Conductive mineral binder composition

Abstract

A mineral binder composition, in particular an electrically conductive mineral binder composition, comprises at least one mineral binder, carbon nanotubes and carbon-containing particles, the carbon-containing particles being chemically and / or physically different from the carbon nanotubes.

Description

Technical Field

[0001] This invention relates to mineral binder compositions, particularly conductive mineral binder compositions. Further, this invention relates to hardened articles and objects based on mineral binder compositions. Further, this invention relates to methods for heat-hardening articles or objects, and the use of mineral binder compositions or hardened articles for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion protection of reinforced concrete structures, as antistatic flooring, and / or as heating components for building or infrastructure structures. Background Technology

[0002] Conventional mineral binder compositions, such as cement-based mortars or concrete, are fairly good electrical insulators with high resistivity.

[0003] For example, the resistivity of concrete can vary depending on several factors, including the type of concrete mix, moisture content, temperature, and the presence of additives or reinforcing materials. However, as a general guideline, the resistivity of typical concrete is around 10⁻⁶. 4 -10 7 Within the Ωm range.

[0004] Conversely, conductive concrete, also known as smart concrete, is a special type of concrete that has been modified to be either conductive or has a lower conductivity than conventional concrete. Conductive concrete can be used, for example, for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion protection of reinforced concrete structures, as antistatic flooring, and / or as heating components in building or infrastructure structures.

[0005] The fundamental principle behind conductive mineral binder compositions lies in incorporating conductive additives, such as carbon black or metal particles, into the mineral binder composition. These additives create a conductive network within the mineral binder composition, allowing current to flow through the material.

[0006] In this regard, US2019 / 0218144A1 (Pellenq et al.) describes, for example, cement composites supported by conductive nanoporous carbon. These nanoporous carbon-supported cement composites can be used in a variety of applications, including, for example, as structural supercapacitors as energy solutions for autonomous housing and other buildings; heated cement for de-icing roads or for basement insulation to resist capillary rise; protection against freeze-thaw (FT) or alkali-silica reaction (ASR) or other crystallization degradation processes in concrete; and as conductive cables, wires, or conductive paths in concrete. The described nanoporous carbons are, for example, carbon black, multi-walled carbon nanotubes, graphene sheets, activated porous carbon, and sucrose char.

[0007] Similarly, WO01 / 72657A1 (National Research Council of Canada) describes a conductive concrete suitable for commercial and large-scale production. This conductive concrete uses carbonaceous particles as the conductive phase to achieve a resistivity as low as 2 Ωcm. The conductive carbonaceous particles used as the conductive phase can be carbon from many different sources and can be in the form of blocks or fibers. Preferred conductive carbonaceous particles are coke scrap, a byproduct of steelmaking.

[0008] Furthermore, WO2012 / 143221A1 (Henkel) describes a composition comprising, based on the total weight of the composition, 5-90 wt.% of at least one inorganic binder, 0.1-10 wt.% of soot, and 0.1-15 wt.% of carbon fiber. This composition can be used to produce flat heating components, particularly for electrically heated floor, wall, or ceiling surfaces.

[0009] However, known conductive mineral binder compositions are not entirely convincing. In particular, when heating applications are involved, it takes a considerable amount of time to achieve the desired temperature using known conductive mineral binder compositions.

[0010] Therefore, there is still a need to develop improved solutions that at least partially overcome the aforementioned shortcomings. Summary of the Invention

[0011] One object of the present invention is to provide an improved solution for conductive mineral binder compositions. In particular, the solution should allow for the production of conductive mineral binder compositions that enable the production of hardened articles that can be heated more efficiently at the highest possible heating rates. Furthermore, the solution should be as flexible as possible.

[0012] Surprisingly, these objectives have been found to be achieved using the composition of claim 1. Specifically, the present invention relates to mineral binder compositions, particularly conductive mineral binder compositions, comprising at least one mineral binder, carbon nanotubes, and carbon-containing particles, said carbon-containing particles being chemically and / or physically different from said carbon nanotubes.

[0013] The combination of carbon nanotubes and carbon-containing particles in this invention results in a synergistic effect between two different types of carbon-based materials. In particular, the heating rate of hardened articles made from the mineral binder composition of this invention is significantly improved compared to similar compositions containing only one type of carbon-based material.

[0014] Specifically, using the compositions of the present invention, hardened articles can be produced that can be heated from room temperature to a desired temperature of 100°C when only 40 volts (V) of voltage is applied over 10 minutes. When using only one type of carbon-based material but under otherwise identical conditions, it would take approximately 50 minutes to reach a temperature of 80°C.

[0015] Furthermore, the heating method for the hardened articles based on the mineral binder composition of the present invention is highly advantageous in terms of power consumption.

[0016] Without being bound by theory, it is believed that combinations of different carbon-based materials significantly increase the number of contact points between conductive particles in the mineral binder composition. This results in the formation of a percolating network that provides continuous links between conductive particles that have percolated the mineral binder composition to a degree sufficient to make the composition conductive, thereby enabling resistance heating in a highly efficient manner.

[0017] Furthermore, the mineral binder compositions of the present invention can achieve different properties, for example, by selecting specific mineral binders and optionally adding aggregates and / or additives. This allows for a wide range of control over processing properties and the properties of hardened articles made from the compositions of the present invention.

[0018] Specifically, the compositions of the present invention or hardened articles made therefrom can be used in very different applications, such as (i) heating of building and infrastructure structures (e.g., with floor heating flooring and / or heating plates), (ii) de-icing and snow melting, such as on roads, bridges, sidewalks, stairs, roofs and airport runways, (iii) electrical grounding and grounding, (iv) electrostatic discharge (ESD) protection, (v) structural monitoring of building and infrastructure structures, and (vi) electromagnetic shielding.

[0019] In summary, the mineral binder compositions of the present invention are highly advantageous and can be used in many applications.

[0020] Other aspects of the invention are the subject of the other independent claims and / or are set forth in the description and dependent claims.

[0021] Invention Embodiments

[0022] A first aspect of the present invention relates to a mineral binder composition, particularly a conductive mineral binder composition, comprising at least one mineral binder, carbon nanotubes, and carbon-containing particles, said carbon-containing particles being chemically and / or physically different from said carbon nanotubes.

[0023] In the context of this invention, "mineral binder composition" refers to a mixture comprising at least one mineral binder. It is feasible, and preferred in the context of this invention, for the mineral binder composition to additionally comprise aggregates and / or other additives.

[0024] The mineral binder compositions of the present invention can be substantially anhydrous and exist in a dry form. The mineral binder compositions of the present invention can also contain some or all of a mixture of water and exist in a fluid or hardened form.

[0025] In particular, the mineral binder composition may be non-conductive in its dry state. It may be necessary to mix the mineral binder composition with water and / or cure the mineral binder composition to obtain a conductive mineral binder composition.

[0026] For the purposes of this invention, the term "particle" specifically refers to solids with an average particle size of less than 1000 μm, particularly less than 500 μm. Particle size, its distribution, or average particle size can be determined, particularly by laser scattering, preferably according to standard ISO 13320:2009. Specifically, the Mastersizer 2000 instrument with the Hydro 2000G scattering unit and the Mastersizer 2000 software from Malvern Instruments GmbH (Germany) can be used for this purpose. In the present case, the average or average particle size corresponds to the D50 value (50% of the particles are smaller than the indicated value, and 50% are correspondingly larger).

[0027] Carbon nanotubes (CNTs) are tubes made primarily of carbon, typically with diameters in the range of less than 100 nm.

[0028] Specifically, the carbon nanotubes are selected from single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and / or nanotubes with undetermined carbon wall structures.

[0029] In particular, although not produced in this way, single-walled carbon nanotubes can be imagined as being cut from a two-dimensional hexagonal lattice of carbon atoms, which rolls up along one of the Bravais lattice vectors of the hexagonal lattice to form a hollow cylinder. Multi-walled carbon nanotubes are typically composed of nested single-walled carbon nanotubes that are weakly bound together by a tree-ring-like structure.

[0030] Unlike carbon nanotubes, carbon fibers are solid wires of carbon atoms. Specifically, carbon fibers are made from loosely packed sheets of graphite stacked parallel to each other. Therefore, although based on the same type of atom, carbon, carbon fibers are structurally very different from carbon nanotubes. Typically, a single carbon fiber has a diameter of about 5–10 μm.

[0031] Particularly preferred are single-walled carbon nanotubes used in the compositions of the present invention. These types of carbon nanotubes have proven to be highly beneficial in increasing the electrical conductivity of mineral binder compositions. However, other types of carbon nanotubes may also be used.

[0032] Carbon nanotubes preferably have an average outer diameter of about 0.4-25 nm, especially 0.6-10 nm, for example 1-5 nm, and particularly 1.2-2.0 nm. The outer diameter can be determined, for example, by optical absorption according to the standard ISO / TS 10868:2017.

[0033] Preferably, the carbon nanotubes have an average length of at least 0.5 μm, particularly at least 1 μm, particularly at least 4 μm, and especially at least 5 μm. For example, the carbon nanotubes have an average length of 0.5–5000 μm, particularly 1–1000 μm, and for example, >5–100 μm. The length of the carbon nanotubes can be determined by standard atomic force microscopy (AFM).

[0034] In particular, the average aspect ratio of the carbon nanotubes, that is, the average ratio of length to diameter, is at least 100, especially at least 1000, especially at least 2500, for example at least 3000.

[0035] The specific surface area of ​​carbon nanotubes is preferably at least 100 m². 2 / g, especially at least 200 m 2 / g, especially at least 300m 2 / g, for example 300-1000 m 2 / g or 300-600 m 2 / g. Specific surface area can be determined by BET surface area analysis using N2 in a conventional manner known to those skilled in the art.

[0036] Carbon nanotubes of this size and properties have been shown to be particularly beneficial in effectively increasing the electrical conductivity of mineral binder compositions combined with other carbon-containing particles.

[0037] Highly preferably, the G / D ratio of the carbon nanotubes is >10, especially >50, particularly >70, for example >90. The G / D ratio defines the Raman spectrum of carbon nanotubes at 1590 cm⁻¹. -1 Peak intensity near (G band) and 1350 cm⁻¹ -1 The intensity ratio of the peak intensity near the (D band). 1590 cm⁻¹ -1 The nearby peak originates from the in-plane vibration of the six-membered ring common to carbon-based materials. 1350 cm⁻¹ -1 The nearby peaks originate from defects in the carbon nanotubes. The intensity G / D ratio can be used as an indicator of the amount of defects in carbon nanotubes. The larger the G / D ratio, the fewer defects exist in the carbon nanotubes.

[0038] Carbon nanotubes with the G / D ratio defined above have low defect density, which has been shown to be beneficial for improving the electrical conductivity of mineral binder compositions and providing hardened articles that can be heated by resistance heating.

[0039] Preferably, the carbon-containing particles are selected from those with a dominant number of participating sp particles. 2 Any carbon material with a hybrid scheme of carbon atoms.

[0040] Particularly preferred, the carbon-containing particles are selected from carbon black, graphene flakes, multi-walled carbon nanotubes, coke particles, and / or activated carbon. Highly preferred, the carbon-containing particles are selected from carbon black. Carbon black is particularly carbon black according to CAS 1333-86-4.

[0041] These carbon-containing particles, especially carbon black, have proven beneficial when combined with carbon nanotubes, particularly single-walled carbon nanotubes.

[0042] The preferred carbon-containing particles have a density of 20-380 kg / m³. 3 Especially 50-150 kg / m 3 The bulk density is defined as the mass of a material's many particles divided by the total volume they occupy.

[0043] In particular, the carbon-containing particles have an average particle size of 10-500 nm, especially 20-300 nm, especially 25-100 nm, especially 30-70 nm or 40-60 nm.

[0044] Carbon-containing particles of this size and properties have proven to be beneficial to the present invention, especially when combined with carbon nanotubes.

[0045] According to a highly preferred embodiment, the carbon particles are selected from carbon black, especially carbon black with a particle size of 25-100 nm, and the carbon nanotubes are single-walled carbon nanotubes, especially single-walled carbon nanotubes with an average length of at least 5 μm and an average diameter of about 1.2-2.0 nm.

[0046] Preferably, the proportion of carbon nanotubes, particularly single-walled carbon nanotubes, is 0.2-1000 ppm, more preferably 1-900 ppm, more preferably 10-500 ppm, and especially 100-400 ppm, relative to the total weight of all dry components of the mineral binder composition. In the context of this invention, "ppm" represents parts per million (ppm) relative to weight. -6 Therefore, 1 ppm equals 0.0001 wt.%.

[0047] In a highly preferred embodiment, carbon nanotubes are used and / or provided in the form of a dispersion in a liquid, particularly water. This facilitates the efficient further distribution of nanotubes within the mineral binder composition.

[0048] Specifically, the proportion of carbon nanotubes in the dispersion is 0.01-2 wt.%, especially 0.1-1 wt.% or 0.2-0.6 wt.%, relative to the total weight of the dispersion.

[0049] The preferred mineral binder composition comprises at least one mineral binder, single-walled carbon nanotubes having an average outer diameter of about 0.4-25 nm, and carbon black, preferably carbon black having a particle size of 25-100 nm.

[0050] The preferred mineral binder composition comprises at least one mineral binder, single-walled carbon nanotubes with an average length of at least 5 μm and an average diameter of about 1.2-2.0 nm, and carbon black, preferably carbon black with a particle size of 25-100 nm.

[0051] Additionally, a dispersant may be present in the dispersion, particularly anionic surfactants, such as those selected from alkylbenzene sulfonates, such as sodium dodecylbenzene sulfonate, and / or those selected from alkyl ether sulfates, such as sodium lauryl ether sulfate. Specifically, the proportion of the dispersant in the dispersion relative to the total weight of the dispersion is 0.1-5 wt.%, especially 0.5-3 wt.% or 1-2 wt.%.

[0052] The proportion of liquid, especially water, in the dispersion relative to the total weight of the dispersion is particularly 93-99.9 wt.%, particularly 95-99 wt.%, particularly 97.5-98.5 wt.%.

[0053] Preferably, the dispersion is 0.005-1 wt.%, especially 0.01-0.5 wt.%, for example 0.01-0.2 wt.% or 0.02-0.1 wt.%, relative to the total weight of all dry components of the mineral binder composition.

[0054] The proportion of carbon particles, especially carbon black, relative to the total weight of all dry components of the mineral binder composition is preferably 0.5-10 wt.%, especially 2-6 wt.%, for example 3-5 wt.% or 3.5-4.5 wt.%.

[0055] Specifically, the weight ratio of carbon particles to carbon nanotubes is 10-1,250,000, particularly 50-125,000, particularly 75-10,000 or 90-1,000.

[0056] In particular, the advantages of this invention are achieved by utilizing this ratio of carbon nanotubes and carbon-containing particles.

[0057] Specifically, the ratio of carbon-containing particles to carbon nanotubes is chosen such that a continuous percolation network of carbon-containing particles and carbon nanotubes is formed or present in the mineral binder composition. In other words, in this case, carbon-containing particles and carbon nanotubes form a continuous percolation network in the mineral binder composition. This is especially true when the mineral binder composition is in a hardened state.

[0058] A percolation network is formed by the continuous connection of carbon-containing particles and carbon nanotubes, which percolate the mineral binder composition to a degree sufficient to make the composition conductive. Percolation theory can be used to explain the conductive behavior of composite materials composed of conductive particles and an insulating matrix. As the content of carbon-containing particles and carbon nanotubes gradually increases, the mineral binder composition undergoes a transformation from insulator to conductor. Percolation occurs when there are pathways of carbon-containing particles and carbon nanotubes that can connect the source electrode and the drain electrode, thereby allowing current to flow.

[0059] Preferred mineral binder compositions comprise at least one mineral binder, carbon nanotubes, and carbon black, wherein the proportion of carbon nanotubes, particularly single-walled carbon nanotubes, is 100-700 ppm, and the proportion of carbon black is 0.1-1 wt.%, in each case relative to the total dry weight of the mineral binder.

[0060] The preferred mineral binder composition comprises at least one mineral binder, carbon nanotubes, and carbon black, wherein the proportion of carbon nanotubes, particularly single-walled carbon nanotubes, is 0.2-1000 ppm, preferably 1-900 ppm, more preferably 10-500 ppm, and especially 100-400 ppm, relative to the total weight of all dry components of the mineral binder composition; and the proportion of carbon black is 3.5-4.5 wt., relative to the total weight of all dry components of the mineral binder composition.

[0061] In the context of this invention, a "mineral binder" is a binder that reacts in a hydration reaction in the presence of water to form a solid hydrate or hydrate phase, particularly an inorganic binder. This can be, for example, a hydraulic binder (e.g., cement or hydraulic lime), a latent hydraulic binder (e.g., slag or blast furnace slag), a pozzolanic binder (e.g., fly ash, volcanic ash, or rice husk ash), or a non-hydraulic binder (gypsum or quicklime). Mixtures of various binders are also possible.

[0062] Specifically, the mineral binder includes a hydraulic binder, preferably cement. Particularly preferred is cement with a clinker content of 35 wt.%. Preferably, the cement is CEM I, CEM II, CEM III, CEM IV, CEM V (according to standard EN197-1) or calcium aluminate cement (according to standard EN 14647:2006-01) or calcium sulfoaluminate cement or mixtures thereof. Specifically, the cement is of the CEM I, CEM II, calcium sulfoaluminate cement or mixtures thereof. Of course, cement produced according to relevant alternative standards, such as relevant ASTM or Chinese standards, is equally suitable. Furthermore, white cement can be used as the mineral binder of this invention.

[0063] The proportion of hydraulic binder in the total mineral binder is preferably at least 5 wt.%, more preferably at least 20 wt.%, even more preferably at least 35 wt.%, and particularly at least 65 wt.%. According to another advantageous embodiment, at least 95 wt.% of the mineral binder consists of hydraulic binder, particularly cement.

[0064] However, it can also be advantageous if the mineral binder contains other binders besides or in place of the hydraulic binder. These are particularly potential hydraulic binders and / or pozzolanic binders. Suitable potential hydraulic and / or pozzolanic binders are, for example, slag, fly ash, and / or silica fume. Similarly, the binder composition may include inert substances such as limestone powder, quartz powder, and / or pigments.

[0065] Furthermore, the mineral binder of the present invention, particularly cement, may contain cement modifiers selected from grinding agents, strength improvers, activators, accelerators, plasticizers, and superplasticizers. The cement modifiers can be ground against the mineral binder during grinding. They can also be mixed with the ground mineral binder.

[0066] Preferably, the mineral binder is selected from cement, hydraulic lime, fly ash, slag, silica fume and / or gypsum.

[0067] In addition to the mineral binder, the mineral binder composition according to the invention preferably contains aggregates and / or additives. If present, the aggregates and / or additives are chemically and / or physically different from carbon-containing particles and carbon nanotubes.

[0068] Preferably, the mineral binder composition of the present invention comprises aggregate. The aggregate can be any material that does not react in the hydration reaction of the mineral binder. The aggregate can be any aggregate commonly used in mineral binder compositions, particularly cement-based binder compositions. Typical aggregates are, for example, rock, crushed stone, gravel, slag, sand (especially quartz sand, river sand, and / or manufactured sand), recycled concrete, glass, expanded glass, pumice, perlite, vermiculite, and / or fine aggregates (e.g., ground limestone, ground dolomite, ground alumina, silica fume, quartz powder, and / or ground steel slag). Aggregates used in the present invention can have any shape and size typically encountered with such aggregates.

[0069] The particle size of the aggregate depends on the application and can be, for example, in the range of 0.1 μm to 32 mm. It is preferable to blend aggregates with different particle sizes to optimize the properties of the mineral binder composition. Aggregates with different chemical compositions can also be used.

[0070] According to embodiments, aggregates with a particle size of not more than 8 mm, more preferably not more than 5 mm, even more preferably not more than 3.5 mm, most preferably not more than 2.2 mm, and especially not more than 1.2 mm or not more than 1.0 mm are used in the mineral binder composition of the present invention.

[0071] The maximum particle size is particularly limited by the planned layer thickness during the application of the mineral binder composition mixed with water. For example, the maximum particle size of the aggregate should be the same as the layer thickness during application.

[0072] According to embodiments, each mineral binder composition of the present invention comprises up to 85 wt.%, preferably 30-80 wt.%, more preferably 40-70 wt.%, of aggregate, preferably sand, especially quartz sand and / or limestone, based on the total dry weight of the mineral binder composition.

[0073] According to embodiments, sand with a particle size of less than 1 mm, preferably less than 0.8 mm, is used in the mineral binder composition of the present invention.

[0074] Mineral binder compositions containing this type of aggregate and mixed with water can be easily transported, easily mixed with additives, and produce a very uniform mineral binder matrix and surface after application. Furthermore, this contributes to achieving a uniform distribution of carbon nanotubes and carbon-containing particles.

[0075] Mineral binder compositions advantageously further comprise additives commonly used in the mortar and / or concrete industry, such as dispersants, plasticizers, superplasticizers, accelerators, retarders, rheology modifiers, thickeners, antisettling agents, pigments, corrosion inhibitors, fibers, strength enhancers, waterproofing additives, alkali-aggregate reaction inhibitors, chromate reducing agents, and / or antimicrobial agents. Combining two or more of these additives in a mineral binder composition can be advantageous.

[0076] Specifically, based on the total dry weight of the mineral binder composition, the proportion of additives is 0-10 wt.%, preferably 0.1-7 wt.%, more preferably 0.2-5 wt.%.

[0077] According to embodiments, the mineral binder composition of the present invention comprises a dispersant and / or a superplasticizer selected from lignin sulfonates, sulfonated vinyl copolymers, polynaphthalene sulfonates, sulfonated melamine-formaldehyde condensates, polyethylene oxide phosphonates, polycarboxylate ethers (PCE), or mixtures thereof. Preferably, the mineral binder composition of the present invention comprises PCE.

[0078] Such additives are particularly beneficial for achieving a uniform distribution of components in mineral binder compositions, especially a uniform distribution of carbon nanotubes and carbon-containing particles.

[0079] According to embodiments, the PCE comprises carboxylic acid groups in free form (i.e., unneutralized carboxylic acid groups) and / or in the form of alkali metal and / or alkaline earth metal salts. Preferably, the PCE does not contain any other anionic groups besides the carboxylic acid groups. Further preferably, the PCE has at least 80 mol% of its side chains, preferably at least 90 mol%, and especially preferably 100 mol% composed of ethylene glycol units. Preferably, the average molecular weight Mw of the side chains is 500-10000 g / mol, preferably 800-8000 g / mol, and especially preferably 1000-5000 g / mol. Side chains of different molecular weights may also be present in the PCE. Most preferably, the PCE is composed of (meth)acrylic acid and methyl polyalkylene glycol (meth)acrylate. The PCE preferably has an average molecular weight Mw of 8000-200000 g / mol, especially 10000-100000 g / mol, as measured relative to PEG standards. w .

[0080] According to a particularly preferred embodiment, the mineral binder composition of the present invention comprises:

[0081] a) at least one mineral binder, 10-65 wt.%, preferably 12-55 wt.%, especially 15-50 wt.%;

[0082] b) Carbon nanotubes with a concentration of 0.2-1000 ppm, preferably 1-900 ppm, more preferably 10-500 ppm, and especially 100-400 ppm;

[0083] c) 0.5-10 wt.%, especially 2-6 wt.%, for example 3-5 wt.% or 3.5-4.5 wt.% of carbon-containing particles;

[0084] d) 0-85 wt.%, preferably 30-80 wt.%, more preferably 40-70 wt.%, sand and / or gravel;

[0085] e) 0-10 wt.%, preferably 0.1-7 wt.%, more preferably 0.2-5 wt.%, of one or more additives selected from dispersants, plasticizers, superplasticizers, accelerators, retarders, rheology modifiers, thickeners, antisettling agents, pigments, corrosion inhibitors, fibers, strength enhancers, waterproofing additives, alkali-aggregate reaction inhibitors, chromate reducing agents and / or antimicrobial agents, and

[0086] f) Optional mixing water, especially water to mineral binder ratio of 0.25-0.8;

[0087] Each is based on the total dry weight of the mineral binder composition, excluding the mixed water.

[0088] According to an embodiment, the mineral binder composition comprises:

[0089] a) at least one mineral binder, 10-65 wt.%, preferably 12-55 wt.%, especially 15-50 wt.%;

[0090] b) Carbon nanotubes with a concentration of 0.2-1000 ppm, preferably 1-900 ppm, more preferably 10-500 ppm, and especially 100-400 ppm;

[0091] c) 0.5-10 wt.%, especially 2-6 wt.%, for example 3-5 wt.% or 3.5-4.5 wt.% of carbon black;

[0092] d) 0-85 wt.%, preferably 30-80 wt.%, more preferably 40-70 wt.%, aggregate, preferably sand and / or gravel;

[0093] e) 0-10 wt.%, preferably 0.1-7 wt.%, more preferably 0.2-5 wt.%, of one or more additives selected from dispersants, plasticizers, superplasticizers, accelerators, retarders, rheology modifiers, thickeners, antisettling agents, pigments, corrosion inhibitors, fibers, strength enhancers, waterproofing additives, alkali-aggregate reaction inhibitors, chromate reducing agents and / or antimicrobial agents, and

[0094] f) Optional water, especially water to mineral binder ratio of 0.25-0.8;

[0095] Each is based on the total dry weight of the mineral binder composition.

[0096] Specifically, the mineral binder composition is a mortar, concrete, flooring material, sealant, and / or grout composition.

[0097] In particular, the mineral binder composition is a flooring composition, especially a self-leveling flooring composition. Such compositions can be used directly in the production of, for example, antistatic flooring and / or flooring with integrated heating capabilities.

[0098] Specifically, the mineral binder composition is a dry composition. In this context, "dry composition" means a mineral binder composition with a moisture content of no more than 0.5 wt.% based on the total weight of the mineral binder composition. In this case, there is no mixed water.

[0099] In another embodiment, the mineral binder composition is a processable composition comprising mixed water. In this case, specifically, the ratio of water to mineral binder in the mineral binder composition is 0.25-0.7.

[0100] Another aspect of the present invention relates to a method for producing a hardened article, comprising the steps of:

[0101] (i) Mix the mineral binder composition of the present invention with water,

[0102] (ii) Dispose of the mixture obtained in step (i) into any desired shape.

[0103] (iii) The mixture of treatments obtained in step (ii) of curing.

[0104] In step (i), the ratio of water to mineral binder in the mineral binder composition is preferably 0.25-0.7.

[0105] Specifically, in step (i), the nanotubes are mixed with other components of the mineral binder composition and / or water in the form of a dispersion as described above.

[0106] Specifically, during step (iii), an electric current is passed through the treated mixture to resistively heat the treated mixture during the curing process. This will accelerate the curing process.

[0107] Therefore, for example, in order to pass current through the mixture being treated, a voltage of 1-100 V, especially 20-60 V, especially 30-50 V, can be applied between the relative positions of the mixture being treated, especially through electrodes, especially graphite electrodes.

[0108] Another aspect of the invention relates to a hardened article comprising the hardened mineral binder composition as described above and / or obtainable by hardening the mineral binder composition as described above with water. Therefore, the carbon-containing particles and carbon nanotubes are preferably formed into a continuous percolation network as described above.

[0109] Specifically, hardened products are or are part of the supporting structure of runways, roads, walkways, stairs, floors, walls, ceilings, roofs or building or infrastructure structures.

[0110] In particular, hardened articles are or form part of the flooring, especially the flooring, in a building. For example, molded articles are or form part of antistatic and / or electrically heated floors.

[0111] In another preferred embodiment, the hardened article is or forms part of an electrical component, particularly a capacitor, especially a supercapacitor. A supercapacitor (also called an ultracapacitor) is a high-capacitance capacitor that has a much higher capacitance than other capacitors but a lower voltage limit. It bridges the gap between an electrolytic capacitor and a rechargeable battery.

[0112] For example, a hardened product is a capacitor electrode.

[0113] Electrical components or capacitors can be used, for example, for energy storage. Therefore, another aspect of the invention relates to a support structure selected from objects such as runways, roads, sidewalks, stairs, floors, walls, ceilings, roofs, or building or infrastructure structures, comprising or consisting of the hardened mineral binder composition as described above or the hardened articles as described above.

[0114] Furthermore, the present invention relates to capacitors, particularly supercapacitors, which include at least one capacitor electrode, said capacitor electrode comprising or consisting of a hardened article as described herein.

[0115] Specifically, the capacitor includes at least two capacitor electrodes, which comprise or are composed of hardened articles as described herein, and are separated by a dielectric. The dielectric is a porous medium permeable to electrolyte substances, such as paper and / or cement.

[0116] However, capacitors may also be based on capacitor electrodes comprising or composed of hardened articles as described herein and at least one other capacitor electrode of a different material (e.g., metal or soil).

[0117] In particular, capacitors can be part of a building or infrastructure structure.

[0118] Specifically, the resistivity of a hardened product or object at 20°C is 10. -6 m to less than 10 4 m, especially 10 -4 m to 10 3 m. Specifically, hardened products have a density of less than 1000. m, especially less than 500 m, especially less than 100 The resistivity was measured in m. The resistivity was specifically determined after 28 days of curing.

[0119] To measure resistivity, a sample can be sandwiched, for example, between conductive electrodes (especially graphite electrodes) connected to a DC power supply. Resistivity (the reciprocal of conductivity) can be determined by applying a voltage and using Ohm's law and the sample's geometry.

[0120] Furthermore, the present invention relates to a method for heating a hardened article or object as described above, wherein an electric current is passed through the hardened article or object, causing the hardened article or object to be heated by resistance heating.

[0121] Therefore, preferably, current is passed through the hardened article or object by applying a voltage of 1-100 V, especially 20-60 V, particularly 30-50 V, for example, between the relative positions of the hardened article or object, especially via an electrode, particularly a graphite electrode.

[0122] Another aspect of the invention relates to the use of the mineral binder compositions or hardened articles as described above for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion protection of reinforced concrete structures, as antistatic flooring, as heating components of building or infrastructure structures, as elements of capacitors (especially supercapacitors), particularly as capacitor electrodes, and / or for storing electrical energy.

[0123] Furthermore, the present invention relates to the use of carbon nanotubes and carbon-containing particles for reducing the resistivity of mineral binder compositions, wherein the carbon-containing particles are chemically and / or physically different from carbon nanotubes.

[0124] The aforementioned special features and embodiments related to the mineral binder composition of the present invention are also advantageously realized in the above-described hardened articles, objects, methods, and uses.

[0125] Other advantageous embodiments of the invention will be apparent from the exemplary embodiments described herein. These embodiments are not intended to limit the scope of the invention in any way. Attached Figure Description

[0126] Figure 1 The temperature evolution of the mineral binder composition of the present invention is shown in comparison with that of two reference compositions.

[0127] Exemplary Implementation

[0128] Mortar Mixture

[0129] To prepare the dry mortar mixture M1 according to the present invention, 490 g of cement (CEM I 52.5), 1350 g of silica sand (CEN), and 1 g of superplasticizer (polycarboxylate ether) were mixed with 3.6 wt.% carbon black (Vulcan XC72R; purchased from Cabot Corporation; average particle size: 50 nm) and 400 ppm single-walled carbon nanotubes (used in the form of an aqueous dispersion of single-walled carbon nanotubes (OCSiAL Tuball)). TM Coat_E H2O 0.4% (sodium dodecylbenzenesulfonate, purchased from OCSiAL Europe; average outer diameter: 1.6 nm; average length >5 μm; G / D ratio >90) was mixed. The amount of nanotubes added was 400 ppm. All wt.% and ppm are relative to the total weight of all dry components of the mineral binder composition.

[0130] As the first comparative mortar mixture R1, the same type of cement, quartz sand, and plasticizer used in mixture M1 will be mixed with 4.5 wt.% carbon black (Vulcan XC72R). In this case, carbon nanotubes are not added. However, the proportions of cement, sand, and plasticizer remain the same as in mixture M1.

[0131] As a second comparative mortar mixture R2, the same type of cement, quartz sand, and superplasticizer used in mixture M1 will be mixed with 900 ppm single-walled carbon nanotubes (used in the form of an aqueous dispersion of single-walled carbon nanotubes (OCSiAL Tuball)). TM Coat_E H2O 0.4% (sodium dodecylbenzenesulfonate) is mixed. The amount of nanotubes added is 900 ppm. In this case, no carbon black is added. Again, the proportions of cement, sand, and superplasticizer are kept the same as in mixture M1.

[0132] The mortar mixture was mixed with water (w / c=0.6) in a Hobart mixer and cured in the form of a cuboid specimen (4 x 4 x 16 cm) to obtain a hardened mortar sample.

[0133] Thermoelectric test

[0134] A hardened mortar sample was sandwiched between conductive graphite electrodes connected to a DC power supply. A 40 V voltage was then applied to the electrodes to resistively heat the sample. The time evolution of the sample temperature was measured using a thermal imaging camera.

[0135] Figure 1 The temperature evolution of the three samples is shown. Clearly, the sample based on the mortar composition M1 of the present invention reaches a temperature of 100°C within approximately 10 minutes. In contrast, the comparative samples based on compositions R1 and R2 only reach approximately 60-70°C within 36 minutes.

[0136] Clearly, when compared with other samples containing only one of two carbon-based materials, the carbon black and carbon nanotubes in the mortar composition M1 of the present invention interact synergistically.

[0137] Therefore, using the mortar composition of the present invention, conductive hardened articles that can be heated at a fairly high rate and in an efficient manner can be produced. Furthermore, by adjusting the formulation of the mineral binder composition, the mortar composition can be easily adjusted to meet specific processing needs and desired properties.

[0138] Those skilled in the art will understand that the invention may be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments disclosed herein are to be considered illustrative rather than restrictive in all respects.

Claims

1. A mineral binder composition, particularly a conductive mineral binder composition, comprising at least one mineral binder, carbon nanotubes, and carbon-containing particles, said carbon-containing particles being chemically and / or physically different from said carbon nanotubes.

2. The mineral binder composition according to claim 1, wherein the carbon nanotubes are single-walled carbon nanotubes.

3. The mineral binder composition according to any one of the preceding claims, wherein the carbon nanotubes have an average outer diameter of about 0.4-25 nm, especially 0.6-10 nm, for example 1-5 nm, especially 1.2-2.0 nm; and wherein the carbon nanotubes have an average length of at least 0.5 μm, especially at least 1 μm, especially at least 4 μm, especially at least 5 μm.

4. The mineral binder composition according to any one of the preceding claims, wherein the carbon-containing particles are selected from carbon black, graphene flakes, multi-walled carbon nanotubes, coke particles and / or activated carbon.

5. The mineral binder composition according to any one of the preceding claims, wherein the carbon-containing particles are selected from carbon black.

6. The mineral binder composition according to any one of the preceding claims, wherein the carbon-containing particles have an average particle size of 10-500 nm, particularly 20-300 nm, particularly 25-100 nm, particularly 30-70 nm or 40-60 nm.

7. The mineral binder composition according to any one of the preceding claims, wherein the carbon-containing particles are selected from carbon black, especially carbon black having a particle size of 25-100 nm, and the carbon nanotubes are single-walled carbon nanotubes, especially single-walled carbon nanotubes having an average length of at least 5 μm and an average diameter of about 1.2-2.0 nm.

8. The mineral binder composition according to any one of the preceding claims, wherein the proportion of carbon nanotubes, particularly single-walled carbon nanotubes, is 0.2-1000 ppm, preferably 1-900 ppm, more preferably 10-500 ppm, especially 100-400 ppm, relative to the total weight of all dry components of the mineral binder composition; and the proportion of carbon particles, particularly carbon black, is 0.5-10 wt.%, especially 2-6 wt.%, for example 3-5 wt.% or 3.5-4.5 wt.%, relative to the total weight of all dry components of the mineral binder composition.

9. The mineral binder composition according to any one of the preceding claims, wherein the ratio of the carbon-containing particles and carbon nanotubes is selected such that a continuous percolation network of carbon-containing particles and carbon nanotubes exists.

10. The mineral binder composition according to any one of the preceding claims, wherein the at least one mineral binder is selected from cement, hydraulic lime, fly ash, slag, silica fume and / or gypsum.

11. The mineral binder composition according to any one of the preceding claims, comprising: a) 10-65 wt.%, preferably 12-55 wt.%, especially 15-50 wt.% of the at least one mineral binder; b) 0.2-1000 ppm, preferably 1-900 ppm, more preferably 10-500 ppm, especially 100-400 ppm of carbon nanotubes; c) 0.5-10 wt.%, especially 2-6 wt.%, for example 3-5 wt.% or 3.5-4.5 wt.% of carbon-containing particles; d) 0-85 wt.%, preferably 30-80 wt.%, more preferably 40-70 wt.%, sand and / or gravel; e) 0-10 wt.%, preferably 0.1-7 wt.%, more preferably 0.2-5 wt.%, of one or more additives selected from dispersants, plasticizers, superplasticizers, accelerators, retarders, rheology modifiers, thickeners, antisettling agents, pigments, corrosion inhibitors, fibers, strength enhancers, waterproofing additives, alkali-aggregate reaction inhibitors, chromate reducing agents and / or antimicrobial agents, and f) Optional water, especially water to mineral binder ratio of 0.25-0.8; Each is based on the total dry weight of the mineral binder composition.

12. A hardened article comprising a hardened mineral binder composition according to any one of the preceding claims and / or obtainable by hardening a mineral binder composition according to any one of the preceding claims with water.

13. An object selected from the supporting structure of a runway, road, sidewalk, staircase, floor, wall, ceiling, roof, or building or infrastructure structure, comprising a hardened mineral binder composition according to any one of claims 1-11 or a hardened article according to claim 12, or composed of a hardened mineral binder composition according to any one of claims 1-11 or a hardened article according to claim 12.

14. A method of heating a hardened article according to claim 12 or an object according to claim 13, wherein an electric current is passed through the hardened article or the object, particularly the hardened article or the object is heated by resistance heating.

15. Use of the mineral binder composition according to any one of claims 1-11 or the hardened article according to claim 12 for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion protection of reinforced concrete structures, as antistatic flooring, as heating elements of building or infrastructure structures, as elements of capacitors, especially supercapacitors, particularly as capacitor electrodes, and / or for storing electrical energy.

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