Composite slurry for producing concrete, use of the composite slurry, method for producing a stabilized composite slurry and method for producing concrete

Abstract

The present disclosure concerns a composite slurry for producing concrete, the use of the composite slurry, a method for producing a stabilized composite slurry and a method for producing concrete. The disclosure provides a composite slurry and according methods comprise the preparation from a mixture of water, one or more additives and a cement under requirements which lead to a better performance, durability and sustainability of the slurry and the produced cement.

Description

[0001] Composite slurry for producing concrete, use of the composite slurry, method for producing a stabilized composite slurry and method for producing concrete

[0002] The present disclosure concerns a composite slurry for producing concrete, the use of the composite slurry, a method for producing a stabilized composite slurry and a method for producing concrete. The disclosure provides a composite slurry and according methods comprise the preparation from a mixture of water, one or more additives and a cement under requirements which lead a better performance, durability and sustainability of the slurry and the produced concrete.

[0003] Background of the Disclosure

[0004] Premixing processes to combine cement and water into a binding agent suspension are known in the art. Goal of the premixing of cement and water is the formation of cementitious hydrate phases. When the suspension with hydrate phases is put into the final concrete, these hydrate phases act as a seeding agent enhancing the reaction of the remaining ingredients of the concrete. This allows a faster production of concrete with an accelerated strength development while also enabling a reduction of CO2 emissions. Once started, the chemical reaction of the cement (“hydration”) can hardly be stopped, and hydrate phases continue to grow. When the hydrate phases reach a certain size, they lose their accelerating potential and start interlocking which leads to increased viscosity and decreased flow properties of the cement suspension. When the flow properties are reduced below a certain threshold, solidification begins.

[0005] The continued growth of the hydration phases leads to a decreased acceleration of the strength development, whereas the interlocking of the hydration phases provide for a solidification of the binding agent suspension into concrete. To maintain a stable acceleration effect over a longer period of time is thus difficult, while at the same time the strong tendency to solidification leads to deposits in the concrete plant and an increased cleaning effort.

[0006] The object of the present invention is to overcome and / or mitigate the disadvantages known in the art.

[0007] Summary of the Disclosure

[0008] In a first aspect, this disclosure relates to a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio

[0009] September 9, 2025 1 / 51 SC2004P-WG between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds.

[0010] In a related aspect, this disclosure relates to a composite slurry for producing concrete comprising a mixture of water and a cement, wherein the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds.

[0011] In a second aspect, this disclosure relates to a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, or less than 0.3 mS cm-1per hour, or less than 0.2 mS cm-1per hour, or less than 0.1 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22mS cm-1, or 8 to 13 mS cm-1. Optionally, a ratio between the one or more additives and the cement is chosen such that the features a) and / or b) and / or c) are obtained.

[0012] In a third aspect, this disclosure relates to a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry.

[0013] In a related aspect, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, characterized in that the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more thereof,

[0014] September 9, 2025 2 / 51 wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer- Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09

[0015] This disclosure thus provides a composite slurry for producing concrete with a sustained and preferably increased acceleration of strength development in the produced concrete. The composite slurry can be stabilized over a long period of time by virtue of a balanced composition, e.g., by adapting the ratio between the one or more additives and the cement.

[0016] In a fourth aspect, this disclosure relates to a use of the composite slurry according to this disclosure.

[0017] In a fifth aspect, this disclosure relates to a method for producing a stabilized composite slurry, characterized by the following steps: i) providing a composite slurry by mixing water, one or more additives and a cement, wherein preferably the composite slurry is according to this disclosure; and ii) storing the composite slurry for a storage period of at least 4 hours and preferably no more than 96 hours.

[0018] In a sixth aspect, this disclosure relates to a method for producing concrete, the method comprising the following steps: i) providing a composite slurry according to this disclosure or according to one of the methods of this disclosure; and ii) mixing the composite slurry with further components, e.g., a further cement, and one or more further additives.

[0019] Brief Description of the Drawings

[0020] Figure 1 shows a schematic representation of a production plant for supplying a composite slurry and a concrete according to this disclosure.

[0021] Figure 2 shows a process diagram with several process variants for supplying a concrete.

[0022] September 9, 2025 3 / 51 SC2004P-WG

[0023] Figure 3 shows data for the flowability of a composite slurry according to this disclosure and two comparative experiments.

[0024] Figure 4 shows the compressive strength of concretes known in the art and concretes produced using the composite slurry according to this disclosure.

[0025] Figure 5 shows the electrical conductivity of a composite slurry produced from limestone powder, cement, and water during its activation and thereafter.

[0026] Figure 6A shows a temperature curve of the composite slurry, monitored in parallel to the conductivity measurement shown in Figure 5. Figure 6B shows a temperature curve of the produced concrete using the composite slurry according to this disclosure, compared to a reference. Figure 6C shows timepoints of maximal temperature development of the produced concrete using the composite slurry according to this disclosure with different amounts of initial cement, compared to a reference, depending on the storage time.

[0027] Figure 7 shows the electrical conductivity of binary composite slurries produced from different additives, i.e. , fly ash, GGBFS (coarse), calcined clay, GGBS (fine), limestone powder, with a cement and water during its activation and thereafter.

[0028] Figure 8 shows the setting behavior for composite slurries according to this disclosure, compared to a reference, in a produced concrete.

[0029] Detailed Description of the Disclosure

[0030] The details of this disclosure relate to the aspects described in the summary of this disclosure. Any of the features of the embodiments described hereinafter may relate to the composite slurry, the use of the composite slurry and the method for producing a stabilized composite slurry. Likewise, the features of the embodiments described hereinafter may relate to the produced concrete, as far as technically applicable.

[0031] If this disclosure refers to “additive” or “an additive”, the possibility of one or more additives is encompassed. If this disclosure refers to “(an) additive(s)”, it may be understood as so-called “secondary cementitious material(s)” (SCMs). The additive(s) are typically powders which influence hardened concrete properties .

[0032] "Activating" the composite slurry refers to a process which initiates the growth of strength determining hydrates, such as C-S-H (Calcium Silicate Hydrates) phases. This activation comprises the application of energy to the composite slurry which may, for example, be

[0033] September 9, 2025 4 / 51 achieved by heating, ultrasonic waves, or high intensity stirring / mixing. Using ultrasonic waves is particularly advantageous in view of the low carbon footprint. C-S-H phases are nano-sized three-dimensional phases. They are nano-crystallized needle-like phases. When referring to their length, this refers to the largest dimension of the phase in any direction.

[0034] Composite slurry for producing concrete

[0035] In a first aspect, this disclosure relates to a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds.

[0036] The funnel flow time according to DIN EN 445:2008-01 is determined at temperatures of 25 °C and atmospheric pressure. A measuring device defined in the standard is a Marsh funnel with a capacity of 1 liter.

[0037] In one embodiment, the composite slurry is stored over a storage period, preferably 24 hours, more preferably 24 hours or less, before measuring the funnel flow time or other parameters. In one embodiment, the funnel flow time is measured after finishing the storage period.

[0038] The one or more additives provides a substrate surface for the formation of the hydration phases which are necessary for the acceleration of concrete formation. This results in a more homogeneous distribution and more uniform growth of the hydration phases and stabilization of the composite slurry compared to pure cement suspensions.

[0039] Providing a long-term flowable composite slurry enables an easier transportability and subsequent processing. Overall, the production of concrete becomes more predictable with respect to its demand and capacity in the subsequent processing, e.g., the availability of molds for precast concrete components. The composite slurry according to this disclosure represents a novel approach in the construction industry.

[0040] The binder suspension according to the invention represents a novelty in the construction industry.

[0041] In one embodiment, the storage period of the composite slurry may be 24 hours or less, or 20 hours or less, or 16 hours or less, or 12 hours or less, and / or 2 hours or more, or 4 hours or more, or 8 hours or more. In one embodiment, the storage period of the composite slurry may be 2 to 24 hours, or 4 to 20 hours, or 8 to 16 hours, or 8 to 12 hours.

[0042] September 9, 2025 5 / 51 In one embodiment, the composite slurry may have a dynamic viscosity under standard conditions (20 °C, atmospheric pressure) and an average shear rate at 1*104Pa of more than 1.0 mPa*s, or more than 1.05 mPa*s, or more than 1.5 mPa*s, or more than 5 mPa*s, and less than 1*104mPa*s, or less than 1*103mPa*s, or less than 1*102mPa*s. In one embodiment, the composite slurry may have a dynamic viscosity under standard conditions (20 °C, atmospheric pressure) and an average shear rate at 1*104Pa of more than 1.0 mPa*s, or more than 1.05 mPa*s, or more than 1.5 mPa*s, or more than 5 mPa*s. In one embodiment, the composite slurry may have a dynamic viscosity under standard conditions (20 °C, atmospheric pressure) and an average shear rate at 1*104Pa of less than 1*104mPa*s, or less than 1*103mPa*s, or less than 1*102mPa*s. In one embodiment, the composite slurry may have a dynamic viscosity under standard conditions (20 °C, atmospheric pressure) and an average shear rate at 1*104Pa of 1.0 mPa*s to 1*104mPa*s, or 1.5 mPa*s to 1*103mPa*s, or 5.0 mPa*s to 1*102mPa*s.

[0043] In one embodiment, the dynamic viscosity is measured according to ASTM C1749 - 12.

[0044] In one aspect, the composite slurry for producing concrete comprises, preferably consists of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that a) the electrical conductivity curve of the composite slurry shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, or less than 0.3 mS cm-1per hour, or less than 0.2 mS cm-1per hour, or less than 0.1 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1.

[0045] Referring to Figure 5, after the mixing of water, additive(s) and cement, the obtained composition will undergo several interdependent reactions which initially leads to an increase in electrical conductivity, the reaching of a maximum in electrical conductivity and a subsequent decay, i.e., a decrease, of electrical conductivity.

[0046] In one embodiment, the composite slurry exhibits a decay of an electrical conductivity at a time

[0047] September 9, 2025 6 / 51 txwhich decay is less than 0.5 mS cm-1per hour, or less than 0.3 mS cm-1per hour, or less than 0.2 mS cm-1per hour, or less than 0.1 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx. In one embodiment, the composite slurry exhibits a decay of an electrical conductivity at a time txwhich decay is 0 mS cm-1per hour or more, or 0.01 mS cm-1per hour or more, or 0.02 mS cm-1per hour or more, or 0.03 mS cm-1per hour or more. In one embodiment, the composite slurry exhibits a decay of an electrical conductivity at a time txwhich decay is 0 to 0.5 mS cm-1per hour, or 0.01 to 0.3 mS cm-1per hour, or 0.02 to 0.2 mS cm-1per hour, or 0.03 to 0.1 mS cm-1per hour.

[0048] In one embodiment, the decay of the electrical conductivity is monitored 12 hours, or 9 hours, or 4 hours, or 2 hours, after the global maximum of the ‘electrical conductivity’-‘time’ curve and is measured as a difference between the two time points tx+ 1 h and tx.

[0049] In one embodiment, the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1. In one embodiment, the composite slurry exhibits an electrical conductivity of 4 mS cm-1or more, or 5 mS cm-1or more, or 6 mS cm-1or more, or 7 mS cm-1or more, or 8 mS cm-1or more. In one embodiment, the composite slurry exhibits an electrical conductivity of 22 mS cm-1or less, or 20 mS cm-1or less, or 17 mS cm-1or less, or 15 mS cm-1or less, or 13 mS cm-1or less.

[0050] In one aspect, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry. Advantageously, the composite slurry according to this disclosure accelerates the setting behaviour of the produced concrete. The concrete according to this disclosure is obtained by mixing the composite slurry according to this disclosure with further components, e.g., a further cement, and one or more further additives. The reference concrete is obtained by mixing the same composition of further components, i.e. , the further cement, the one or more further additives with water, but without the composite slurry according to this disclosure.

[0051] In one embodiment of the composite slurry, a produced concrete reaches a target compressive strength of 15 N / mm2between 1 and 12 hours, or between 2 and 12 hours, or between 3 and 10 hours, or between 4 and 8 hours, or between 1 and 6 hours, or between 2 and 6 hours, or

[0052] September 9, 2025 7 / 51 between 2 and 4 hours, earlier than a reference concrete prepared without the composite slurry. In one embodiment of the composite slurry, a produced concrete reaches a target compressive strength of 15 N / mm2at least 1 hour, or at least 2 hours, at least 3 hours, at least 4 hours, earlier than a reference concrete prepared without the composite slurry. In one embodiment of the composite slurry, a produced concrete reaches a target compressive strength of 15 N / mm212 hours or less, or 10 hours or less, at 8 hours or less, or 6 hours or less, or 4 hours or less, earlier than a reference concrete prepared without the composite slurry.

[0053] In one embodiment, the composite slurry is manufactured by

[0054] - providing a mixture of water, the one or more additives and the cement;

[0055] - subjecting the mixture to an ultrasound treatment for at least 2 h; and

[0056] - optionally storing the treated mixture for an interval between 0 and 8 hours.

[0057] Advantageously, the composite slurry may be stored for a considerable time without losing its activity and ability to form concrete.

[0058] In one embodiment, the mixture is subjected to an ultrasound treatment for at least 2 h, or at least 3 h, or at least 4 h, or at least 5 h. In one embodiment, the mixture is subjected to an ultrasound treatment for 12 h or less, 11 h or less, 10 h or less, or 9 h or less. In one embodiment, the mixture is subjected to an ultrasound treatment for 2 to 12 h, or 3 to 11 h, or 4 to 10 h, or 5 to 9 h.

[0059] In one embodiment, the mixture is subjected to an ultrasound treatment for 2 to 12 h, by means of an ultrasound device comprising at least one ultrasonic probe and at least one ultrasonic oscillator, such as a piezoelectric element, which applies ultrasound to the at least one ultrasonic probe, wherein the at least one ultrasonic probe may be designed as a sonotrode and preferably operate, when determined at T = 25 °C and p = 1013.25 hPa, with an amplitude of the ultrasound emitted of 15 to 500 pm, with a frequency of the ultrasound emitted of 16 kHz to 30 kHz, in particular of 18 kHz to 22 kHz, and with an intensity of the ultrasound emitted of 25 to 250 W / cm2. The said values can be determined electroacoustically in water, for example, using a hydrophone

[0060] According to this disclosure, a cement may be a chemical substance or a chemical composition which acts as a binder that sets, hardens, and adheres to other materials to bind them together, used for construction. Cement is often used in combination with sand and gravel or crushed rock, referred to as “aggregate”. After mixing with water and allowing subsequent reactions,

[0061] September 9, 2025 8 / 51 concrete is obtained. In construction, the used cement is usually inorganic and is often calcium silicate- based.

[0062] In one embodiment of the composite slurry, the temperature development of the produced concrete using the composite slurry shows at least one change of sign of slope within 10 h after initiating concrete production. Referring to Figure 6B, after mixing the composite slurry with further components, e.g., a further cement, and one or more further additives, to produce concrete will initiate a further cascade of exothermic reactions. The composite slurry according to this disclosure accelerates the cascade of exothermic reactions and hence also the setting into concrete. Advantageously, setting into concrete becomes faster compared to methods known in the art. In one embodiment, the temperature development of the produced concrete using the composite slurry shows at least one change of sign of slope between 4 and 10 h, or between 5 and 9 h, or between 6 and 8 h, after initiating concrete production.

[0063] In one embodiment, the composite slurry may have a flowability measured as a funnel flow time according to DIN EN 445:2008-01 after a storage period of at most 24 hours of at least 7 seconds and at most 50 seconds, or at most 40 seconds, or at most 20 seconds. In one embodiment, the composite slurry has a funnel flow time after a storage period of at most 24 hours of at 7 to 50 seconds, or 8 to 40 seconds, or 9 to 30 seconds, or 10 to 20 seconds.

[0064] In one embodiment, the composite slurry is pumpable and / or stirrable after a storage period of 24 hours. This is advantageous for subsequent processing.

[0065] In one embodiment, the composite slurry has a solid content of at least 20 wt.%, or at least 30 wt.%, or at least 40 wt.%, and / or at most 70 wt.%, and / or at most 60 wt.%. In one embodiment, the composite slurry has a solid content of 20 to 70 wt.%, or 30 to 65 wt.%, or 40 to 60 wt.%.

[0066] The one or more additives form a substrate for the formation of hydrate phases. A particularly good compromise between crystal nucleation and rapid hardening resulting from addition of further components, such as aggregate, is achieved when the one or more additives comprise limestone or, preferably, consist of limestone.

[0067] In the context of this disclosure which broadly relates to construction, an “aggregate” refers sand, gravel or crushed rock that has been mined or quarried for use as a building material. The “aggregate” may be based on the list of materials including basalt, dolomite, granite, gravel, limestone, sand and sandstone.

[0068] In one embodiment, the composite slurry comprises a mixture of water, one or more additives and a cement.

[0069] September 9, 2025 9 / 51 In one embodiment, the composite slurry comprises a mixture of water, a first additive and a cement. In one embodiment, the composite slurry comprises a mixture of water, a first additive and a cement, wherein the mass fraction of the first additive is from 80 to 95 wt.%, based on the total mass of cement and the first additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement and the first additive of the composite slurry. In one embodiment, the composite slurry comprises a mixture of water, 80 to 95 wt.% limestone powder and 5 to 20 wt.% cement, wherein the total mass of cement and the limestone powder are 100 wt.%.

[0070] In one embodiment, the composite slurry comprises a mixture of water, a first additive, a second additive and a cement. In one embodiment, the composite slurry comprises a mixture of water, a first additive, a second additive and a cement, wherein the mass fraction of the first additive is from 60 to 90 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, wherein the mass fraction of the second additive is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry. In one embodiment, the composite slurry comprises a mixture of water, 60 to 90 wt.% limestone powder, 5 to 20 wt.% of a further additive which is different to limestone powder, and 5 to 20 wt.% cement, wherein the total mass of cement, the limestone powder and the further additive are 100 wt.%. In one embodiment, the composite slurry comprises a mixture of water, 60 to 90 wt.% limestone powder, 5 to 20 wt.% of calcined clay, and 5 to 20 wt.% cement, wherein the total mass of cement, the limestone powder and the calcined clay are 100 wt.%.

[0071] In one embodiment, the composite slurry comprises a mixture of water, a first additive, a second additive, a third additive and a cement. In one embodiment, the composite slurry comprises a mixture of water, a first additive, a second additive, a third additive and a cement, wherein the mass fraction of the first additive is from 60 to 85 wt.%, based on the total mass of cement, the first additive, the second additive and the third additive of the composite slurry, wherein the mass fraction of the second additive is from 5 to 10 wt.%, based on the total mass of cement, the first additive, the second additive and the third additive of the composite slurry, wherein the mass fraction of the third additive is from 5 to 10 wt.%, based on the total mass of cement, the first additive, the second additive and the third additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement, the first additive, the second additive and the third additive of the composite slurry. In one embodiment, the composite slurry comprises a mixture of water, 60 to 85 wt.% limestone powder, 5 to 10 wt.% of a second additive which is different to limestone powder, 5 to 10 wt.% of a third additive

[0072] September 9, 2025 10 / 51 SC2004P-WQ which is different to limestone powder and the second additive, and 5 to 20 wt.% cement, wherein the total mass of cement, the limestone powder, the second additive and the third additive are 100 wt.%. In one embodiment, the composite slurry comprises a mixture of water, 60 to 85 wt.% limestone powder, 5 to 10 wt.% of calcined clay, 5 to 10 wt.% of fly ash, and 5 to 20 wt.% cement, wherein the total mass of cement, the limestone powder, the calcined clay and the fly ash are 100 wt.%.

[0073] In one embodiment, the composite slurry consists of a mixture of water, one or more additives and a cement.

[0074] In one embodiment of the composite slurry, the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more additives, wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer- Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09.

[0075] Ground granulated blast-furnace slag (GGBFS; sometimes also: GGBS) is obtained by quenching molten iron slag, which is a by-product of iron and steel-making, from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder. GGBFS is a latent hydraulic binder forming calcium silicate hydrates (C-S-H) after contact with water. In one embodiment, GGBFS comprises (in wt.%) 30 to 50 CaO, 28 to 38 SiO2, 8 to 24 AI2O3, 1 to 18 of both MnO and MgO.

[0076] Quartz powder means grinded siliceous rock and may be understood as finely divided crystalline quartz and may also be understood as an accumulation of very small particles produced during the crushing, grinding, drilling, or sawing of silica-containing materials.

[0077] Silica fume means amorphous silicon dioxide, i.e. , an oxide of silicon with the chemical formula SiO2. Silica dust may be understood as finely divided crystalline quartz and may also be understood as an accumulation of very small particles produced during the crushing, grinding, drilling, or sawing of silica-containing materials.

[0078] Limestone powder is composed mainly of the two minerals calcite and aragonite, which are

[0079] September 9, 2025 11 / 51 different crystal forms of calcium carbonate (CaCCh), and ground into a powder.

[0080] Calcined clay, also referred to as metakaolin, is produced by heating a source of kaolinite to a temperature between 650 °C and 750 °C. Kaolinite is a clay mineral with the chemical composition AhSi2O5(OH)4.

[0081] Pozzolans are a broad class of siliceous and aluminous materials which can either be natural or artificial. Artificial pozzolans include for example metakaolin and industrial by-products such as fly ash and silica fume from silicon smelting. Silica fume, also referred to as microsilica (CAS number 69012-64-2, EINECS number 273-761-1), is an amorphous polymorph of silicon dioxide. Silica fume is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production and consists of spherical particles with an average particle diameter of about 150 nm.

[0082] Fly ash is a solid, particulate residue of combustions with an equivalent spherical diameter between 1 pm and 1 mm. The chemical composition of fly ash depends on the combustion material and includes substantial amounts of SiC>2 (both amorphous and crystalline), AI2O3 and CaO.

[0083] In one embodiment, the specific surface area of the one or more additives is at least 2.5 m2 / g, or at least 3.0 m2 / g, or at least 4.0 m2 / g, or at least 5.0 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer-Emmett-Teller (BET) measurement according to ISO 9277:2010. In one embodiment, the specific surface area of the one or more additives is 20.0 m2 / g or less, or 17.0 m2 / g or less, or 14.0 m2 / g or less, or 10.0 m2 / g or less. In one embodiment, the specific surface area of the one or more additives is 2.5 to 20.0 m2 / g, or 3.0 to 17.0 m2 / g, or 4.0 to 14.0 m2 / g, or 5.0 to 10.0 m2 / g. In one embodiment, limestone powder is used as an additive with a specific surface area of 2.5 to 20.0 m2 / g, or 3.0 to 17.0 m2 / g, or 4.0 to 14.0 m2 / g, or 5.0 to 10.0 m2 / g.

[0084] In one embodiment, the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;9s of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09. Advantageously, the said particle size distribution provides for desirable setting qualities in the produced concrete. In one embodiment, the one or more additives has a particle size distribution with a Dv;is between 1 and 5 pm. In one embodiment, the one or more additives has a particle size distribution with a DV;95 between 45 and 90 pm. In one embodiment, the limestone powder has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;9s of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09.

[0085] September 9, 2025 12 / 51 In one embodiment of the composite slurry, the mass fraction of the additive is at least 50 wt.% and / or at most 90 wt.%, based on the total mass of cement and additive of the composite slurry. In one embodiment of the composite slurry, the mass fraction of the additive is at least 50 wt.%, or at least 60 wt.%, or at least 70 wt.%, based on the total mass of cement and additive of the composite slurry. In one embodiment of the composite slurry, the mass fraction of the additive is at most 90 wt.%, at most 80 wt.%, based on the total mass of cement and additive of the composite slurry. This provides a large amount of substrate surface area, so that the vast majority of hydrate phases are formed on a substrate.

[0086] In one embodiment of the composite slurry, the mass fraction of water is at least 40 wt.% and / or at most 80 wt.%, or at most 70 wt.%, or at most 60 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry. In one embodiment of the composite slurry, the mass fraction of water is at least 50 wt.%, or at least 60 wt.%, or at least 70 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry. In one embodiment of the composite slurry, the mass fraction of water is at most 90 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry.

[0087] In one embodiment of the composite slurry, the mass fraction of cement is at least 10 wt.% and / or at most 50 wt.%, based on the total mass of cement and the one or more additives of the composite slurry. In one embodiment, the mass fraction of cement is at least 10 wt.%, or at least 20 wt.%, or at least 30 wt.%, based on the total mass of cement and the one or more additives of the composite slurry. In one embodiment, the mass fraction of cement is at most 50 wt.%, or at most 40 wt.%, based on the total mass of cement and the one or more additives of the composite slurry. This measure prevents spontaneous and accelerated setting, respectively hardening, of the composite slurry before the addition of further concrete components, such as additional cement and / or additives, admixtures and aggregate.

[0088] In one embodiment of the composite slurry, the mass fraction of cement is at least 10 wt.% and / or at most 50 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry. In one embodiment, the mass fraction of cement is at least 10 wt.%, or at least 20 wt.%, or at least 30 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry. In one embodiment, the mass fraction of cement is at most 50 wt.%, or at most 40 wt.%, based on the total mass of cement, water and the one or more additives of the composite slurry. This measure prevents spontaneous and accelerated setting, respectively hardening, of the composite slurry before the addition of further concrete components, such as additional cement and / or additives, admixtures and aggregate.

[0089] September 9, 2025 13 / 51 In one embodiment, the mass fraction of cement, water and the one or more additives is at least 99.0 wt.%, or at least 99.2 wt.%, or at least 99.5 wt.%, based on the total mass of the composite slurry. In one embodiment, the mass fraction of cement, water and the one or more additives is 100.0 wt.% or less, or 99.9 wt.% or less, or 99.8 wt.% or less, based on the total mass of the composite slurry. In one embodiment, the mass fraction of cement, water and the one or more additives is 99.0 to 100.0 wt.%, or 99.2 to 99.9 wt.%, or 99.5 to 99.8 wt.%, based on the total mass of the composite slurry.

[0090] In one embodiment of the composite slurry, the ratio of cement to additive in the composite slurry is at least 0.1 and / or at most 1.0. The said ratio concerns the mass ratio of cement to additive in the composite slurry. In one embodiment, the ratio of cement to additive in the composite slurry is at least 0.05, or at least 0.1, or at least 0.15, or at least 0.2, or at least 0.25, or at least 0.3, or at least 0.35, or at least 0.4. In one embodiment, the ratio of cement to additive in the composite slurry is at most 1.0, or at most 0.9, or at most 0.8, or at most 0.7, or at most 0.6, or at most 0.5, or at most 0.4, or at most 0.3, or at most 0.2. In one embodiment, the ratio of cement to additive in the composite slurry is at least 0.03 and at most 0.25, or at least 0.05 and at most 0.2. In one embodiment, the ratio of cement to additive in the composite slurry is at least 0.03 and at most 0.25, or at least 0.05 and at most 0.2, wherein the additive comprises limestone powder.

[0091] In one embodiment, the composite slurry is activated during its preparation by an energy input, preferably by ultrasound treatment. The duration and intensity of the energy input may vary depending on the ratio of cement and to additive. An increased proportion of additive may require an increased energy input.

[0092] In one embodiment, the activation may be performed by means of an ultrasound device comprising at least one ultrasonic probe and at least one ultrasonic oscillator, such as a piezoelectric element, which applies ultrasound to the at least one ultrasonic probe. In one embodiment, the at least one ultrasonic probe may be designed as a sonotrode and preferably operate, when determined at T = 25 °C and p = 1013.25 hPa, with an amplitude of the ultrasound emitted of 15 to 500 pm, with a frequency of the ultrasound emitted of 16 kHz to 30 kHz, in particular of 18 kHz to 22 kHz, and with an intensity of the ultrasound emitted of 25 to 250 W / cm2. The said values can be determined electroacoustically in water, for example, using a hydrophone.

[0093] In one embodiment of the composite slurry, a change, in particular a decrease, in the electrical conductivity of the composite slurry at a measurement time of 1 hour is at most 2.0 mS / cm, or at most 1.0 mS / cm, or at most 0.8 mS / cm, or between 0 and 0.7 mS / cm, or between 0.1 and 0.6

[0094] September 9, 2025 14 / 51 mS / cm, at a suspension temperature of 25°C and atmospheric pressure. Preferably, the change in electrical conductivity is measured after activation of the composite slurry. In one embodiment, the change in the electrical conductivity can be at most 0.8 mS / cm, or at most 0.6 mS / cm, or between 0 and 1 mS / cm, and / or at least 0.01 mS / cm, or at least 0.05 mS / cm.

[0095] The inventors recognized that an increase or decrease in ion concentrations, especially calcium ion concentrations, is accompanied by a change in conductivity. A particularly stable composite slurry is obtained when the change in conductivity is small.

[0096] In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is at least 2 hours, at least 4 hours, or at least 12 hours, at least 24 hours. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 90 days or less, or 70 days or less, or 50 days or less, or 40 days or less, or 30 days or less, or 10 days or less, or 5 days or less, or 3 days or less. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 2 hours to 90 days, or 4 hours to 50 days, or 12 hours to 50 days, or 24 hours to 50 days, or 12 hours to 40 days, or 12 hours to 40 days, or 24 hours to 40 days, or 24 hours to 30 days, or 24 hours to 10 days, or 24 hours to 5 days.

[0097] In one embodiment, the composite slurry is essentially free of organic polymers.

[0098] Use of the composite slurry

[0099] In one aspect, this disclosure relates to the use of the composite slurry according to this disclosure for producing concrete. Advantageously, the composite slurry is stable and can be stored for a sufficiently long storage period, while providing for an accelerated setting of the produced concrete.

[0100] In one embodiment, preferably related to the use of the composite slurry, in a setting experiment performed according to DIN EN 196-3:2017-03 an initial set and / or a setting point of the produced concrete is shifted to a shorter time frame of 60 min or more when using the composite slurry according to this disclosure compared to a reference concrete produced without the composite slurry. The reference concrete is obtained by mixing the same composition of further components, i.e., the further cement, the one or more further additives with water, but without the composite slurry according to this disclosure. Advantageously, storage of the composite slurry contributes to reaching an initial set and / or a setting point faster than in the absence of storage.

[0101] According to DIN EN 196-3:2017-03, the setting experiment is performed with an upright

[0102] September 9, 2025 15 / 51 standing Vicat ring to determine the initial set (point) and, respectively, an inversely oriented Vicat ring to determine the setting point of the produced concrete. Additionally, a respectively defined needle is used to determine the initial set (point) and, respectively, the setting point of the produced concrete. The readout of the setting experiment is the penetration depth of the needle. Predefined values of the penetration depth of the needle give access to the timepoints for both the initial set and the setting point.

[0103] In one embodiment of the setting experiment an initial set and / or a setting point of the produced concrete is shifted to a shorter time frame of 60 min or more, or 70 min or more, or 80 min or more, or 90 min or more, or 100 min or more. In one embodiment of the setting experiment an initial set and / or a setting point of the produced concrete is shifted to a shorter time frame of 240 min or less, or 230 min or less, or 220 min or less, or 210 min or less, or 200 min or less. In one embodiment of the setting experiment an initial set and / or a setting point of the produced concrete is shifted to a shorter time frame of 60 to 240 min, or 70 to 230 min, or 80 to 220 min, or 90 to 210 min, or 100 to 200 min.

[0104] In one embodiment, preferably related to the use of the composite slurry, in a setting experiment of the produced concrete a temperature is monitored, wherein the temperature reaches a maximal value during the setting experiment denoted a timepoint of maximal temperature, wherein the timepoint of maximal temperature is shifted to a shorter time frame of 20 min or more, 60 min or more, or 100 min or more, when using the composite slurry according to this disclosure compared to a reference concrete produced without the composite slurry.

[0105] In one embodiment, preferably related to the use of the composite slurry for producing concrete, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is at least 2 hours, at least 4 hours, or at least 12 hours, at least 24 hours. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 90 days or less, or 70 days or less, 50 days or less, or 40 days or less, or 30 days or less, or 10 days or less, or 5 days or less, or 3 days or less. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 2 hours to 90 days, or 4 hours to 50 days, or 12 hours to 50 days, or 24 hours to 50 days, or 12 hours to 40 days, or 12 hours to 40 days, or 24 hours to 40 days, or 24 hours to 30 days, or 24 hours to 10 days, or 24 hours to 5 days.

[0106] Method for producing a stabilized composite slurry

[0107] In one aspect this disclosure provides a method for producing a stabilized composite slurry, characterized by the following steps:

[0108] September 9, 2025 16 / 51 i) providing a composite slurry by mixing water, one or more additives and a cement, wherein preferably the composite slurry is according to this disclosure; and ii) storing the composite slurry for a storage period of at least 2hours and preferably no more than 96 hours.

[0109] In one embodiment, the storage period of the composite slurry is at most 96 hours, or at most 48 hours, or at most 24 hours. The storage of the composite slurry provides for a stabilization and relatively constant material properties over the storage period.

[0110] In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is at least 2 hours, at least 4 hours, or at least 12 hours, at least 24 hours. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 90 days or less, or 70 days or less, or 50 days or less, or 40 days or less, or 30 days or less, or 10 days or less, or 5 days or less, or 3 days or less. In one embodiment, the storage period of the composite slurry after its preparation, preferably after activation by energy input, is 2 hours to 90 days, or 4 hours to 50 days, or 12 hours to 50 days, or 24 hours to 50 days, or 12 hours to 40 days, or 12 hours to 40 days, or 24 hours to 40 days, or 24 hours to 30 days, or 24 hours to 10 days, or 24 hours to 5 days.

[0111] The storage simplifies the processing of the composite slurry and provides for a less laborintense use. In particular, there is no need to adjust the dosage of the composite slurry depending on the storage time at which the aggregate is to be added during concrete production.

[0112] In one embodiment, providing the composite slurry comprises an activation by an energy input, preferably by ultrasonic treatment, over a treatment period. In one embodiment, the treatment period is from 15 min to 10 hours, or from 20 min to 6 hours, or from 30 min to 4 hours, or from 60 min to 3 hours. In one embodiment, the treatment period is 15 min or more, or 20 min or more, or 30 min or more, or 60 min or more. In one embodiment, the treatment period is 10 hours or less, or 6 hours or less, or 4 hours or less, or 3 hours or less. Beyond the said treatment period, a further energy input may be effected. For example, an energy input may be effected while stirring the stabilized composite slurry during storage.

[0113] In one embodiment, the activation may be performed by means of an ultrasound device comprising at least one ultrasonic probe and at least one ultrasonic oscillator, such as a piezoelectric element, which applies ultrasound to the at least one ultrasonic probe. In one embodiment, the at least one ultrasonic probe may be designed as a sonotrode and preferably operate, when determined at T = 25 °C and p = 1013.25 hPa, with an amplitude of the

[0114] September 9, 2025 17 / 51 ultrasound emitted of 15 to 500 pm, with a frequency of the ultrasound emitted of 16 kHz to 30 kHz, in particular of 18 kHz to 22 kHz, and with an intensity of the ultrasound emitted of 25 to 250 W / cm2. The said values can be determined electroacoustically in water, for example, using a hydrophone.

[0115] In one embodiment, the storage of the composite slurry may take place in the absence of mechanical agitation, such as stirring. In one embodiment, the storage of the composite slurry may take place while stirring the composite slurry, or while providing a different means of mechanical agitation, such as rocking, of the composite slurry.

[0116] In one embodiment of the method, the extent of the energy input is monitored by determining an average temperature of the composite slurry. As a general rule, the extent of the energy input positively correlates with an increase of the slurry temperature, so that monitoring the slurry temperature gives an indication how much energy is transferred when preparing the slurry.

[0117] An increased temporal formation of hydrate phases is accompanied by a temporal change in electrical conductivity. A particularly good quality of the composite slurry is achieved when an increase in electrical conductivity has been passed and has transitioned into a decrease in electrical conductivity. It is advantageous to finish the energy input when the aforementioned increase has been passed and a sign change from a “positive increase” in electrical conductivity into a “negative increase”, which is equivalent to a decrease in electrical conductivity, has occurred. This does not necessarily mean that the energy input must be terminated at this point. In one embodiment, an energy input may continue beyond the timepoint at which an increase in electrical conductivity has been passed and has transitioned into a decrease in electrical conductivity.

[0118] In one embodiment, monitoring the energy input by measuring the average temperature of the composite slurry may be such that it is related to the timepoint when an increase in average temperature has been passed and has transitioned into a decrease of the average temperature. In one embodiment, after reaching said timepoint, a predefined safety time interval, e.g., 30 minutes, can be defined during which a further energy input can be effected, after which further energy input the actual storage time may begin.

[0119] In one embodiment of the method, the activation is carried out by intermittent or continuous energy input over the treatment period at least until a sign change of the slope of the electrical conductivity is achieved.

[0120] September 9, 2025 18 / 51 Method for producing concrete

[0121] In one aspect, this disclosure relates to a method for producing concrete, the method comprising the following steps: i) providing a composite slurry according to this disclosure or according to one of the methods of this disclosure; and ii) mixing the composite slurry with further components, e.g., a further cement, and one or more further additives.

[0122] In combination with the further components, e.g., a further cement, one or more further additives, one or more further admixtures, and / or aggregate, the concrete hardens with a high early compressive strength compared to conventionally produced concrete and compared to a concrete with a premixed cement suspension without prior activation.

[0123] According to the methods of this disclosure, the produced concrete may exhibit an early compressive strength which is two to four times higher than that of conventionally produced concrete of a similar composition.

[0124] The inventors of the present disclosure found that the composite slurry disclosed herein remains in a flowable state after activation, which activation may be preferably by ultrasound, and still allowing subsequent processing steps into a concrete. This finding allows using the composite slurry in a much more flexible way in a concrete manufacturing process than what has been possible with other previously known binder compositions, such as cement.

[0125] In one embodiment, the cement mass ratio of cement in the slurry to cement in the bulk components may range from 0.01 to 0.75. The cement mass ratio may be at least 0.01, at least 0.05, at least 0.10 or at least 0.25. The cement mass ratio may be at most 0.75, at most 0.70, at most 0.65 or at most 0.60. The cement mass ratio may be from 0.01 to 0.75, from 0.05 to 0.70, from 0.10 to 0.65 or from 0.25 to 0.60. Generally, using more (activated) slurry, i.e. a higher cement mass ratio will result in a concrete or mortar mixture that solidifies quicker than a mixture with a lower cement mass ratio. Whereas extremely fast solidification is not always desired, a broad range of options concerning cement mass ratios is desirable. The methods disclosed herein provide for the option of very high cement mass ratios.

[0126] Specific embodiments

[0127] In one embodiment, this disclosure provides a composite slurry for producing concrete

[0128] September 9, 2025 19 / 51 comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds, wherein the composite slurry has a solid content of 30 to 60 wt.%, wherein the mass fraction of water is at least 40 wt.% and / or at most 70 wt.%, based on the total mass of cement (57), water (56) and the one or more additives of the composite slurry (41).

[0129] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, a first additive and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds, wherein the mass fraction of the first additive is from 80 to 95 wt.%, based on the total mass of cement and the first additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%.

[0130] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds, wherein the composite slurry comprises a first additive and a second additive, wherein the mass fraction of the first additive is from 60 to 90 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, wherein the mass fraction of the second additive is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry.

[0131] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry, measured as funnel flow time according to DIN EN 445:2008- 01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds, wherein the mass fraction of the additive is at least 50 wt.% and / or at most 90 wt.%, based on the total mass of cement and additive of the composite slurry.

[0132] September 9, 2025 20 / 51 SC2004P-WG

[0133] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry, measured as funnel flow time according to DIN EN 445:2008- 01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds, characterized in that the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more thereof, wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer-Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09.

[0134] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1, wherein the composite slurry has a solid content of 30 to 60 wt.%, wherein the mass fraction of water is at least 40 wt.% and / or at most 70 wt.%, based on the total mass of cement (57), water (56) and the one or more additives of the composite slurry (41).

[0135] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), a first additive and a cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-‘time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits

[0136] September 9, 2025 21 / 51 an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1, wherein the mass fraction of the first additive is from 80 to 95 wt.%, based on the total mass of cement and the first additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%.

[0137] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1, wherein the composite slurry comprises a first additive and a second additive, wherein the mass fraction of the first additive is from 60 to 90 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, wherein the mass fraction of the second additive is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry.

[0138] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-‘time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1, wherein the mass fraction of the additive is at least 50 wt.% and / or at most 90 wt.%, based on the total mass of cement and additive of the composite slurry.

[0139] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water (53), one or more additives and a

[0140] September 9, 2025 22 / 51 SC2004P-WG cement (52), wherein a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity, e.g. at a time tx, which decay is less than 0.5 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’-time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1, characterized in that the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more thereof, wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer-Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321:2006-09.

[0141] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry, wherein the composite slurry has a solid content of 30 to 60 wt.%, wherein the mass fraction of water is at least 40 wt.% and / or at most 70 wt.%, based on the total mass of cement (57), water (56) and the one or more additives of the composite slurry (41).

[0142] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, a first additive and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry, wherein the mass fraction of the first additive is from 80 to 95 wt.%, based on the total mass of cement and the first additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%.

[0143] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry, wherein the composite slurry comprises a first additive and a second additive, wherein the mass fraction

[0144] September 9, 2025 23 / 51 SC2004P-WG of the first additive is from 60 to 90 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, wherein the mass fraction of the second additive is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry, and wherein the mass fraction of the cement is from 5 to 20 wt.%, based on the total mass of cement, the first additive and the second additive of the composite slurry.

[0145] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry, wherein the mass fraction of the additive is at least 50 wt.% and / or at most 90 wt.%, based on the total mass of cement and additive of the composite slurry.

[0146] In one embodiment, this disclosure provides a composite slurry for producing concrete comprising, preferably consisting of, a mixture of water, one or more additives and a cement, wherein a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry, characterized in that the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more thereof, wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer-Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321:2006-09.

[0147] Detailed description of the drawings

[0148] Figure 1 shows an example of a production plant 1 for producing a composite slurry 41 according to this disclosure and for producing concrete 31 from it. The production plant comprises a treatment vessel 2 in which an energy input can be applied to the composite slurry in form of ultrasound. This energy input enables an activation of the composite slurry provided in the treatment vessel 2. For this purpose, the treatment vessel 2 has a device 16 for generating and introducing ultrasound into the composite slurry.

[0149] Furthermore, the production plant 1 has a crystallization and / or storage container 3, which is connected to the treatment vessel 2 via a transfer conduit 18. A control device 17, e.g., a

[0150] September 9, 2025 24 / 51 throttle valve or a valve, arranged in the transfer conduit 18 can be used for transfer after a predetermined activation time.

[0151] The production plant 1 optionally features a concrete mixer 5. The concrete mixer 5 has a mixing apparatus, e.g. a stirring shaft 25 and / or a screw-conveyor, which is connected to the crystallization and / or storage container 3 via a transfer conduit 23. A control device 24, for example in the form of a throttle valve or a valve, arranged in the transfer conduit 23 can be actuated for transfer after a predetermined storage time.

[0152] Both the treatment vessel 2 and the crystallization and / or storage container 3 have a stirrer 13 and 19 comprising a drive motor, a stirring shaft 14 and 20, and a stirring device 15, 21, e.g., stirrer blades, stirrer anchors, stirring helix, and similar devices.

[0153] The treatment vessel 2 has a first inlet conduit 9 for cement and a second inlet conduit 10 for an additive.

[0154] Cement and additive can be fed in measured quantities from the corresponding storage containers 7 and 8 into the treatment vessel 2 via feed conduits 9 and 10.

[0155] Furthermore, water can be supplied from a storage container 11 to the treatment vessel 2 via a separate feed conduit 12. In total, the treatment vessel has several feed conduits 9, 10, and 12.

[0156] The crystallization and / or storage container 3 has an outlet 22 for discharging a composite slurry according to this disclosure from the crystallization and / or storage container into a transport container 4, e.g., a canister or a barrel, or a transport vehicle.

[0157] The concrete mixer 5 has an outlet 30 for concrete and a feed conduit for aggregate and water 28 and 29 from a respective stock tank 26 and 27. Concrete 31 is fed through the outlet 30 into a transport container 6, a mold for curing into a precast concrete element, or a transport vehicle for transport to a construction site.

[0158] The production plant shown in Figure 1 is just one embodiment of many possible production plants for supplying a composite slurry according to this disclosure.

[0159] The special feature of production plant 1 is the possibility of discharging an activated composite slurry of additive, water, and cement from the production plant, which activated composite slurry remains flowable for a comparably long time and can therefore be processed over a longer period than cement slurries known in the art.

[0160] The composite slurry 41 can be provided according to a method shown in Figure 2 and can be

[0161] September 9, 2025 25 / 51 further processed in several different methods. In a first step 101, a production plant for providing an activated composite slurry, is provided.

[0162] In a second step 102, additive 51, cement 52, and water 53 are fed into the treatment vessel 2 to provide a composite slurry.

[0163] In a next step, the composite slurry is activated 103 by an energy input 61, in particular ultrasound.

[0164] The ultrasonic input into the slurry can be embodied by an ultrasonic sonotrode, which is part of the device 16 for the generation and input of ultrasound, which preferably operates in the following range (values refer to T = 25 °C and normal pressure):

[0165] Intensity of emitted ultrasound: 25 - 250 W / cm2

[0166] If ultrasound is applied to a medium the particles and the medium are set into vibration. This vibration transfers kinetic energy from the ultrasound waves. The intensity (I) corresponds to the power, e.g., watts, that is transported per unit area. The unit is power per unit area (e.g., W / cm2).

[0167] - Amplitude of emitted ultrasound: 15 - 500 pm

[0168] The amplitude (u) describes the deflection of the ultrasonic wave (e.g., in pm). At a constant frequency, higher amplitudes result in an increase in intensity. The greater the amplitude, the greater the pressure differences during high-pressure and low-pressure cycles.

[0169] Frequency of emitted ultrasound: preferably 10 - 30 kHz

[0170] The frequency (f) describes the rate of vibrations at the tip of the ultrasonic probe. Since the formation, growth, and implosion of vapor bubbles is a time-dependent process, higher frequencies result in smaller cavitation bubbles.

[0171] Specific energetic input (into the medium - water): preferably 25 - 250 Ws / mL

[0172] The aforementioned values can be determined electro-acoustical ly in water using for example a hydrophone.

[0173] The activation provides the composite slurry according to this disclosure. Unlike cement slurries in the art, the composite slurry according to this disclosure has a long-lasting flowability and, at the same time, higher early compressive strengths during subsequent processing into concrete than non-activated cement slurries. The method according to the invention can therefore

[0174] September 9, 2025 26 / 51 already be terminated at this point. However, subsequent processing into concrete 54 is also possible according to this disclosure.

[0175] For storage and / or property optimization, the activated composite slurry 41 can be stored for at least 4 hours. Further processing into concrete can be carried out by mixing the activated composite slurry with other components of the concrete 55 (e.g., additional cement, additional additives, admixtures, and / or aggregate). Further optional components for adjusting the material properties of the concrete are water 56 and cement 57.

[0176] Among other things, the method enables the provision of an activated composite slurry which has non-curing properties and, after the addition of further concrete components (e.g., further cement, further additives, admixtures, and / or aggregate), exhibits an increased early strength of the concrete produced therefrom, compared to a conventional cement slurry. This advantageously combines two properties, which are actually contradictory, within the scope of the method.

[0177] Studies have shown that hydrate phases are specifically built on the additive. While cement cures quickly as a result of the formation of hydrate phases, the use of additive as a substrate for the hydrate phases inhibits or slows down the curing of the composite slurry until aggregate is added.

[0178] The additive stabilizes the hydrate phases for several hours, up to 96 hours, so that the composite slurry remains liquid, storable, pumpable, and therefore transportable over this period.

[0179] The flowability of the composite slurry according to the invention is illustrated in Figure 3 in comparison with cement slurries known in the art.

[0180] The flowability of slurries in the building materials sector is determined by measuring the funnel flow time (see DIN EN 445:2008-01) in a standardized measuring instrument known as a Marsh funnel with a volume of 1 liter. To ensure the pumpability and further processability of slurries, a certain viscosity (flowability) must be ensured. The measurement was carried out at 25°C and under normal pressure or atmospheric pressure.

[0181] Due to the proceeding reaction between cement and water and the associated curing of cement slurries, the flowability generally decreases rapidly depending on the type of cement.

[0182] Figure 3 shows the funnel flow times according to DIN EN 445:2008-01 for three different slurries with equal solid concentrations:

[0183] September 9, 2025 27 / 51 Measurement curve 301 describes a highly reactive cement slurry with a fast reaction rate.

[0184] Measurement curve 302 shows a cement slurry with a low reaction rate.

[0185] Measurement curve 303 shows a slurry of a mixture of cement and additive without significant solidification.

[0186] As shown in Figure 3, the funnel flow time of both cement slurries increases rapidly, indicating ongoing solidification. This makes further processing and / or conveying of the slurry increasingly difficult.

[0187] In contrast, the composite slurry according to the invention remains flowable over the period considered and can be conveyed and pumped without restriction.

[0188] Another advantage for the further processing of the composite slurry is the increased early strength that can be achieved with concrete produced from the composite slurry.

[0189] Another advantage of a cement slurry is the consistency of the properties determined in the concrete. Due to the rapid setting of a cement slurry according to the art, the properties of the slurry are only “stable” for a short period of time.

[0190] In contrast, a cement-additive slurry can be stabilized over a long period of time through targeted composition, i.e. , through the ratio of cement to additive.

[0191] Figure 4 shows the early compressive strength development up to a concrete age of 24 hours. A significant increase in early compressive strength is particularly evident in the period between 8 and 12 hours. The figure shows the compressive strength development for

[0192] 401 Reference concrete = concrete without any pretreatment;

[0193] 402 for a cement slurry after 2 hours = concrete with activated cement slurry after 2 hours of ultrasonic activation;

[0194] 403 Cement-additive slurry after 3 hours of ultrasonic activation;

[0195] 404 Cement-additive slurry of the measured curve 403 after 6 hours of storage;

[0196] 405 Cement-additive slurry of the measured curve 403 after 12 hours of storage;

[0197] 406 Cement-additive slurry of the measured curve 403 after 24 hours of storage.

[0198] Figure 4 shows an increase in early compressive strength through the addition of activated

[0199] September 9, 2025 28 / 51 cement slurry and cement-additive slurry.

[0200] The cement-additive slurry in particular shows a significant increase in early compressive strength and good consistency of results over a storage period of up to 24 hours.

[0201] Figure 5 shows a measured curve labeled KSM of an electrical conductivity measurement of a limestone powder-cement slurry. The characteristic of this measurement is the increase in conductivity up to a maximum at approximately 1.5 hours.

[0202] During the period until the maximum was reached and beyond, the slurry was treated with ultrasound.

[0203] A decrease in electrical conductivity was observed after 1.5 hours, which continued even after the ultrasound treatment had ended. Before the maximum is exceeded, there is a targeted and increased formation of hydrate phases, which gradually decreases after the maximum electrical conductivity is exceeded. As a result, a slurry essentially started saturating with hydrate phases and thus stabilized is formed. However, the slurry remains flowable and pumpable.

[0204] During the measurements shown in Figure 5, the temperature of the composite slurry was measured. It can be seen that the temperature initially rises to approximately 35-37 °C within the first 5 minutes of the measurement and then drops to 25 °C. The heating is caused, among other things, by hydration and enthalpy effects. The drop of the maximum temperature follows an exponentially declining curve. As can be seen in Figure 6A, the maximum conductivity at around 1.5 hours cannot be attributed to temperature effects, but rather to the development of hydration phases within the composite slurry.

[0205] Figure 6B shows a temperature curve of the produced concrete using the composite slurry according to this disclosure (611), compared to a reference (612). The values in paratheses denote the measured temperature maximum Tmaxand the time t it occurred in h:mm after start of the measurement. The figure shows the temperature development for

[0206] 611 a concrete produced from an activated composite slurry which was stored for a 24 h period before use (Tmax =30.9 °C, t = 6:51 h);

[0207] 612 Reference concrete = concrete without any pretreatment (Tmax =29.4 °C, t = 11:10 h).

[0208] The reference concrete (612) in this example was produced without a composite slurry. The concrete comprises cement (Portland cement CEM I 52,5 R), sand (0 / 2, 38%), two sorts of gravel (2 / 8, 15%; 8 / 16, 47%), and a plasticizer (Polycarboxylatether) which were mixed with

[0209] September 9, 2025 29 / 51 water. The produced concrete has a w / c ratio of 0.43.

[0210] The concrete according to the disclosure (611) was produced with an activated composite slurry, consisting of cement (Portland cement CEM I 52,5 R) and one additive (calcitic limestone powder) in a mass ratio of 80 / 20, which was mixed with water. The composite slurry was activated with ultrasound (600 W, 90 s per 1 L) and stored for a 24 h time period before use. For the production of concrete further cement (Portland cement CEM I 52,5 R), sand (0 / 2, 38%), two sorts of gravel (2 / 8, 15%; 8 / 16, 47%), and a plasticizer (Polycarboxylatether) were added and admixed with water. The produced concrete has a w / c ratio of 0.43. The figure shows a difference of the maximum in temperature of approximately 4 h, between the reference concrete (612) and the concrete according to the disclosure. The maximum temperature of 30.9 °C of the concrete produced from a composite slurry according to the disclosure (611) was measured after a time period of approximately 7 h after starting the measurement. Whereas the reference concrete produced from a composite slurry according to the art has a measured temperature maximum of 29.4 °C which occurred after a time period of approximately 11 h after starting the measurement.

[0211] Figure 6C shows timepoints of maximal temperature development of the produced concrete using the composite slurry according to this disclosure with different amounts of initial cement (5 wt.%, 10 wt.%, and 20 wt.%), depending on the storage time, compared to a reference. Figures 6C - 1 / 2 / 3 show the temperature development for

[0212] 621 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 3 h period before use (Tmax =35.3 °C, t = 8:46 h);

[0213] 622 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 2 d period before use (Tmax =40.9 °C, t = 7:32 h);

[0214] 623 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 7 d period before use (Tmax =36.3 °C, t = 7:32 h);

[0215] 624 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0216] 631 a concrete produced from an activated composite slurry comprising additive and 10 wt- % cement which was stored for a 3 h period before use (Tmax =35.5 °C, t = 9:10 h);

[0217] 632 a concrete produced from an activated composite slurry comprising additive and 10 wt- % cement which was stored for a 2 d period before use (Tmax =37.5 °C, t = 7:34 h);

[0218] 633 a concrete produced from an activated composite slurry comprising additive and 10 wt-

[0219] September 9, 2025 30 / 51 SC2004P-WG

[0220] % cement which was stored for a 7 d period before use (Tmax =38.5 °C, t = 7:56h);

[0221] 634 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0222] 641 a concrete produced from an activated composite slurry comprising additive and 20 wt- % cement which was stored for a 3 h period before use (Tmax =33.9 °C, t = 8:34 h);

[0223] 642 a concrete produced from an activated composite slurry comprising additive and 20 wt- % cement which was stored for a 2 d period before use (Tmax =37.2 °C, t = 8:01 h);

[0224] 644 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0225] The measurements of the temperature development of concretes produced according to the disclosure show a shorter time period for reaching the temperature maximum from composite slurries according to the disclosure in comparison to reference concretes. This acceleration effect is enhanced for concretes produced from composite slurries with storage times of 2 d or 7 d compared to 3 h.

[0226] Figure 7 shows the behavior of the electrical conductivity of binary composite slurries produced from different additives, i.e., fly ash, GGBFS (coarse), calcined clay, GGBS (fine), limestone powder, with a cement and water during its activation and thereafter. All slurries have a w / c value of 1.5 and were activated with ultrasound (600 W, 90 s per 1 L). The temperature of measurement is 20 °C. The abbreviation CEM I R denotes the Portland cement CEM I 52,5 R, and CEM I N denotes the Portland cement CEM I 52,5 N. The mass ratio is in all cases cement / additive 80 / 20. Figure 7 shows the behavior of the electrical conductivity for

[0227] 701 CEM I R+ limestone powder;

[0228] 702 CEM I R + GGBFS (fine);

[0229] 703 CEM I R + GGBFS (coarse);

[0230] 704 CEM I R + calcined clay;

[0231] 705 CEM I R + Fyl ash.

[0232] Figure 8 shows the setting behavior for composite slurries according to the disclosure with different cement contents and storage times, compared to a reference, in a produced concrete. The measurement was conducted in accordance with DIN EN 196-3:2016. For all concretes produced from an activated composite slurry according to the disclosure the CEM I N cement and the limestone powder used in all measurements is calcitic limestone powder. All slurries

[0233] September 9, 2025 31 / 51 were activated with ultrasound (600 W, 90 s per 1 L). The reference concrete was produced from CEM I R cement. Figure 8 shows the setting behavior of

[0234] 801 a concrete produced from an activated composite slurry comprising80% additive and 20 wt-% cement which was stored for a 30 d period before use;

[0235] 802 a concrete produced from an activated composite slurry comprising 90% additive and 10 wt-% cement which was stored for a 30 d period before use;

[0236] 803 a concrete produced from an activated composite slurry comprising 95% additive and 5 wt-% cement which was stored for a 30 d period before use;

[0237] 804 a reference concrete = concrete without any additive and pretreatment;

[0238] 805 initial set;

[0239] 806 setting point;

[0240] 811 a concrete produced from an activated composite slurry comprising 90% additive and 10 wt-% cement which was stored for a 7 d period before use;

[0241] 812 a concrete produced from an activated composite slurry comprising 95% additive and 5 wt-% cement which was stored for a 7 d period before use;

[0242] 813 a concrete produced from an activated composite slurry comprising 80% additive and 20 wt-% cement which was stored for a 3 h period before use;

[0243] 814 reference concrete = concrete without any additive and pretreatment;

[0244] 815 setting point;

[0245] 816 setting point.

[0246] Examples

[0247] Table 1: The compressive strength of concretes produced with the composite slurry according to this disclosure depends, among other factors, on the type of the chosen limestone powder and its physical characteristics.

[0248] September 9, 2025 32 / 51

[0249]

[0250] September 9, 2025 33 / 51 Reference numerals

[0251] 1 Production plant

[0252] 2 Treatment vessel

[0253] 3 Crystallization and / or storage container

[0254] 4 Transport container

[0255] 5 Concrete mixer

[0256] 6 Transport container

[0257] 7 Storage container

[0258] 8 Storage container

[0259] 9 Feed conduit

[0260] 10 Feed conduit

[0261] 11 Storage container

[0262] 12 Feed conduit

[0263] 13 Stirrer

[0264] 14 Stirring shaft

[0265] 15 Stirring device

[0266] 16 Device for generating and introducing ultrasound

[0267] 17 Control device

[0268] 18 Transfer conduit

[0269] 19 Stirrer

[0270] 20 Stirring shaft

[0271] 21 Stirring device

[0272] September 9, 2025 34 / 51 2 Outlet 3 Transfer conduit 4 Control device 5 Stirring shaft 6 Stock tank 7 Stock tank 8 Aggregate 9 Water 0 Outlet for concrete 1 Concrete 1 Composite slurry 1 Additive 2 Cement 3 Water

[0273] 55 Concrete

[0274] 56 Water

[0275] 57 Cement

[0276] 61 Energy input

[0277] 101 Providing a production plant for the production of an activated composite slurry

[0278] 102 Feeding

[0279] 103 Activation

[0280] September 9, 2025 35 / 51 104 Storing

[0281] 301 Measured curve (cement slurry - highly reactive)

[0282] 302 Measured curve (cement slurry - low reactive)

[0283] 303 Measured curve (cement + additive)

[0284] 401 Measured curve - reference concrete

[0285] 402 Measured curve concrete with activated cement slurry after 2 hours of ultrasonic activation

[0286] 403 Cement-additive slurry after 3 hours of ultrasonic activation

[0287] 404 Cement-additive slurry after 6 hours of storage

[0288] 405 Cement-additive slurry after 12 hours of storage

[0289] 406 Cement-additive slurry after 24 hours of storage.

[0290] 611 a concrete produced from an activated composite slurry which was stored for a 24 h period before use (Tmax =30.9 °C, t = 6:51 h);

[0291] 612 Reference concrete = concrete without any pretreatment (Tmax =29.4 °C, t = 11:10 h).

[0292] 621 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 3 h period before use (Tmax =35.3 °C, t = 8:46 h);

[0293] 622 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 2 d period before use (Tmax =40.9 °C, t = 7:32 h);

[0294] 623 a concrete produced from an activated composite slurry comprising additive and 5 wt-% cement which was stored for a 7 d period before use (Tmax =36.3 °C, t =

[0295] September 9, 2025 36 / 51 7:32 h);

[0296] 624 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0297] 631 a concrete produced from an activated composite slurry comprising additive and 10 wt-% cement which was stored for a 3 h period before use (Tmax =35.5 °C, t = 9:10 h);

[0298] 632 a concrete produced from an activated composite slurry comprising additive and 10 wt-% cement which was stored for a 2 d period before use (Tmax =37.5 °C, t = 7:34 h);

[0299] 633 a concrete produced from an activated composite slurry comprising additive and 10 wt-% cement which was stored for a 7 d period before use (Tmax =38.5 °C, t = 7:56h);

[0300] 634 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0301] 641 a concrete produced from an activated composite slurry comprising additive and 20 wt-% cement which was stored for a 3 h period before use (Tmax =33.9 °C, t = 8:34 h);

[0302] 642 a concrete produced from an activated composite slurry comprising additive and 20 wt-% cement which was stored for a 2 d period before use (Tmax =37.2 °C, t = 8:01 h);

[0303] 644 Reference concrete = concrete without any pretreatment (Tmax =37.1 °C, t= 9:54 h).

[0304] 701 CEM I R+ limestone powder;

[0305] 702 CEM I R + GGBFS (fine);

[0306] 703 CEM I R + GGBFS (coarse);

[0307] 704 CEM I R + calcined clay;

[0308] 705 CEM I R + Fyl ash.

[0309] September 9, 2025 37 / 51 801 a concrete produced from an activated composite slurry comprising 80% additive and 20 wt-% cement which was stored for a 30 d period before use;

[0310] 802 a concrete produced from an activated composite slurry comprising 90% additive and 10 wt-% cement which was stored for a 30 d period before use;

[0311] 803 a concrete produced from an activated composite slurry comprising 95% additive and 5 wt-% cement which was stored for a 30 d period before use;

[0312] 804 a reference concrete = concrete without any additive and pretreatment;

[0313] 805 initial set;

[0314] 806 setting point;

[0315] 811 a concrete produced from an activated composite slurry comprising 90% additive and 10 wt-% cement which was stored for a 7 d period before use;

[0316] 812 a concrete produced from an activated composite slurry comprising 95% additive and 5 wt-% cement which was stored for a 7 d period before use;

[0317] 813 a concrete produced from an activated composite slurry comprising 80% additive and 20 wt-% cement which was stored for a 3 h period before use;

[0318] 814 reference concrete = concrete without any additive and pretreatment;

[0319] 815 initial set;

[0320] 816 setting point.

[0321] September 9, 2025 38 / 51

Claims

Claims1. Composite slurry (41) for producing concrete (31 , 55) comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a ratio between the one or more additives and the cement is chosen such that the flowability of the composite slurry (41), measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of no more than 24 hours is at least 5 seconds and no more than 60 seconds.

2. Composite slurry (41) for producing concrete (31 , 55) comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a ratio between the one or more additives and the cement is chosen such that a) the electrical conductivity curve of the composite slurry (41) shows at least one change of sign of the slope of the electrical conductivity, and / or b) the composite slurry exhibits a decay of an electrical conductivity which decay is less than 0.5 mS cm-1per hour, or less than 0.3 mS cm-1per hour, or less than 0.2 mS cm-1per hour, or less than 0.1 mS cm-1per hour, wherein optionally the composite slurry during storage has an average temperature between 10 and 35 °C, wherein preferably the decay of the electrical conductivity is monitored one hour after the global maximum of the ‘electrical conductivity’- time’ curve and is measured as a difference between the two time points tx+ 1 h and tx, and / or c) the composite slurry exhibits an electrical conductivity in a range of 4 to 22 mS cm-1, or 8 to 13 mS cm-1.

3. Composite slurry (41) for producing concrete (31 , 55) comprising, preferably consisting of, a mixture of water (53), one or more additives and a cement (52), wherein a ratio between the one or more additives and the cement is chosen such that a produced concrete reaches a target compressive strength of 15 N / mm2between 2 and 12 hours earlier than a reference concrete prepared without the composite slurry.

4. Composite slurry (41) according to one of the preceding claims, wherein the composite slurry is manufactured by- providing a mixture of water, the one or more additives and the cement;- subjecting the mixture to an ultrasound treatment for at least 2 h; and- optionally storing the treated mixture for an interval between 0 and 8 hours.September 9, 2025 39 / 51SC2004P-WG5. Composite slurry according to one of the preceding claims, wherein the temperature development of a produced concrete using the composite slurry (41) shows at least one change of sign of slope within 10h after initiating concrete production.

6. Composite slurry according to one of the preceding claims, characterized by a flowability measured as funnel flow time according to DIN EN 445:2008-01 after a storage period of at most 24 hours of at least 7 seconds and at most 50 seconds.

7. Composite slurry according to one of the preceding claims, characterized in that the composite slurry (41) is pumpable and / or stirrable after a storage period of 24 hours.

8. Composite slurry according to one of the preceding claims, characterized in that the solid content of the composite slurry (41) is at least 20 wt.%, or at least 30 wt.%, or at least 40 wt.%, and / or at most 70 wt.%.

9. Composite slurry according to one of the preceding claims, characterized in that the additive is chosen from at least one of the following: ground granulated blast-furnace slag (GGBFS), quartz powder, silica fume, limestone powder, calcined clay, pozzolan, fly ash and / or a mixture of one or more thereof, wherein preferably the specific surface area of the one or more additives is at least 2.5 m2 / g, wherein the specific surface area is measured as the nitrogen adsorption at 77 K in a Brunauer-Emmett-Teller (BET) measurement according to ISO 9277:2010, and / or wherein preferably the one or more additives has a particle size distribution with a Dv;is of 5 pm or lower and / or a Dv;95 of 45 pm or higher, wherein the particle size distribution is determined according to DIN ISO 13321 :2006-09.

10. Composite slurry according to one of the previous claims, characterized in that the mass fraction of the additive is at least 50 wt.% and / or at most 90 wt.%, based on the total mass of cement (52) and additive of the composite slurry (41).

11. Composite slurry according to one of the preceding claims, characterized in that the mass fraction of water (56) is at least 40 wt.% and / or at most 80 wt.%, or at most 70 wt.%, or at most 60 wt.%, based on the total mass of cement (57), water (56) and the one or more additives of the composite slurry (41).

12. Composite slurry according to one of the preceding claims, characterized in that the mass fraction of cement (52) is at least 10 wt.% and / or at most 50 wt.%, based on the total mass of cement (57), water (56) and the one or more additives of the composite slurry (41).September 9, 2025 40 / 5113. Composite slurry according to one of the preceding claims, characterized in that the mass fraction of cement, water and the one or more additives is at least 99.0 wt.% based on the total mass of the composite slurry.

14. Composite slurry according to one of the preceding claims, characterized in that the ratio of cement (52) to additive in the composite slurry (41) is at least 0.1 and / or at most 1.0.

15. Composite slurry according to one of the preceding claims, characterized in that the storage period of the composite slurry (41) after its preparation, preferably after activation by energy input, is at least 4 hours or preferably 24 hours.

16. Composite slurry according to one of the preceding claims, characterized in that the composite slurry is essentially free of organic polymers.

17. Use of the composite slurry according to one of the preceding claims for producing concrete.

18. Use of the composite slurry according to claim 17, wherein in a setting experiment performed according to DIN EN 196-3:2017-03 an initial set and / or a setting point of the produced concrete is shifted to a shorter time frame of 60 min or more when using the composite slurry according to any one of claims 1 to 17 compared to a reference concrete produced without the composite slurry.

19. Use of the composite slurry according to claim 17 or claim 18, wherein in a setting experiment of the produced concrete a temperature is monitored, wherein the temperature reaches a maximal value during the setting experiment denoted a timepoint of maximal temperature, wherein the timepoint of maximal temperature is shifted to a shorter time frame of 20 min or more, 60 min or more, or 100 min or more, when using the composite slurry according to any one of claims 1 to 16 compared to a reference concrete produced without the composite slurry.

20. Method for producing a stabilized composite slurry, characterized by the following steps: i) providing a composite slurry (41) by mixing water (56), one or more additives and a cement (52), wherein preferably the composite slurry is according to one of the claims 1 to 16; and ii) storing the composite slurry (41) for a storage period of at least 4 hours and preferably no more than 96 hours.September 9, 2025 41 / 5121. Method according to claim 20, wherein providing the composite slurry (41) comprises an activation (103) by an energy input (61), preferably by ultrasonic treatment, over a treatment period.

22. Method according to claim 20 or claim 21, characterized in that the extent of the energy input (61) is monitored by determining an average temperature of the composite slurry.

23. Method according to claim 21 or claim 22, characterized in that the activation is carried out by intermittent or continuous energy input (61) over the treatment period at least until a sign change of the slope of the electrical conductivity is achieved.

24. Method for producing concrete (33, 55), the method comprising the following steps: i) providing a composite slurry (41) according to one of claims 1 to 16 or according to one of the method claims 20 to 23; and ii) mixing the composite slurry with further components, e.g., a further cement, and one or more further additives.September 9, 2025 42 / 51

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