Construction binder and associated construction material

Abstract

The invention relates in particular to a construction binder comprising more than 10% by weight of one or more raw clay matrices, at least 8% by weight of one or more activators, the one or more activators preferably comprising clinker, at least two precursors and at least one deflocculating polymer, the at least two precursors comprising at least one calcined clay matrix and at least one other precursor, the construction binder comprising at least 2% by weight of one or more calcined clay matrices. The invention also relates to a method for preparing such a construction binder and to construction materials based on this binder.

Description

Description Title: CONSTRUCTION BINDER AND ASSOCIATED CONSTRUCTION MATERIAL Technical field

[0001] The invention relates to the field of construction and more particularly to that of low-carbon construction materials. In particular, it relates to a construction binder comprising a raw clay matrix, an activator and at least two precursors including a calcined clay matrix. Furthermore, the invention relates to a construction material produced from a construction binder according to the invention. Prior art

[0002] Below we describe the known prior art from which the invention was developed.

[0003] Cement is the second most consumed resource in the world, with more than 4 billion tons produced worldwide each year. This consumption is constantly increasing, driven by the growing demand for housing and infrastructure. Cement is particularly used for the manufacture of masonry units that rely on cementitious materials as binders. Due to the constant development of new infrastructure in most countries around the world, there is a constant demand for the supply of construction binders, especially raw materials for the formation of Portland cement. However, the production and use of Portland cement is associated with a high environmental footprint. The cement used in the construction industry is generally Portland cement. It is a hydraulic binder that, when mixed with water, hardens and sets.After hardening, cement retains its strength and stability even when exposed to water. There is a wide variety of cements used worldwide. However, all conventional cements contain clinker at a percentage ranging from 5% for some blast furnace cements to a minimum of 95% for Portland cement, which is the most widely used cement in the world today. Clinker is produced by firing a mixture of approximately 80% limestone and 20% aluminosilicates (such as clays). This firing, clinkerization, is generally carried out at a temperature of over 1200°C, making such a cement preparation process highly energy-intensive. In addition, the chemical conversion of limestone into lime also releases. carbon dioxide. As a result, the cement industry generates approximately 8% of global CO2 emissions.

[0004] Indeed, it is estimated that the manufacture of a Portland-type construction binder generates on average 0.8 kg of CO2 per kg of Portland cement clinker produced. Various solutions have therefore been developed to attempt to at least partially replace certain components of the construction binders used for the formation of Portland-type cements. These solutions are primarily aimed at reducing the carbon footprint.

[0005] Clay has been avoided until recently because low concentrations were sufficient to interact negatively with superplasticizers such as PCEs used in concrete. Thus, in concrete, raw clays were long considered an impurity brought for example by aggregates (e.g. sand). A low clay content inhibits the effect of plasticizers and superplasticizers and has a negative impact on the water demand of concrete. This induces a sharp increase in the amount of water required to obtain a given flow, resulting in a loss of mechanical performance on the hardened product. However, it has recently been shown that the preparation of construction binder from raw clay, added even before the addition of fillers, could allow the generation of construction materials with high levels of mechanical strength (WO22157209, EP3932886, WO20 178538, WO20141285).

[0006] Since then, new construction binders and materials containing a significant amount of raw clay are being developed and allow for significantly reduced carbon footprints.

[0007] In order to promote their democratization, these low-carbon solutions must be able to present a high mechanical resistance at early age so that industrial processes can substitute Portland cement with these low-carbon solutions without consequences. Thus, there is a need for new construction materials based on raw clay with improved mechanical properties at early age (1 day). Summary of the invention

[0008] The invention aims to overcome these drawbacks. The following presents a simplified summary of selected aspects, embodiments and examples of the present invention for the purpose of providing a basic understanding of the invention. However, The summary of the invention does not constitute an exhaustive overview of all aspects, embodiments and examples of the invention. The sole purpose of the summary is to present selected aspects, embodiments and examples of the invention in a concise form as an introduction to the more detailed description of the aspects, embodiments and examples of the invention which follow the summary.

[0009] The invention relates in particular to a construction binder comprising more than 10% by weight of raw clay matrix(s), at least 8% by weight of activator(s) (preferably said activator(s) comprising clinker), at least two precursors, and at least one deflocculating polymer, said at least two precursors comprising at least one calcined clay matrix and at least one other precursor, said construction binder comprising at least 2% by weight of calcined clay matrix(s). As will be detailed later, these mass proportions are preferably calculated relative to the dry weight of construction binder.

[0010] Preferably, the raw clay matrix, the calcined clay matrix, and the activator(s) are present in an amount such that: - the mass ratio between the calcined clay matrix and the raw clay matrix is ​​between 0 and 0.66, excluding limits, and - the mass ratio between the calcined clay matrix and the activator(s) is between 0 and 0.40, excluding limits.

[0011] More preferably, the raw clay matrix, the calcined clay matrix, and the activator(s) are present in an amount such that: - the mass ratio between the calcined clay matrix and the raw clay matrix is ​​between 0 and 0.33, excluding limits, and - the mass ratio between the calcined clay matrix and the activator(s) is between 0 and 0.20, excluding limits.

[0012] The applicant has developed a low-carbon construction binder having improved early mechanical strength. The developed binder may have a somewhat degraded mechanical strength at 28 days compared to a CEM I or CEM III A type construction binder. On the other hand, as illustrated in the examples, the early mechanical strength of a construction material using a construction binder according to the invention is improved by more than 18% to more than 50% depending on the compositions compared to a CEM III A.

[0013] Indeed, the substitution of part of the activator by a calcined clay matrix (eg metakaolin) allows, in the presence of raw clay matrix and another precursor (eg a slag), to increase the mechanical resistance at an early age.

[0014] According to other optional characteristics of the construction binder, the latter may optionally include one or more of the following characteristics, alone or in combination: - it comprises at least 25% by weight of raw clay matrix relative to the dry weight of construction binder. The presence of such a quantity of raw clay matrix makes it possible to reduce the environmental footprint of the binder. In addition, when combined with the calcined clay matrix and at least one other precursor, it makes it possible to improve the Rc at early age. - the activator(s) are selected from: clinker, CEM I; lime, silicates such as sodium silicates, and carbonates such as sodium carbonate; or combinations thereof. As presented in the examples, the combination of CEM I, with a raw clay matrix, a calcined clay matrix and another precursor makes it possible to improve the Rc at early age. - it comprises at least 30% by weight of activator(s), preferably at least 30% by weight of CEM I as activator; relative to the dry weight of construction binder. As presented in the examples, the combination of CEM I, with a raw clay matrix, a calcined clay matrix and another precursor makes it possible to improve the Rc at early age. - it contains at most 50% by weight of CEM I; relative to the dry weight of construction binder. - it contains at most 15% by weight of calcined clay matrix; relative to the dry weight of the construction binder. As shown in the examples, a reduced content of calcined clay matrix can be favorable to the Rc at young age. - it comprises at least 10% by weight of at least one other precursor; relative to the dry weight of the construction binder. As presented in the examples, the combination of calcined clay matrix with a raw clay matrix and another precursor allows for Rc at a young age. - it contains at most 25% by weight of at least one other precursor; relative to the dry weight of the construction binder. - the at least one other precursor is selected from: slags such as blast furnace slags, steelworks slags, cupola slags; fly ash; natural pozzolans; silica fumes; fillers micronized limestones; siliceous fillers; micronized siliceous fillers such as glass powder; synthetic vaterite; diatomaceous earth; ground slag or combinations thereof. - the at least one other precursor is selected from: blast furnace slag, micronized limestone filler; vaterite such as micrometric or nanometric vaterite; or combinations thereof. - the calcined clay matrix and the at least one other precursor are present in an amount such that the mass ratio by weight between the calcined clay matrix and the at least one other precursor is between 0 and 0.50 (limits not included). As shown in the examples, this is favorable to the Rc at young age. - the calcined clay matrix and the raw clay matrix are present in such a quantity that the mass ratio by weight between the calcined clay matrix and the raw clay matrix is ​​between 0 and 0.33 (limits not included). As shown in the examples, this is favorable to the Rc at young age. - the calcined clay matrix and the activator(s) are present in an amount such that the mass ratio by weight between the calcined clay matrix and the activator(s) is between 0 and 0.20 (limits not included), preferably, the activator(s) comprise clinker and the calcined clay matrix and the clinker are present in an amount such that the mass ratio by weight between the calcined clay matrix and the clinker is between 0 and 0.20 (limits not included). As shown in the examples, this is favorable to the Rc at early age. - the activator(s) and precursor(s) are present in an amount such that the dry weight mass ratio between the activator(s) and precursor(s) is less than or equal to 2. As shown in the examples, this is favorable to Rc at a young age.

[0015] According to another object, the invention relates to a method for preparing a construction binder according to the invention. In particular, the method may comprise a step of mixing the constituents of the construction binder and then a step of adding water.

[0016] According to another object, the invention relates to a construction material formed from a construction binder according to the invention. Brief description of the drawings

[0017] Other characteristics and advantages of the invention will be better understood upon reading the description which follows and with reference to the appended drawings, given for illustrative purposes and in no way limiting.

[0018] [Fig. 1] shows a schematic illustration of a manufacturing method according to one embodiment of the present invention. The steps outlined in dotted lines are optional.

[0019] The figures do not necessarily respect the scales, particularly in thickness, and this is for illustration purposes.

[0020] Aspects of the present invention are described with reference to flowcharts and / or block diagrams of methods according to embodiments of the invention. In the figures, the flowcharts and block diagrams illustrate the architecture, functionality and operation of possible implementations of systems and methods according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a system, a device, a module implementing the specified logical function(s). In some implementations, the functions associated with the blocks may appear in a different order than indicated in the figures. For example, two blocks shown in succession may, in fact, be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functionality involved.Each block of the block diagrams and / or flowchart, and combinations of blocks in the block diagrams and / or flowchart, can be implemented by special hardware systems that perform the specified functions or acts. Description of the embodiments

[0021] Below, we describe a summary of the invention and the associated vocabulary, before presenting the disadvantages of the prior art, and then showing in more detail how the invention overcomes them.

[0022] In the remainder of the description, the term “binder” or “construction binder” within the meaning of the invention may be understood as a formulation making it possible to ensure the agglomeration of materials between them, in particular during the setting and then hardening of a construction material. Thus, it makes it possible in particular to ensure the agglomeration of sand and other constituents of a construction material with the constituents of the binder. The binder according to the invention is in particular a hydraulic binder, that is to say that hardening takes place on contact with water.

[0023] The expression "clay matrix", within the meaning of the invention, may correspond to one or more rock materials based on phyllosilicates, hydrated silicates or aluminosilicates with a lamellar structure, said clay matrix being composed at least in part of fine particles generally originating from the alteration of silicates with a three-dimensional framework or from the precipitation of a supersaturated fluid. A clay matrix may thus comprise a mixture of such rock materials which may, for example, comprise kaolinite, serpentine, pyrophyllite, talc, smectite, vermiculite, illite, glauconite, mica, chlorite, palygorskite, sepiolite, interstratified materials or mixtures thereof (Alain Meunier. Clays, 2005). In addition, a clay matrix may include silts or loams.A clay matrix may come from, but is not limited to, construction site spoil, quarry fines, clay-limestone fines, washing fines, clay sludge, stripping materials, clay excavation materials such as excavated earth, or sediments, including dredged sediments and varves, phyllosilicate rocks and alterites such as turbidites, marls, pelites, ruffes, laterites, schists, mica schists.

[0024] For the purposes of the invention, the expression “raw clay matrix” may correspond to a clay matrix that has not undergone a calcination step. For example, this corresponds to a clay matrix that has not undergone a temperature rise greater than 300°C, preferably greater than 200°C and more preferably a temperature greater than 150°C. Indeed, the raw clay matrix may undergo a drying step by heating requiring a temperature rise generally substantially equal to or less than 150°C but no calcination step. A raw clay matrix may preferably comprise a mixture of rock materials which may, for example, comprise kaolinite, serpentine, pyrophyllite, talc, smectite, vermiculite, illite, glauconite, mica, chlorite, palygorskite, sepiolite, interstratified rocks or mixtures thereof, as well as silts.For the purposes of the invention, the expression "calcined clay matrix" may correspond to a clay matrix that has undergone a calcination step. For example, this corresponds to a clay matrix that has undergone a temperature increase greater than 300°C, preferably greater than 500°C and more preferably a temperature greater than 700°C. A calcined clay matrix may be formed from a mixture of rock materials that may, for example. example include kaolinite, illite, smectite, micas such as muscovite, bentonite, chlorite, vermiculite, or mixtures thereof, as well as silts.

[0025] For the purposes of the invention, a "deflocculant" may correspond to a compound capable of dissociating aggregates and colloids, particularly in aqueous suspension. Deflocculating agents have, for example, been used in the context of drilling or oil extraction to make clay more fluid and facilitate extraction or drilling. The expression "organic deflocculant" may correspond to a deflocculant comprising at least one carbon atom and preferably at least one carbon-oxygen bond. The expression "deflocculant polymer" may correspond, for the purposes of the invention, to a deflocculating agent comprising at least one monomer repetition.

[0026] The term "Portland cement" refers to a hydraulic binder composed primarily of hydraulic calcium silicates, the setting and hardening of which is made possible by a chemical reaction with water. Portland cement generally contains at least 95% by weight of clinker and a maximum of 5% by weight of secondary constituents such as alkalis (Na2O, K2O), magnesia (MgO), gypsum (CaSC ■ 2 H2O) or various traces of metals. For example, Portland cement may refer to CEM I, which generally comprises 95% by weight of ground clinker and 5% by weight of ground gypsum.

[0027] The term "clinker" can refer to a constituent of cement and comes from the firing of a mixture composed of approximately 80% by weight of limestone and 20% by weight of aluminosilicates (such as clays). This firing, clinkerization, is generally carried out at a temperature of over 1200°C, which is particularly energy-intensive and generates high greenhouse gas emissions. The clinker is generally ground and can then be mixed with blast furnace slag to produce composite cements.

[0028] The term "raw earth" can refer to a granular mineral material, for example, derived from sedimentary rock or sedimentary deposits. Raw earth has different names depending on its composition or origin. Raw earth can, for example, refer to clay, sandy clay, clay-loam, silty clay, fine silty clay, silty clay-sandy, silty, fine clayey silty, fine silty clay, very fine silty, sandy silty, sandy-loam, sandy-clay and sandy soils. Raw earth can also refer to waste rock (from discovery or production), exposed clay, and earth excavated, such as excavated clay soil, to clayey sands from sewage treatment plants, sludge or even sediments.

[0029] The expression "excavated clayey soil" corresponds, within the meaning of the invention, to a clayey soil obtained following a step where the soil has been dug, for example during sediment dredging, reclamation and / or earthworks operations, with a view to constructing, building or backfilling. In particular, within the meaning of the invention, the excavated clayey soil may or may not be moved outside the excavation site. Preferably and according to an advantage of the invention, the excavated soil is used on the excavation site or at a distance of less than 500 km, preferably less than 200 km, more preferably less than 50 km. Thus, the method according to the invention may comprise a step of removing raw soil and transporting raw soil over a distance of less than 500 km before its use in the method.Furthermore, advantageously, the excavated clay soil within the scope of the invention is a raw excavated clay soil, i.e. it has not undergone a calcination step. In particular, i.e. it has not undergone any prior heat treatment. For example, this corresponds to a clay soil that has not undergone a temperature rise greater than 300°C, preferably greater than 200°C and more preferably a temperature greater than 150°C. Indeed, the raw clay soil may undergo a drying step requiring a temperature rise generally substantially equal to 150°C but no calcination step. A calcination step may, for example, correspond to a heat treatment at more than 600°C for several seconds. An excavated clay soil may have different grain size profiles.In the context of the invention, an excavated clayey soil may comprise particles of a size greater than 2 pm, preferably greater than 20 pm, preferably greater than 50 pm and for example greater than 75 pm as determined according to the ASTM D422-63 standard or the ASTM D6913-04(2009) standard. Preferably, the excavated clayey soil does not comprise any aggregate of a size greater than 2 cm as determined according to the NE EN 933-1 standard, preferably no aggregate of a size greater than 0.5 cm. This particle size can in particular be evaluated after deagglomeration and / or grinding.

[0030] The term "sand" can refer to particles, originating from the disintegration of rocks, whose size is between 0.063 mm and 2 mm.

[0031] The term "silt" can refer to particles with grain sizes intermediate between clays and sands (between approximately 2 and 63 micrometers).

[0032] The term "micronized" may refer to a component of the construction binder which has undergone an operation aimed at transforming it into a set of micrometric particles, i.e. having a D50 of between 1 pm and 200 pm.

[0033] The term "nanometric" can refer to a component of the construction binder having a D50 between 1 nm and 200 nm.

[0034] The term "D50" refers to the median diameter at which 50% (by volume or mass, preferably by mass) of the grains, particles, aggregates, or sediments are smaller than a given diameter. For example, if a sieve and sediment analysis method indicates a D50 = 5.8 mm, then 50% of the particles in the sample (by volume or mass, preferably by mass) are larger than 5.8 mm. D50 is generally used to represent the particle size of a group of particles. D50 is preferably measured according to standard NF ISO 11277 (2020), according to standard NF EN ISO 17892.4 (2018), according to standard ASTM D422-63 or according to standard ASTM D6913-04 (2009) or in particular for fine particles standard ISO 13320:2020 (eg D10 or <65 pm).The expressions "granulometric property" or "granulometric profile" or "particle size distribution" may correspond to values ​​of parameters relating to the particle size distribution, for example in the raw clay matrix or in raw earths. There are many parameters relating to the particle size distribution such as D50, D10, D90.

[0035] In the remainder of the description, the term "% by weight" in relation to the binder, or in relation to the construction material, must be understood as being a proportion relative to the dry weight of binder. The dry weight corresponds to the weight before the addition of water, for example, necessary for the formation of the construction material. When the values ​​of % by weight are given in the form of intervals, the limits are included unless otherwise specified.

[0036] The term "substantially equal" within the meaning of the invention corresponds to a value varying by less than 20% compared to the compared value, preferably by less than 10%, even more preferably by less than 5%.

[0037] The construction industry must evolve to optimize its productivity while addressing societal and environmental challenges. Construction binders called LC3 for "Limestone Calcined Clay Cement" or construction binders based on raw clay are becoming increasingly important thanks to a reduced carbon footprint compared to conventional Portland cement. However, these solutions may have degraded setting times and therefore degraded mechanical resistance at an early age (eg 1 day) compared to a classic Portland cement (CEMI).

[0038] Faced with this observation, the applicant has developed a new solution to increase the mechanical resistance at an early age (e.g. 1 day) while further reducing the carbon footprint of this construction material. As will be detailed later, the solution developed is based on the preparation of a binder comprising a mixture of raw clay and calcined clay in combination with an activator, another precursor and a deflocculating polymer.

[0039] Thus, according to a first aspect, the invention relates to a construction binder.

[0040] A construction binder according to the present invention comprises one or more raw clay matrix(ies), one or more activator(s), at least two precursors, and at least one deflocculating polymer. In particular, said at least two precursors comprise one or more calcined clay matrix(ies) and at least one other precursor, said construction binder comprising at least 2% by weight of calcined clay matrix(ies).

[0041] Preferably, a construction binder according to the invention comprises more than 10% by weight of raw clay matrix(es), at least 2% by weight of calcined clay matrix(es), at least 8% by weight of activator(s), at least one deflocculating polymer, and at least one other precursor. RAW CLAY MATRIX

[0042] The raw clay matrix may, for example, contain at least one mineral species selected from: Illite, Kaolinite, Smectite, Vermiculite, Chlorite, Montmorillonites, Muscovite, Halloysite, Sepiolite, and Palygorskite.

[0043] Preferably, the raw clay matrix comprises at least two types of clays selected from: Illite, Kaolinite, Smectite, Vermiculite, Chlorite, Montmorillonites, Muscovite, Halloysite, Sepiolite, Interstratified, Pyrophyllite, talcs, Serpentines and Palygorskite. This includes so-called interstratified clays which are complex combinations of several clays. Even more preferably, the raw clay matrix comprises at least one mineral species selected from: Kaolinite, Illite, Smectite, Palygorskite, Sepiolite, Chlorite, Montmorillonites, and Vermiculite.

[0044] Table 1 below presents the chemical characteristics of these mineral species. [Table 1]

[0045] According to a preferred embodiment, a binder for construction material according to the invention will comprise at least two different types of clays and will comprise smectite (Smectite, Bentonite, Montmorillonites), kaolinite, and / or illite.

[0046] The type of clay can be determined by methods known to the person skilled in the art, for example after specific preparation of the samples using the so-called oriented blade method (see Thiry et al. - 2013 - Technique for preparing clay minerals for analysis by X-ray diffraction and introduction to the interpretation of diagrams). In particular, it will be possible to use X-ray diffractometry. For example, the following conditions can be used: - Apparatus: Diffractometer, for example a BRUKER D8 ADVANCE (Bragg-Brentano geometry); for example with the following settings: Copper tube (At Ka1 ~ 1.54 Â) Generator power: 40 kV, 40 mA; Primary optics: fixed slit 0.16°; Soller slit 2.5°; Secondary optics: Soller slit 2.5°; LynXeye XE-T detector Acquisition parameters: Scan from 4 to 90°20; Scan speed of 0.03°20 / second, Counting time: 480 seconds per step; Rotating sample.

[0047] The raw clay matrix may, preferably, correspond at least in part to an excavated clay soil, preferably an excavated clay soil not calcined, such as treated raw excavated clay soil. The raw clay matrix may advantageously have been treated, said treatment being selected from: grinding, sorting, sieving and / or drying. Preferably, the raw clay matrix used in the binder has been ground.

[0048] Advantageously, the raw clay matrix will comprise crushed raw clay. Preferably, the raw clay matrix may have a D50 of less than or equal to 500 pm, preferably less than or equal to 250 pm, more preferably less than or equal to 100 pm or even more preferably less than or equal to 50 pm.

[0049] In addition, the raw clay matrix may have a D50 greater than or equal to 0.1 pm, preferably greater than or equal to 1 pm, more preferably greater than or equal to 10 pm or even more preferably greater than or equal to 20 pm, more preferably greater than 40 pm. This makes it possible to limit the constraints on industrial production tools dedicated to grinding.

[0050] More preferably, the raw clay matrix may have a D50 of between 10 pm and 500 pm, preferably between 15 pm and 250 pm, more preferably between 20 pm and 150 pm or even more preferably between 20 pm and 50 pm. The presence of a clay ground so as to reach such diameters can make it possible to improve the performance of the construction binder and the construction material according to the invention.

[0051] Advantageously, the raw clay matrix may comprise at least 2% by weight of silt particles, preferably at least 4% by weight, more preferably at least 6% by weight. For example, the raw clay matrix may comprise at most 50% by weight of silt particles, preferably at most 30% by weight, more preferably at most 20% by weight. For example, the raw clay matrix may comprise from 2% to 50% by weight of silt particles, preferably from 4% to 30% by weight, more preferably from 6% to 20% by weight. The silt particles are in particular particles having a diameter of between 2 μm and 63 μm.

[0052] The raw clay matrix may comprise at least 1% by weight of sand, preferably at least 2% by weight, more preferably at least 3% by weight. For example, the raw clay matrix may comprise at most 70% by weight of sand, preferably at most 50% by weight, more preferably at most 40% by weight. For example, the raw clay matrix may comprise from 1% to 70% by weight of sand particles, preferably from 2% to 50% by weight, more preferably from 3% to 40% by weight. Sand corresponds in particular to particles with a diameter between 63 pm and 2 mm.

[0053] As mentioned, in the context of the present invention, a construction binder comprises more than 10% by weight of raw clay matrix(s),

[0054] For example, a construction binder according to the invention may comprise at least 11% by weight of raw clay matrix, preferably at least 15% by weight of raw clay matrix, more preferably at least 20% by weight of raw clay matrix, even more preferably at least 25% by weight of raw clay matrix.

[0055] A construction binder according to the invention may comprise at most 80% by weight of raw clay matrix, preferably at most 70% by weight of raw clay matrix, more preferably at most 60% by weight of raw clay matrix, even more preferably at most 50% by weight of raw clay matrix, for example at most 40% by weight of raw clay matrix or even at most 30% by weight of raw clay matrix.

[0056] Generally, a construction binder according to the invention may comprise from 11% to 80% by weight of raw clay matrix, preferably from 15% to 70% by weight of raw clay matrix, more preferably from 20% to 60% by weight of raw clay matrix, even more preferably from 25% to 50% by weight of raw clay matrix, relative to the dry weight of the construction binder; for example from 25% to 40% by weight of raw clay matrix, relative to the dry weight of the construction binder.

[0057] Preferably, the raw clay matrix comprises clay contents in the mineralogical sense of the term of at least 10% by dry weight, more preferably at least 20% by dry weight, and even more preferably at least 30% by dry weight. However, a raw clay matrix comprising low clay contents in the mineralogical sense may be used. In particular, the raw clay matrix may correspond to fine clay-limestone or clay-silica / quartz comprising at least 50% by dry weight of limestone, silica or quartz, preferably at least 60%, more preferably at least 70% or even more preferably at least 80% by dry weight of limestone, silica or quartz.

[0058] Advantageously, the raw clay matrix used will have a humidity of less than 10%, preferably less than 8%, more preferably less than 6% and even more preferably less than 4%. However, preferably, the raw clay matrix used will have a humidity of greater than 2%. The humidity of the clay matrix can be measured as described in the standard NF ISO 11465 - August 1994 or in the standard ISO 12570:2000. Briefly, the determination of the humidity rate is carried out by hot drying (thermogravimetric analysis).

[0059] As described, a construction binder according to the present invention will comprise at least two different precursors. In particular, it will comprise at least one calcined clay matrix which is considered herein as a precursor as well as another precursor which is not a calcined clay matrix.

[0060] In particular, a construction binder according to the invention is such that the precursors comprise at least 4% by weight of a calcined clay matrix and at least 8% by weight of at least one other precursor, relative to the dry weight of the construction binder. CALCINED CLAY MATRIX(ES)

[0061] A construction binder according to the present invention comprises at least 2% by weight of calcined clay matrix(s), relative to the dry weight of the construction binder.

[0062] For example, a construction binder according to the invention may comprise at least 2% by weight of calcined clay matrix, preferably at least 3% by weight of calcined clay matrix, more preferably at least 4% by weight of calcined clay matrix relative to the dry weight of the construction binder.

[0063] A construction binder according to the present invention may comprise at most 20% by weight of calcined clay matrix, preferably at most 15% by weight of calcined clay matrix, more preferably at most 12.5% ​​by weight of calcined clay matrix, even more preferably at most 10% by weight of calcined clay matrix, relative to the dry weight of the construction binder.

[0064] Generally, a construction binder according to the present invention comprises from 2% to 20% by weight of calcined clay matrix, preferably from 3% to 15% by weight of calcined clay matrix, more preferably from 4% to 12.5% ​​by weight of calcined clay matrix, even more preferably from 4% to 10% by weight of calcined clay matrix, relative to the dry weight of the construction binder.

[0065] There are many methods for preparing a calcined clay matrix and there can be many different calcined clay matrices. Generally, a calcined clay matrix will have undergone a calcination step at a temperature of at least 500°C, preferably at least 600°C.

[0066] The calcination may be a natural calcination such as for a calcined clay matrix from a natural pozzolanic rock. This calcined clay matrix has generally been formed from volcanic basaltic projections or of similar composition. However, preferably, the calcination is an anthropogenic calcination.

[0067] The calcination may be a so-called flash calcination carried out for a period of less than one hour, preferably less than one minute and more preferably less than one second (e.g. generally less than one second near a heat source at more than 900°C after an initial temperature rise). Alternatively, the heat treatment may be carried out for several hours (e.g. at least 3 hours, preferably at least 4 hours).

[0068] Heat treatments can be carried out in rotary kilns, screw kilns, or calcination towers. Advantageously, the calcination equipment used is powered by carbon-free energy and / or has been retrofitted, for example to be 100% electric.

[0069] In addition, calcination may be followed by a cooling step, for example a cooling step of at least 3°C ​​per minute. This cooling may, for example, be carried out in the form of quenching.

[0070] Preferably, the calcined clay material is at least partially dehydroxylated. Thus, the structure in the form of sheets in the raw state is at least partially destroyed leading to a disorganized or even amorphous structure. In addition, it exhibits pozzolanic activity. In particular, flash-type heat treatment can increase the surface defects of the crystallites and thus increases the number of reactive sites.

[0071] The calcined clay matrix can be formed with all the clay matrices already mentioned above. Preferably, the raw clay matrix that was calcined comprised kaolinite, montmorillonite and / or illite. Thus, preferably, the calcined clay matrix comprises metakaolin, metamontmorillonite or metaillite. ANOTHER PRECURSOR

[0072] As mentioned, a construction binder according to the present invention comprises at least one other precursor, for example of the pozzolan type, which is not a calcined clay matrix.

[0073] For example, the at least one other precursor may be slag, concrete washing fines, concrete recycling fines, natural or artificial pozzolan, ash, shale, or a combination thereof.

[0074] The at least one other precursor may for example comprise slags such as blast furnace slags, steelworks slags or cupola slags, volcanic ash, fly ash, silica fume, ash from plant materials such as rice ash, bauxite residues, limestone fillers such as micronized limestone fillers, siliceous fillers, micronized siliceous fillers such as glass powder, synthetic vaterite, diatomaceous earths (e.g. diatomites), ground slags or combinations thereof. In particular, steelworks slags may be electric steelworks slags or oxygen converter steelworks slags.

[0075] Preferably, the at least one other precursor comprises slags such as blast furnace slags, steel mill slags, or cupola slags. More preferably, the at least one other precursor consists of slags such as blast furnace slags, steel mill slags, or cupola slags.

[0076] Preferably, the limestone filler comprises a natural limestone mainly consisting of calcium carbonate with different polymorphs, such as calcite, vaterite and / or aragonite, but which may also contain a certain quantity of magnesium carbonate and / or dolomite. The limestone filler may also be a natural marl.

[0077] The at least one other precursor may in particular be a composition comprising at least 30% by dry weight of carbonate, calcium carbonate or potassium carbonate, preferably at least 30% by dry weight of calcium carbonate; more preferably at least 50% by dry weight of calcium carbonate; even more preferably at least 70% by dry weight of calcium carbonate. In this embodiment, the at least one other precursor is preferably a precursor resulting from chemical synthesis.

[0078] The calcium carbonate present in the at least one other precursor is preferably in the form of vaterite. For example, the calcium carbonate may thus comprise at least 10% by weight of vaterite; or at least 20% by weight of vaterite; or at least 30% by weight of vaterite; or at least 40% by weight of vaterite; or at least 50% by weight of vaterite; or at least 60% by weight of vaterite; or at least 70% by weight of vaterite; or at least 80% by weight of vaterite; or at least 90% by weight of vaterite; or at least 95% by weight of vaterite; or at least 99% by weight of vaterite. Vaterite in the presence of water forms aragonite. Vaterite can be obtained by any type of method known to those skilled in the art.

[0079] In particular, the at least one other precursor is a micronized limestone filler. That is to say, it comprises calcium carbonate in the form of particles smaller than 100 μm. Advantageously, the at least one other precursor comprises calcium carbonate present, for example in the form of vaterite, in the form of particles having a D50 value less than or equal to 25 μm, preferably less than or equal to 15 μm, more preferably less than or equal to 10 μm and even more preferably less than or equal to 5 μm. The measurement of D50 can be carried out by any conventional method for determining the size of the particles, such as, but not limited to, multi-detector laser scattering or laser diffraction or sieving. Preferably, the measurement of D50 is carried out according to the ISO 13320:2020 standard.

[0080] A construction binder according to the present invention may comprise at least 9% by weight of the at least one other precursor, preferably at least 14% by weight of the at least one other precursor, more preferably at least 16% by weight of the at least one other precursor, even more preferably at least 19% by weight of the at least one other precursor.

[0081] A construction binder according to the present invention may comprise at most 35% by weight of the at least one other precursor, preferably at most 30% by weight of the at least one other precursor, more preferably at most 27.5% by weight of the at least one other precursor, even more preferably at most 25% by weight of the at least one other precursor.

[0082] Generally, a construction binder according to the present invention comprises from 9% to 35% by weight of the at least one other precursor, preferably from 14% to 30% by weight of the at least one other precursor, more preferably from 16% to 27.5% by weight of the at least one other precursor, even more preferably from 19% to 25% by weight of the at least one other precursor. ACTIVATOR

[0083] As mentioned, a construction binder according to the present invention comprises at least 10% by weight of activator(s).

[0084] The activator(s) used in a construction binder according to the present invention may comprise an alkaline activating composition.

[0085] Advantageously, the activator is an alkaline activation composition. It then preferably comprises at least one base, such as a weak base or a strong base. The alkaline activation composition may preferably comprise one or more compounds having a pKa greater than or equal to 8, more preferably greater than or equal to 10, more preferably greater than or equal to 12, even more preferably greater than or equal to 14. The activation composition may be or comprise lime, carbonates, cement such as Portland cement CEM I, composite cement (CEM II), blast furnace cement (CEM III / A), supersulfated or ettringitic cement, aluminous cement and composite cement (CEM V / A) conforming to standards NE EN 197-1 and NE EN 197-4 or even masonry cement (MC) conforming to standard NE EN 413-1.

[0086] The activator(s) used in a construction binder according to the present invention may comprise clinker, silicates, carbonates, sulfates, gypsum (or its dehydrated forms bassanite and anhydrite), hydroxides, lactates, organophosphates, lime and combinations thereof.

[0087] A construction binder according to the present invention may comprise at least 10% by weight of activator(s); preferably at least 15% by weight of activator(s); preferably at least 20% by weight of activator(s), preferably at least 25% by weight of activator(s), more preferably at least 30% by weight of activator(s), even more preferably at least 35% by weight of activator(s).

[0088] A construction binder according to the present invention may comprise at most 60% by weight of activator(s), preferably at most 55% by weight of activator(s), more preferably at most 50% by weight of activator(s), even more preferably at most 45% by weight of activator(s). In particular, it may comprise at most 40% by weight of activator(s) and more preferably at most 35% by weight of activator(s), relative to the dry weight of construction binder. For example, it may comprise at most 30% by weight of activator(s) relative to the dry weight of construction binder.

[0089] Generally a construction binder according to the present invention comprises from 10% to 60% by weight of activator(s), preferably from 15% to 55% by weight of activator(s), more preferably from 20% to 50% by weight of activator(s), even more preferably from 25% to 45% by weight of activator(s).

[0090] In particular, a construction binder according to the present invention comprises at most 50% by weight of clinker relative to the dry weight of the construction binder, preferably at most 45% by weight of clinker relative to the dry weight of the construction binder, more preferably at most 40% by weight of clinker relative to the dry weight of the construction binder, even more preferably at most 35% by weight of clinker relative to the dry weight of the construction binder. The clinker may advantageously be combined with gypsum to form the activator. The clinker may be used in a ground or micronized form.

[0091] However, the presence of clinker may be beneficial to the mechanical properties of the building material produced with the construction binder. Thus, the construction binder according to the present invention may comprise at least 10% by weight of clinker relative to the dry weight of the construction binder, preferably at least 15% by weight of clinker relative to the dry weight of the construction binder, more preferably at least 20% by weight of clinker relative to the dry weight of the construction binder, even more preferably at least 25% by weight of clinker relative to the dry weight of the construction binder. For example, at least 30% by weight of clinker relative to the dry weight of the construction binder.

[0092] For example, the construction binder according to the present invention comprises from 10% to 55% by weight of clinker relative to the dry weight of the construction binder, preferably from 15% to 50% by weight of clinker relative to the dry weight of the construction binder, more preferably from 20% to 45% by weight of clinker relative to the dry weight of the construction binder, even more preferably from 25% to 40% by weight of clinker relative to the dry weight of the construction binder. The clinker may advantageously be combined with gypsum to form the activator.

[0093] A precursor and an activator used in the context of the invention will preferably be different compounds. However, the precursor(s) and activator(s) may be added to a composition to form the construction binder in the form of a single mixture comprising the precursor(s) and activator(s). This is the case, for example, when using CEM II, CEM III, CEM IV or CEM V. DEFLOCCULATING POLYMER

[0094] As mentioned, a construction binder according to the present invention comprises at least one deflocculant, preferably an organic deflocculant.

[0095] The presence of one or more deflocculant(s) can improve the performance of the material formed from the construction binder. Thus, advantageously, a binder according to the present invention comprises an organic deflocculant, advantageously a deflocculant polymer.

[0096] A construction binder according to the present invention may comprise at least 0.1% by weight of deflocculating polymer, preferably at least 0.25% by weight of deflocculating polymer, more preferably at least 0.5% by weight of deflocculating polymer, even more preferably at least 0.75% by weight of deflocculating polymer.

[0097] A construction binder according to the present invention comprises, for example, at most 7% by weight of deflocculating polymer, preferably at most 5% by weight of deflocculating polymer, more preferably at most 4% by weight of deflocculating polymer, even more preferably at most 3% by weight of deflocculating polymer.

[0098] Generally, a construction binder according to the present invention may comprise from 0.1% to 7% by weight of deflocculating polymer, preferably from 0.25% to 5% by weight of deflocculating polymer, more preferably from 0.5% to 4% by weight of deflocculating polymer, even more preferably from 0.75% to 3% by weight of deflocculating polymer.

[0099] Many compounds can act as a deflocculating polymer and many are generally known to those skilled in the art.

[0100] In particular, the deflocculating polymer may comprise one or more poly(oxyethylene) or poly(oxypropylene) chains; the poly(oxyethylene) or poly(oxypropylene) chains having a molecular mass of at least 1000 g / mol.

[0101] Preferably, the deflocculating polymer is selected from: a non-ionic surfactant, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant or combinations thereof.

[0102] In the context of the invention, the deflocculating polymer is in particular a non-ionic surfactant such as a polyoxyethylene ether. The polyoxyethylene ether may for example be selected from: a lauryl poly(oxyethylene) ether.

[0103] The deflocculating polymer may also be an anionic agent such as an anionic surfactant. In particular, the anionic agent may be selected from: sulfonates such as alkylaryl sulfonates or lignosulfonates (eg sodium lignosulfonates); amino alcohols; fatty acids; humates (eg sodium humates); carboxylic acids (R-COOH); polyacrylates (eg sodium polyacrylate or ammonium polyacrylate); carboxymethylcelluloses and their mixtures.

[0104] The deflocculating polymer may be a mixture of compounds, such as a mixture comprising at least two compounds selected from: non-ionic deflocculant, and / or anionic deflocculant.

[0105] The invention cannot be limited to the deflocculating polymers mentioned above or their salts. Any type of organic deflocculating agent known to those skilled in the art can be used instead of the said deflocculating polymers mentioned above.

[0106] The deflocculating polymers that can be used according to the present invention may take a solid form or a liquid form.

[0107] In addition, deflocculating polymers can be used in combination with complementary compounds. These complementary compounds may, for example, include alkanolamines, glycols, glycerol, sugars, carbohydrate acids, carboxylic acids, or their salts.

[0108] Preferred alkanolamines are, for example, selected from the group consisting of 2-amino-2-methyl-1-propanol; mono-, di- or triethanolamine; isopropanolamines (1-amino-2-propanol, diethanolisopropanolamine, ethanoldiisopropanolamine, diisopropanolamine and triisopropanolamine), and N-alkylated ethanolamines such as N-methyldiisopropanolamine, or N-methyldiethanolamine, tetrahydroxyethylethylenediamine, tetrahydroxyisopropylethylenediamine, as well as mixtures of two or more of these alkanolamines.

[0109] Examples of preferred glycols are monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, polyethylene glycol, in particular with one or more ethylene units, for example PEG 200, neopentyl glycol, hexylene glycol, propylene glycol, dipropylene glycol and polypropylene glycol.

[0110] Examples of preferred sugars are sugars that belong to the group of monosaccharides or disaccharides. Examples of sugars include, but are not limited to, lyxose, gulose, glyceraldehyde, threose, erythrose, xylose, ribose, arabinose, altrose, glucose, mannose, idose, galactose, chitobiose, tallose, fructose, sorbose, lactose, raffinose, maltose, sucrose, lactulose, trehalose, cellobiose, somaltose, allose, palatinose, mannobiose and xylobiose.

[0111] An example of a preferred carbohydrate acid in the context of the present invention is a monosaccharide having a carboxyl group. It may belong to one of the classes of aldonic acids, ursonic acids, uronic acids or aldaric acids. Preferably, it is an aldonic acid. Examples of carbohydrate acids include, but are not limited to, glyceric acid, xylonic acid, gluconic acid, ascorbic acid, neuraminic acid, glucuronic acid, galacturonic acid, iduronic acid, tartaric acid, mucilic acid and saccharic acid. The carbohydrate acid may be in the form of the free acid or a salt.

[0112] Examples of preferred carboxylic acids are oxalic acid, malonic acid, adipic acid, lactic acid, citric acid, and tartaric acid. The carboxylic acid may be in the form of the free acid or in the form of a salt. PREFERRED MASS RATIOS

[0113] As illustrated in the examples, the applicant has discovered that certain mass ratios between the constituents of the construction binder make it possible to obtain advantageous mechanical resistance properties at young age and at 28 days.

[0114] For example, certain ratios make it possible to obtain a high Rc at 1 day (e.g. greater than 10 MPa) while maintaining an Rc at 28 days greater than 22.5 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa; as measured according to standard NF EN 196-1.

[0115] Advantageously, in a construction binder according to the present invention, the calcined clay matrix and the at least one other precursor are present in an amount such that the mass ratio by weight between the calcined clay matrix and the at least one other precursor is between 0 and 0.50 (limits not included). Indeed, as illustrated in the examples, such ratios make it possible to obtain a high Rc at 1d (e.g. greater than 10 Mpa) while maintaining an Rc at 28d greater than 40 MPa.

[0116] Advantageously, in a construction binder according to the present invention, the calcined clay matrix and the raw clay matrix are present in an amount such that the mass ratio by weight between the calcined clay matrix and the raw clay matrix is ​​between 0 and 1 (limits not included), preferably between 0 and 0.66 (limits not included) and more preferably between 0 and 0.33 (limits not included). Indeed, as illustrated in the examples, such mass ratios make it possible to obtain a high Rc at 1d (eg greater than 10 MPa) while maintaining an Rc at 28d greater than 40 MPa.

[0117] Advantageously, in a construction binder according to the present invention, the calcined clay matrix and the activator(s) are present in an amount such that the mass ratio by weight between the calcined clay matrix and the activator(s) is between 0 and 1 (limits not included), preferably between 0 and 0.8 (limits not included), more preferably between 0 and 0.6 (limits not included), even more preferably between 0 and 0.4 (limits not included). Indeed, as illustrated in the examples, such mass ratios make it possible to obtain a high Rc at 1d while maintaining a high Rc at 28d. In particular, the calcined clay matrix and the activator(s) are present in an amount such that the mass ratio by weight between the calcined clay matrix and the activator(s) is between 0 and 0.20 (limits not included).Indeed, as illustrated in the examples, such mass ratios make it possible to obtain a high Rc at 1d (e.g. greater than 10 MPa) while maintaining an Rc at 28d greater than 40 MPa. When several activators are present, the mass ratio is preferably calculated by taking the sum of the weights of the activators in the composition.

[0118] Furthermore, in a construction binder according to the present invention, the clay matrix and the precursors may be present in an amount such that the mass ratio in dry weight between the clay matrix and the precursors is greater than or equal to 1, preferably ranging from 1 to 1.5. When several precursors are present, the mass ratio is preferably calculated by taking the sum of the weights of the precursors of the composition.

[0119] Furthermore, in a construction binder according to the present invention, the activator(s) and precursor(s) may be present in an amount such that the dry weight mass ratio between the activator(s) and precursor(s) is less than or equal to 3, preferably ranging from 1 to 3, more preferably from 1.1 to 2.5. When several activators are present, the mass ratio is preferably calculated by taking the sum of the weights of the activators in the composition. This is also the case for the precursors.

[0120] Furthermore, in a construction binder according to the present invention, the clay matrix and the activator(s) may be present in an amount such that the dry weight mass ratio between the clay matrix and the activator(s) is greater than or equal to 0.5, preferably ranging from 0.5 to 1, more preferably from 0.5 to 0.75. FAVORITE COMPOSITIONS

[0121] As illustrated in the examples, the construction binders according to the present invention make it possible to achieve mechanical strengths, as measured according to standard NF EN 196-1, of at least 6 MPa at 1 day. Preferably, the construction binders according to the present invention make it possible to achieve mechanical strengths, as measured according to standard EN 196-1, of at least 8 MPa at 1 day, more preferably at least 9 MPa at 1 day, and even more preferably at least 10 MPa at 1 day, for example at least 11 MPa at 1 day.

[0122] Furthermore, as illustrated in the examples, the construction binders according to the present invention make it possible to achieve mechanical strengths, as measured according to standard NF EN 196-1, of at least 38 MPa at 28 days. Preferably, the construction binders according to the present invention make it possible to achieve mechanical strengths, as measured according to standard NF EN 196-1, of at least 39 MPa at 28 days, more preferably of at least 40 MPa at 28 days, and even more preferably of at least 41 MPa at 28 days.

[0123] Compositions for achieving such preferred values ​​are described below.

[0124] The invention also relates to a construction binder comprising: more than 10% by weight of raw clay matrix(s), at least 10% by weight of activator(s), preferably at least 10% by weight of clinker, at least 2% by weight of calcined clay matrix(s), at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

[0125] The invention also relates to a construction binder comprising: more than 20% by weight of raw clay matrix(s), from 20% to 55% by weight of clinker, at least 4% by weight of calcined clay matrix(s), at least 8% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

[0126] The invention also relates to a construction binder comprising: At least 20% by weight, preferably from 25% to 35% by weight of raw clay matrix(s), from 35% to 55% by weight of activator(s), preferably from 35% to 55% by weight of clinker, from 2.5% to 15% by weight of calcined clay matrix(s), from 8% to 25% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and from 0.50% to 4% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

[0127] The invention also relates to a construction binder comprising: from 25% to 35% by weight of raw clay matrix(s), from 40% to 55% by weight of activator(s), preferably from 40% to 55% by weight of clinker, from 2.5% to 7.5% by weight of calcined clay matrix(s), from 10% to 25% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and from 0.50% to 4% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

[0128] The invention also relates to a construction binder comprising: from 27.5% to 32.5% by weight of raw clay matrix(s), from 42.5% to 52.5% by weight of activator(s), preferably from 42.5% to 52.5% by weight of clinker, from 4% to 6% by weight of calcined clay matrix(s), from 12.5% ​​to 22.5% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and from 0.50% to 3% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

[0129] According to another aspect, the invention relates to a method for preparing a construction binder according to the invention. Furthermore, the method according to the invention may comprise steps for forming a construction material from the construction binder according to the invention.

[0130] Several embodiments, preferred or not, have been described previously in relation to the construction binder according to the invention. Thus, a method for preparing the construction binder according to the invention may comprise, alone or in combination, each of the characteristics described above in relation to a construction binder according to the invention and its constituents.

[0131] As illustrated in Figure 1, the preparation method 100 according to the invention comprises at least one step 120 of mixing the components of the construction binder.

[0132] Furthermore, the preparation method 100 according to the invention may comprise steps of preparation 110 of the raw clay matrix, of adding water 130 to the components of the construction binder, of adding aggregates 140 and a shaping step 150.

[0133] As illustrated in Figure 1, the preparation method 100 according to the invention may comprise a step 110 of preparing the raw clay matrix.

[0134] In particular, the step 110 of preparing the raw clay matrix may include a modification of the contents of the different particle size fractions of the raw clay matrix. The raw clay matrix may advantageously have been pretreated. Preferably, the pretreatment is selected from: grinding, sorting, sieving and / or drying of the clay matrix. The pretreatment may, for example, include fractionation. The preparation step 110 may generally be carried out with decomposers, dryers, screens, and / or grinders. The drying may in particular allow a reduction in the moisture content of the raw clay matrix without raising the temperature above 500°C. The dryer will, for example, be a rotary dryer.

[0135] The dried raw clay matrix may advantageously undergo a screening step, for example in a screen. This step will preferably eliminate aggregates with a diameter greater than or equal to 2 cm, more preferably a diameter greater than or equal to 1 cm. The screen will be, for example, a rotary screen.

[0136] The grinding may, for example, be carried out using a hammer mill, a ball mill or a rod mill. As will be detailed, the grinding may be carried out in such a way as to control the D50 of the materials used. Preferably, during the formation of the binder, the raw clay matrix may have a D50 of less than or equal to 200 pm, preferably less than or equal to 150 pm, more preferably less than or equal to 100 pm, even more preferably less than or equal to 80 pm.

[0137] A method 100 for preparing the raw clay matrix according to the invention comprises a step 120 of mixing the components of the construction binder. In particular, this mixing step 120 can be carried out a few moments before using the binder. Alternatively, the mixing step 120 can be carried out well before, and the binder thus formed stored in the dry state for subsequent mixing. Preferably, the method according to the invention uses a binder formed extemporaneously. Alternatively, the method according to the invention allows the formation of a binder which will be used at least 6 hours, preferably at least 24 hours after its preparation and for example on another site.

[0138] The mixing step 120 may generally be carried out with a mixing member such as a kneader or a mixer, for example a powder mixer. In particular, a method according to the invention may include the use of hoppers, weighing means, volumetric dosing means, transport means such as endless screws and / or aeraulic systems, a mixer and / or a kneader.

[0139] The mixing step 120 is generally carried out for a sufficient time to create an intimate mixture between the different constituents of the binder. The parameters for achieving such a result may vary depending on the constituents of the binder. The mixing step 120 may include mixing the constituents of the binder for at least 5 seconds before adding water and / or aggregates, preferably for at least 10 seconds before adding water and / or aggregates, more preferably for at least 20 seconds before adding water and / or aggregates and even more preferably for at least 30 seconds before adding water and / or aggregates.The mixing will generally take place for a period of less than or equal to 20 minutes, preferably for at most 15 minutes before the addition of water and / or aggregates, more preferably for at most 10 minutes before the addition of water and / or aggregates and even more preferably for at most 5 minutes before the addition of water and / or aggregates.

[0140] In particular, the mixing step 120 may be carried out in several sub-steps. For example, initially, the method may comprise a premix of a raw clay matrix and at least one deflocculant. In addition, during this premixing, the method according to the invention may advantageously comprise the addition of at least one activator. Preferably, this premix will not be hydrated.

[0141] As illustrated in Figure 1, a preparation method 100 according to the invention may include a step of adding water 130. In particular, this step of adding water 130 makes it possible to initiate the hydration of the cement which leads to the setting and hardening of the cement or concrete by the formation of hydrated constituents which have binding properties but also ensure the workability of the fresh binder or fresh concrete to facilitate its installation.

[0142] In particular, this step of adding water 130 makes it possible to achieve a W / C ratio, that is to say a mass ratio between water and dry matter of between 0.3 and 0.7, preferably between 0.4 and 0.6.

[0143] As illustrated in Figure 1, a preparation method 100 according to the invention may include a step of adding aggregates 140. In particular, this step 140 aggregate addition allows to generate a construction material from the construction binder.

[0144] The aggregates may also include mineral aggregates, i.e., those mainly made up of mineral matter, and / or plant aggregates, i.e., those mainly made up of material of plant origin. The aggregates may also include marine aggregates, i.e., those mainly made up of organic or inorganic matter from the seabed, such as siliceous aggregates and carbonate substances (e.g., maerl and shell sand).

[0145] Mineral aggregates may, for example, correspond to sand, gravel, gravel, fillers (or fine materials), powders, fossilized waste and their combination.

[0146] Plant aggregates may, for example, correspond to wood (chips or fibers), hemp such as seed hemp, straw, wool such as sheep's wool, hemp shiv, miscanthus, sunflower, typha, corn, flax such as oilseed flax, rice husks, wheat husks, rapeseed, seaweed, bamboo, cellulose wadding, defibrated fabric and their combinations.

[0147] As illustrated in Figure 1, a preparation method 100 according to the invention may include a shaping step 150. In particular, this shaping step 150 is not obligatory but may be implemented when used in the form of construction systems or prefabrication elements or when carrying out various surface treatments such as brushed concrete.

[0148] Thus, according to another aspect, the invention relates to a construction material capable of being manufactured by the method 100 according to the invention. In particular, the invention relates to a construction material manufactured by the method 100 according to the invention. Preferably, the invention relates to a construction material manufactured using a construction binder according to the invention. The construction materials may for example be selected from: a mortar, a coating, a plaster, an insulator, a lightweight concrete, a prefabrication element or a mineral paint.

[0149] Advantageously, the construction binder according to the invention is used to form a construction material so that the fillers (or aggregates) represent between 200% and 900% by weight of the construction binder. For example, in a construction material according to the invention, the construction binder according to the invention preferably represents between 10% and 33% by weight of the construction material.

[0150] In particular, a building material formed from the building binder according to the invention will comprise at least 4% by weight of raw clay and at least 1% by weight of calcined clay. Preferably, the building material will comprise at least 5% by weight of raw clay and at least 1% by weight of calcined clay. Preferably, it comprises less than 5% by weight of calcined clay.

[0151] The construction material according to the invention may have a minimum compressive strength on cylinders at 1 day as measured by standard NF EN 206-1 greater than or equal to 8 MPa; preferably greater than or equal to 9 MPa, preferably greater than or equal to 10 MPa.

[0152] Furthermore, the construction material according to the invention may have a minimum compressive strength on cylinders at 28 days as measured by standard NF EN 206-1 greater than or equal to 39 MPa, preferably greater than or equal to 40 MPa.

[0153] The construction binder according to the invention can be used for the manufacture of: - Insulating construction material: binder according to the invention and lightweight aggregates of the “plant or porous” type; - Mortar and concrete sprayed by dry or wet method, Poured concrete / mortar, Compacted concrete / mortar, Extruded concrete / mortar, Coatings, grout, glue, - Concrete foam, Lightweight concrete: the construction binder according to the invention may, for example, comprise straw, rice husk, hemp shiv, seaweed, wood chips, sunflower, sargassum, reed, wheat husks or other cereals and their mixtures; Fiber-reinforced concrete, carbon fibers, glass, polypropylene, linen, hemp, yucca, jute, kenaf, Mauritanian ampelodesmos, coconut, oil palm, oil date palm, banana and pineapple..., - High-temperature performance concrete, - Liquid screed, Mortar, - Construction systems or prefabrication elements: manufacture of concrete blocks or slabs in the factory from the binder according to the invention such as posts including silica fumes, earth concrete, a wood frame / earth concrete coupling, earth mortar walls, reinforced earth concrete, Mineral paint, and - Insulation modules.

[0154] The invention also relates to the use of the construction binder according to the invention, for the production of composite materials or prefabricated blocks.

[0155] Composite materials are, for example, building panels such as prefabricated panels, while prefabricated blocks are, for example, door or window lintels, prefabricated wall elements, or any other prefabricated building element.

[0156] Thus, in particular, the invention relates to a prefabricated element capable of being formed from a construction binder according to the invention. Advantageously, this prefabricated element will have been formed from a construction binder according to the invention.

[0157] Preferably, this prefabricated element, such as a partition, has a face with a surface area of ​​at least 1 m 2 , more preferably at least 1.5 m 2 , even more preferably at least 2 m2 .

[0158] Furthermore, the prefabricated element may have a thickness of between 0.3 cm and 20 cm, advantageously between 0.5 cm and 10 cm and preferably between 1 cm and 7 cm.

[0159] The foregoing description of the invention has been detailed so that a person skilled in the art, having ordinary skill in the art, can, using the foregoing description and the following illustrative examples, make and use the products of the present invention and practice the claimed methods. EXAMPLES

[0160] The invention is described in more detail below with reference to the following experimental examples. These examples are provided for illustrative purposes only and are not intended to be limiting unless otherwise indicated. Thus, the invention should in no way be construed as being limited to the following illustrative examples, but rather should be construed as encompassing all variations that become apparent as a result of the teaching provided herein. Preparation of a construction binder:

[0161] In all the examples presented below, the formulations according to the invention are prepared according to an identical protocol. The clay matrix is ​​pretreated using a lump crusher or bucket crusher, for example at 100 rpm, then ground, for example by a blade mill at 1200 rpm. Elements larger than 2 mm are removed. A dry premix is ​​made between a raw clay matrix, a calcined clay matrix, an activator, another precursor and a deflocculating polymer in predetermined quantities, then water is added and the solution is mixed at low speed, i.e. approximately sixty revolutions per minute for thirty seconds. Then, sand is added to the premix and the whole is mixed at a higher speed, i.e. approximately 120 revolutions per minute for one minute.

[0162] The mass ratio of water to dry matter in the composition (also called construction binder) is adjusted to a value between 0.4 and 0.6. In a particular example, the construction material, a mortar, comprises 25% by weight of binder, 75% by weight of sand; this mixture being supplemented with water for a mass ratio of water to dry matter of the binder adjusted to a value of 0.45.

[0163] The mortar based on the construction binder thus formed is then poured into a mold and left to mature at room temperature, i.e. around 20 degrees Celsius for twenty-eight days in water.

[0164] Alternatively, the mortar may be poured into a mold and then left to mature for less than twenty-four hours in a curing stage, at room temperature, i.e. approximately 25 degrees Celsius or preferably under heat treatment. During this curing stage, the mold may be sealed or the top layer of the building material may be covered with a curing compound to limit / prevent evaporation.

[0165] Table 2 below shows, for different construction binder formulations including three comparative formulations (REF1, REF2, REF3) and four formulations according to the invention (1, 2, 3, 4). The mass of the components relating to each formulation is expressed as a percentage of the total mass of the construction binder (dry weight). In addition, the W / C value is reported. [Table 2] m ID Raw clay A *c * .. * ■ i- Other Agent 3Metakaolm tivator . . . E / C deflocculant precursor CEMI 0 100% (including 5% gypsum) CEMIIIB 0 30% 0 70% 0 0.45 REF1 29.6% 49.3% 0.0% 19.7% 1.4% 0.45 REF2 39.4% 39.5% 0.0% 19.7% 1.4% 0.45 REF3 24.6% 49.3% 24.7% 0.0% 1.4% 0.5 1 29.6% 39.4% 9.9% 19.7% 1 .4% 0.45 2 29.6% 49.3% 4.9% 14.8% 1 .4% 0.45 3 29.6% 44.4% 4.9% 19.7% 1.4% 0.45 4 29.6% 49.3% 9.9% 9.8% 1.4% 0.45 Methodology for measuring the mechanical properties of construction binders:

[0166] Once maturation is complete, the mechanical resistance is measured. The mechanical resistance of a construction binder is its compressive strength, such compression being measured according to standard NF EN 196-1, for a prism with a side of 40 millimeters and a length of 160 millimeters and is expressed in Mega Pascal (MPa). Comparison of the construction binders according to the invention with known construction binders:

[0167] Table 3 below shows the results of mechanical resistance at 1 day and 28 days based on the formulations detailed in Table 2. [Table 3] |n Rc 1d Rc 1d Rc 28d (MPa) (Compared to REF1) (MPa) CEMI >15 - >40 CEMIIIB 6 - >40 REF1 8.11 - 45 REF2 7.94 -2.1% 36 REF3 11.4 +40.6% 35.75 1 9.6 +18.4% 39.75 2 12 +48.0% 41.75 3 11 .3 +39.4% 43.5 4 12.2 +50.4% 39.75

[0168] Table 3 below shows that the reference formulation REF1, which does not contain metakaolin, has a fairly low Rc at 1 day (8.11) but a high RC at 28 days. Thus, a formulation combining Raw Clay Matrix, Activator, Precursor, and deflocculant makes it possible to achieve high mechanical strengths at 28 days, but the Rc at young age is relatively low. As is illustrated by REF2, the increase in the quantity of raw clay matrix concomitant with a reduction in the quantity of activator leads to a reduction in the Rc at young age but also that at 28 days. In addition, the replacement of the other precursor by a calcined clay matrix makes it possible to increase the Rc at young age but significantly degrades the Rc at 28 days (35.75 MPa).

[0169] The study of the formulations according to the present invention shows that the combined use of a raw clay matrix, a calcined clay matrix, an activator and another precursor makes it possible to maintain a mechanical resistance at 28 days greater than 39 MPa while increasing the Rc at young age (1 day) by between 18% and 50%.

[0170] Table 4 below shows the ratios between the different constituents of the formulations. [Table 4] _ . _ . _ . Report Report Report Report Report Report Clay . .. . .. ID Arg 3 raw clay Activator Calcined raw clay, r ® 1 ? , r ® 1 ?!! 3 !! calcmee calcmee Precursors Precursors Activator Other Raw clay Precursor activator M REF1 1.5 2.5 0.6 na na na REF2 2 2.0 1 .0 na na na REF3 1 2.0 0.5 na 1 .0 0.5 1 1 1 ,33 0,75 0,50 0,33 0,25 2 1 .50 2.50 0.60 0.33 0.17 0.10 3 1.20 1.80 0.67 0.25 0.17 0.11 4 1.50 2.50 0.60 1.01 0.33 0.20

[0171] Table 4 above shows that construction binders perform best when certain ratios of constituents are used. In particular, such optimal mass ratios relate to the amount of calcined clay matrix to the other constituents of the construction binder. Thus, the best results are obtained when the mass ratio of the calcined clay matrix to the at least one other precursor is between 0.5 and 1, preferably between 0.2 and 0.4.

[0172] Also a good balance between Rc at 1 day and Rc at 28 days is obtained when the mass ratio between the calcined clay matrix and the raw clay matrix ranges from 0.1 to 4, preferably from 0.1 to 0.3, more preferably from 0.15 to 0.2. Finally, a good balance between Rc at 1 day and Rc at 28 days is obtained when the mass ratio between the calcined clay matrix and the activator ranges from 0.05 to 3, preferably between 0.05 and 0.2, more preferably from 0.05 to 0.15.

[0173] The invention may be the subject of numerous variants and applications other than those described above. In particular, unless otherwise indicated, the different structural and functional characteristics of each of the implementations described above should not be considered as combined and / or closely and / or inextricably linked to each other, but on the contrary as simple juxtapositions. Furthermore, the structural and / or functional characteristics of the different embodiments described above may be the subject in whole or in part of any different juxtaposition or any different combination.

Claims

Claims 1. Construction binder comprising more than 10% by weight of raw clay matrix(s), at least 8% by weight of activator(s), preferably said activator(s) comprising clinker, at least two precursors, and at least one deflocculating polymer, said at least two precursors comprising at least one calcined clay matrix and at least one other precursor, said construction binder comprising at least 2% by weight of calcined clay matrix(s), the raw clay matrix, the calcined clay matrix, and the activator(s) are present in an amount such that: - the mass ratio between the calcined clay matrix and the raw clay matrix is ​​between 0 and 0.33, excluding limits, and - the mass ratio between the calcined clay matrix and the activator(s) is between 0 and 0.20, excluding limits.

2. Construction binder according to claim 1, characterized in that it comprises at least 25% by weight of raw clay matrix relative to the dry weight of construction binder.

3. Construction binder according to one of claims 1 or 2, characterized in that the activator(s) are selected from: clinker, CEM I, lime, silicates such as sodium silicate, carbonates such as sodium carbonate or combinations thereof.

4. Construction binder according to any one of claims 1 to 3, characterized in that it comprises at least 30% by weight of activator(s), preferably at least 30% by weight of CEM I as activator; relative to the dry weight of construction binder.

5. Construction binder according to any one of claims 1 to 4, characterized in that it comprises at most 50% by weight of CEMI; relative to the dry weight of construction binder.

6. Construction binder according to any one of claims 1 to 5, characterized in that it comprises at most 15% by weight of calcined clay matrix; relative to the dry weight of the construction binder.

7. Construction binder according to any one of claims 1 to 6, characterized in that the at least one other precursor is selected from: slags such as blast furnace slags, steelworks slags, cupola slags; fly ash, natural pozzolans, silica fumes, micronized limestone fillers, micronized siliceous fillers such as glass powder, siliceous fillers, synthetic vaterite, diatomaceous earths, ground slag or combinations thereof.

8. Construction binder according to any one of claims 1 to 7, characterized in that the at least one other precursor is selected from: blast furnace slag, micronized limestone filler; vaterite such as micrometric or nanometric vaterite; or combinations thereof.

9. Construction binder according to any one of claims 1 to 8, characterized in that the calcined clay matrix and the at least one other precursor are present in an amount such that the mass ratio by weight between the calcined clay matrix and the at least one other precursor is between 0 and 0.50, limits not included.

10. Construction binder according to any one of claims 1 to 9, characterized in that the activator(s) comprise clinker and the calcined clay matrix and the clinker are present in an amount such that the mass ratio by weight between the calcined clay matrix and the clinker is between 0 and 0.20; limits not included.

11. Construction binder according to any one of claims 1 to 10, characterized in that the activator(s) and the precursor(s) are present in an amount such that the mass ratio by dry weight between the activator(s) and the precursor(s) is less than or equal to 2.

12. Construction binder according to any one of claims 1 to 11, characterized in that it comprises: - more than 10% by weight of raw clay matrix(es), - at least 10% by weight of activator(s), preferably at least 10% by weight of clinker, - at least 2% by weight of calcined clay matrix(es), - at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and - at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

13. Construction binder according to any one of claims 1 to 11, characterized in that it comprises: - more than 20% by weight of raw clay matrix(es), - from 20% to 55% by weight of clinker, - at least 4% by weight of calcined clay matrix(es), - at least 8% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and - at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

14. Construction binder according to any one of claims 1 to 11, characterized in that it comprises: - At least 20% by weight, preferably 25% to 35% by weight of raw clay matrix(s), - from 35% to 55% by weight of activator(s), preferably from 35% to 55% by weight of clinker, - from 2.5% to 15% by weight of calcined clay matrix(es), - from 8% to 25% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and - from 0.50% to 4% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

15. Construction binder according to any one of claims 1 to 11, characterized in that it comprises: - from 25% to 35% by weight of raw clay matrix(es), - from 40% to 55% by weight of activator(s), preferably from 40% to 55% by weight of clinker, - from 2.5% to 7.5% by weight of calcined clay matrix(es), - from 10% to 25% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and - from 0.50% to 4% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; - in relation to the weight of construction binder.

16. Construction binder according to any one of claims 1 to 11, characterized in that it comprises: - from 27.5% to 32.5% by weight of raw clay matrix(es), - from 42.5% to 52.5% by weight of activator(s), preferably from 42.5% to 52.5% by weight of clinker, - from 4% to 6% by weight of calcined clay matrix(es), - from 12.5% ​​to 22.5% by weight of at least one other precursor, preferably selected from blast furnace slag, cupola slag, steelworks slag, fly ash, natural pozzolans, silica fumes, micronized limestone fillers; synthetic vaterite, or combinations thereof; and - from 0.50% to 3% by weight of at least one deflocculating polymer, preferably selected from anionic and / or zwitterionic deflocculating polymers; relative to the weight of construction binder.

17. Construction binder according to any one of claims 1 to 11, characterized in that it comprises at most 10% by weight of calcined clay matrix; relative to the dry weight of the construction binder.

18. Construction binder according to any one of claims 1 to 11, characterized in that it comprises at least 10% by weight of the at least one other precursor; relative to the dry weight of the construction binder.

19. Construction binder according to any one of claims 1 to 11, characterized in that it comprises at most 25% by weight of at least one other precursor; relative to the dry weight of the construction binder.

20. Method for preparing (100) a construction binder according to any one of claims 1 to 19, characterized in that it comprises a step of mixing (120) the constituents of the construction binder then a step of adding water (130).

21. A building material formed from a building binder according to any one of claims 1 to 19 and further aggregates.

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