 to 600 °C, forming an intermediate phase known as metakaolin. At about 925 °C, the kaolinite lattice completely disintegrates, and above 950 °C, the reaction of Al₂O₃ and SiO₂ to form mu-hit begins. Above 1,100 °C, only mullite, cristobalite (SiO₂), and the melt phase are present. Corresponding transformation reactions exist for all other clay minerals as well.

[0021] The reactivity of calcined clay depends, among other things, on its phase composition, firing temperature, firing duration, and the calcining technique used. This is because the raw clay initially exhibits a high specific surface area and a relatively high proportion of crystalline phases. During firing, some of the crystalline phases transform into amorphous phases, resulting in the high reactivity. The high specific surface area is largely retained. As the firing temperature increases, the amorphous phases transform into new crystalline phases, and the reactivity decreases. Furthermore, the specific surface area also decreases, which likewise negatively affects the reactivity.

[0022] Furthermore, kaolinitic clay is known to be the most reactive.

[0023] The reactivity of clays can be described, for example, by the so-called R 3The pozzolanicity of the clay can be tested according to ASTM C1897-20. Furthermore, it can be characterized according to DIN 196-5:2011-06.

[0024] The firing or calcination of clays takes place, for example, in a rotary kiln or a fluidized bed calciner, eddy current calciner, flash calciner, or gas suspension calciner, in which the clay raw material to be calcined is dispersed in a gas stream and thereby calcined. EP 4 015 478 A1 discloses a process for producing calcined clay intended to serve as a clinker substitute. According to the process, a clay raw material is preferably dried and then granulated. The granules produced are calcined at 600 to 800°C and ground after calcination. The clay raw material can be ground before calcination, and clay raw materials from different sources can also be mixed and homogenized. A clay raw material with a high water content can also be mixed with a dry clay raw material before granulation.To produce the cement, the burnt granules are ground together with Portland cement clinker and other clinker substitutes.

[0025] EP 4 001 236 A1 addresses the improvement of the reactivity of calcined clay for use as a clinker substitute. For this purpose, a raw clay material containing clay minerals as well as quartz and / or feldspar is ground and the ground clay material is classified into a fine and a coarse fraction. Due to the different hardness, the fine fraction mainly contains clay minerals, and the coarse fraction mainly contains quartz and / or feldspar. Only the fine fraction is subsequently calcined and used as a clinker substitute. This results in a highly reactive clinker substitute, as the inert components quartz and feldspar are either absent or present only in small quantities. Furthermore, according to EP 4 001 236 A1, metakaolin can be used in addition to the calcined clay.

[0026] German patent DE 10 2015 1 18 391 A1 discloses a process for producing a cement clinker substitute consisting primarily of calcined clay. At least two different clay raw materials are provided, from which a clay mixture is produced and subsequently calcined to form the cement clinker substitute. Furthermore, the water demand and / or the workability of the cement clinker substitute or of a binder with the cement clinker substitute are measured and used to adjust the mixing ratio of the at least two different clay raw materials. The clay mixture can also be analyzed for its mineralogical composition before calcination, and this composition can likewise be used to adjust the mixing ratio based on the water demand. However, specific mineralogical compositions are not disclosed.Furthermore, according to DE 10 2015 118 391 A1, the water demand and compressive strength of cement mixtures with different contents of a first and a second clay are compared. The higher the water demand, the lower the compressive strength.

[0027] The object of the present invention is to provide cost-effectively producible, pourable, dry, flour-like cement mixtures with natural and tempered pozzolans as clinker substitute (SCM), wherein the cement mixtures should exhibit good strength properties.

[0028] Other tasks include providing methods for producing cement mixtures and specifying uses of calcined clays in such cement mixtures.

[0029] Furthermore, a cost-effective manufacturing process for a clinker substitute for a cement mixture with good strength properties should be provided, and the use of the clinker substitute in a cement mixture should be demonstrated.

[0030] Other tasks include providing a dry concrete mix, a dry mortar mix, a fresh concrete mix and a fresh mortar mix, each containing one of the two cement mixes.

[0031] These problems are solved by a cement mixture with the features of claim 1, a method with the features of claim 13, a use with the features of claim 20, a cement mixture with the features of claim 21, a method with the features of claim 26, a use with the features of claim 30, a method with the features of claim 31, a cement mixture with the features of claim 40, a method with the features of claim 45, a use with the features of claim 46, a dry mortar mixture with the features of claim 47, a fresh mortar mixture with the features of claim 48, a dry concrete mixture with the features of claim 49, and a fresh concrete mixture with the features of claim 50. Advantageous embodiments of the invention are characterized in the respective dependent claims.

[0032] The invention will now be explained in more detail with the aid of an example drawing. The drawing shows:

[0033] Figure 1: The one with the R 3 -Test determined the reactivity of a first calcined clay with low reactivity, a second calcined clay with high reactivity, as well as mixtures of the two calcined clays and co-calcined clays produced from two different clay raw materials.

[0034] Figure 2: The compressive strengths of Portland composite cements CEM II / C-M (Q-LL) with a first, less reactive clay and a second, reactive calcined clay compared to Portland composite cements with a mixture of the two calcined clays in different proportions and to Portland composite cements with co-calcined clays made from two different clay raw materials in different proportions

[0035] Figure 3: Spread of fresh masses produced from the Portland composite cements according to Figure 2

[0036] Figure 4: Compressive strengths of different Portland composite cements CEM II / CM with a first, less reactive calcined clay and limestone flour, as well as with one further inert or reactive cement component for comparison, and of a Portland composite cement with a co-calcined clay and limestone flour. Figure 5: Spread of fresh mixes produced from the Portland composite cements according to Figure 4.

[0037] Figure 6: The compressive strengths of composite cements CEM V / A (QS) with a first and a second calcined clay compared to composite cements with a mixture of the two calcined clays produced by separate calcination and compared to composite cements with clays produced by co-calcination

[0038] Figure 7: Spread of fresh masses produced from the composite cements

[0039] Figure 8: The compressive strengths of the two Portland composite cements with the first and second clays calcined in a laboratory furnace compared to a Portland composite cement with a clay co-calcined in a pilot plant furnace from two different clay raw materials and a Portland composite cement with clay co-calcined in a laboratory furnace from two different clay raw materials

[0040] Figure 9: The compressive strengths of cements containing an additional reactive calcined clay and a natural pozzolan compared to a cement containing both components

[0041] Within the scope of the invention, it was surprisingly discovered that even the use of a small amount of a reactive calcined clay in combination with a less reactive clay can significantly improve the 28-day compressive strength of a cement mixture. Compared to a cement mixture containing only the less reactive clay, the resulting cement mixture exhibits increased compressive strength. Surprisingly, this increase in strength is higher than would have been expected based on calculations comparing the compressive strength of a cement mixture containing only the reactive calcined clay with that of a cement mixture containing only the less reactive calcined clay.This increase in strength was also observed when the clay raw materials of the less reactive and the more reactive clay were mixed together and calcined together (co-calcination), and the resulting calcined clay was used as a clinker substitute in a cement mixture. The invention therefore also relates to the production of this clinker substitute.

[0042] A similar, disproportionate increase in strength was also observed when the reactive calcined clay was combined in small quantities with a natural pozzolan (P). Fly ash, as defined in DIN EN 197-1:2011-11, is not a pozzolan.

[0043] The reactivity of calcined clays depends primarily on the mineral phase composition of the clay raw materials, especially the content of kaolinite, montmorillonite, illite / muscovite, and clinochlore. The higher the content of these mineral phases, particularly the kaolinite content, the more reactive the resulting calcined clay.

[0044] Clay raw material refers to raw material originating from a single clay pit or deposit. It is known that variations in the composition of the clay raw material can occur within a single clay pit, but these variations are generally minor. If the clay raw material is extracted from the same clay pit and blended together, it is still considered clay raw material from that specific clay pit.

[0045] If, on the other hand, different clay raw materials from different clay pits are mixed together, it is called a clay raw material mixture.

[0046] The dry, hydraulically setting, flour-like cement mixture according to the invention thus comprises 95-100 wt.% main components and 0-5 wt.% minor component(s), each based on the sum of main and minor components, and, in addition to the main and minor components, at least one setting regulator or consists thereof. Analogous to the definition in DIN EN 197-1:2011-11, within the scope of the invention, a main component is an inorganic substance whose proportion is more than 5% of the total sum of all main and minor components. Accordingly, a minor component is an inorganic substance whose proportion is not more than 5% of the total sum of all main and minor components. Preferably, these are minor components according to DIN EN 197-1:2011-11. However, within the scope of the invention, the main and minor components are not limited to the substances mentioned in DIN EN 197-1:2011-11.

[0047] According to a first embodiment of the invention, the cement mixture comprises as a main or secondary component a) Portland cement clinker, preferably in an amount of 40 to 95 wt.%, more preferably 50 to 90 wt.%, more preferably 65 to 85 wt.%, based on the sum of main and secondary components, and b) a calcined clay component, comprising at least one first calcined clay with an amorphous phase content of 5 to 45 wt.%, more preferably 10 to 43 wt.%, more preferably 20 to 40 wt.%, and at least one second calcined clay with an amorphous phase content of 50 to 95 wt.%, more preferably 65 to 90 wt.%, more preferably 75 to 90 wt.%, each determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

[0048] According to the invention, the calcined clay component also comprises a total amount of second calcined clay of 2 to 25 wt.%, preferably 5 to 20 wt.%, most preferably 10 to 15 wt.%.

[0049] Furthermore, the absolute content of amorphous phases in the second calcined clay is preferably at least 20 wt%, preferably at least 30 wt%, preferably at least 35 wt% higher than the content of amorphous phases in the first calcined clay.

[0050] Within the scope of the invention, specified mass fractions of the cement mixture or its components relative to one another naturally always refer to the dry mass, unless otherwise stated. The dry mass is the mass after drying to constant weight at 40°C.

[0051] Furthermore, the quantities of mineral phases of clay raw materials and calcined clays are determined by X-ray diffractometry and evaluation using Rietveld without internal standard and PONKCS (Partial or No Known Crystal Structures).

[0052] And the chemical composition of the clay raw materials and the calcined clays is determined by means of X-ray fluorescence analysis according to DIN EN 196-2:2013-10.

[0053] The fact that the clay component contains at least one first or second calcined clay means that it can also contain a mixture of different first or second calcined clays.

[0054] This generally applies to the wording "at least one" or "at least one" in the context of the application. If "at least one" or "at least one component" can be included, this means, within the context of this application, that a mixture of different components can also be included.

[0055] Preferably, the first calcined clay is produced from a first clay raw material or a first clay raw material mixture with a content of kaolinite, hue, muscovite, montmorillonite and / or clinochlore in total of 30 to 45 wt.%, preferably 35 to 40 wt.%.

[0056] And / or preferably the second, reactive calcined clay is produced from a second clay raw material or a second clay raw material mixture with a content of kaolinite, hue, muscovite, montmorillonite and / or clinochlore in total of 50 to 90 wt.%, preferably 50 to 80 wt.%, particularly preferably 55 to 80 wt.%, most particularly preferably 55 to 65 wt.%.

[0057] Of course, not all of the aforementioned mineral phases need to be present. The proportion of any one of the listed mineral phases can also be 0% by mass.

[0058] Furthermore, the content of the aforementioned mineral phases in the second clay raw material or the second clay raw material mixture is preferably at least 15 wt.%, preferably at least 20 wt.%, higher than the content of the aforementioned mineral phases in the first clay raw material or the first clay raw material mixture. That is to say, the contents of the aforementioned mineral phases differ preferably by at least 15 wt.%, preferably at least 20 wt.%, in absolute terms.

[0059] Preferably, the cement mixture also has a proportion of calcined clay component of 5 to 60 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 35 wt.%, based on the sum of main and minor components.

[0060] Preferably, the at least one first clay raw material also has a kaolinite content of 5 to 25 wt.%, preferably 15 to 20 wt.%, and / or the at least one second clay raw material preferably has a kaolinite content of 30 to 70 wt.%, preferably 30 to 60 wt.%, particularly preferably 40 to 50 wt.%.

[0061] The two calcined clays are clinker substitutes in the form of natural tempered pozzolans.

[0062] Consequently, at least one first calcined clay and / or at least one second calcined clay have a reactive silica content > 25 wt.%, determined by testing the pozzolanicity according to DIN EN 196-5:2011-06.

[0063] Furthermore, the first calcined clay preferably has a residual clay mineral content of 0 to 50 wt.%, preferably 10 to 45 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

[0064] Furthermore, the second calcined clay preferably has a residual clay mineral content of 0 to 10% wt.%, preferably 1 to 5 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

[0065] The cement mixture preferably has a Blaine value of 4500 to 8000 cm⁻¹. 2 / g, preferably from 5500 to 7500 cm 2 / g, determined according to DIN EN 196-6:2019-03.

[0066] Preferably, the sum of Portland cement clinker and calcined clay component in the cement mixture is at least 55% by mass, more preferably at least 70% by mass, particularly preferably at least 80% by mass, and most preferably at least 85% by mass, based on the sum of the main and minor components. The cement mixture can also consist exclusively of Portland cement clinker and the calcined clay component, based on the sum of the main and minor components.

[0067] If other components are present, the cement mixture preferably comprises limestone flour and / or precipitated calcium carbonate (PCC) and / or blast furnace slag and / or fly ash and / or natural pozzolan as a further main or minor component. It may also contain another calcined clay, different from the first and second calcined clays.

[0068] The advantage of limestone flour and / or precipitated calcium carbonate is that various carboaluminates are formed with the calcined clay. This improves the strength.

[0069] Furthermore, the cement mixture preferably consists of at least 95% by mass, more preferably 98% by mass, and particularly preferably 100% by mass of the main and minor components and setting regulators. The cement mixture according to the invention is therefore preferably a CEM II / CM, CEM IV / A, or CEM V / A.

[0070] Furthermore, the Portland cement clinker of the cement mixture according to the invention preferably has a CsA content of 1 to 14 wt.%, more preferably 2 to 13 wt.%, and particularly preferably 4 to 11 wt.%, as determined by X-ray diffraction. Cement mixtures with a higher CsA content and a matched SOs content, in combination with calcined clays, exhibit very good strength development.

[0071] Preferably, the cement mixture also has an SOs content of 2 to 5 wt.%, preferably 4 to 4.5 wt.%, based on the total mass of the cement mixture, determined by chemical X-ray fluorescence analysis according to DIN EN 196-2:2013-10. A sufficiently high SOs content counteracts a delay in hydration. This is because soluble aluminates originating from the calcined clays can delay the hydration of C3S. Therefore, enough SO3 must be present to bind the soluble aluminates in the form of ettringite and monosulfate.

[0072] The SO3 content of the cement mixture results primarily from the setting regulator. Consequently, the setting regulator content is adjusted to achieve the desired SO3 content.

[0073] The at least one setting regulator is preferably gypsum, hemihydrate, or anhydrite, i.e., a calcium sulfate component. The fact that the cement mixture contains at least one setting regulator means (as mentioned above) that it can also contain a mixture of different setting regulators.

[0074] Furthermore, the Portland cement clinker preferably has a CsS content of 50 to 75 wt.%, more preferably 55 to 70 wt.%, determined by X-ray diffractometry and evaluation by Rietveld analysis without an internal standard. This results in the formation of more calcium hydroxide for the pozzolanic reaction. Additionally, the cement mixture preferably has a CsA content of 1 to 12 wt.%, more preferably 2 to 11 wt.%, and particularly preferably 4 to 9 wt.%, determined by X-ray diffractometry and evaluation by Rietveld analysis without an internal standard. This results in faster strength development.

[0075] The cement mixture according to the invention is preferably a CEM 42.5 or a CEM 52.5 according to DIN EN 196-1 :2016- 11.

[0076] The cement mixture according to the invention is preferably produced by mixing the individual cement mixture components together.

[0077] The individual components of the cement mixture can be pre-ground before mixing and / or at least partially ground together. It is therefore within the scope of the invention to grind the components of the cement mixture according to the invention together in any combination before mixing with the other components of the cement mixture.

[0078] Furthermore, before mixing with the other cement mixture components, the two calcined clays are produced from the two clay raw materials or clay raw material mixtures.

[0079] The calcination process is carried out in a known manner in an oven, preferably in a flash calciner or a rotary kiln. For calcination in a flash calciner, the starting material is prepared to a fineness of < 5 mm, preferably < 2 mm. For calcination in a rotary kiln, granulation is carried out in a known manner, in particular by means of pelletizing discs, or pressed pellets are produced by extrusion.

[0080] Calcination preferably takes place at a maximum firing temperature of 650 to 1200 °C, preferably 750 to 900 °C.

[0081] The total calcination time in the flash calciner is preferably 2 to 5 minutes. In the rotary kiln, it is preferably 20 to 30 minutes. The calcined clay is then ground. This can be done separately for each calcined clay, or the two calcined clays can be ground together.

[0082] The two calcined clays can also be ground together with the Portland cement clinker and the setting regulator, or with other cement mixture components.

[0083] As already explained, it was also found within the scope of the invention that a joint calcination of the two different clay raw materials in the mass proportions specified above and the use of the calcined clay produced therefrom as a clinker substitute in the cement mixture improves the strength of the cement mixture.

[0084] Preferably, the clay produced by the joint calcination has an amorphous phase content of 20 to 70 wt.%, preferably 30 to 60 wt.%, most preferably 40 to 50 wt.%, determined in each case by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

[0085] Preferably, the clay produced by the joint calcination has a residual clay mineral content of 0 to 45 wt.%, preferably 5 to 40 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

[0086] In principle, the clay produced by co-calcination can also be a reactive second calcined clay or be used as such.

[0087] The cement mixture, the cement mixture components and the two clay raw materials otherwise also exhibit the characteristics specified above.

[0088] Furthermore, the firing conditions also correspond to those specified above. As already explained, it was also found within the scope of the invention that the use of the reactive, second calcined clay in combination with a natural pozzolan improves the strength of a cement mixture.

[0089] According to this further embodiment of the invention, the cement mixture comprises as a main or secondary component a) Portland cement clinker, preferably in an amount of 40 to 95 wt.%, more preferably 50 to 90 wt.%, more preferably 65 to 85 wt.%, based on the sum of main and secondary components, b) a reactive calcined clay component consisting of at least one reactive calcined clay with an amorphous phase content of 50 to 95 wt.%, more preferably 65 to 90 wt.%, more preferably 75 to 90 wt.%, in each case determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS, and c) a natural pozzolan component consisting of at least one natural pozzolan.

[0090] According to the invention, the cement mixture has a total amount of reactive calcined clay component of 2.5 to 30 wt.%, preferably 5 to 25 wt.%, most preferably 7.5 to 20 wt.%, based on the sum of reactive clay component and natural pozzolan component.

[0091] Preferably, the cement mixture also comprises a proportion of reactive calcined clay component and natural pozzolan component totaling 5 to 60 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 35 wt.%, based on the sum of main and minor components.

[0092] Furthermore, the sum of Portland cement clinker, reactive calcined clay component and natural pozzolan component in the cement mixture is preferably at least 55 wt.%, preferably at least 70 wt.%, particularly preferably at least 80 wt.%, most preferably at least 85 wt.%, based on the sum of main and minor components, or the cement mixture consists of Portland cement clinker, the calcined reactive clay component and the natural pozzolan component, based on the sum of main and minor components.

[0093] The cement mixture and its other components otherwise exhibit the same characteristics as those specified for the cement mixture with the two differently reactive clays. The production of the cement mixture is also analogous.

[0094] The clay raw material or clay raw material mixture from which the reactive calcined clay is produced may have a slightly different kaolinite content than previously stated. Preferably, it has a kaolinite content of 25 to 70 wt.%, more preferably 30 to 60 wt.%, and particularly preferably 35 to 50 wt.%.

[0095] The cement mixtures according to the invention are preferably used in a dry concrete mixture or a dry mortar mixture and / or in a fresh concrete mixture or a fresh mortar mixture or for the production thereof.

[0096] The following raw materials with the following properties were used in the exemplary applications: Table 1: Properties of Portland cement PZ1, Dyckerhoff GmbH

[0097] Table 2: Properties of Portland cement PZ2, Dyckerhoff GmbH (Buzzi) Table 3: Properties of Portland cement PZ3, Strong R, Dyckerhoff GmbH

[0098] Table 4: Properties of the first, less reactive clay raw material TRM1

[0099] Table 5: Properties of the second, reactive clay raw material TRM2 Table 6: Properties of blast furnace slag (HÜS) Table 7: Properties of limestone flour KS

[0100] Table 8: Properties of calcium sulfate CS Table 9: Properties of quartz flour Q

[0101] Table 10: Properties of fly ash FA Table 11: Properties of pumice (B)

[0102] Example 1:

[0103] In this embodiment, the two clay raw materials TRM1 and TRM2 were calcined separately in a preheated laboratory oven (chamber oven) for 1 hour at 750 °C. Prior to calcination, the two clay raw materials TRM1 and TRM2 were dried for 24 hours at 40 °C, then crushed in a jaw crusher to 11, 8 and 4 mm, respectively, ground in a disc mill for 1 minute, and then sieved at 150 pm.

[0104] Furthermore, the two clay raw materials TRM1 and TRM2 were prepared as described above, then milled together, and the resulting clay raw material mixture was subsequently calcined in the laboratory furnace (co-calcination). Clay raw material mixtures with 95 wt% TRM1 / 5 wt% TRM2, 90 wt% TRM1 / 10 wt% TRM2, and 85 wt% TRM1 / 15 wt% TRM2 were produced.

[0105] The two calcined clays CT1 (LO) and CT2 (LO), produced from the two clay raw materials TRM1 and TRM2 by separate calcination, exhibited the following properties: Table 12: Properties of the two calcined clays CT1 (LO) and CT2 (LO) produced in the laboratory furnace (LO)

[0106] Clay mixtures TM containing 95 wt% CT1 were obtained from the two calcined clays CT1(LO) and CT2(LO). ( LO) / 5 M.-% CT2 (L0 ), 90 M% CT1 (L0 ) / 10 M.%

[0107] CT2(LO) and 85 wt% CT1(LO) / 15 wt% CT2(LO) were produced and the reactivity of the clay mixtures was determined:

[0108] Table 13: Reactivity of the clay mixtures TM And the calcined clays produced by calcining the clay raw material mixtures exhibited the following properties: Table 14: Properties of the calcined clays produced by co-calcination in the laboratory furnace (LO).

[0109] Furthermore, the results of the R 3 -Tests shown in Figure 1. Using the calcined clays, the following cement mixtures (CEM II / CM (Q-LL)) with Portland cement and limestone flour KS were produced:

[0110] Table 15: Composition of cement mixtures

[0111] Furthermore, the 1-day, 2-day, 7-day, and 28-day compressive strengths and the slump were determined according to DIN EN 196-1:2016-11 and DIN EN 1015-3:2007-05 for the cement mixtures. Figure 2 shows the results of the compressive strength measurements. Figure 3 shows the results of the slump measurements. Figure 2 shows that the 28-day compressive strength of the cement mixture ZM OCTI (LO) KS, which contains only the first, less reactive, calcined clay CT1 (LO), is significantly lower than the 28-day compressive strength of the cement mixture ZMI OOCT2 (LO) KS, which contains only the second, more reactive, calcined clay CT2 (LO>).

[0112] The cement mixtures ZM95 / 5 (i_o) KS, ZM90 / 10 (LO) KS, and ZMss / is (LO) KS, which contain 95%, 90%, and 85% wt. respectively of the less reactive calcined clay CT1 (LO) and 5%, 10%, and 15% wt. respectively of the more reactive calcined clay CT2(LO) (based on the sum of the two clays), also exhibit very good 28-day compressive strengths. In particular, the 28-day compressive strengths are significantly higher than would have been expected with the small proportions of the more reactive calcined clay CT2(LO). Even a small amount of the more reactive calcined clay CT2(LO) thus results in an above-average increase in strength.

[0113] This increase in strength was also observed in the cement mixtures with the co-calcined clays, but only in the cement mixtures ZMCO9O / (LO)KS and ZMCO85 / I5(LO)KS with a minimum proportion of 10 wt.% of reactive clay raw material TRM2 in the clay raw material mixture. However, the increase in strength was higher than when using the two separately calcined clays CT1(LO) and CT2(LO).

[0114] The increases in strength were surprising in relation to the R shown in Figure 1. 3 -values. Because the R 3 The R3 values ​​of the co-calcined clays and clay mixtures are all within the range of the R3 value of the less reactive, calcined clay CT1 (LO).

[0115] The slump was such that all cement mixtures could be easily worked. Comparative example:

[0116] In the comparative example, the calcined clay CT1 (LO), produced as described in embodiment 1, and the calcined clay CTCO85 / I5 (LO), produced by co-calcination, were used to produce a cement mixture CEM II / CM with Portland cement and limestone flour KS. Furthermore, additional cement mixtures were produced using the calcined clay CT1 (LO), in which granulated blast furnace slag (latent hydraulic), fly ash, and quartz flour (inert) were used instead of the second calcined clay.

[0117] Table 16: Composition of the cement mixtures

[0118] Figure 4 shows the results of the compressive strength measurements. Figure 5 shows the results of the spread measurements.

[0119] Figure 4 also shows the above-average increase in strength described in the first embodiment. In particular, it is evident that the other cement constituents used do not produce the same increase in strength as the second calcined clay. Specifically, neither the fly ash nor the granulated blast furnace slag contributes to this increase in strength. Apparently, the combination of the two clays has a synergistic effect.

[0120] Example 2:

[0121] In this embodiment, the calcined clays produced as described in embodiment 1 were also used, and the following cement mixtures CEM V / A with Portland cement and blast furnace slag HÜS were produced from them:

[0122] Table 17: Composition of the cement mixtures

[0123] Figure 6 shows the results of the compressive strength measurements. Figure 7 shows the results of the spread measurements.

[0124] Figure 6 also shows the above-average increase in strength described in the first embodiment, particularly with the cement mixtures ZM95 / 5. <LO) HÜS, ZMSIO / IO (LO) HÜS und ZM85 / 15 (LO) HÜS, welche die beiden getrennt calcinierten T one CT 1 (LO> and CT2(LO> included.

[0125] The increase in strength was also evident in the cement mixtures ZMCO9O / (LO) HÜS and ZMco85 / i5 (LO) HÜS, which contain the co-calcined clays CTCO9O / IO (LO) and CTco85 / i5 (LO).

[0126] The spread of all cement mixtures was such that the cement mixtures could be processed well.

[0127] Example 3:

[0128] In this embodiment, the two clay raw materials TRM1 and TRM2 were processed and milled together as described in the first embodiment. The resulting clay raw material mixture was then calcined (co-calcined) in a rotary kiln (pilot kiln TO, 6 m long, 40 cm diameter) at 900°C for 30 minutes. A clay raw material mixture of 85 wt.% TRM1 / 15 wt.% TRM2 was produced for this purpose. The milled and sieved clay raw material mixtures were then granulated with water on a granulating plate to produce granules with a size of 0.5 to 3 cm. After calcination, the co-calcined clay (CTco85 / i5 cro) was milled to a dso value of 20 pm.

[0129] The calcined clay CTCO85 / I 5 (TO) produced by calcining the clay raw material mixture exhibited the following properties:

[0130] Table 18: Properties of calcined clay produced by co-calcination in the pilot plant (TO).

[0131] Using the calcined clay CTCO85 / I 5 (TO), the following cement mixture (CEM ll / CM) was produced with Portland cement and limestone flour KS:

[0132] Table 19: Composition of the cement mixture Furthermore, the 1-day, 2-day, 7-day and 28-day compressive strengths of the cement mixture ZMC were determined according to DIN EN 196-1 :2016-11. O 85 / 5 (TO) KS determined.

[0133] Figure 8 shows the results of the compressive strength measurements of the cement mixture ZMCO85 / I 5 (TO) KS and the two cement mixtures ZM OCTI (LO) KS and ZMI OOCTI (LO) KS with exclusively the separately calcined clays CT1 (LO) and CT2(LO) in the laboratory furnace and the cement mixture ZMC. O85 / I 5 (LO) KS, which contains the co-calcined clay CTCO85 / I 5 (LO) from the laboratory kiln, is shown in embodiment 1. The compressive strengths theoretically calculated from the mixtures with the pure calcined clays CT1 and CT2 are shown as a horizontal line. The calculation was based on the measured compressive strengths of the two cement mixtures ZM OCTI (LOJ KS) and ZMWOCT2 (LO) KS, containing only the separately calcined clays CT1 (LO) and CT2 (LO). A linear increase in strength with increasing content of the more reactive clay CT2 (LO) was assumed.

[0134] It can be seen that the cement mixture ZMCO85 / I 5 (TO) KS also contains the industrially calcined clay CTcoss / w <TO) eine überdurchschnittlich gesteigerte Druckfestigkeit aufweist. Die Druckfestigkeit ist nahezu so hoch wie die Druckfestigkeit der Zementmischung ZM OCT2 (LO) KS, die ausschließlich den reaktiven calcinierten Ton CT2(LO> contains.

[0135] The dashed horizontal lines further illustrate the increase in strength. Since clays are known to react more slowly, the 28-day compressive strength is particularly important. However, the 7-day compressive strength is also significantly increased.

[0136] Example 4:

[0137] In this embodiment, a commercially available calcined clay CT3(T) was used. U O), produced by calcining raw clay in a tunnel kiln (TuO). To produce the calcined clay CT3(TUO), the raw clay was formed into a plastic strand with a central through-hole (cross-section of the strand approximately 15x15 cm), cut into pieces approximately 30 cm long, and the pieces were calcined in a gas-fired tunnel kiln. The maximum temperature was approximately 850°C.

[0138] The commercially available calcined clay CT3(T UO) exhibited the following properties: Table 20: Properties of the tunnel kiln (TuO) calcined clay CT3 <TUO)

[0139] Using the reactive calcined clay CT3(T U The following cement mixtures (CEM II) were produced using O) and the less reactive pumice (B) with Portland cement PZ3 (white cement): Table 21: Composition of the cement mixture

[0140] Furthermore, the 1-day, 2-day, 7-day, and 28-day compressive strengths of the cement mixtures were determined according to DIN EN 196-1:2016-11. Figure 9 shows the results of the compressive strength measurements. It can be seen that the cement mixture ZM i5 B / 5 CT3(Tuo) with 25 wt.% of the industrially calcined clay CT3 (Tuo), based on the sum of the clay CT3 (Tuo) and the pumice B, exhibits an above-average increase in compressive strength. The compressive strength is almost as high as that of the cement mixture ZM 2OCT3 (TU O), which exclusively contain the reactive calcined tone CT3(T U O) contains.

[0141] Finally, it is pointed out that all the aforementioned, in particular claimed, features of the clinker substitute, the cement mixtures, the dry mortar mixture, the dry concrete mixture, the fresh mortar mass, the fresh concrete mass, the methods, and the uses are particularly advantageous on their own and in any combination and are the subject of the present invention.

[0142] Furthermore, according to the invention, the upper and lower limits specified for each range can all be combined with one another.

Claims

Claims 1. A dry, hydraulically setting cement mixture comprising 95-100 wt.% main components and 0-5 wt.% minor components, each based on the sum of main and minor components, and, in addition to the main and minor components, at least one setting regulator, wherein the cement mixture comprises as a main or minor component: a) Portland cement clinker, preferably in an amount of 40 to 95 wt.%, more preferably 50 to 90 wt.%, more preferably 65 to 85 wt.%, based on the sum of main and minor components, and b) a calcined clay component, comprising at least a first calcined clay with an amorphous phase content of 5 to 45 wt.%, more preferably 10 to 43 wt.%, more preferably 20 to 40 wt.%, and at least a second calcined clay with an amorphous phase content of 50 to 95 wt.%, more preferably 65 to 90 % by mass, most preferably 75 to 90% by mass.-%, determined in each case by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS, characterized in that the calcined clay component has a total amount of second calcined clay of 2 to 25 wt.% preferably 5 to 20 wt.%, most preferably 10 to 15 wt.%.

2. Cement mixture according to claim 1, characterized in that the content of amorphous phases in the second calcined clay is increased by at least 20 wt.%, preferably by at least 20 wt.%. 30 wt.%, preferably at least 35 wt.%, higher than the content of amorphous phases in the first calcined clay.

3. Cement mixture according to claim 1 or 2, characterized in that the cement mixture has a proportion of calcined clay component of 5 to 60 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 35 wt.%, based on the sum of main and minor components.

4. Cement mixture according to one of the preceding claims, characterized in that the at least one first calcined clay and / or the at least one second calcined clay has a content of reactive silica > 25 wt.%, determined by testing the pozzolanicity according to DIN EN 196-5:2011-06.

5. Cement mixture according to one of the preceding claims, characterized in that the at least one first calcined clay has a residual clay mineral content of 0 to 50 wt.%, preferably 10 to 45 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

6. Cement mixture according to one of the preceding claims, characterized in that the at least one second calcined clay has a residual clay mineral content of 0 to 10 wt.%, preferably 1 to 5 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS.

7. Cement mixture according to any one of the preceding claims, characterized in that the sum of Portland cement clinker and calcined clay component in the cement mixture is at least 55 wt.%, preferably at least 70 wt.%, particularly preferably at least 80 wt.%, most preferably at least 85 wt.%, based on the sum of main and minor components, or the cement mixture consists of Portland cement clinker and the calcined clay component, based on the sum of main and minor components.

8. Cement mixture according to one of the preceding claims, characterized in that the cement mixture has an SOs content of 2 to 5 wt.%, preferably 4 to 4.5 wt.%, determined by chemical X-ray fluorescence analysis according to DIN EN 196-2:2013-10.

9. Cement mixture according to one of the preceding claims, characterized in that the cement mixture comprises limestone flour and / or precipitated calcium carbonate (PCC) and / or blast furnace slag and / or fly ash and / or natural pozzolan as a further main or secondary component.

10. Cement mixture according to one of the preceding claims, characterized in that the cement mixture is a normal cement according to DIN 197-1 :2011-11 or DIN 197-5:2021-07, preferably a CEM II, CEM IV or a CEM V.

11. Cement mixture according to one of the preceding claims, characterized in that The at least one setting regulator is a CaSO4-containing setting regulator, preferably gypsum or hemihydrate or anhydrite.

12. Cement mixture according to one of the preceding claims, characterized in that the cement mixture consists of at least 95 wt.%, preferably 98 wt.%, particularly preferably 100 wt.% of the main and minor components and setting regulators.

13. Method for producing a cement mixture according to any of the preceding claims, comprising the following process steps: a) providing the Portland cement clinker, the setting regulator, the at least one first calcined clay and the at least one second calcined clay and optionally or if present further cement mixture components, b) producing the cement mixture by mixing together all cement mixture components.

14. Method according to claim 13, characterized in that the at least one first calcined clay is produced prior to provision by calcining a first clay raw material or a first clay raw material mixture, wherein the first clay raw material or the first clay raw material mixture has a content of kaolinite, hue, muscovite, montmorillonite and / or clinochlore in total of 30 to 45 wt.%, preferably 35 to 40 wt.%.

15. Method according to claim 14, characterized in that the first clay raw material or the first clay raw material mixture has a kaolinite content of 5 to 25 wt.%, preferably 15 to 20 wt.%.

16. A method according to any one of claims 13 to 15, characterized in that the at least one second calcined clay is produced prior to provision by calcining a second clay raw material or a second clay raw material mixture, wherein the second clay raw material or the second clay raw material mixture has a content of kaolinite, hue, muscovite, montmorillonite and / or clinochlore in total of 50 to 90 wt.%, preferably 50 to 80 wt.%, preferably 55 to 80 wt.%, particularly preferably 55 to 65 wt.%.

17. Method according to claim 16, characterized in that the second clay raw material or the second clay raw material mixture has a kaolinite content of 30 to 70 wt.%, preferably 30 to 60 wt.%, preferably 40 to 50 wt.%.

18. Method according to one of claims 13 to 17, characterized in that the content of the mineral phases kaolinite, hue, muscovite, montmorillonite and / or clinochlore in the second clay raw material or the second clay raw material mixture is, in absolute terms, at least 15 wt.%, preferably at least 20 wt.%, higher than the content of these mineral phases in the first clay raw material or the first clay raw material mixture.

19. Method according to any one of claims 13 to 18, characterized in that the calcination of the first clay raw material or the first clay raw material mixture takes place at a temperature of 650 to 950 °C, preferably 750 to 900 °C, and / or The calcination of the second clay raw material or the second clay raw material mixture takes place at a temperature of 650 to 950 °C, preferably 750 to 900 °C.

20. Use of at least one first calcined clay with an amorphous phase content of 5 to 45% wt.%, preferably 10 to 43 wt.%, most preferably 20 to 40 wt.%, and at least one second calcined clay with an amorphous phase content of 50 to 95 wt.%, more preferably 65 to 90 wt.%, most preferably 75 to 90 wt.%, each determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS, in a dry, hydraulically setting cement mixture comprising Portland cement clinker and at least one setting regulator, preferably in a cement mixture according to any one of claims 1 to 12.

21. A dry, hydraulically setting cement mixture comprising 95-100 wt.% main components and 0-5 wt.% minor components, each based on the sum of main and minor components, and, in addition to the main and minor components, at least one setting regulator, wherein the cement mixture comprises as a main or minor component: a) Portland cement clinker, preferably in an amount of 40 to 95 wt.%, more preferably 50 to 90 wt.%, more preferably 65 to 85 wt.%, based on the sum of main and minor components; b) a reactive calcined clay component comprising at least one reactive calcined clay with an amorphous phase content of 50 to 95 wt.%, more preferably 65 to 90 wt.%, more preferably 75 to 90 wt.%, each determined by X-ray diffraction and evaluation by Rietveld without internal standard and PONKCS; and c) a natural pozzolan component consisting of at least one natural pozzolan, characterized in that the cement mixture has a total amount of reactive calcined clay component of 2.5 to 30 wt.%, preferably 5 to 25 wt.%, most preferably 7.5 to 20 wt.%, based on the sum of reactive clay component and natural pozzolan component.

22. Cement mixture according to claim 21, characterized in that the cement mixture has the features of one of claims 8 to 12.

23. Cement mixture according to claim 21 or 22, characterized in that the cement mixture comprises a proportion of reactive calcined clay component and natural pozzolan component in total of 5 to 60 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 35 wt.%, based on the sum of main and minor components.

24. Cement mixture according to one of claims 21 to 23, characterized in that the sum of Portland cement clinker, reactive calcined clay component and natural pozzolan component in the cement mixture is at least 55 wt.%, preferably at least 70 wt.%, particularly preferably at least 80 wt.%, most preferably at least 85 wt.%, based on the sum of main and minor components, or the cement mixture consists of Portland cement clinker, the calcined clay component and the natural pozzolan component, based on the sum of main and minor components.

25. Cement mixture according to one of claims 21 to 24, characterized in that the at least one reactive calcined clay has the features of claim 4 or 6.

26. A method for producing a cement mixture according to any one of claims 21 to 25, comprising the following process steps: a) providing the Portland cement clinker, the setting regulator, the at least one reactive calcined clay and the at least one natural pozzolan and optionally or if present, further cement mixture components, b) producing the cement mixture by mixing together all the cement mixture components.

27. Method according to claim 26, characterized in that the at least one reactive calcined clay is produced prior to provision by calcining a clay raw material or a clay raw material mixture, wherein the clay raw material or clay raw material mixture has a content of kaolinite, hue, muscovite, montmorillonite and / or clinochlore in total of 50 to 90 wt.%, preferably 50 to 80 wt.%, preferably 55 to 80 wt.%, particularly preferably 55 to 65 wt.%.

28. Method according to claim 27, characterized in that the clay raw material or clay raw material mixture has a kaolinite content of 25 to 70 wt.%, preferably 30 to 60 wt.%, particularly preferably 35 to 50 wt.%.

29. Method according to one of claims 26 to 28, characterized in that The calcination of the clay raw material or clay raw material mixture takes place at a temperature of 650 to 950 °C, preferably 750 to 900 °C.

30. Use of at least one reactive calcined clay with an amorphous phase content of 50 to 95 wt.%, preferably 65 to 90 wt.%, most preferably 75 to 90 wt.%, each determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS, in a cement mixture according to any one of claims 21 to 25.

31. Process for producing a clinker substitute in the form of calcined clay, comprising the following process steps: a) Production of a clay raw material mixture comprising at least a first clay raw material with a total content of kaolinite, sulfur, muscovite, montmorillonite, and clinochlore of 30 to 45 wt.%, preferably 35 to 40 wt.%, and at least a second clay raw material with a total content of kaolinite, sulfur, muscovite, montmorillonite, and clinochlore of 50 to 90 wt.%, preferably 50 to 80 wt.%, more preferably 55 to 85 wt.%, particularly preferably 55 to 65 wt.%; b) Calcining the clay raw material mixture to produce the calcined clay, characterized in that the clay raw material mixture has a total amount of the second clay raw material, based on the sum of the first and second clay raw materials, of 2.5 to 30 wt.%, more preferably 5 to 25 wt.%, particularly preferably exhibits 7.5 to 20% by mass.

32. Method according to claim 31, characterized in that A mixture of clay raw materials is produced, consisting of at least one first clay raw material and at least one second clay raw material.

33. Method according to claim 31 or 32, characterized in that the content of the mineral phases kaolinite, hue, muscovite, montmorillonite and / or clinochlore in the second clay raw material or the second clay raw material mixture is, in absolute terms, at least 15 wt.%, preferably at least 20 wt.%, higher than the content of these mineral phases in the first clay raw material or the first clay raw material mixture.

34. Method according to one of claims 31 to 33, characterized in that the at least one first clay raw material has a kaolinite content of 5 to 25 wt.%, preferably 15 to 20 wt.%.

35. Method according to one of claims 31 to 34, characterized in that the at least one second clay raw material has a kaolinite content of 30 to 70 wt.%, preferably 30 to 60 wt.%, preferably 40 to 50 wt.%.

36. Method according to one of claims 31 to 35, characterized in that a calcined clay with a content of amorphous phases of 20 to 70 wt.%, preferably 30 to 60 wt.%, most preferably 40 to 50 wt.%, is produced, in each case by means of X-ray diffractometry and evaluation by means of Rietveld without internal standard and PONKCS.

37. Method according to one of claims 31 to 36, characterized in that a calcined clay with a residual content of clay minerals of 0 to 45 wt.%, preferably 5 to 40 wt.%, determined by X-ray diffractometry and evaluation by Rietveld without internal standard and PONKCS, is produced.

38. Method according to one of claims 31 to 37, characterized in that a calcined clay with a content of reactive silica > 25 wt.%, determined by testing the pozzolanicity according to DIN EN 196-5:2011-06, is produced.

39. Method according to one of claims 31 to 38, characterized in that the calcination takes place at a temperature of 650 to 950 °C, preferably 750 to 900 °C.

40. A dry, hydraulically setting cement mixture comprising 95-100 wt.% main components and 0-5 wt.% minor components, each based on the sum of main and minor components, and, in addition to the main and minor components, at least one setting regulator, wherein the cement mixture comprises as a main or minor component: a) Portland cement clinker, preferably in an amount of 40 to 95 wt.%, more preferably 50 to 90 wt.%, more preferably 65 to 85 wt.%, based on the sum of main and minor components, and b) a calcined clay component, characterized in that the calcined clay component comprises at least one calcined clay produced according to one of claims 31 to 39.

41. Cement mixture according to claim 40, characterized in that the cement mixture has the features of one of claims 8 to 12.

42. Cement mixture according to claim 40 or 41, characterized in that the cement mixture has a proportion of calcined clay component of 5 to 60 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 35 wt.%, based on the sum of main and minor components.

43. Cement mixture according to one of claims 40 to 42, characterized in that the calcined clay component consists of at least 80 wt.%, preferably at least 90 wt.%, preferably 100 wt.% of at least one calcined clay produced according to one of claims 31 to 39.

44. Cement mixture according to one of claims 40 to 43, characterized in that the sum of Portland cement clinker and calcined clay component in the cement mixture is at least 55 wt.%, preferably at least 70 wt.%, particularly preferably at least 80 wt.%, most preferably at least 85 wt.%, based on the sum of main and minor components, or the cement mixture consists of Portland cement clinker and the calcined clay component, based on the sum of main and minor components.

45. A method for producing a cement mixture according to any one of claims 40 to 43, comprising the following process steps: a) providing the Portland cement clinker and the setting regulator and optionally or if available, further cement mixture components, b) producing the calcined clay according to the method according to any one of claims 31 to 39, c) producing the cement mixture by mixing together all cement mixture components.

46. ​​Use of the calcined clay produced according to the method according to one of claims 31 to 39 in a dry, hydraulically setting cement mixture comprising Portland cement clinker and at least one setting regulator, preferably in a cement mixture according to one of claims 40 to 43.

47. Dry mortar mixture comprising a cement mixture according to any one of claims 1 to 12 or according to any one of claims 21 to 28. 25 or according to one of claims 40 to 43 and / or manufactured according to one of claims 13 to 19, or according to one of the claims 26 to 29 or according to claim 45, and at least one additive.

48. Fresh mortar mass comprising a dry mortar mixture according to claim 47 and water.

49. Dry concrete mix comprising a cement mix according to any one of claims 1 to 12 or according to any one of claims 21 to 22. 25 or according to one of claims 40 to 43 and / or manufactured according to one of claims 13 to 19, or according to one of the claims 26 to 29 or according to claim 45, and at least one additive.

50. Fresh concrete mass comprising a dry concrete mixture according to claim 49 and water.

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