PROCEDURE FOR SELECTING THE COMPOSITION OF A BUILDING MATERIAL CONTAINING EXCAVATED CLAY SOIL, PROCEDURE AND SYSTEM FOR PREPARING SUCH A BUILDING MATERIAL

Description

[0001] The invention relates to the field of construction materials, and more particularly to materials that can be used in construction, such as construction binders or concretes. The invention concerns a method for selecting the composition of a construction material comprising raw excavated clay soil.

[0002] The invention also relates to a building material formed from raw excavated clay soil and a system for preparing a building material comprising raw excavated clay soil. [Previous art]

[0003] Cement is the second most consumed resource in the world, with over 4 billion tons of material produced globally each year, and this consumption is constantly increasing, driven by the growing demand for housing and infrastructure. Cement is a binder, usually hydraulic, which When mixed with water, it hardens and sets into a mass.After hardening, cement retains its strength and stability, even when exposed to water. A wide variety of cements are used worldwide. Furthermore, cement preparation processes are becoming increasingly sophisticated, and automated systems have been developed for preparing various concretes (FR2751911, EP2296854). Nevertheless, all conventional cements contain clinker, with percentages ranging from 5% for some blast furnace cements to a minimum of 95% for Portland cement, which is currently the most widely used cement in the world. Clinker is produced by firing a mixture composed of approximately 80% limestone and 20% aluminosilicates (such as clays). This firing process, called clinkerization, takes place at a temperature exceeding 1200°C, making cement preparation a highly energy-intensive process. Moreover, the chemical conversion of limestone into lime also releases carbon dioxide.As a result, the cement industry generates approximately 8% of global CO2 emissions. Faced with this challenge, industry and researchers are studying ways to reduce the impact of carbon dioxide emissions generated by the cement industry.

[0004] In addition to these carbon emissions, the management of excavated soil is also a factor in large urban development projects. This excavated soil is generally stockpiled or used for backfilling quarries or landscaping parks, but this represents a potential use far below the available volumes. Furthermore, it has been proposed to use this excavated soil for manufacturing construction materials; however, this application faces the problem of insufficient mechanical strength in earthen constructions on the one hand, and the suboptimal carbon footprint when using metakaolin on the other.

[0005] Indeed, the cements proposed based on raw earth, as described in document FR3016376, either have physical properties, such as improved mechanical resistance, reduced capillary absorption, or reduced permeability to liquids, that are too weak; or they require the addition of a portion of Portland cement to be able to present acceptable mechanical properties.

[0006] Regarding metakaolin-based cements, the mixture of lime or sodium hydroxide and metakaolin during cement hydration induces a pozzolanic reaction. This reaction improves the binding properties of metakaolin-based cements. Due to these properties, metakaolin-based construction materials have been proposed, notably those containing flash-treated metakaolin combined with sodium hydroxide, as described in document FR3034094. However, the formation of metakaolin requires the thermal treatment of kaolinitic clays to achieve the dehydroxylation of the kaolinite crystalline structure, resulting in an unfavorable carbon balance, particularly when considering the transport of excavated soil to the thermal treatment units.

[0007] It has been proposed to use organic materials such as peat, seaweed, foliage, needles, or sawdust to form a raw building material (DE354069). It has also been proposed to form building materials from slurry when it is added to cement (DE19530964). Another proposal has been for an uncalcined building material comprising clay, lime, blast furnace slag, an alkali compound, and water (WO03089383). Specifically, it discloses a composition comprising 50 to 90% by weight of clay, 2 to 30% by weight of lime, 4 to 48% by weight of blast furnace slag, 0.04 to 0.9% by weight of an alkali compound, and water. Finally, a system for distributing admixtures and controlling concrete trucks for the preparation of a construction material was proposed (FR2751911).This system is configured to determine the correct amount of admixture to deliver in an unused concrete load or to wash a concrete mixer truck.

[0008] Thus, there is a need for new uses of excavated clay soil that can advantageously allow a reduction of greenhouse gas emissions and the preparation of construction material such as a construction binder or site concrete with a low carbon footprint while exhibiting mechanical properties at least equivalent to or even superior to the mechanical properties of cements commonly used in the construction field. [Technical problem]

[0009] The invention therefore aims to overcome the drawbacks of the prior art. In particular, the invention aims to provide a method for selecting the composition of a construction material comprising excavated clay soil, said method making it possible to form a construction material, such as a construction binder, which reduces the emission of greenhouse gases, such as carbon dioxide, while providing mechanical characteristics suitable for its use in the construction field, and to provide on-site concrete comprising such a binder and capable of improving the comfort of inhabitants compared to concrete made from Portland cement.

[0010] The invention further aims to provide a building material made from excavated clay soil with mechanical properties suitable for use in construction, while also offering a way to valorize excavated clay soil. The invention also aims to provide a process and system for preparing a building material containing excavated clay soil that reduces greenhouse gas emissions compared to a conventional building material such as Portland cement. [Brief description of the invention]

[0011] It is thus determined that the following "excavated clay soil" is, according to the invention, expressly always "raw excavated clay soil".

[0012] To this end, a method for selecting the composition of a construction material comprising excavated clay soil is disclosed, but not claimed, said construction material composition comprising quantities of deflocculating agent and activating agent adapted to the excavated clay soil, said method being implemented by a computer device comprising a calculation module, said method comprising: A step of receiving, by the calculation module, a measured value of at least one physicochemical property of an excavated clay soil; and A step of selecting, by the calculation module, a quantity of deflocculating agent and a quantity of activation agent adapted to the excavated clay soil on the basis of a comparison of the measured value(s) to reference values, said reference values ​​comprising correlations between measured values ​​of at least one physicochemical property of a clay soil and quantities of deflocculating agent and activation agent adapted to said clay soil to form a construction material.

[0013] Such a selection process offers the advantage of being able to select at least some of the constituents of a construction material based on excavated clay soil in order to form a construction material, such as a building binder or site-mixed concrete, with mechanical properties equivalent to those of conventional construction materials using clinker. Indeed, with prior art methods, construction materials obtained from excavated soil are generally not sufficiently strong from a mechanical point of view to allow for widespread use. Furthermore, the constituents selected via the selection process (i.e., excavated clay soil, deflocculant, and activator) allow for the formation of a construction material using a less energy-intensive preparation process.

[0014] Finally, the construction material containing excavated clay soil which preferably has not undergone a combustion stage, retains advantageous hygrothermal properties which improve the comfort of the inhabitants compared to concrete made from Portland cement. According to other characteristics of the selection process :

[0015] At least one physicochemical property is selected from among: clay content in the excavated clay soil, clay type, particle size distribution, impurity content, non-clay mineral fraction content, pollution content, elemental analysis, metal oxide content, salinity, pH, and total clay exchange capacity of the excavated clay soil. Preferably, at least one physicochemical property is selected from among: clay content in the excavated clay soil, clay type, particle size distribution, non-clay mineral fraction content, elemental analysis, metal oxide content, salinity, pH, and total clay exchange capacity of the excavated clay soil.Preferably, at least one physicochemical property is selected from among: the clay content in the excavated clay soil, the nature of the clays, the particle size distribution, the content of non-clay mineral fractions, the metal oxide content, and the total clay exchange capacity of the excavated clay soil. Such physicochemical properties are best suited to providing deflocculating agent and activation agent values ​​appropriate for the excavated clay soil under consideration. Alternatively, at least one physicochemical property is measured on pre-treated excavated clay soil, said pretreatment being selected from: crushing, sorting, sieving, and / or drying of the excavated clay soil. This advantageously minimizes the error in the measurements.Preferably, the pretreatment includes at least one fractionation step, for example by sieving or sedimentation, more preferably fractionation at 50 µm and, for example, fractionation at 20 µm. It includes, beforehand, determining the desired mechanical properties of the construction material, and the step of selecting the quantities of deflocculant and activating agent further includes excluding quantities of deflocculant and activating agent that would prevent the construction material from achieving the desired mechanical properties. Thus, an operator can easily establish an objective performance criterion for the construction material with the expected composition. This results in time and performance gains within the framework of a process for utilizing excavated soil for a construction application.The step of selecting, by the calculation module, a quantity of deflocculant agent and a quantity of activation agent adapted to the excavated clay soil involves the implementation of a pre-calibrated calculation algorithm. The pre-calibrated calculation algorithm was obtained by implementing a supervised learning statistical method.

[0016] It is disclosed, but not claimed; moreover, a calibration process of a calculation algorithm for determining the composition of a construction material, such as a construction binder or site concrete, for example implemented by a digital device comprising a learning module, characterized in that it comprises: A first stage of reception, by the learning module, of a measured value of at least one physicochemical property of an excavated clay soil; A second stage of reception, by the learning module, of a quantity value of deflocculating agent and a quantity value of activating agent which, once added to the excavated clay soil, allow the formation of a construction material; A third stage of reception, by the learning module, of a measured value of at least one mechanical property of the construction material formed from the excavated clay soil, the value of at least one physicochemical property of which was received during the first reception stage, and from the quantities of deflocculating agent and activating agent received during the second reception stage;and A step of creating a correlation, by the learning module, between the measured values ​​received in order to calibrate a calculation algorithm. ;

[0017] The combination of excavated clay soil, a deflocculant, and an activator produces a building material with appreciable mechanical properties, and the selection process allows for the selection of appropriate quantities. However, considering the complexity and variability of the physicochemical properties of excavated clay soils, the inventors have developed a calibration process for a calculation algorithm that overcomes this complexity. This calibration process makes it possible to propose quantities of deflocculant and activator that are highly adapted to the excavated clay soil. It should be noted that the order of receipt is not important and serves to clarify the description of the process.

[0018] According to a another aspect,the invention also relates to a preparation process of a building material made from raw excavated clay soil, the process comprising: A step of measuring at least one physicochemical property of the raw excavated clay soil; A step of selecting, according to a selection process, the composition of a construction material comprising raw excavated clay soil; and A step of mixing raw excavated clay soil, deflocculating agent and activating agent according to the selected composition.

[0019] Such a simple and quick process reduces greenhouse gas emissions during its implementation compared to the implementation of a conventional construction material preparation process such as Portland cement. According to other characteristics of the preparation process, it also includes:

[0020] ∘ a step of measuring the physico-chemical or mechanical properties of the building material being formed, during the mixing step, ∘ a step of comparing the measured values ​​to predetermined values ​​of the physico-chemical or mechanical properties of the building material being formed, and ∘ when the measured values ​​differ from the predetermined values ​​of the physico-chemical or mechanical properties of the building material being formed, a step of adding at least one additional ingredient.

[0021] Thus, verifying the properties of the building material as it forms allows for online quality control, preferably in real time, to ensure that the formed building material exhibits mechanical properties as close as possible to the expected mechanical properties. Indeed, a deviation can be identified during mixing and corrected before the building material is finalized. a fortiori used.

[0022] A computer program product configured to perform a selection process is disclosed, but not claimed, hereby.

[0023] According to another aspect, the invention discloses, but is not claimed, a computer program product configured to perform a calibration process disclosed, but not claimed, by this present invention.

[0024] In another respect, the invention also relates to a building material formed from excavated clay soil raw characterized in that it comprises raw excavated clay soil, an activation agent and a deflocculant agent, said deflocculant agent representing at least 0.1% by weight of the construction material, preferably at least 0.25% by weight of the construction material.

[0025] Said agent, said deflocculating agent being selected from: a non-ionic surfactant such as a polyoxyethylene ether, or an anionic agent selected from: alkylaryl sulfonates, amino alcohols, carbonates, fatty acids, humates, carboxylic acids, lignosulfonates, polyacrylates, phosphates or polyphosphates such as sodium hexametaphosphate, sodium tripolyphosphate, sodium orthophosphate, carboxymethylcelluloses, or an amine selected for example from: 2-amino-2-methyl-1-propanol; mono-, di- or triethanolamine; isopropanolamines and N-alkylated ethanolamines.

[0026] The activating agent is not always found in the construction binder or in-situ concrete because it can react with constituents of the excavated clay soil and be transformed. However, a construction material according to the invention, formed from excavated clay soil, also includes an activating agent.

[0027] Such a building material formed from excavated clay soil has mechanical properties suitable for use in the construction field while also providing a way to valorize excavated clay soils.

[0028] According to other optional characteristics of the building material according to the invention, it comprises a mixture of different types of clays.

[0029] In addition, it may contain at least 2% by weight of silt particles, preferably at least 4% by weight, and more preferably at least 6% by weight. The silt particles are in particular particles with a diameter between 2 µm and 50 µm.

[0030] A construction material according to the invention may contain metal oxides at a content of at least 2% by weight of the construction material.

[0031] A construction material according to the invention may further include blast furnace slags.

[0032] A construction material according to the invention may comprise from 30% to 80% by weight of excavated clay soil, from 0.1% to 10% by weight of deflocculating agent, and from 5% to 10% by weight of blast furnace slag. In this case, the construction material preferably corresponds to a construction binder.

[0033] A building material according to the invention may comprise: between 5 and 20% by weight of raw clay from excavated clay soil; between 0.1 and 3% by weight of deflocculating agent; between 3 and 15% by weight of an activating agent; between 25 and 45% by weight of sand; and between 35 and 55% by weight of aggregates; said construction material then preferably corresponds to a site-mixed concrete.

[0034] As shown in the examples, the construction materials according to the invention exhibit improved mechanical performance.

[0035] Furthermore, the excavated clay soil may advantageously have been pre-treated, such pre-treatment being selected from: crushing, sorting, sieving and / or drying of the excavated clay soil. The pre-treatment may, for example, include fractionation.

[0036] In another aspect, the invention relates to a method for preparing a construction material according to the invention from excavated clay soil comprising: a step of excavating clay soil; optionally a step of screening the excavated clay soil when the excavated clay soil contains stones retained by a 2 cm screening; and a step of mixing 340 of excavated clay soil, preferably the fraction less than 50 µm, with deflocculating agent and activating agent.

[0037] According to a another aspect, the invention also relates to a building material preparation system comprising raw excavated clay soil, said system comprising: A soil crusher; At least one container containing excavated clay soil; At least one container containing a deflocculant agent; At least one container containing an activator agent; A mixing device, with automated transport means between the containers and the mixing device; A control module configured to generate output signals to the automated transport means to transport determined quantities of deflocculant and activator agent to the mixing device.

[0038] Said agent, said deflocculating agent being selected from: a non-ionic surfactant such as a polyoxyethylene ether, or an anionic agent selected from: alkylaryl sulfonates, amino alcohols, carbonates, fatty acids, humates, carboxylic acids, lignosulfonates, polyacrylates, phosphates or polyphosphates such as sodium hexametaphosphate, sodium tripolyphosphate, sodium orthophosphate, carboxymethylcelluloses, or an amine selected for example from: 2-amino-2-methyl-1-propanol; mono-, di- or triethanolamine; isopropanolamines and N-alkylated ethanolamines.

[0039] Advantageously, the construction material preparation system according to the invention includes a communication means configured to receive data on a quantity of deflocculant agent and a quantity of activation agent determined, adapted to the excavated clay soil; the control module being configured to generate output signals to the automated transport means so as to transport the determined quantities of deflocculant agent and activation agent to the mixing device.

[0040] Preferably, the construction material preparation system according to the invention comprises: A means for measuring at least one physicochemical property of the excavated clay soil, A calculation means capable of implementing a computer program configured to perform: A step of obtaining a measured value of at least one physicochemical property of the excavated clay soil; and A step of determining a quantity of deflocculating agent and a quantity of activation agent adapted to the excavated clay soil on the basis of a comparison of the measured value(s) to reference values.

[0041] In particular, the invention also relates to a building material preparation system comprising excavated clay soil, said system comprising: At least one container containing excavated clay soil; At least one container containing a deflocculating agent; At least one container containing an activating agent; A mixing device, with automated transport means between the containers and the mixing device; A means for measuring at least one physicochemical property of the excavated clay soil; A calculation means capable of implementing a computer program configured to perform: ∘ A step of obtaining a measured value of at least one physicochemical property of the excavated clay soil, and ∘ A step of determining a quantity of deflocculating agent and a quantity of activating agent adapted to the excavated clay soil based on a comparison of the measured value(s) to reference values;and A control module configured to generate output signals for automated transport systems to transport the determined quantities of deflocculant and activating agent to the mixing device.

[0042] Such a system allows for the automated formation of a construction binder or possibly site concrete (with the addition of fillers) from excavated clay soil, these construction materials having mechanical properties equivalent to the mechanical properties of conventional materials with a much higher carbon footprint.

[0043] Other advantages and features of the invention will become apparent from the following description, given by way of illustrative and non-limiting example, with reference to the attached Figures: [ Fig 1] represents the steps in a process for selecting the composition of a building material containing excavated clay soil. The steps shown in dotted lines are optional. Fig 2 ] represents the steps in a calibration process for a calculation algorithm to determine the composition of a site construction material. The steps shown in dotted lines are optional. Fig 3 ] represents the steps in a process for preparing a building material from excavated clay soil. The steps shown in dotted lines are optional. Fig 4 ] represents a method for preparing a construction material according to an embodiment of the invention. Fig 5 ] represents a process for preparing a construction material according to an embodiment of the invention. The steps in dotted lines are optional. Fig 6[ ] represents a diagram showing a functional architecture of the system for preparing a construction material comprising excavated clay soil according to the invention. Solid arrows represent means of transport and dashed arrows represent data transfers or instructions, including said means of transport.

[0044] Aspects of the present invention are described with reference to flowcharts and / or functional diagrams of processes, devices (systems), and computer program products according to embodiments of the invention. In the figures, the flowcharts and functional diagrams illustrate the architecture, functionality, and operation of possible implementations of systems and processes according to various embodiments of the present invention.

[0045] In this respect, each block in the flowcharts or block diagrams can represent a system, device, module, or code, which comprises one or more executable instructions to implement the specified logical function(s). In some implementations, the functions associated with the blocks may appear in a different order than shown in the figures. For example, two blocks shown successively may, in fact, be executed almost simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functionality involved. Each block in the schematic diagrams and / or flowchart, and combinations of blocks in the schematic diagrams and / or flowchart, can be implemented by special hardware systems that perform the specified functions or actions, or perform combinations of special hardware and computer instructions. [Description of the invention]

[0046] In the rest of the description, the expression " clay soil"Clay" should be understood as corresponding to soil originating from a formation containing clay, or more generally from a loose, fine-grained soil, and therefore containing one or more rock materials based on hydrated silicates or aluminosilicates with a lamellar structure. In particular, clay soil can, for example, correspond to sandy-clay loam soils, clay-loam soils, sandy-clay soils, or clay soils. Preferably, clay soil contains at least 25% clay by weight, preferably at least 30% clay by weight, and even more preferably at least 40% clay by weight. The clay content by weight can be determined by standard methods of the prior art, such as the particle size analysis method described in standard NF X31-107.Furthermore, preferably, a clay soil within the framework of the invention comprises at most 95% by weight of clay, preferably at most 90% by weight of clay, more preferably at least 80% by weight of clay.

[0047] The expression " excavated clay soil"In the sense of the invention, this corresponds to clay soil obtained following a stage where the ground has been excavated, for example, during leveling and / or earthmoving operations, for the purpose of construction, building, or backfilling. In particular, in the sense of the invention, the excavated clay soil may or may not be transported from the production site. Preferably, and according to an advantage of the invention, the excavated soil is used on the production site or at a distance of less than 200 km. Furthermore, the clay soil excavated according to the invention is raw excavated clay soil, that is to say, it has not undergone a calcination stage. In other words, it has not been subjected to any prior heat treatment." This corresponds to clay soil that has not been subjected to a temperature rise above 300°C, preferably above 200°C and more preferably above 150°C.Indeed, raw clay soil can undergo a heating stage requiring a temperature rise generally of approximately 150°C, but no calcination stage. Clay as conventionally used has a relatively constant particle size profile with sizes less than 2 µm. Excavated clay soil can exhibit different particle size profiles. In the context of the invention, excavated clay soil may contain particles larger than 2 µm, preferably larger than 20 µm, preferably larger than 50 µm, and for example, larger than 75 µm as defined according to ASTM D422-63. Preferably, the excavated clay soil does not contain aggregates larger than 2 cm as defined according to NF EN 933-1.

[0048] The expression " % by weight"In relation to excavated clay soil, the composition, binder, or site concrete must be understood as a proportion relative to the dry weight of the composition, binder, or site concrete. The dry weight corresponds to the weight before the addition of water, for example, necessary for the formation of a construction material."

[0049] The expression " building material "In the context of the present invention, this corresponds to a construction binder or site concrete. The site concrete will in particular include fillers such as aggregates and / or sand."

[0050] By "we mean deflocculant agent "A deflocculant is any compound which, in aqueous suspension, will dissociate aggregates and colloids. Deflocculants, for example, have been used in drilling or oil extraction to make clay more fluid and facilitate extraction or drilling."

[0051] By "we mean activation agent", any composition whose function is to accelerate the dispersion of an aluminosilicate source promoting the formation of stable hydrates with low solubility and the formation of a compact structure with these hydrates, thus increasing the mechanical resistance of materials incorporating such an activation composition.

[0052] The term " particle size "In the sense of the invention, corresponds to the distribution of the elements and particles of clay soil according to the relative weight importance of the different classes of particles, identified by their size and constituting the mineral skeleton of the soil. Five granulometric classes exist: - Clays (0 to 2 micrometers) - Fine silts (2 to 20 micrometers) - Coarse silts (20 to 50 micrometers) - Fine sands (50 to 200 micrometers) - Coarse sands (200 to 2000 micrometers).

[0053] The expression " nature of clays"Related to the meaning of the invention, refers to the chemical and / or mineralogical properties of clays. This corresponds in particular to the chemical composition of clays, but also to their mineralogy and physical characteristics (such as specific surface area, porosity, and morphology). For example, this may correspond to the identification of clay by its common name (e.g., kaolinite, illite, montmorillonite, smectite, bentonite, chlorite, and vermiculite)."

[0054] The expression " metallic trace elements " corresponds in the sense of the invention to metallic chemical elements and in particular they correspond in the sense of the invention to metals selected from: iron, lead, mercury, uranium, chromium, copper, cadmium, silver, gold, zinc, nickel or titanium.

[0055] The term " roughly equal" in the sense of the invention corresponds to a value varying by less than 20% from the compared value, preferably by less than 10%, even more preferably by less than 5%.

[0056] By "model" or "rule" or " calculation algorithm", it is necessary to understand in the sense of the invention a finite sequence of operations or instructions allowing the selection of values ​​of quantity of deflocculant agent and of activation agent, that is to say for example of forming predefined groups Y associated with scores or categories according to correlation with quantities of deflocculant agent D and of activation agent A on the one hand and one or more values ​​of physicochemical properties of excavated clay soil E. The implementation of this finite sequence of operations makes it possible for example to assign a label Y 0 to an observation described by a set of characteristics D 0 , A 0 , E 0 , thanks for example to the implementation of a function f capable of reproducing Y having observed D, A and E. Y = f D A E + e where e symbolizes noise or measurement error.

[0057] Here Y could, for example, be the ability (yes / no) to form a building material.

[0058] Advantageously, the calculation algorithm can establish predefined groups and associate other values, such as the mechanical property values ​​(M) of the construction material that can be formed from these quantities. Thus, with the formula "M = f(D,A,E) + e", it is possible to select quantity values ​​that allow the formation of construction materials with predetermined mechanical properties.

[0059] By " supervised learning method ", in the sense of the invention, means a method for defining a function f from a basis of n labeled observations (X 1...n , Y 1...n , D 1...n , , A 1...n , , E 1...n ) where for example Y = f (D,A,E) + e or M = f (D,A,E) + e.

[0060] By "we mean to treat " calculate " determine " display " extract » compare or more broadly executable operation"Operations," as used in the invention, refers to an action performed by a device or processor unless the context indicates otherwise. In this context, operations relate to actions and / or processes of a data processing system, such as a computer system or electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities in the computer system's memory or other information storage, transmission, or display devices. Specifically, computational operations are performed by the device's processor, the resulting data is written to a corresponding field in a data memory, and this field or these fields can be returned to a user, for example, through a suitable Human-Machine Interface, such as, by way of non-limiting example, the screen of a connected device, formatting such data.These operations can be based on applications or software.

[0061] The terms or expressions " application " software " program code ", And " executable code "Code" refers to any expression, code, or notation within a set of instructions designed to trigger data processing to perform a specific function, either directly or indirectly (e.g., after conversion to another code). Examples of program code may include, but are not limited to, a subroutine, a function, an executable application, source code, object code, a library, and / or any other sequence of instructions designed for execution on a computer system.

[0062] By "we mean processor", as defined in the invention, at least one hardware circuit configured to execute operations according to instructions contained in a code. The hardware circuit may be an integrated circuit. Examples of a processor include, but are not limited to, a central processing unit, a graphics processing unit, an application-specific integrated circuit (ASIC), and a programmable logic device. A single processor or several other units may be used to implement the invention."

[0063] By "we mean couple ", in the sense of the invention, connected, directly or indirectly with one or more intermediate elements. Two elements can be coupled mechanically, electrically or linked by a communication channel.

[0064] The expression " human-machine interface"In the context of the invention, this refers to any element enabling a human being to communicate with a computer, including, but not limited to, a keyboard and means that, in response to commands entered via the keyboard, display information and, optionally, allow selection of elements displayed on the screen using a mouse or touchpad. Another example is a touchscreen that allows the user to directly select elements on the screen by touching them with a finger or an object, and optionally display a virtual keyboard."

[0065] In the demands, the term "to understand" Or "include" does not exclude other elements or other steps.

[0066] Throughout this description, the same references are used to designate the same elements. These references shall not be construed as limiting the scope of the invention. Furthermore, the various features presented and / or claimed may be advantageously combined. Their presence in the description or in separate dependent claims does not preclude this possibility.

[0067] As previously mentioned, the current situation is that excavated soil is abundant, often considered waste, and therefore represents an additional burden for developers during site development. This management, and in particular the pollution that can be generated by transporting this excavated soil, is compounded by the pollution generated during the production of conventional cement (e.g., Portland cement).

[0068] Faced with this situation, the inventors identified a process for selecting a composition for a construction material using excavated clay soil, resulting in a construction binder with mechanical properties similar to those of conventional cement (e.g., Portland cement). Using this process, as will be demonstrated in the examples, they are able to generate a construction binder that could be advantageously, but not exclusively, used as a replacement for Portland cement, lime, or CSA. Thus, the waste (i.e., excavated clay soil), combined in specific proportions with a deflocculating agent and an activating agent, can become a raw material in a construction process.

[0069] Furthermore, given its preparation process and the use of excavated clay soil, the construction material according to the invention has the advantage of having a carbon footprint at least twice as low as most of the most widely used construction materials or hydraulic binders in the world today (i.e., Portland cement). Indeed, a construction material according to the invention is primarily composed of clay soil and has a clinker content of zero or less than equivalent products, and, with equivalent mechanical properties, allows for a reduction in CO2 emissions and production costs. Moreover, the clay soil preferably has not undergone a calcination step, an energy-intensive process that also generates greenhouse gas emissions, particularly carbon dioxide.

[0070] Finally, advantageously, as will be shown in the examples, a construction binder according to the invention allows the manufacture of construction materials with mechanical properties at least equivalent to Portland cement and far superior to "low carbon" materials, such as those described previously.

[0071] Thus, it is disclosed, but not claimed, a method 100 for selecting the composition of a building material containing excavated clay soil. Since the construction binder can then be used to form site concrete, following for example the addition of a filler, the selection process 100 can alternatively correspond to a selection process 100 for the composition of site concrete.

[0072] In particular, for the preparation of a building material from excavated clay soil to be possible, the composition of the building material must include quantities of deflocculating agent and activating agent adapted to the excavated clay soil.

[0073] For this purpose, a process, preferably implemented by a computer device including a calculation module, includes a receiving step 130, by the calculation module, of a measured value of at least one physicochemical property of an excavated clay soil; and a selection step 170, by the calculation module, of a quantity of deflocculating agent and a quantity of activation agent adapted to the excavated clay soil.Furthermore, a process according to the invention may include steps such as: preliminary treatments 110 of the excavated clay soil, measurements 120 of the physicochemical properties of the excavated clay soil, acceptance 140 of the desired mechanical property value of the construction material, generation 150 of a plurality of combinations of quantity values ​​of deflocculating agent and activating agent, determination 160 of a desired mechanical property value of the construction material, or determination of at least one physicochemical or mechanical property value of the construction material in formation.

[0074] As illustrated in the figure 1 , the selection process may include a step of 110 pre-treatment of the excavated clay soil. Thus, advantageously, the measurement value(s) are obtained from a sample of excavated clay soil that has undergone a prior treatment step 110 of the excavated clay soil.

[0075] This preliminary treatment step may, for example, include or consist of fractionation, crushing, sorting (e.g., according to color), sieving and / or drying of the excavated clay soil.

[0076] In particular, since, within the scope of the present invention, the clay soil is excavated soil, it may contain coarse elements or large fractions that it would be advantageous to remove in the early stages of the process. Specifically, the process may include removing elements with a dimension greater than 1 cm (centimeter), preferably with a dimension greater than 0.2 cm. Preferably, the process may include removing elements with a size greater than 1 cm, preferably greater than 475 µm (micrometer), and more preferably greater than 75 µm as defined in ASTM D422-63.

[0077] Furthermore, the process may include a step of measurement 120 of at least one physicochemical property of an excavated clay soil.This step is preferably carried out on a sample of excavated clay soil and can be performed on-site or in a specialized laboratory. Indeed, depending on the physicochemical property or properties being measured, it may or may not be possible to use portable instruments.

[0078] Measurement step 120 may, for example, include a measurement step of: the clay content in the excavated clay soil, measured for example by a granulometric method such as that described in standard NF X31-107; the nature of the clays, obtained for example by X-ray diffractometry; the content of impurities and in particular of trace metal elements, obtained for example by elemental analysis via an ICP-MS device; the salinity using a conductivity meter measuring the conductivity of a wash water of the clay soil; the pH using a pH meter measuring the pH of a wash water of the clay soil; and the total exchange capacity of the clay of the excavated clay soil measured for example by the so-called methylene blue method according to standard NF EN 933-9+A1.

[0079] Measurement step 120 may therefore, for example, include the use of a pH meter, an X-ray diffractometer, a conductivity meter, an electron microscope, a mercury porosimeter, a spectrofluorometer, an ICP-MS (Inductively Coupled Plasma Mass Spectrometry), an HPLC-MS (liquid chromatography coupled with mass spectrometry), a GC-MS (gas chromatography coupled with mass spectrometry), the measurement of specific surface area by the BET method (specific surface area measurement, for Brunauer-Emmett-Teller), a particle size analyzer, or even a TGA rheometer (for thermogravimetric analysis).

[0080] The process includes a step of reception 130 of measured value of at least one physicochemical property of an excavated clay soil. This step can in particular be implemented by the calculation module of the digital device.

[0081] The physicochemical properties of the excavated soil, the measured value of which is received, can be selected from among: the clay content in the excavated clay soil, the type of clay, the particle size distribution, the impurity content, the presence of pollutants, the liquid limit, the plastic limit, the metal oxide content, the salinity, the pH, and the total clay exchange capacity of the excavated clay soil. For example, the physicochemical properties of the excavated soil, the measured value of which is received, can be selected from among: the clay content in the excavated clay soil, the type of clay, the particle size distribution, the impurity content, the metal oxide content, the salinity, the pH, and the total clay exchange capacity of the excavated clay soil.Preferably, the physicochemical property of the excavated soil, the measured value of which is received, can be selected from among: the clay content in the excavated clay soil, the liquid limit, and the plastic limit. More preferably, the physicochemical property of the excavated soil, the measured value of which is received, includes the clay content in the excavated clay soil.

[0082] In particular, the impurity content can correspond to the content of metals and advantageously of metal oxides such as: iron oxide or aluminum oxide.

[0083] Preferably, measured values ​​are received for at least two physicochemical properties of an excavated clay soil, more preferably for at least three, and even more preferably for at least four. Indeed, depending on the number of physicochemical properties taken into account, the result of the selection process can be of higher quality.

[0084] The physicochemical property(ies) are physicochemical properties of soils that have been widely studied, such as pH, particle size, and clay content.

[0085] In particular, the process involves receiving 130 a combination of measured values ​​selected from: the clay content in the excavated clay soil and the nature of the clays; the clay content and the total clay exchange capacity of the excavated clay soil; the clay content and the amount of pollutants; the pH and the clay content in the excavated clay soil; or the total clay exchange capacity of the excavated clay soil and the particle size.

[0086] Furthermore, as presented to the figure 1 The process may include the reception 140 of a desired mechanical property value of a construction material.

[0087] Indeed, beyond simply selecting the composition of a construction material, the process can advantageously allow for the selection of a composition that enables the preparation of a construction material with specific mechanical properties. Thus, a user can, according to their needs, select the precise quantities required to obtain a construction material that meets their requirements.

[0088] The desired mechanical properties of the construction material can be selected from a range of factors, including compressive strength, drying shrinkage, setting time, flexural strength, tensile strength, Young's modulus, and Poisson's ratio. For example, the process may involve determining a desired compressive strength value for the construction material. This value could be a lower bound (e.g., 20 MPa, for megapascals, or 30 MPa) or a fixed value (e.g., 40 MPa).

[0089] Preferably, when the process involves receiving 140 a desired mechanical property value for the construction material, the selection step 170 of the quantities of deflocculating agent and activating agent further includes an exclusion 171 of quantities of deflocculating agent and activating agent that will not allow the construction material to exhibit the desired mechanical property value. For example, this could involve selecting, via the calculation algorithm, all values ​​of A and D that, starting from a measured value of E, yield a value M = 40 MPa. Alternatively, in the absence of a calculation algorithm, this could involve filtering all values ​​from a database for which the value of M is less than 30 MPa.

[0090] The receiving step 130, which involves measuring at least one physicochemical property of excavated clay soil, may be followed by a step of generation 150 of a plurality of combinations of quantity values ​​of deflocculating agent on the one hand and of activating agent on the other hand.Following the generation of this plurality of values, the calculation module can implement a value selection step (170 values) as described below. Furthermore, the process may include a step of determination 160 of at least one value of physicochemical property or of expected mechanical properties for the construction material. This step is implemented, for example, by a calculation module.

[0091] From the measured values ​​of physicochemical properties of the excavated clay soil and the values ​​of the quantity of deflocculant and activation agent generated, it is possible to determine a mechanical property value of a construction material formed from the excavated soil and the quantities of deflocculant and activation agent considered.

[0092] The process includes a step of selection 170 of a quantity of deflocculant agent and a quantity of activation agent adapted to the excavated clay soil. This step can, for example, be implemented by a calculation module.

[0093] The quantity of deflocculant and activating agent can be expressed as a volume, a mass, or a proportion. Preferably, the quantity is a proportion relative to the amount of excavated clay soil to be added to the construction material composition. Alternatively, if the quantity is a volume or a mass, then it is associated with the amount of excavated clay soil to be added to the construction material composition.

[0094] Furthermore, the selection of a quantity of deflocculant and an quantity of activating agent may involve determining the nature of the deflocculant and / or activating agent to be added. For example, the nature of these agents may correspond to a family of chemical molecules, a particular chemical molecule, or a combination of molecules.

[0095] Indeed, the deflocculant can be a combination of molecules, and selecting a quantity of deflocculant can then correspond to selecting a quantity of each of the molecules composing the deflocculant. The same applies to the activating agent, which can be a single molecule or a plurality of molecules.

[0096] Advantageously, the selection is based on a comparison of the measured physicochemical property value(s) of an excavated clay soil with reference values. In particular, the reference values ​​include correlations between measured values ​​of at least one physicochemical property of a clay soil and quantities of deflocculating agent and activating agent adapted to said clay soil to form a construction material. deflocculant agent

[0097] The deflocculant agent is selected from: a non-ionic surfactant such as a polyoxyethylene ether, or an anionic agent selected from: alkylaryl sulfonates, amino alcohols, carbonates, fatty acids, humates, carboxylic acids, lignosulfonates, polyacrylates, phosphates or polyphosphates such as sodium hexametaphosphate, sodium tripolyphosphate, sodium orthophosphate, carboxymethylcelluloses, or an amine selected for example from: 2-amino-2-methyl-1-propanol; mono-, di- or triethanolamine; isopropanolamines and N-alkylated ethanolamines.

[0098] The deflocculant agent can also be selected, for example, from sodium polyacrylate and ammonium polyacrylate.

[0099] In the context of the invention, the deflocculating agent is in particular a non-ionic surfactant such as a polyoxyethylene ether. The polyoxyethylene ether may, for example, be selected from: a poly(oxyethylene) lauryl ether.

[0100] Preferably, the deflocculating agent is selected from: a lignosulfonate (e.g., sodium lignosulfonate), a polyacrylate, a humate.

[0101] The deflocculant agent is preferably in the form of a salt. Activation Agent

[0102] It is the activation agent, in conjunction with the excavated clay soil and the deflocculating agent, that will give the construction material its mechanical properties of interest.

[0103] Without being limited by theory, the activation agent can allow the formation of a network between the clay sheets which will bring its mechanical properties to the construction material according to the invention.

[0104] In particular, the activating agent may contain metal oxides and / or be an alkaline activating composition.

[0105] Preferably, the metal oxides are oxides of transition metals. More preferably, the metal oxides are selected from: iron oxides such as FeO, Fe3O4, Fe2O3, Fe2O3, alumina Al2O3, manganese(II) oxide MnO, titanium(IV) oxide TiO2 and mixtures thereof.

[0106] Metallic oxides can preferably originate from a composition of blast furnace slags, for example, formed during the production of pig iron from iron ore.

[0107] Metal oxides are present at a content of at least 2% by weight of the construction material, preferably at least 5% by weight of the construction material, more preferably at least 10% by weight of the construction material.

[0108] When the activating agent is an alkaline activating composition, the alkaline composition may preferably comprise a compound having a pKa greater than or equal to 10, more preferably greater than or equal to 12, and even more preferably substantially equal to 14. The alkaline composition may, for example, comprise an organophosphate compound such as sodium tripolyphosphate, designated by the acronym NaTPP.

[0109] In particular, the activating agent may comprise a mixture of sodium hydroxide and sodium silicate.

[0110] Advantageously, the activating agent can be an alkaline activating composition further comprising metal oxides. As will be shown in the examples, construction binders prepared from such an activating agent exhibit good mechanical properties. Thus, preferably, the activating agent can comprise metal oxides and at least one compound having a pKa greater than or equal to 10.

[0111] In addition, selection step 170 may include a determination 172 of a quantity of additive to be incorporated into the composition of the construction material. Indeed, the selection process can lead to a construction material composition containing certain additives in specific concentrations. These additives modify the chemical and / or mechanical properties of the final construction material.

[0112] The additive is selected for example from: a plasticizer, a synthetic or natural rheological stabilizing agent, an anti-shrinkage agent, a water-retaining agent, an air-entraining agent, a synthetic resin, a pigment and mixtures thereof.

[0113] The plasticizer can, for example, be a polyacrylate, a polynaphthalene sulfonate, a polycarboxylate, or a polyphosphonate.

[0114] In addition, selection step 170 may include a determination 173 of a quantity of charge to be incorporated into the formulation in order to form a site-mixed concrete. These fillers allow for the modification of the mechanical properties of the final construction material.

[0115] The filler can, for example, be selected from recycled or non-recycled aggregates, powders, sand, gravel, crushed concrete and / or fibers.

[0116] Fibers are selected from a variety of sources, including plant fibers such as cotton, flax, hemp, cellulose, bamboo, and miscanthus, and synthetic fibers such as metallic, glass, carbon, and polypropylene fibers, as well as blends thereof. The presence of fibers can contribute to the creation of a building material with improved mechanical and insulating properties.

[0117] Advantageously, and as previously discussed, step 170 of determining a quantity of deflocculating agent and a quantity of activating agent suitable for the excavated clay soil involves the implementation of a pre-calibrated calculation algorithm.

[0118] This calculation algorithm may have been built from different learning models, including partitioning, supervised or unsupervised.

[0119] An unsupervised statistical learning model can, for example, be selected from an unsupervised Gaussian mixture model, a hierarchical clustering agglomerative (in Anglo-Saxon terminology), or a hierarchical clustering divisive (in Anglo-Saxon terminology).

[0120] A supervised statistical learning model can, for example, be selected from kernel methods (e.g. Large Margin Separators - Support Vector Machines SVM, Kernel Ridge Regression) described, for example, in Burges, 1998 (Data Mining and Knowledge Discovery. A Tutorial on Support Vector Machines for Pattern Recognition), set methods (e.g. Bagging, Boosting, Decision Trees, Random Forest) described, for example, in Brieman, 2001 (Machine Learning. Random Forests), or neural networks described, for example, in Rosenblatt, 1958 (The perceptron: a probabilistic model for information storage and organization in the brain).

[0121] Preferably, the previously calibrated calculation algorithm was obtained by implementing a supervised learning statistical method.

[0122] Revealed, but not claimed, is a 200 calibration process for a calculation algorithm.This calculation algorithm is specifically designed to determine the composition of a construction material. A calibration process can be implemented using a digital device with a learning module.

[0123] As illustrated in the figure 2 , such a calibration process includes a step of reception 230 of a measured value of at least one physicochemical property of an excavated clay soil.

[0124] Preferably, 230 is received from several measured values, and in particular from the values ​​of at least two physicochemical properties of an excavated clay soil, more preferably from at least three, and even more preferably from at least four. Indeed, depending on the number of physicochemical properties taken into account, the calibration process will be of higher quality.

[0125] The calibration process also includes a step of reception 240 of a quantity value of deflocculating agent and a quantity value of activating agent.These values ​​correspond to quantities of agents which, once added to excavated clay soil, allow the formation of a building material.

[0126] The quantity of deflocculant and activating agent can be expressed as a volume, a mass, or a proportion. Preferably, the quantity is a proportion relative to the quantity of excavated clay soil to be added to the construction material composition. Alternatively, if the quantity is a volume or a mass, it is associated with a quantity of excavated clay soil to be added to the construction material composition. Furthermore, the acceptance of the quantity of deflocculant and activating agent may include specifying the nature of the deflocculant and / or activating agent. For example, the nature of these agents may be a family of chemical molecules, a specific chemical molecule, or a combination of molecules.

[0127] These values ​​may have been obtained through tests, which will be described in the examples section. The calibration process incorporates only the quantities of agents necessary for the formation of a construction material.

[0128] Indeed, the calibration process may include a step of formation 250 of a construction material according to the received values. Alternatively, and preferably, a plurality of combinations of agent quantity values ​​were tested on a plurality of clay soils excavated to form a database that could be used as input data in the calibration process.

[0129] The process then involves a step of creation 270 of a correlation between the measured values ​​received in order to calibrate a calculation algorithm. This correlation step, based on measured values, allows us to build a calculation algorithm from a statistical learning model. Thus, the calculation algorithm can take the form of a function f in an equation of the type Y = f E A D

[0130] Preferably, as presented in the figure 2 Prior to the creation step 270, the calibration process may also include a step of reception 260 of a measured value of at least one mechanical property of the formed construction material. Indeed, in addition to using the quantity values ​​of the agents and the physicochemical property values ​​of the excavated clay soil, the calibration process can use one or more measured values ​​of the resulting construction material. Thus, the calculation algorithm can take the form of a function f in an equation of the type: M = f E A D

[0131] Preferably, there is reception of 260 of several measured values ​​and in particular of the values ​​of at least two physicochemical properties of the construction material, more preferably of at least three and even more preferably of at least four.

[0132] Furthermore, as illustrated in the figure 2 ,The calibration process may include a preliminary treatment step 210 of a clay soil sample, which may precede a measurement step 220 of at least one physicochemical property of the clay soil. Furthermore, once the correlation is established, it can be saved 280 on a storage medium such as RAM or non-volatile memory.

[0133] Advantageously, a calibration process may include a step of update 290 of the calculation algorithm by repeating the previous steps described above and at a minimum: Receiving 230 a measured value of at least one physicochemical property of an excavated clay soil, Receiving 240 a quantity of deflocculating agent and a quantity of activating agent which, once added to the excavated clay soil, will form a construction material and Creating 270 a correlation between the received measured values ​​in order to calibrate a calculation algorithm.

[0134] According to a another aspect, the invention relates to a process 300 for preparing a building material from excavated clay soil.

[0135] Such a method according to the invention, illustrated in the figure 3 , This process has the advantage of being considered low-carbon, meaning that its greenhouse gas emissions, particularly carbon dioxide emissions, are reduced compared to those of known construction binder preparation processes. These reductions in greenhouse gas emissions are primarily due to the absence of a calcination step, which is particularly energy-intensive.

[0136] Furthermore, the preparation of a construction binder according to the invention allows for the production of on-site concrete made at least partially from raw materials sourced from the construction site. Such characteristics further contribute to reducing the environmental footprint of the concrete produced. Once a suitable quantity of deflocculating agent and an appropriate quantity of activating agent have been selected for the excavated clay soil, it is possible to prepare a construction material from the excavated clay soil using conventional methods.

[0137] The preparation process according to the invention comprises a step of measurement 310 of at least one physicochemical property of the excavated clay soil.

[0138] Such a step can be carried out well before the mixing step 340. This is the case, for example, if preliminary studies are conducted and there is no need for immediate use of the excavated soil. Alternatively, the measurement step 310 of at least one physicochemical property of the excavated clay soil can be carried out just before the selection steps 100 of the composition of a building material, corresponding to a process implementation step 100, and the mixing step 340. This is the case, for example, in an automated process for preparing a building material from excavated clay soil, where the excavated clay soil is analyzed online with a portable measuring device and then continuously mixed with selected quantities of agents to form a building material in a very short time.

[0139] Preferably, there is measurement of several values ​​and in particular the values ​​of at least two physicochemical properties of the excavated clay soil, more preferably of at least three and even more preferably of at least four.

[0140] Furthermore, as illustrated in the figure 3 and to the figure 4 , A preparation method according to the invention may include a 100% selection of the composition of a building material containing excavated clay soil.

[0141] Furthermore, it includes a step of mixture 340 of excavated clay soil, deflocculating agent and activating agent depending on the selected composition.

[0142] During the mixing stage, water can be added so that the ratio between the mass of water and the mass of construction material is less than 1 and for example between 0.4 and 0.8. In addition, water can advantageously be added after the excavated clay soil and the deflocculating agent have been mixed dry.

[0143] Preferably, the process according to the invention may include a mixing step to obtain a suspension of dispersed or deflocculated excavated clay soil. During mixing, preferably, the deflocculating agent is added before the activating agent so that the activating agent is mixed with the dispersed or deflocculated excavated clay soil. This mixing step 340 of the clay suspension may advantageously, but not exclusively, be carried out in a device selected from: a mixer and a concrete mixer truck or, more generally, in any device suitable for mixing clay soil.

[0144] Preferably, the preparation process may include a screening step 330 of the excavated clay soil. This screening step takes place before the mixing step 340 and before or after the measuring step 310. In particular, it is carried out in such a way as to remove aggregates whose diameter is greater than 20 mm (for millimeter).

[0145] More broadly, the preparation process may include a step of preparing the excavated clay soil, said preparation being able to include, for example: drying, grinding, sieving, storage.

[0146] Preferably, the pretreatment or screening step includes at least one fractionation step such as sieving, more preferably a fractionation step such as sieving at 50 µm. Advantageously, but not exclusively, the sieved elements or particles, such as, for example, sand and / or aggregate fractions, can be reused in the formulation of the construction material, and in particular, in-situ concrete. The most suitable fraction for preparing the construction material is the fraction not retained by the sieve. Thus, a process 300 according to the invention for preparing a construction material from excavated clay soil will advantageously include a fractionation step 335 of the excavated clay soil, possibly screened, said fractionation being preferably carried out at 50 µm.

[0147] Alternatively, the excavated clay soil may not be pre-treated, and all of the clay soil is used to obtain the construction material. In this case, the process yields on-site concrete.

[0148] This allows for the efficient use of all excavated clay soil, particularly when its physicochemical properties are sufficient to produce a building material with the desired mechanical properties. Thus, the entire soil can be utilized from the outset without necessarily needing to isolate the clay for processing and material formulation.

[0149] As illustrated in la figure 5 , A process 300 according to the invention for preparing a building material from excavated clay soil will advantageously comprise: an excavation step 320 of clay soil; a screening step 330 of the excavated clay soil when the excavated clay soil contains stones retained by a 2 cm screening; a mixing step 340 of excavated clay soil, preferably the fraction less than 50 µm, of deflocculating agent and of activating agent.

[0150] Furthermore, advantageously, the preparation process may also include a pollutant treatment step. Such a pollutant treatment step can reduce the concentration of pollutants in the excavated clay soil, such as traces of metallic elements, hydrocarbons (e.g., Polycyclic Aromatic Hydrocarbons and C10 to C40), PCBs (Polychlorinated Biphenyls), BTEX (benzene, toluene, ethylbenzene, xylenes), and TOC (total organic carbon).

[0151] In addition, conventionally, before, concurrently or after the addition of the activation composition, a process according to the invention may include the addition of additives or fillers to modify the mechanical properties of the final construction material.

[0152] Advantageously, the preparation process may include a 350 measurement of one or more values ​​of physico-chemical or mechanical properties of the construction material, during the mixing stage (i.e. the construction material is forming), a 360 comparison of the measured values ​​to predetermined values ​​of physico-chemical or mechanical properties of the construction material in formation.

[0153] Thus, it is possible to carry out quality control of the construction material during its formation.

[0154] Furthermore, when the measured values ​​differ from the predetermined physicochemical or mechanical properties of the building material being formed, the preparation process may include a step 370 involving the addition of at least one supplementary ingredient. Here, the supplementary ingredient may, for example, be selected from: a deflocculating agent, an activating agent, and excavated clay soil in such a way as to modify the predetermined composition. The supplementary ingredient may also be selected from: additives or fillers as described previously.

[0155] This ensures that the building material being formed will exhibit mechanical properties as close as possible to the expected mechanical properties. Indeed, any deviation can be identified during mixing and corrected before the material is used.

[0156] Furthermore, as illustrated in the figure 4, the process is completed by a 380 recovery step of the formed construction material.

[0157] According to a another aspect, the invention relates to a system 400 for preparing a building material comprising excavated clay soil. Alternatively, as mentioned, the invention relates to a system 400 for preparing site concrete comprising excavated clay soil.

[0158] Such a method according to the invention, illustrated in the figure 5 The system may include containers 410, 420, and 430 for the various components of the construction material. For example, it may include at least one container 410 for excavated clay soil, at least one container 420 for a deflocculating agent, and at least one container 430 for an activating agent. In addition, it may include at least one container 440 for fillers and / or additives. Furthermore, the system may include a cleaning container for a cleaning solution.

[0159] Particularly in the case of excavated clay soil, container 410 may not be an object but simply a location where the excavated clay soil is stored. A container may also be selected from a tank, a container, a tub, or a silo.

[0160] Furthermore, the system according to the invention includes a mixing device 450. Such a device is particularly capable of homogenizing and / or mixing the precursor ingredients of the construction binder.

[0161] This mixing device 450 is specifically coupled to automated conveying means (represented respectively by an arrow between the containers 410, 420, 430, 440 and the mixing device 450) positioned between the containers 410, 420, 430 and the mixing device 450. These conveying means can, for example, be flexible or rigid pipes, belts, conveyors, or screws. Furthermore, in combination with the conveying means, the system can include pumps, valves, solenoid valves, and flow restrictors. In particular, the flow restrictors can be arranged in functional switching with each of the conveying means to independently regulate the quantity of each ingredient distributed to the mixing device 450. In addition, the system according to the invention can include a measuring means 460 for at least the physicochemical properties of the excavated clay soil.Such a means of measurement 460 can for example be a pH meter, an X-ray diffractometer, a conductivity meter, an electron microscope, a mercury porosimeter, a spectrofluorometer, an ICP-MS, an HPLC-MS, a GC-MS, the measurement of specific surface area by the BET method, a particle size analyzer, or even a rheometer.

[0162] Furthermore, the system according to the invention may include a computing means 470 suitable for, preferably configured to, implement a computer program configured to perform: A step of obtaining a measured value of at least one physicochemical property of the excavated clay soil; and A step of determining a quantity of deflocculating agent and a quantity of activating agent suitable for the excavated clay soil on the basis of a comparison of the measured value(s) to reference values.

[0163] Furthermore, the system according to the invention includes a control module 480 configured to generate output signals for automated transport systems. These output signals will enable the system to transport predetermined quantities of deflocculating agent and activating agent to the mixing device 450. In addition, they will enable the system to transport a predetermined quantity of excavated clay soil to the mixing device 450.

[0164] Preferably, the system for preparing a construction material according to the invention may further comprise: a screener, preferably compact, a planetary mixer.

[0165] The System 400 according to the invention includes a soil crusher. This soil crusher specifically eliminates agglomerates that could affect the quality of the construction binder or the on-site concrete. Furthermore, the clay soil, reduced to powder, ensures a homogeneous consistency in the on-site concrete.

[0166] Even more preferably, the construction material preparation system according to the invention includes a screener for isolating pebbles with a diameter greater than 10 cm, preferably greater than 2 cm. The construction material preparation system may also include a sorting means, for example a sieve, for isolating particles with a diameter less than 50 µm, preferably particles with a diameter less than 20 µm. Advantageously, but not exclusively, the elements or particles thus separated, such as, for example, sand and / or aggregate fractions, can be reused in the formulation of the construction material, and in particular, in-situ concrete.

[0167] Alternatively, the excavated clay soil may not be pre-treated, and all of the clay soil is used to obtain the construction material. In this case, the process yields on-site concrete.

[0168] In addition, it may include a decontamination device to treat the excavated soil before use.

[0169] Thus, according to a another aspect, the invention relates to a building material formed from excavated clay soil. In particular, this construction material can be prepared according to a preparation process according to the invention described above. For example, this construction material is directly prepared according to a preparation process according to the invention described above.

[0170] The disclosed construction material may include a deflocculant and excavated clay soil. It should be noted that the preparation of the construction material involves the addition of an activating agent. However, since this activating agent may react with the excavated clay soil, it is not always present in the construction material. Nevertheless, the construction material according to the present invention comprises a deflocculant, an activating agent, and excavated clay soil.

[0171] Given the possibility of adding fillers, the invention also relates to a site-mixed concrete characterized in that it comprises a deflocculating agent and excavated clay soil. Alternatively, in the absence of added fillers, the invention also relates to a construction binder characterized in that it comprises a deflocculating agent and excavated clay soil.

[0172] Advantageously, the building material according to the invention comprises a mixture of different types of clay. In particular, it may comprise a combination of clays selected from: Illite and kaolinite, Illite and kaolinite and bentonite, Illite and Bentonite, Kaolinite and bentonite, Illite and Montmorillonite, or A combination of Kaolinite, Illite, Smectite, Bentonite, Chlorite, Montmorillonite, Muscovite, Hallocyte, Sepiolite, Attapulgite, and Vermiculite.

[0173] Furthermore, advantageously, the construction material formed from excavated clay soil is characterized in that it comprises at most 80% by weight of particles larger than 2 µm, preferably at most 60% by weight of particles larger than 2 µm. The content of particles larger than 2 µm can, for example, be measured according to standard NF X31-107. Thus, the excavated soil preferably undergoes a pretreatment step resulting in a particle size distribution centered on a fraction with a diameter of 50 µm or less, preferably 20 µm or less.

[0174] Preferably, a construction material according to the invention comprises at least 50% by weight of excavated clay soil, at least 60% by weight of excavated clay soil, at least 70% by weight of excavated clay soil, at least 80% by weight of excavated clay soil, and more preferably at least 90% by weight of excavated clay soil. This is advantageously the case when the construction material is a construction binder.

[0175] Indeed, the selection of quantities of deflocculant and activating agent has the advantage of allowing the formation of a construction binder containing a high quantity of excavated clay soil without altering the mechanical properties of the resulting construction materials. When the construction material is site-mixed concrete, it may contain at least 10% by weight of excavated clay soil, at least 15% by weight of excavated clay soil, at least 20% by weight of excavated clay soil, at least 30% by weight of excavated clay soil, at least 40% by weight of excavated clay soil, or at least 50% by weight of excavated clay soil.

[0176] The deflocculant may represent at least 0.1% by weight of the construction material, at least 0.20% by weight of the construction material, at least 0.25% by weight of the construction material, preferably at least 0.5% by weight of the construction material, more preferably at least 1% by weight of the construction material, even more preferably at least 1.5% by weight of the construction material, and for example at least 2% by weight of the construction material. This is advantageously the case when the construction material is site-mixed concrete.

[0177] The deflocculating agent may represent at least 0.30% by weight of the construction material, at least 0.5% by weight of the construction material, preferably at least 1% by weight of the construction material, more preferably at least 1.5% by weight of the construction material, even more preferably at least 2% by weight of the construction material, and for example at least 2.5% by weight of the construction material. This is advantageously the case when the construction material is a construction binder.

[0178] In addition, the deflocculant agent may represent at most 20% by weight of the construction material, preferably at most 15% by weight of the construction material, and more preferably at most 10% by weight of the construction material.

[0179] In particular, the deflocculant may represent between 0.25 and 10% by weight of the construction material, preferably between 0.5 and 10% by weight of the construction material, more preferably between 1 and 10% by weight of the construction material, even more preferably between 2 and 8% by weight of the construction binder, and for example between 2 and 5% by weight of the construction binder. Thus, the deflocculant may preferably represent between 0.1 and 5% by weight of the construction material.

[0180] In particular, the deflocculating agent constitutes at least 0.5% by weight of the excavated clay soil, preferably at least 1% by weight of the excavated clay soil, more preferably at least 2% by weight of the excavated clay soil, even more preferably at least 3% by weight of the excavated clay soil, and for example at least 4% by weight of the excavated clay soil. Indeed, with such concentrations of deflocculating agent, the binder formulation according to the invention can then be used in combination with an activation composition to form a material with advantageous mechanical properties.

[0181] Furthermore, the deflocculating agent represents no more than 20% by weight of the excavated clay soil, preferably no more than 10% by weight. Indeed, an excessively high concentration is not necessary to produce a material with advantageous mechanical properties.

[0182] In particular, the deflocculant agent represents between 0.5 and 20% by weight of the excavated clay soil, preferably between 1 and 10% by weight of the excavated clay soil, more preferably between 3 and 10% by weight of the excavated clay soil and even more preferably between 4 and 10% by weight of the excavated clay soil.

[0183] The activating agent is, for example, present at a content of at least 5% by weight of the construction material, preferably at least 7% by weight of the construction material, and more preferably at least 8% by weight of the construction material. This is advantageously the case when the construction material is site-mixed concrete.

[0184] The activating agent may be present at a content of at least 10% by weight of the construction material, preferably at least 15% by weight of the construction material, more preferably at least 20% by weight of the construction material, even more preferably at least 25% by weight of the construction binder, and for example at least 30% by weight of the construction binder.

[0185] Furthermore, the activating agent may represent no more than 50% by weight of the construction material, preferably no more than 45% by weight of the construction material, and more preferably no more than 40% by weight of the construction material. This is advantageously the case when the construction material is a construction binder.

[0186] The activating agent may also represent a maximum of 15% by weight of the construction material, preferably a maximum of 12% by weight of the construction material, and more preferably a maximum of 10% by weight of the construction material. This is advantageously the case when the construction material is site-mixed concrete.

[0187] In particular, the activating agent may represent between 3 and 12% by weight of the construction material, preferably between 4 and 10% by weight of the construction material, and more preferably between 5 and 10% by weight of the construction material. This is advantageously the case when the construction material is site-mixed concrete.

[0188] In particular, the activating agent may represent between 10 and 80% by weight of the construction material, preferably between 15 and 80% by weight, more preferably between 20 and 80% by weight, even more preferably between 30 and 80% by weight, and for example between 40 and 60% by weight. This is advantageously the case when the construction material is a construction binder.

[0189] In a particular embodiment, a building material, preferably a building binder according to the invention, comprises: 30% to 80% by weight of excavated clay soil, 1% to 10% by weight of deflocculating agent, and 10% to 50% by weight of an activating agent.

[0190] Preferably, a construction material, preferably a construction binder, according to the invention comprises: 50% to 75% by weight of excavated clay soil, 1% to 10% by weight of deflocculating agent, and 15% to 50% by weight of an activating agent.

[0191] More preferably, a construction material, preferably a construction binder according to the invention, comprises: 50% to 70% by weight of excavated clay soil, 2% to 5% by weight of deflocculating agent, and 15% to 45% by weight of an activating agent.

[0192] More preferably, a construction material, preferably a construction binder, according to the invention comprises: 50% to 60% by weight of excavated clay soil, 2% to 5% by weight of deflocculating agent, and 25% to 45% by weight of metal oxides.

[0193] Even more preferably, a building material, preferably a building binder, according to the invention comprises: 30% to 80% by weight of excavated clay soil, 1% to 10% by weight of deflocculating agent, 10% to 40% by weight of metal oxides, and 2% to 15% by weight of a strong base.

[0194] Even more preferably, a building material, preferably a building binder, according to the invention comprises: 30% to 80% by weight of excavated clay soil, 0.1% to 10% by weight of deflocculating agent, and 15% to 50% by weight of blast furnace slag.

[0195] Even more preferably, a building material, preferably a building binder according to the invention, comprises: 30% to 80% by weight of excavated clay soil, 0.1% to 10% by weight of deflocculating agent, 10% to 45% by weight of blast furnace slag, and 5% to 20% by weight of an alkaline composition such as triphosphate.

[0196] Preferably, a construction material according to the invention is a site-mixed concrete comprising: between 5 and 45% by weight, preferably between 5 and 30% by weight, more preferably between 10 and 20% by weight of a construction binder according to the invention; between 25 and 45% by weight, preferably between 30 and 40% by weight of sand, for example from site soil, preferably from excavated clay soil; between 35 and 55% by weight, preferably between 40 and 50% by weight of aggregates, for example from site soil, preferably from excavated clay soil; and preferably between 2 and 10% by weight of water.

[0197] More preferably, a construction material according to the invention is a site-mixed concrete comprising: between 5 and 20% by weight of raw clay from excavated clay soil, preferably between 5 and 15% by weight of raw clay from excavated clay soil; between 0.1 and 3% by weight of deflocculating agent; between 3 and 15% by weight, preferably between 5 and 12% by weight of an activating agent; for example between 5% and 10% by weight of blast furnace slag; between 25 and 45% by weight, preferably between 30 and 40% by weight of sand, for example from site soil, preferably from excavated clay soil; between 35 and 55% by weight, preferably between 40 and 50% by weight of aggregates, for example from site soil, preferably from excavated clay soil; and preferably between 2 and 10% by weight of water.

[0198] The sands and aggregates may come from quarries. In addition, the binder may contain quarry clay in addition to clay from the excavated clay soil.

[0199] In addition, site concrete may contain admixtures such as plasticizers, superplasticizers, rheological maintainers or air entrainers.

[0200] In addition, the water-to-dry-matter mass ratio of the construction binder is advantageously controlled and is preferably less than 1, more preferably substantially equal to 0.6.

[0201] Moreover, From another perspective, the invention relates to a building material formed from a construction binder according to the invention.

[0202] Furthermore, the invention relates to a construction material obtained from a preparation process according to the invention. The invention relates to a construction material obtained from a preparation process according to the invention.

[0203] The invention allows, in particular, the manufacture of: Insulating building material: made from a construction binder according to the invention, supplemented with lightweight aggregates of a "vegetable or porous" type; lightweight concrete: made from a construction binder according to the invention, supplemented with a foaming agent such as aluminum powder. This will trap air within the material and improve its insulating properties; prefabricated elements: manufacturing of concrete blocks or slabs in a factory from the construction binder according to the invention; and insulation modules.

[0204] As illustrated by the examples below, the present invention provides a solution based on a mixture of raw clay matrix, deflocculating agent and activation composition to offer a building material with mechanical properties similar to the standard while exhibiting a reduced carbon footprint. EXAMPLES : Methodology for measuring the physicochemical properties of clay soil :

[0205] The clay soil is pre-sifted to remove all elements or particles with a diameter greater than 20 µm. Such pre-treated clay soil is particularly suitable for the formation of a construction binder according to the invention.

[0206] The pH is measured from 20 g of pre-treated clay soil mixed with 100 mL of distilled water. After stirring for 20 minutes at 150 rpm (revolutions per minute), the suspension is filtered, and the pH of the filtered solution is determined.

[0207] The clay content is measured conventionally by the granulometric method described in standard NF X31-107.

[0208] The nature of clays is conventionally measured by X-ray diffractometry. Generation of reference values

[0209] As previously presented, the values ​​of include correlations between measured values ​​of at least one physicochemical property of a clay soil and values ​​of quantities of deflocculating agent and activating agent.

[0210] These reference values ​​are generated from a plurality of clay soil samples coupled with varying amounts of deflocculating agent and activating agent in a process for preparing a construction binder described below.

[0211] The generation of reference values ​​can, for example, implement an experimental design such as a simplex design, a screening design, a factorial design, a response surface design, a mixture design, a Taguchi design.

[0212] Table 1 below presents the physicochemical properties of different samples of excavated soil, while Table 2 shows an example of a design of experiments to generate reference values. [Table 1] Clay soil Physicochemical property pH Clay content Nature of clays Sample A 7 à 8 90 % à 100 % Smectite and Montmorillionite Sample B 4à6 90 % à 100 % Kaolinite [Table 2] Reference Clay soil deflocculant agent Activation Agent Nature Concentration Nature Concentration MUP42 Sample A n / A 0% by weight of binder LHF + Alkaline Solution 23% by weight of binder MUP5B Sample A n / A 0% by weight of binder LHF + Triphosphate 43% binder by weight MUP12 Sample A n / A 0% by weight of binder Blast furnace slag 25% by weight of binder MUP11 Sample A sodium humates 2.73% by weight of binder Blast furnace slag 25% by weight of binder MUP2 Sample A sodium humates 2.96% by weight of binder Metal oxides 12% by weight of binder MUP5 Sample A sodium humates 3.13% by weight of binder LHF + Triphosphate 42% binder by weight MUP41 Sample A sodium humates 3.39% by weight of binder LHF + Alkaline Solution 22% by weight of binder MUP3 Sample A sodium humates 3.97% by weight of binder Metal oxides 9% by weight of binder Preparation of a construction binder:

[0213] Construction binders, particularly those used for generating reference values, are prepared according to an identical protocol: a premix is ​​made by combining clay soil and a deflocculating agent in predetermined quantities, for example, according to a design of experiments. Water is then added, and the suspension is mixed at low speed, approximately 600 rpm, for 30 seconds. Next, an activating agent is added to the premix, and the premix is ​​then mixed at high speed, approximately 1,500 rpm, for three minutes.

[0214] The water-to-dry-matter mass ratio of the composition (also called construction binder) is adjusted to a value less than 1, more preferably approximately equal to 0.6.

[0215] The construction binder thus formed is then poured into a mold and left to mature at room temperature, i.e. about 20 degrees Celsius, for twenty-eight days.

[0216] The mechanical properties of the construction binder are then evaluated. Methodology for measuring the mechanical properties of construction binders :

[0217] Once the curing process is complete, the building binder is removed from the mold and its mechanical strength is measured. The mechanical strength of a building binder refers to its compressive strength, measured according to standard NF EN 196-1.

[0218] The results of the measurements carried out on the experiments described in Table 2 are presented below in Table 3. [Table 3] Reference Mechanical resistance (in MPa) MUP42 (comparative example) 27 MUP5B (comparative example) 25 MUP12 (comparative example) 21 MUP11 41 MUP2 37 MUP5 45 MUP41 43 MUP3 37

[0219] These results show that depending on the quantities of activation agent and deflocculant agent used, the performance of the binder formed will be different, and in particular its mechanical resistance.

[0220] Furthermore, they show that the presence of a deflocculating agent makes it possible to obtain mechanical resistances greater than 30 MPa. Selection of the composition of a construction binder:

[0221] Following the preparation of reference values ​​and, if necessary, a calculation algorithm, it is possible to implement a process for selecting the appropriate quantities of deflocculating and activating agents for a given excavated clay soil.

[0222] Initially, a sample of the excavated clay soil is sieved to remove all elements or particles with a diameter greater than 20 µm.

[0223] The physicochemical properties of the pre-treated excavated clay soil sample are then analyzed as described above.

[0224] The values ​​obtained are then transmitted to a computer device configured to implement the process according to the invention.

[0225] The latter then generates values ​​for the quantity of deflocculating agent and activation which, when coupled with a predetermined quantity of excavated soil, will form a construction binder. Formation of a construction binder according to the invention

[0226] The excavated clay soil is then sieved to remove all elements or particles with a diameter greater than 2 cm, and then a predetermined quantity of pretreated excavated clay soil is mixed simultaneously or sequentially with the selected quantity values ​​of deflocculating agent and activation.

[0227] Construction binders or site concretes formed according to the invention exhibit compressive strengths equivalent to those obtained with concrete made using Portland cement. Thus, the present invention makes it possible to select the appropriate composition for forming a low-carbon construction binder from excavated clay soil, with sufficient mechanical properties to make it a construction material meeting the majority of the sector's needs.

Claims

1. A construction material formed from a raw excavated clay soil, characterized in that it includes a raw excavated clay soil, an activating agent, and a deflocculating agent, said deflocculating agent accounting for at least 0.1 wt% of the construction material, preferably at least 0.25 wt% of the construction material, said deflocculating agent being selected from: - a nonionic surfactant such as a polyoxyethylene ether, or - an anionic agent selected from: alkylaryl sulfonates, amino alcohols, carbonates, silicates, fatty acids, humates, carboxylic acids, lignosulfonates, polyacrylates, phosphates, or polyphosphates such as sodium hexametaphosphate, sodium tripolyphosphate, sodium orthophosphate, carboxymethylcelluloses, or - an amine selected from: 2-amino-2-methyl-1-propanol; mono-, di-, or triethanolamine; isopropanolamines and N-alkylated ethanolamines.

2. The construction material according to claim 1, characterized in that it includes a mixture of different types of clays.

3. The construction material according to one of claims 1 or 2, characterized in that it presents a content of metal oxides of at least 2 wt% of the construction material, said construction material then preferably corresponding to a construction binder.

4. The construction material according to any one of claims 1 to 3, characterized in that it includes blast furnace slag.

5. The construction material according to claim 4, <b>characterized in that it includes: - 30% to 80 wt% of a raw excavated clay soil, - 0.1 % to 10 wt% of a deflocculating agent, and - 5 to 10 wt% of blast furnace slag; preferably said construction material then corresponding to a construction binder.

6. The construction material according to any one of claims 1 to 3, <b>characterized in that it includes: - between 5 and 20 wt% of raw clay from the raw excavated clay soil; - between 0.1 and 3 wt% of a deflocculating agent; - between 3 and 15 wt% of an activating agent; - between 25 and 45 wt% of sand; and - between 35 and 55 wt% of aggregates; preferably said construction material then corresponding to a site concrete.

7. The construction material according to any one of claims 1 to 6, characterized in that it includes at least 2 wt% of silt particles.

8. The construction material according to any one of claims 1 to 7, characterized in that the raw excavated clay soil has been pretreated, said pretreatment being selected from: crushing, sorting, sieving, and / or drying of the raw excavated clay soil.

9. A method (300) for preparing a construction material according to any one of claims 1 to 8 from a raw excavated clay soil, the method including: - A step of measuring (310) at least one physicochemical property of the raw excavated clay soil; - A selection (100) of the composition of the construction material including the raw excavated clay soil, said composition of the construction material including deflocculating agent and activating agent quantities adapted to the raw excavated clay soil, said selection (100) being implemented by a computer device including a calculation module, said selection (100) including: - A step of receiving (130), from the calculation module, a measured value of at least one physicochemical property of a raw excavated clay soil, said at least one physicochemical property being selected from : the content of clays in the raw excavated clay soil, the nature of the clays, the particle size, the impurity content, the content of non-clay mineralogical fractions, the content of contaminants, the elemental analysis, the content of metal oxides, the salinity, the pH, and the total exchange capacity of the clay in the raw excavated clay soil; and - A step of selecting (170), by the calculation module, a deflocculating agent quantity and an activating agent quantity adapted to the raw excavated clay soil based on a comparison of the one or more measured values with reference values, said reference values including correlations between measured values of at least one physicochemical property of a clay soil and deflocculating agent and activating agent quantities adapted to said raw excavated clay soil to form the construction material and, - A step of mixing (340) a raw excavated clay soil, a deflocculating agent, and an activating agent according to the selected composition.

10. The method (300) according to claim 9, characterized in that the at least one physicochemical property is measured on a pretreated raw excavated clay soil, said pretreatment being selected from: crushing, sorting, sieving, and / or drying of the raw excavated clay soil.

11. The method (300) according to anyone of claims 9 or 10, characterized in that the selection (100) comprises receiving (140) a desired mechanical property value of the construction material and in that the step of selecting (170) the deflocculating agent and activating agent quantities further includes excluding (171) the deflocculating agent and activating agent quantities which will not allow the construction material to exhibit the desired mechanical property value.

12. The method (300) according to anyone of claims 9 to 11, characterized in that the step of selecting (170), by the calculation module, a deflocculating agent quantity and of activating agent quantity adapted to the raw excavated clay soil includes implementing a previously calibrated calculation algorithm.

13. The method (300) according to claim 12, characterized in that the previously calibrated calculation algorithm has been obtained by implementing a statistical supervised learning method.

14. The method (300) according to anyone of claims 9 to 13, further comprising: - a step of measuring (350) physicochemical or mechanical properties of the construction material being formed, during the mixing step, - a step of comparing (360) the measured values with predetermined values of physicochemical or mechanical properties of the construction material being formed, and - when the measured values differ (360-n) from the predetermined values of physicochemical or mechanical properties of the construction material being formed, a step of adding (370) at least one complementary ingredient.

15. The method (300) according to anyone of claims 9 to 13, characterized in that it comprises a step of screening (330) the raw excavated clay soil to remove aggregates, the diameter of which is greater than 20 mm.

16. A system (400) for preparing a construction material including a raw excavated clay soil, said system comprising: - a soil crusher, - At least one container (410) including a raw excavated clay soil, - At least one container (420) including a deflocculating agent, said deflocculating agent being selected from: - a nonionic surfactant such as a polyoxyethylene ether, or - an anionic agent selected from: alkylaryl sulfonates, amino alcohols, carbonates, silicates, fatty acids, humates, carboxylic acids, lignosulfonates, polyacrylates, phosphates, or polyphosphates such as sodium hexametaphosphate, sodium tripolyphosphate, sodium orthophosphate, carboxymethylcelluloses, or - an amine selected, for example, from: 2-amino-2-methyl-1-propanol; mono-, di-, or triethanolamine; isopropanolamines and N-alkylated ethanolamines, - At least one container (430) including an activating agent, said activating agent being an alkaline activating composition, - A mixing device (450), with automated transport means between the containers (410, 420, 430) and the mixing device (450), - A control module (480) configured to generate output signals for use by the automated transport means so as to transport determined quantities of the deflocculating agent and the activating agent to the mixing device (450).

17. The system (400) for preparing a construction material according to claim 16, characterized in that it includes a communication means configured to receive data on a determined deflocculating agent quantity and a determined activating agent quantity, adapted to the raw excavated clay soil; the control module (480) being configured to generate output signals for use by the automated transport means so as to transport the determined deflocculating agent and activating agent quantities to the mixing device (450).

18. The system (400) for preparing a construction material according to any one of claims 16 or 17, characterized in that it includes: - A means for measuring (460) at least one physicochemical property of the raw excavated clay soil, - A calculation means (470) adapted to implement a computer program configured to perform: - A step of obtaining a measured value of at least one physicochemical property of the raw excavated clay soil; and - A step of determining a deflocculating agent quantity and an activating agent quantity suitable for the raw excavated clay soil based on a comparison of the one or more measured values with reference values.

19. The system (400) for preparing a construction material according to any one of claims 16 to 18, characterized in that it comprises a sorting means for isolating particles with a diameter of less than 50 µm.