WO2011161384A1

WO2011161384A1 - Hydraulic composition, the delayed setting of which is initiated by an accelerator

Info

Publication number: WO2011161384A1
Application number: PCT/FR2011/051452
Authority: WO
Inventors: Liam Guise; Hélène LOMBOIS-BURGER; Serge Sabio; Alain Jacquet
Original assignee: Lafarge
Priority date: 2010-06-24
Filing date: 2011-06-23
Publication date: 2011-12-29
Also published as: FR2961805A1; FR2961805B1

Abstract

The present invention relates to a hydraulic composition, comprising cement, a retarding agent, a superplasticizer and an agent comprising a compound chosen from a water-soluble salt, a lamellar double hydroxide, hydrate nuclei, a granular element having a BET specific surface area of greater than 5 m²/g, or a mixture of these compounds. Over at least 45 minutes after the addition of the accelerator, the variation in the slump of the hydraulic composition, measured according to the EN 12350-2 standard, is less than 50 mm or the variation in the spreading of the hydraulic composition, measured with a cone according to the EN 12350-2 standard, is less than 100 mm. The compressive strength of the hydraulic composition is at least equal to 1 MPa 24 hours after the start of setting of the hydraulic composition.

Description

HYDRAULIC COMPOSITION HAVING DELAYED DELAYED TAKING

The invention relates to a delayed hydraulic composition having its setting triggered by an accelerating agent.

A delayed hydraulic composition is a hydraulic composition comprising a hydraulic setting retarding agent which causes retardation of setting of the hydraulic composition. The beginning of the transition of the hydraulic composition from the plastic state to the rigid state is then delayed. An accelerator is a setting accelerator that speeds up the transition of the hydraulic composition from the plastic state to the rigid state.

For certain applications, it would be desirable to have a hydraulic composition, especially a concrete, whose setting would be delayed by several days, and that during this period, when the hydraulic composition is to be used, the setting of the hydraulic composition can be triggered at any time by the use of an accelerator. The hydraulic composition could thus advantageously be stored for several days after its manufacture and be used only at the desired time. It would be desirable that the start of setting takes place less than 24 hours after the addition of the accelerating agent to the delayed hydraulic composition.

However, to obtain a setting delay of several days, the amount of retarding agent that must be added during the manufacture of the hydraulic composition can be important. Conventional accelerating agents in the field of construction, in particular based on calcium salt or sodium salt, may then not be sufficiently effective for the setting of the hydraulic composition to begin less than 24 hours after the addition of water. accelerator.

In addition, after adding the accelerator agent to the hydraulic composition, it is necessary that the duration during which the hydraulic composition can be used, called the workability window, is greater than several dozen minutes. The workability of a concrete is generally determined by a measure of slump or spreading of the concrete. The window of workability then corresponds to the duration during which the slump or the spreading of the concrete remains higher than a threshold, determined in particular according to the type of concrete and the concrete application. Also the problem to be solved by the invention is to provide a hydraulic composition which is delayed for several days and which is triggered by an accelerator, allowing the setting of the hydraulic composition begins less than 24 hours after the addition of water. accelerating agent and that the upper workability window of the hydraulic composition is greater than or equal to 45 minutes after addition of the accelerator agent.

For this purpose, the present invention relates to a hydraulic composition, comprising:

from 0.1 to 5% by weight of dry extract of a retarding agent relative to the weight of the hydraulic binder;

from 0.05 to 5% by mass of solids content of a superplasticizer relative to the weight of the dry hydraulic binder; and

from 0.1 to 10% by weight of dry extract of an accelerating agent relative to the weight of the hydraulic binder, the accelerating agent comprising at least one compound chosen from a water-soluble salt, a double-layered hydroxide, seeds hydrate, a granular element having a BET specific surface area greater than 5 m ² / g, or a mixture of these compounds,

in which :

for at least 45 minutes after the addition of the accelerating agent, the variation of the slump of the hydraulic composition measured according to the EN 12350-2 standard is less than 50 mm or the variation of the spreading of the hydraulic composition measured with a cone according to EN 12350-2 is less than 100 mm;

the compressive strength of the hydraulic composition being at least equal to 1 MPa 24 hours after the beginning of the setting of the hydraulic composition; and

the hydraulic composition, without a retarding agent, belongs to a class of resistance, as defined by the standard EN 206-1, determined for a compressive strength measured 28 days after the manufacture of the hydraulic composition and the hydraulic composition comprising The retarding agent belongs to the same strength class determined for a compressive strength measured 28 days after addition of the accelerating agent. The present invention also relates to a method for manufacturing a hydraulic composition as defined above, comprising the following successive steps:

-mix the hydraulic binder, the retarding agent, the superplasticizer and water to make the hydraulic composition in the fresh state; and

-add the accelerator agent to the hydraulic composition in the fresh state to trigger the setting of the hydraulic composition.

The invention offers one of the advantages described below.

Advantageously, the triggering of the delayed hydraulic composition may be initiated by an intentional action of the user for several days at any time.

Another advantage of the present invention is that at least some of the accelerating agents according to the invention do not provide or bring little additional alkaline agents, especially sodium, to the hydraulic composition.

Finally, the invention has the advantage of being used in one of the industries such as the building industry, the chemical industry (adjuvants) and the cement industry, in the construction markets (building, civil engineering, roads or prefabrication plant), or in concrete plants.

Other advantages and characteristics of the invention will become clear from reading the description and examples given by way of purely illustrative and nonlimiting that will follow.

By the term "hydraulic binder" is meant according to the present invention a powdery material which, mixed with water, forms a paste which sets and hardens as a result of hydration reactions, and which, after curing, retains its strength and stability even under water. The hydraulic binder can be a cement according to EN 197-1.

By the term "hydraulic composition" is meant according to the present invention a mixture of a hydraulic binder, with mixing water, optionally aggregates, optionally adjuvants, and optionally mineral additions. A hydraulic composition may for example be a concrete, in particular a high performance concrete, a very high performance concrete, a self-placing concrete, a self-leveling concrete, a self-compacting concrete, a fiber concrete, a concrete ready to job or colored concrete. By the term "concrete" is meant for example concretes having undergone a finishing operation such as bush-hammered concrete, deactivated or washed concrete, or polished concrete. This definition also includes prestressed concrete. The term "concrete" includes mortars; in this concrete case comprises a mixture of a hydraulic binder, sand, water, possibly adjuvants and possibly mineral additions. The term "concrete" according to the present invention indistinctly refers to fresh concrete or hardened concrete. Preferably, the hydraulic composition according to the present invention is a cement slurry, a mortar or a concrete. The hydraulic composition according to the present invention can be used directly on site in the fresh state and cast in a formwork suitable for the application in question, or it can be used in prefabrication, or as a jointing coating on a solid support.

By the term "aggregates" is meant according to the present invention refers to gravel, chippings and / or sand.

By the term "mineral additions" is meant according to the present invention a finely divided mineral material used in concrete to improve certain properties or to bring it particular properties. These are, for example, fly ash (as defined in the EN 450 standard), silica fumes (as defined in the standard prEN 13263: 1998 or NF P 18-502), slag (such as defined in standard NF P 18-506), calcareous additions (as defined in standard NF P 18-508) and siliceous additions (as defined in standard NF P 18-509).

By the term "Portland cement" is meant according to the present invention a CEM I type cement, CEM II, CEM III, CEM IV or CEM V according to the standard "Cement" NF EN 197-1.

By the term "clays" is meant according to the present invention aluminum silicates and / or magnesium silicates, especially phyllosilicates with sheet structure, typically spaced from about 7 to about 14 Angstroms. Clays frequently encountered in sands include montmorillonite, illite, kaolinite, muscovite and chlorites. The clays can be of type 2: 1 but also of type 1: 1 (kaolinite) or 2: 1: 1 (chlorites).

By the expression "plasticizer / water reducer" is meant according to the present invention an adjuvant which, without modifying the consistency, makes it possible to reduce the water content of a given concrete, or which, without modifying the content in water, increases the slump / spread of the concrete, or produces both effects at the same time. The EN 934-2 standard specifies that the water reduction must be greater than 5%. The water reducers may, for example, be based on lignosulfonic acids, carboxylic acids or treated carbohydrates.

By the term "superplasticizer" or "superfluidifier" or "super-water reducer" is meant according to the present invention a plasticizer / reducer of water that reduces the amount of water required for a concrete by more than 12%. A superplasticizer has a fluidizing action since, for the same quantity of water, the workability of the concrete is increased when the superplasticizer is used.

By the term "setting" is meant according to the present invention the transition to the solid state by chemical reaction of hydration of a hydraulic binder. The setting is usually followed by the hardening period.

By the term "hardening" is meant according to the present invention the increase of the mechanical strengths of a hydraulic binder after the end of setting.

At the time of its manufacture, the hydraulic composition comprises a hydraulic binder and a retarding mixture comprising a retarding agent and optionally a superplasticizer and a rheology modifying agent.

Self-timer agent

The retarding agent corresponds to the definition of the retarding agent mentioned in standard NF EN 934-2.

According to an exemplary embodiment of the invention, the retarding agent comprises a compound chosen from:

sugars and derived products, in particular sucrose, glucose, reducing sugars (lactose, maltose, etc.), cellobiose, gallactose, etc., derivatives, for example glucolactone, etc. ;

carboxylic acids or their salts, especially gluconic acid, gluconate, tartaric acid, citric acid, gallic acid, glucoheptonic acid, saccharic acid and salicylic acid. Associated salts include, for example, ammonium salt, alkali metal salt (e.g., sodium salt, potassium salt, etc.), alkaline earth metal salt (e.g., calcium salt, magnesium salt, etc.). However other salts can also be used;

phosphonic acids and their salts, in particular aminotri (methylenephosphonic acid), pentasodium salt of aminotri (methylenephosphonic acid), hexamethylenediamine tetra (methylenephosphonic acid), diethylenetriamine penta (methylenephosphonic acid and its sodium salt);

phosphates and their derivatives;

sorbitan esters;

alkylpolyglucosides (APG) and their derivatives; zinc salts, especially zinc oxide, zinc borate and soluble salts of zinc (nitrate, chloride);

borates, especially boric acid, zinc borate and boron salts;

surfactants adapted to coat the surface of the cement grains, in particular certain cellulose ethers and acrylates; and

surfactants adapted to coat the surface of the cement grains, in particular cellulose ethers, acrylates, alginates, stearates; and

the mixtures of these compounds.

Preferably, the retarding agent comprises a carboxylic acid, a phosphonic acid or their salts.

Preferably, the retarding agent comprises a hydroxycarboxylic acid or a hydroxycarboxylic acid salt. According to an exemplary embodiment of the invention, the retarding agent comprises a gluconate.

superplasticizer

The superplasticizer comprises polyalkylene oxide polyphosphonate polymer, polyalkylene oxide polyphosphate polymer, polyalkylene oxide polysulfonate polymer, or polyalkylene oxide polycarboxylate polymer (also known as polyox polycarboxylate or PCP). Preferably, the superplasticizer comprises a polycarboxylate polymer of polyalkylene oxide.

An example of a superplasticizer corresponds to a copolymer comprising at least one unit of formula (I)

and at least one unit of formula (II)

wherein R1, R2, R3, R6, R7 and R8 are independently a hydrogen atom, a linear or branched alkyl radical -C ₂ o C, or an aromatic radical, or a radical -COOR 1 1 R1 1 independently are hydrogen atom, a linear or branched alkyl radical C l -C _4, a monovalent cation, divalent or trivalent or an ammonium group;

R10 is a hydrogen atom, a linear or branched alkyl radical -C ₂ o C, or an aromatic radical;

R4 and R9 are independently a linear or branched C ₂ to R 5 alkyl radical is a hydrogen atom, a C 1 to C ₂₀ alkyl group or an anionic or cationic group, for example a phosphonate group, a sulfonate group, a group carboxylate, etc. ;

W is an oxygen or nitrogen atom or an NH radical;

m and t are independently integers from 0 to 2;

n and u are independently integers equal to 0 or 1;

q is an integer equal to 0 or 1;

r and v are independently integers from 0 to 500;

and the molar mass of said copolymer is from 10,000 to 400,000 daltons.

Preferably, the radical R 1 or R 6 is a hydrogen atom. Preferably, the radical R2 or R7 is a hydrogen atom. Preferably, the radical R3 or R8 is a methyl radical or hydrogen. Preferably, the radical R4 or R9 is an ethyl radical.

Preferably, the copolymer used according to the invention or a salt thereof has an integer from 1 to 300, preferably from 20 to 250, more preferably from 40 to 200, even more preferably from 40 to 150. The superplasticizer may correspond to a salt of the copolymer defined above.

The copolymer may comprise several different units according to formula (I) having, in particular, different radicals R5.

The superplasticizer can be an immediate-acting superplasticizer whose maximum fluidizing action is obtained in the first fifteen minutes at 20 ° C after the addition of water to the hydraulic binder for conventional dosages. The superplasticizer can be a delayed efficiency superplasticizer whose maximum fluidizing action is obtained after the first fifteen minutes at 20 ° C after the addition of water to the hydraulic binder for conventional dosages. The measurement of the fluidizing action of the immediate-acting superplasticizer and the delayed-efficiency superplasticizer is measured by a measurement of spreading and / or settling.

The increase of the fluidifying action of the superplasticizer with delayed efficiency can be obtained by an increase of the capacity of the superplasticizer with delayed efficiency to be adsorbed on the mineral components (in particular the grains of cement) of the hydraulic composition. For this purpose, one possibility is to increase the density of anionic charges of the superplasticizer. An increase in the charge density of the superplasticizer can be obtained by two different phenomena that can occur simultaneously:

the increase in the number of charges borne by the polymer; and

the reduction of the molecular weight of the polymer.

The reduction of the molecular weight of the superplasticizer can be achieved by choosing a superplasticizer comprising a main chain and pendant chains connected to the main chain and which can separate from the main chain when the superplasticizer is in the hydraulic composition.

The separation of pendant chains and / or the increase of the number of charges carried by the superplasticizer can be obtained by choosing a superplasticizer comprising hydrolysable chemical functions which, under the effect of hydroxide ions (OH ^" ) in the hydraulic composition, can to transform to provide carboxylate functions (COO ^" ). The hydrolysable chemical functions are in particular anhydrides, esters and amides. A hydrolyzable polymer is a polymer comprising hydrolysable chemical functions under the conditions of basicity and in the workability window of the hydraulic composition and a hydrolyzable monomer is a monomer comprising a hydrolysable function under the conditions of basicity and in the workability window. of the hydraulic composition. An example of a superplasticizer is that described in EP-A-537872, US20030127026 and US20040149174.

An example of a superplasticizer is obtained by polymerization:

an ionic monomer of the phosphonic, sulphonic or carboxylic type, preferably carboxylic and advantageously of the (meth) acrylic type; and

a polyoxyalkylene glycol (C ₁ -C ₄ ) (meth) acrylate type monomer, for example of the polyethylene glycol (PEG) (meth) acrylate type, whose molecular weight is, for example, from 100 to 10,000, of preferably from 500 to 5000 and advantageously from 750 to 2500.

The molar ratio between the unit according to formula (I) and the unit according to formula (II) may vary, for example from 90/10 to 45/55, preferably from 80/20 to 55/45.

It is possible to use one or more other monomer (s), for example those chosen from:

(a) acrylamide type, for example N, N-dimethylacrylamide, 2,2'-dimethylamino (meth) acrylate or its salts, 2,2'-dimethylaminoalkyl (meth) acrylate or its salts with the alkyl group and in particular ethyl and propyl, and in general any monomer comprising an amine or amide type function;

(b) hydrophobic type, for example alkyl (meth) acrylate comprising from 1 to 18 carbon atoms, in particular methyl or ethyl.

The amount of this other monomer may be from 5 to 25 mol% of the total monomers.

In the case where the superplasticizer is a delayed acting superplasticizer, the anionicity of the superplasticizer can increase in the concrete in the workability window.

The superplasticizer may comprise a hydrolysable polymer in the concrete.

During the manufacture of the concrete, the pH being basic, hydrolysis reactions occur which lead to a modification of the structure of the hydrolyzable polymer and to a modification of the properties of the hydrolysable polymer, namely an increase in the fluidizing action of the hydrolysable polymer. According to an exemplary embodiment of the invention, the hydrolysable polymer is a PCP.

Examples of delayed efficiency superplasticizers are described in EP 1 136 508, WO 2007/047407, US 2009/0312460 and PCT / US2006 / 039991.

The shape of the superplasticizer can vary from a liquid form to a solid form, through a waxy form.

Rheology modifying agent or AMR The rheology modifier comprises a compound selected from a viscosifier, a water retainer, a thresholding agent, or a thixotropic agent. It is clear that the rheology modifying agent can simultaneously have several of the functions of the agents indicated above.

A water-retaining agent may be as defined in standard NF EN 934-2.

Examples of water retaining agents are cellulose ethers.

A viscosifying agent is an agent that increases the viscosity of a hydraulic composition. An exemplary measurement representative of the viscosity of a hydraulic composition corresponds to the measurement of the flow time of the hydraulic composition to be tested through a device, for example V-funnel. Examples of viscosifying agents are cellulose ethers, natural or modified gums, especially diutane, welan, xanthan, synthetic polymers, in particular polyacrylamides, polyacrylates, ethylene polyoxides, natural or modified polymers. , especially starch, associative polymers, etc.

A thresholding agent is an adjuvant suitable for increasing the flow threshold of the hydraulic composition. Examples of thresholding agents are certain polysaccharides (diutane for example), certain clays, etc.

A thixotropic agent is a compound inducing a variation over time of the rheology (spontaneous structuring at rest, destructuration under shear). Examples of thixotropic agent include clays.

Preferably, the rheology modifier is water soluble.

According to an exemplary embodiment of the invention, the rheology modifier agent comprises a cellulose or a cellulose derivative. According to an exemplary embodiment of the invention, the rheology modifier agent comprises a cellulose ether. According to a variant of the invention, a cellulose ether used according to the invention is methylhydroxypropylcellulose. According to another variant of the invention, at least one cellulose ether used according to the invention is methylcellulose.

In the following description, the mixture comprising the retarding agent and optionally the superplasticizer and the rheology modifier agent is called retardation mixture.

Accelerator agent

The accelerator agent according to the invention, used to trigger the setting of the delayed hydraulic composition, comprises a compound chosen from a salt water-soluble, a double-layered hydroxide, hydrate seeds, a granular element of BET specific surface area greater than 5 m ² / g, or a mixture of these compounds.

Preferably, the accelerating agent comprises a water-soluble salt, a double-layered hydroxide or hydrate seeds.

According to an exemplary embodiment of the invention, the accelerator comprises a mixture of a double-layered hydroxide and hydrate seeds.

The inventors have demonstrated that by using such accelerating agents, the variation of the slump of the hydraulic composition after the addition of the accelerating agent, measured according to the EN 12350-2 standard, is less than 50 mm or the variation of the spreading of the hydraulic composition after the addition of the accelerating agent, measured with a cone according to the EN 12350-2 standard, is less than 100 mm for at least 45 minutes. When the sagging of the hydraulic composition is too important to be able to measure according to EN 12350-2, it is the spreading of the hydraulic composition that is measured using the same cone as that which is conventionally used. to measure sagging according to EN 12350-2. Preferably, the consistency of the hydraulic composition after addition of the accelerating agent is maintained in the same consistency class with respect to the slump, as defined by EN 206-1, for at least 45 minutes. This means that if, after the addition of the accelerating agent, the consistency class of the hydraulic composition is, for example, S4, then the consistency class of the hydraulic composition remains the class S4 for at least 45 minutes.

In addition, the inventors have demonstrated that the compressive strength of the hydraulic composition is at least equal to 1 MPa, preferably at least 2 MPa, 24 hours after the beginning of the setting of the hydraulic composition.

According to an exemplary embodiment, the water-soluble salt may be a calcium salt (for example a nitrate, a nitrite, a chloride or a formate) or an aluminum salt (for example a nitrate, a hydroxide, a sulphate or a fluoride ).

According to an exemplary embodiment of the invention, the water-soluble salt comprises an alkaline accelerator. Preferably, the water-soluble salt comprises an alkaline accelerator selected from a sodium silicate or metasilicate, an alkali aluminate, an alkali carbonate and an alkali hydroxide or a mixture thereof. According to an exemplary embodiment of the invention, the water-soluble salt comprises sodium silicate. By "double lamellar hydroxide" or "LDH" is meant according to the present invention a class of materials comprising positively charged layers and charge compensation anions located in the regions between the layers.

According to an exemplary embodiment of the invention, the LDHs have the general formula:

[M ²⁺ _1-X N ³⁺ _X (ΟΗ) ₂ ] ^{χ +} [Α Η ₂ 0] ^χ - with M ²⁺ selected from the group comprising especially Ca ²⁺ , Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ and Zn ²⁺ ;

N ³⁺ selected from the group including Al ³⁺ , Ga ³⁺ , Fe ³⁺ , Cr ³⁺ ; and

A ^{q "is} an organic or inorganic anion, charge q, for example NO ^3", Cl ^", C03 ^2", S04 ^{2 ".}

x is less than or equal to 1

1-x / x is generally from 1 to 6 which means that x is generally from about 0.15 to about 0.5.

According to an exemplary embodiment of the invention, the double-layered hydroxide has the formula Mg ₂ Al (OH) ₆ N0 ₃ , 2H ₂ 0.

According to an exemplary embodiment of the invention, the accelerating agent comprises a mixture of water-soluble salt and double-layered hydroxide.

According to an exemplary embodiment of the invention, the hydrate seeds comprise hydrated lime hydrate seeds or hydrated calcium silicate seeds and / or hydrated calcium aluminate seeds. Preferably, the hydrate seeds comprise hydrated calcium silicate seeds.

According to an exemplary embodiment of the invention, the granular element having a BET specific surface area greater than 5 m ² / g is chosen from the group comprising silica, alumina or calcium carbonate obtained for example by precipitation or by grinding. .

Advantageously, when the accelerating agent comprises a mixture of an alkaline accelerator and another compound chosen from a double-layered hydroxide, hydrate seeds and a granular element having a BET specific surface area greater than 5 m ² / g the amount of alkaline accelerator in the hydraulic composition is less than what would have been necessary if the alkaline accelerator had been used alone.

Hydraulic composition

The hydraulic binder comprises Portiand cement. Suitable cements are the Portiand cements described in the book "Lea's Chemistry of Cernent and Concrete ". Portland cements include slag, pozzolana, fly ash, shale, limestone and composite cements. It is for example a CEM I, CEM II, CEM III, CEM IV or CEM V cement according to the "Cement" NF EN 197-1 standard.

The hydraulic composition can comprise from 220 to 500 kg, preferably from 250 to 450 kg of the hydraulic binder per cubic meter of the fresh hydraulic composition.

The hydraulic composition can comprise from 220 to 500 kg, preferably from 250 to 450 kg of Portland cement per cubic meter of the hydraulic composition in the fresh state.

The hydraulic composition may comprise the hydraulic composition comprises from 400 to 1800 kg, preferably from 500 to 1600 kg, more preferably from 600 to 1100 kg of sand per cubic meter of the fresh hydraulic composition.

The sand has a D10 greater than 0.1 mm and a D90 less than 4 mm. The sand can be of any mineral nature, limestone, siliceous or silico-limestone or other. Sand can be a mixture of sands of different natures. The D90, also denoted D _v 90 is the 90 ^th percentile of the volume distribution of particle size. In other words, 90% of the grains are smaller than D90 and 10% are larger than D90. D10, also denoted D _v 10 corresponds to the io ^th percentile of the volume distribution of particle size. In other words, 10% of the grains are smaller than D10 and 90% are larger than D10.

The hydraulic composition can comprise from 150 to 1000 kg, preferably from 200 to 900 kg, more preferably from 300 to 900 kg of the gravel per cubic meter of the fresh hydraulic composition. Gravel has a D10 greater than 4 mm and a D90 less than 10 mm

The composition may, in addition, comprise other aggregates, for example granules having a particle size strictly greater than 20 mm.

for example, granules having a particle size strictly greater than 20 mm.

The hydraulic composition may further comprise from 5% to 40%, preferably from 10% to 30%, more preferably from 15% to 25% by weight relative to the weight of the hydraulic binder of a particulate material (also called inorganic addition) or a mixture of particulate materials. For example, the particulate material has an average particle size of less than 100 μηη. The particulate material may comprise pozzolanic or non-pozzolanic materials or a mixture thereof.

The term "particle" as used in the context of the present invention should be understood in a broad sense and corresponds not only to compact particles having more or less a spherical shape but also to angular particles, flattened particles, particles flake-shaped, fiber-shaped particles, or fibrous particles, etc. It will be understood that the "size" of the particles in the context of the present invention means the smallest transverse dimension of the particles. For example, in the case of fiber-shaped particles, the size of the particles corresponds to the diameter of the fibers. The particles of a material are understood to mean the particles taken individually (that is to say the unitary elements of the material), knowing that the material may be in the form of particle agglomerates. By the term "average size" is meant according to the present invention the particle size which is greater than the size of 50% by volume of the particles and smaller than the size of 50% by volume of the particles of a particle distribution. .

An example of particulate material is slag, especially granulated blast furnace slag.

Suitable pozzolanic materials include fumed silica, also known as micro-silica, which is for example a by-product of the production of silicon or ferrosilicon alloys. It is known as a pozzolanic reactive material. Its main constituent is amorphous silicon dioxide. The individual particles generally have a diameter of about 5 to 10 nm. Individual particles can agglomerate to form aggregates from 0.1 to 1 μηι. Aggregates from 0.1 to 1 μηη can aggregate to form aggregates of 20 to 30 μηη. The silica fumes generally have a BET surface area of 10 - 30 m ² / g. BET specific surfaces can be measured using a Beckman Coulter SA 3100 analyzer with nitrogen as the adsorbed gas.

Other pozzolanic materials include fly ash which generally have a D10 greater than 10 μηη and a D90 less than 120 μηη and have, for example, a D50 of 30 to 50 μηι. The D90, also denoted D _v 90 is the 90 ^th percentile of the volume distribution of particle size. In other words, 90% of the grains are smaller than D90 and 10% are larger than D90. The D50, also denoted D _v 50 corresponds to the 50 ^th percentile of the volume distribution of particle size. In other words, 50% of the grains are smaller at D50 and 50% are larger than D50. D10, also denoted D _v 10 corresponds to the io ^th percentile of the volume distribution of particle size. In other words, 10% of the grains are smaller than D10 and 90% are larger than D10.

The average sizes and particle distributions can be determined by laser particle size (in particular using a Malvern MS2000 laser particle size analyzer) for particles smaller than 63 μηη, or by sieving for particles larger than 63 μηι. Nevertheless, when the individual particles have a tendency to aggregate, it is preferable to determine their size by electron microscopy, since the apparent size measured by laser diffraction granulometry is then larger than the actual particle size, which is likely to distort interpretation (agglomeration and flocculation).

The Blaine surface area can be determined as described in EN 196-6 paragraph 4.

Other pozzolanic materials include materials rich in aluminosilicate such as metakaolin and natural pozzolans with volcanic, sedimentary, or diagenic origins.

Suitable non-pozzolanic materials include materials containing calcium carbonate (eg ground or precipitated calcium carbonate), preferably crushed calcium carbonate. Ground calcium carbonate may, for example, be the Durcal ^® 1 (OMYA, France). The non-pozzolanic materials preferably have an average particle size of less than 5 μηη, for example from 1 to 4 μηη. Non-pozzolanic materials may be ground quartz, for example C800 which is a substantially non-pozzolanic silica filler supplied by Sifraco, France. The preferred BET surface area (determined by known methods previously described) of calcium carbonate or crushed quartz is 2 - 10 m ² / g, generally less than 8 m ² / g, for example from 4 to 7 m ² / g, preferably less than about 6 m ² / g. Precipitated calcium carbonate is also suitable as a non-pozzolanic material. Individual particles generally have a size (primary) of the order of 20 nm. The individual particles agglomerate into aggregates having a (secondary) size of 0.1 to 1 μηι. Aggregates with a (secondary) size of 0.1 to 1 μηη can themselves form aggregates with a (ternary) size greater than 1 μηι. A single non-pozzolanic material or a mixture of non-pozzolanic materials may be used, for example ground calcium carbonate, ground quartz or precipitated calcium carbonate or a mixture thereof. A mixture of pozzolanic materials or a mixture of pozzolanic and non-pozzolanic materials can also be used.

According to an exemplary embodiment, the time between the end of the workability window and the beginning of setting of the hydraulic composition is less than 36 hours, preferably less than 24 hours, more preferably less than 16 hours, in particular without the addition of an accelerator.

The present invention makes it possible not to modify the strength class of the hydraulic composition as defined by the standard EN 206-1. Thus, if the formulation of the concrete is determined, without a retarding agent, to obtain a given strength class, that is to say a compressive strength at 28 days greater than a given threshold, the concrete according to the the invention to which the retarding agent is added and which is triggered by the addition of the accelerating agent, will have a compressive strength greater than the given threshold 28 days after the initiation.

By the expression "workability window" of a hydraulic composition is meant according to the present invention, the duration during which the slump of the hydraulic composition, measured according to the EN 12350-2 standard, remains greater than or equal to 10 mm.

According to an exemplary embodiment of the invention, the amount of the retarding agent in the hydraulic composition is from 0.1 to 5% by weight of dry extract of the retarding agent relative to the mass of the dry hydraulic binder, preferably from 0.1 to 1.0% by weight of dry extract of the retarding agent relative to the weight of the dry hydraulic binder.

According to an exemplary embodiment of the invention, the amount of the superplasticizer in the hydraulic composition is 0.05 to 5% by mass of dry extract of the superplasticizer relative to the mass of the dry hydraulic binder, preferably 0.05 at 1% by mass of dry extract of the superplasticizer relative to the mass of the dry hydraulic binder, more preferably from 0.05 to 0.75% by mass of dry extract of the superplasticizer relative to the mass of the dry hydraulic binder, even more preferably from 0.05 to 0.5% by weight of dry extract of the superplasticizer relative to the mass of the dry hydraulic binder.

According to an exemplary embodiment of the invention, the amount of the rheology modifying agent in the hydraulic composition is from 0.01 to 2% by weight. mass of dry extract of the rheological modifier with respect to the mass of the dry hydraulic binder, preferably from 0.01 to 0.5% by weight of dry extract of the rheology modifier relative to the mass of the dry hydraulic binder, more preferably from 0.025 to 0.4% by weight of dry extract of the rheology modifier relative to the mass of the dry hydraulic binder.

The hydraulic binder may comprise Portland cement, according to EN 197-1.

The final amount of the retarding mixture depends on the properties under consideration (eg desired open time, concrete formula, etc.).

The hydraulic composition is obtained by mixing aggregates, hydraulic binder, admixtures and water.

In general, the mass ratio of effective water / dry binder (W / C ratio) can be in general from 0.45 to 0.65.

The hydraulic composition may, in addition to the retarding mixture, comprise other types of adjuvants commonly used in concrete.

Examples of adjuvants which can be used are: antifoaming agents, corrosion inhibitors, shrinkage reducing agents, fibers, pigments, pumpability assistants, alkali reducing agents, reinforcing agents, water-repellent compounds and their mixtures.

According to an exemplary embodiment of the invention, the hydraulic composition further comprises an inert clay agent, that is to say an adjuvant allowing the at least partial neutralization of the harmful effects due to the presence of the clay in a hydraulic composition, in particular a hydraulic composition comprising a superplasticizer.

According to an exemplary embodiment of the invention, once the accelerating agent is added to the hydraulic composition, the amount of accelerating agent in the hydraulic composition is from 0.1 to 10% by weight of solids content of the composition. accelerating agent with respect to the weight of the hydraulic binder, preferably from 0.15 to 5%, more preferably from 0.2 to 3% by weight of dry extract of the accelerating agent relative to the weight of the hydraulic binder .

Manufacturing process

The present invention relates to a method for manufacturing a hydraulic composition, comprising the following successive steps:

-mix the hydraulic binder, the retarding agent, the superplasticizer and water to make the hydraulic composition in the fresh state; and - Add the accelerator agent to the hydraulic composition in the fresh state to trigger the setting of the hydraulic composition at any time chosen in the window of workability of the hydraulic composition.

During and / or after the addition of the accelerating agent, the hydraulic composition may be kneaded or agitated so as to be homogenized.

According to an exemplary embodiment of the invention, the hydraulic composition further comprises a rheology modifying agent comprising a compound chosen from a viscosing agent, a water-retaining agent or a thresholding agent, the process comprising the transport and / or storing the hydraulic composition in the fresh state without stirring the hydraulic composition before the addition of the accelerating agent.

According to an exemplary embodiment of the invention, when the retarding mixture further comprises the superplasticizer and the rheology modifying agent, the present invention relates to a method for manufacturing a hydraulic composition as defined above, comprising the following successive steps:

- mixing the hydraulic binder and water to make the hydraulic composition in the fresh state;

-Transport and / or store the hydraulic composition in the fresh state without agitation of the hydraulic composition; and

adding an accelerating agent to the hydraulic composition in the fresh state to trigger the setting of the hydraulic composition.

Preferably, all of the components of the retarding mixture are added from the start, during the mixing of the hydraulic composition, for example in a concrete batching plant; the cement and the complete retarding mixture, namely retarding agent, superplasticizer and rheology modifier are spoiled. Mixing in the concrete mixing plant can be done either in a mixer permanently located in the concrete mixing plant, or in a truck mixer when it is used directly as a mixer.

According to an exemplary embodiment of the invention, some of the adjuvants of the retarding mixture can be introduced in powder form directly into the various constituents of the hydraulic composition irrespective of their physical states (in liquid or solid form).

According to an exemplary embodiment of the invention, some of the adjuvants of the retarding mixture may also be introduced in the form of a liquid or semi-liquid solution in the mixing water. The retarding agent and optionally the superplasticizer and the rheology modifying agent may be added separately during the manufacture of the hydraulic composition. A mixture of the retarding agent, the superplasticizer and optionally the rheology modifying agent can nevertheless be produced beforehand, the mixture then being directly added to the hydraulic composition.

According to an exemplary embodiment of the present invention, the hydraulic composition comprises the retarding agent and the superplasticizer. Advantageously, the variation of the slump of the hydraulic composition, measured according to the EN 12350-2 standard, is less than 50 mm or the variation of the spreading of the hydraulic composition, measured with a cone according to the EN 12350 standard. -2, is less than 100 mm for at least 12 hours, preferably for at least 1 day, more preferably for at least 2 days, more preferably at least 3 days, without triggering the setting of the hydraulic composition. Preferably, the consistency of the hydraulic composition is maintained in the same consistency class with respect to the slump, as defined by EN 206-1, for at least 12 hours, preferably for at least 1 day, plus preferably for at least 2 days, even more preferably at least 3 days, without triggering the setting of the hydraulic composition. This means that, if just after the manufacture of the hydraulic composition, the consistency class of the hydraulic composition is for example S4, then the consistency class of the hydraulic composition remains the S4 class for at least 12 hours, preferably during less 1 day, more preferably for at least 2 days, even more preferably at least 3 days, without triggering the setting of the hydraulic composition.

According to an exemplary embodiment of the present invention, the hydraulic composition further comprises a rheology modifier comprising a compound selected from a viscosifying agent, a water retainer or a thresholding agent. The process can then further include transporting and / or storing the fresh hydraulic composition without agitation of the hydraulic composition. The rheology modifying agent makes it possible to maintain the homogeneity of the hydraulic composition even without agitation. Preferably, the transport of the hydraulic composition is carried out for more than ten minutes, preferably more than 20 minutes, even more preferably more than 30 minutes, without agitation of the hydraulic composition. Advantageously, the delayed hydraulic composition according to the invention once manufactured then need not be agitated until its use, that is to say until triggering the setting of the hydraulic composition. By the term "agitation" of the hydraulic composition is meant according to the present invention any mechanical system used to perform a vigorous mixing operation of the hydraulic composition. This does not take into account the stresses (tremors, etc.) that necessarily undergoes the hydraulic composition during a transport operation. The hydraulic composition can therefore be transported and / or stored in bags, drums, or any type of container without agitation of the hydraulic composition. Preferably, the delayed hydraulic composition according to the invention is stored in closed packaging, for example in a hermetically sealed container. By way of example, the hydraulic composition can be transported in bags of the order of one cubic meter. Advantageously, the hydraulic composition can be transported horizontally (without agitation of the hydraulic composition), that is to say on a vehicle not including a mixer, for example in a truck other than a truck spinning top. According to an exemplary embodiment, the freshly-cooled hydraulic composition can be transported and / or stored without agitation of the hydraulic composition for at least 12 hours, preferably for at least 1 day, more preferably for at least 2 days, even more preferably at least 3 days. The hydraulic composition can be stored outdoors at temperatures ranging from 5 ° C to 30 ° C. Even at temperatures below 10 ° C., the variation of the slump of the hydraulic composition, measured according to the EN 12350-2 standard, is less than 50 mm or the variation of the spreading of the hydraulic composition, measured with a cone according to the standard EN 12350-2, is less than 100 mm for at least 12 hours, preferably for at least 1 day, more preferably for at least 2 days, still more preferably at least 3 days, without triggering the setting of the hydraulic composition.

The exemplary embodiment according to which the hydraulic composition further comprises a rheology modifying agent which makes it possible to avoid any bleeding phenomenon (rise in water on the surface of the concrete), sedimentation (higher concentration of aggregates on the surface). concrete base) or consolidation (absence of paste at the intergranular contacts). These phenomena can degrade the visual appearance of the concrete and / or hinder or even prevent in practice any remanipulation of the concrete (including its remixing and its use), although the hydraulic composition is not agitated during its transport and / or storage. According to another embodiment of the present invention, the hydraulic composition does not comprise a rheology modifying agent. The method then further comprises transporting and / or storing the hydraulic composition in the fresh state while stirring the hydraulic composition, for example in a truck mixer.

When the hydraulic composition is to be used, the contents of the bag or drum containing the hydraulic composition can be poured into a mixer (eg a concrete mixer) at the site where the hydraulic composition is used. The accelerator agent according to the invention is then added to the hydraulic composition to trigger the setting of the hydraulic composition.

According to an exemplary embodiment, the method comprises adding to the hydraulic composition an antifoaming agent with the accelerating agent. Alternatively, the antifoaming agent can be added to the hydraulic composition at any time, for example during the manufacture of the hydraulic composition during mixing of the constituents of the hydraulic composition.

Once the accelerating agent is added to the hydraulic composition, the hydraulic composition (in the fresh state or in the cured state) comprises:

the hydraulic binder;

a retarding agent, a superplasticizer, optionally a rheology modifying agent, aggregates; and

the accelerator agent according to the invention.

According to an exemplary embodiment of the invention, the process comprises adding to the hydraulic composition from 0.1 to 10% by weight of dry extract of the accelerating agent relative to the weight of the hydraulic binder, preferably from 0.15 to 5%, more preferably 0.2 to 3% by weight of dry extract of the accelerating agent relative to the weight of the hydraulic binder.

Examples illustrate the invention without limiting its scope.

EXAMPLES

In the examples, the products and materials used are available from the following suppliers:

Product or material Supplier

(1) Lafarge Portland cement - Saint Pierre La Cour or Le Havre

(2) BL 200 TM Omya filler material

(3) Sand 0/5 mm Saint Bonnet, France

(4) Chippings 5/10 mm Saint Bonnet, France (5) CHRYSOPIast CER ™ Chryso Adjuvant

(6) CHRYSOFIuid Optima 100 ™ Chryso Adjuvant

(7) BASF GLENIUM 27 ™ Adjuvant

(8) MHPC 20000 P ™ Aqualon Culminate Adjuvant - Ashland

(9) Adjuvant CHRYSOJet RS 38 ™ Chryso

(10) Adjuvant Surfynol MD20 ™ Air Products

(1 1) Clones lllite SOCODIS - lllite du Puy

(12) Kaolinite Clay AGS - Kaolinite BS3

(13) BASF X-Seed Adjuvant

Cement was the cement produced by Lafarge from the site of

Saint Pierre The Court or the site of Le Havre. It was of the CEM I 52.5 type according to EN 197-1.

The BL 200 ™ filler material was a limestone mineral addition. Sand 0/5 mm and chippings 5/10 mm of Saint Bonnet were alluvial silico-limestone type.

CHRYSOPIast CER ™ is generally marketed as a plasticizer. However, it can also have a delaying action. In the present examples, CHRYSOPIast CER ™ has been called a retarding agent even though it also has a fluidizing action. CHRYSOPIast CER ™ included gluconate.

GLENIUM 27 ™ Adjuvant was a PCP superplasticizer with immediate action.

Culminai adjuvant MHPC 20000 P ™ was a rheology modifier for methylhydroxypropylcellulose.

CHRYSOJet adjuvant RS 38 ™ was a sodium metasilicate setting accelerator. In the remainder of the description, the expression "sodium metasilicate" is used when the accelerator CHRYSOJet RS 38 ™ has been used.

Surfynol MD20 ™ adjuvant was an antifoam agent.

CHRYSOFluid Optima 100 ™ adjuvant was an immediate acting superplasticizer of the polyox phosphonate type.

Mortar formulations

The formulation (1) of mortar used to carry out the tests is described in Table 1 below:

Table 1: Formulation (1) Mortar

Proportion component (in g)

for 1 L of

fresh mortar Lafarge cement 484

Saint Peter The Court

Sand 0-5 of Saint Bonnet 1461

Total water 287

Adjuvants See examples

The formulation (2) of mortar used to carry out the tests is described in Table 2 below:

Table 2: Mortar formulation (2)

Concrete formulations

The formulation (3) of concrete used to carry out the tests is described in Table 3 below:

Table 3: Concrete Formulation (3)

Component Proportion (in kg) for 1 m ³

fresh concrete

Lafarge cement 280 Saint Pierre The Court

BL 200 ™ 50 limestone filler

Sand 0-5 of Saint Bonnet 990

Chippings 5-10 of Saint Bonnet 830

Total water 200

Adjuvants See examples The formulation (4) of concrete used to carry out the tests is described in Table 4 below:

Table 4: Concrete formulation (4)

The formulation (5) of concrete used to carry out the tests is described in Table 5 below:

Table 5: Concrete formulation (5)

The formulation (6) of concrete used to carry out the tests is described in Table 6 below: Table 6: Concrete formulation (6)

Method of preparing a mortar according to formulation (1) or (2)

• Put the sands in the bowl of a Perrier kneader;

• At T = 0: start mixing at low speed (140 rpm) and simultaneously add the wetting water in 30 seconds, then continue mixing at low speed (140 rpm) for up to 60 seconds;

• At T = 60 seconds: stop mixing and let stand for 4 minutes;

• At T = 5 minutes (T0 for the rheology maintenance test): Add the cement, the mineral addition and the rheology modifier and knead at low speed (140 rpm) for 1 minute;

• At T = 6 minutes: add the mixing water (+ optional adjuvants) in 30 seconds (while mixing at low speed (140 rpm);

• At T = 6 minutes and 30 seconds: knead at high speed (280 rpm) for 1 minute;

• At T = 7 minutes and 30 seconds: stop mixing.

Method of preparing a concrete according to the formulation (3), (4), (5) or (6)

• Put the sands and chippings in the bowl of a Zykios mixer (30 or 50 L capacity), Sipe (230 L capacity) or Pemat (500 L capacity);

• AT = 0: start mixing and add the dampening water at the same time in 30 seconds, then continue mixing for up to 60 seconds; • At T = 60 seconds: stop mixing and let stand for 4 minutes;

• At T = 5 minutes (T0 for the rheology maintenance test): add Portland cement and rheology modifier and mix for 1 minute;

• At T = 6 minutes: add the mixing water (+ optional adjuvants) in 30 seconds while mixing;

• At T = 6 minutes and 30 seconds: knead for 1 minute 30 seconds;

· At T = 8 minutes: stop mixing.

Mortar or concrete release method

The mortar or concrete was kneaded a few minutes by incorporating the accelerator with possibly water and an antifoaming agent.

Method for measuring the spread of a hydraulic composition

The principle of the spreading measurement consisted in filling a spreading measurement cone trunk with the hydraulic composition to be tested and then in freeing said composition from the spreading measurement cone frustum in order to determine the diameter of the disk obtained when the hydraulic composition has finished spreading. The truncated cone of the spreading measurement corresponded to a ½ scale reproduction of the cone as defined by standard NF P 18-451, 1981. The truncated cone of the spreading measurement had the following dimensions:

-diameter of the circle of the upper base: 50 +/- 0.5 mm;

-diameter of the circle of the lower base: 100 +/- 0.5 mm; and

height: 150 +/- 0.5 mm.

The whole operation was carried out at 20 ° C. The measurement of the spreading was carried out as follows:

• Fill the reference cone trunk in a single step with the hydraulic composition to be tested;

• Distribute the hydraulic composition evenly in the truncated cone;

• Shave the upper surface of the cone;

• lift the truncated cone vertically; and

• Measure the spread in four diameters at 45 ° with calipers. The result of the spread measurement was the average of the four values at +/- 1 mm.

Method of measuring the sag of a hydraulic composition The slump was measured as described in EN 12350-2 "Test for Fresh Concrete - Part 2: Slump Test".

Method of measuring the compressive strength

Compressive strength was measured for mortars as described in EN 196-1 "Test method for cements" and for concretes as described in EN 12390-2 "Test for hardened concrete - Part 2: Making and preserving test specimens for strength tests "and PR EN 12390-3: 1999" Test for hardened concrete - Part 3: Compressive strength of test pieces "with cylindrical specimens having a diameter of 1 1 cm and a height of 22 cm.

Method for measuring the setting time of a hydraulic composition

A temperature recorder has been used, for example a temperature recorder sold by the company Testo. The hydraulic composition was placed in an adiabatic enclosure. The recorder has been arranged in the hydraulic composition. The temperature was recorded every minute. The temperature of the hydraulic composition tended to decrease after the manufacture of the hydraulic composition to stabilize at a constant temperature plateau to the point at which the temperature temporarily increased. For measurements made at more than 15 ° C, the start of setting corresponded, unless otherwise indicated, to the time elapsing between the moment the accelerator was added to the hydraulic composition and the moment when the temperature Increased by two degrees with respect to the temperature step for a hydraulic composition.

Method of triggering a mortar

Twenty-four hours after the time T0 corresponding to the manufacture of the mortar, the mortar or concrete was kneaded for 5 minutes in a Perrier mixer at high speed (280 rpm) by incorporating the accelerating agent with possibly water.

BET specific surface measurement method

The specific surface of the different powders was measured as follows. A powder sample was taken with the following mass: 0.1 to 0.2 g for a specific surface area estimated at more than 30 m ² / g; 0.3 g for a specific surface area estimated at 10-30 m ² / g; 1 g for a specific surface area estimated at 3-10 m ² / g; 1.5 g for a specific surface area estimated at 2-3 m ² / g; 2 g for a specific surface area estimated at 1.5-2 m ² / g; 3 g for a specific surface area estimated at 1 -1.5 m ² / g. A cell of 3 cm ³ or 9 cm ³ , depending on the volume of the sample was used. The entire measuring cell (cell + glass rod) was weighed. Then the sample was added to the cell: the product had to be more than one millimeter from the top of the cell throat. The whole (cell + glass rod + sample) was weighed. The measuring cell was put on a degassing station and the sample was degassed. The degassing parameters were 30 min / 45 ° C for Portland cement, gypsum, pozzolans; 3 hours / 200 ° C for slags, fly ash, aluminous cement, limestone; and 4 h / 300 ° C for control alumina. The cell was quickly plugged with a plug after degassing. The set was weighed and the result noted. All weighing operations were performed without the cap. The mass of the sample was obtained by subtracting the mass of the cell from the mass of the cell + degassed sample.

Then the sample was analyzed after putting it on the measuring station. The analyzer was Beckman Coulter SA 3100. The measurement was based on nitrogen adsorption by the sample at a given temperature, in which case the temperature of the liquid nitrogen was -196 ° C. The apparatus measured the pressure of the reference cell in which the adsorbate was at its saturation vapor pressure and the pressure of the sample cell in which known volumes of adsorbate were injected. The curve resulting from these measurements was the adsorption isotherm. Knowledge of the dead volume of the cell was necessary in the measurement process: a measurement of this volume was therefore made with helium before the analysis.

The mass of the previously calculated sample has been entered as a parameter. The BET surface area was determined by the software by linear regression from the experimental curve. The reproducibility standard deviation obtained from 10 measurements on a surface-specific silica 21.4 m ² / g was 0.07. The reproducibility standard deviation obtained from 10 measurements on a specific surface cement 0.9 m ² / g was 0.02. Once every two weeks a check has been made on a reference product. Twice a year, a check was made with the reference alumina supplied by the manufacturer.

EXAMPLE 1

Four mortars MO, M1, M2 and M3 were prepared according to the formulation (1) at 20 ° C. One liter of each mortar M1, M2 and M3 was made. For each mortar MO, M1, M2 and M3, the retarding agent was CHRYSOPIast CER ™. Each mortar MO, M1, M2 and M3 included 0.5% by mass of dry extract of the agent retarder with respect to the mass of cement. The superplasticizer was CHRYSOFluid Optima 100 ™. Each mortar MO, M1, M2 and M3 included 0.2% by mass of dry extract of superplasticizer relative to the mass of cement.

The MO mortar was a reference mortar that did not include an accelerator.

For each mortar M1, M2 and M3, the accelerator was a mixture of double-layered hydroxide Mg ₂ Al (OH) ₆ N0 ₃ , 2H ₂ 0, called LDH below, and sodium metasilicate (CHRYSOJet RS 38 ™).

The mortar M1 comprised 1% by weight of LDH with respect to the mass of cement and 0.75% by mass of solids content of sodium metasilicate relative to the mass of cement.

The mortar M2 comprised 3% by weight of LDH relative to the mass of cement and 0.75% by mass of solids content of sodium metasilicate relative to the mass of cement.

The M3 mortar comprised 5% by weight of LDH with respect to the mass of cement and 0.75% by mass of sodium metasilicate solids relative to the mass of cement.

Mortars M1, M2 and M3 were kept at rest, without agitation. The corresponding accelerator for each mortar M1, M2 and M3 was added 24 hours after manufacture. The setting times were measured from the moment of addition of the accelerator, the spreads were measured during the addition of the accelerator and the compressive strengths were measured 24 hours after the addition of the accelerator. addition of the accelerator (for the mortar MO, the reference from which the setting time was measured was 24 h after the manufacture of the mortar MO). The results of these tests are collated in the following Table 7:

Table 7

The setting time of the MO mortar in which no accelerator was added was about 4 days. The addition of LDH for the M1, M2 and M3 mortars resulted in a setting time of less than 24 hours and 24 h compression strengths greater than 1 MPa. However, for a concentration strictly greater than 3% by weight of LDH with respect to the mass of cement, the spreading could be insufficient.

EXAMPLE 2

An M4 mortar was prepared according to the formulation (1) at 20 ° C. One liter of M4 mortar was produced. The retarding agent was CHRYSOPIast CER ™. The M4 mortar comprised 0.5% by weight of dry extract of the retarding agent relative to the mass of cement. The superplasticizer was CHRYSOFluid Optima 100 ™. The M4 mortar comprised 0.2% by weight of dry extract of superplasticizer relative to the mass of cement.

The accelerator for the M4 mortar included CSH (X-Seed adjuvant) germs. The M4 mortar comprised 1.6% by weight of dry extract of the X-Seed adjuvant relative to the cement mass.

The M4 mortar was kept at rest, without agitation. The accelerator was added 24 hours after manufacture. Shot time measurements have been realized, setting times being measured from the moment of addition of the accelerator. The results of these tests are summarized in Table 8 below:

Table 8

The addition of CSH germs resulted in a setting time of less than 24 hours and 24-hour compressive strengths greater than 1 MPa.

EXAMPLE 3

Four mortars M1 1, M12, M13 and M14 were prepared according to the formulation

(2) mortar at 20 ° C. One liter of each mortar M1 1, M12, M13 and M14 was produced. The retarding agent for each mortar M1 1, M12, M13 and M14 was CHRYSOPIast CER ™. Each mortar M1 1, M12, M13 and M14 included 0.35% by weight of dry extract of the retarding agent relative to the mass of cement. The superplasticizer was GLENIUM 27 ™. Each mortar M1 1, M12, M13 and M14 included 0.40% by mass of dry extract of superplasticizer relative to the mass of cement.

Mortar M1 1 was a reference mortar that did not include an accelerator.

The accelerator for the M12 mortar was sodium metasilicate

(CHRYSOJet RS 38 ™). The M12 mortar included 0.75% by weight of sodium metasilicate solids relative to the cement mass.

The accelerator for the M13 mortar included CSH (X-Seed) germs. The M13 mortar included 0.75% by weight of dry extract of X-Seed adjuvant relative to the cement mass.

The accelerator for the M14 mortar was LDH Mg ₂ Al (OH) ₆ N0 ₃ , 2H ₂ 0. The M14 mortar comprised 3% by weight of LDH with respect to the cement mass.

Mortars M1 1, M12, M13 and M14 were kept at rest, without agitation. The corresponding accelerator for each mortar M12, M13 and M14, was added 24 hours after manufacture The setting times were measured from the moment of addition of the accelerator, the spreads were measured during the addition of the accelerator and the compressive strengths were measured 24 hours and 28 days after the addition of the accelerator (for the M1 mortar 1, the reference to from which the setting time was measured was 24 hours after the manufacture of the mortar M1 1). The results of these tests are summarized in Table 9 below:

Table 9

The set time of mortar M1 1 in which no accelerator was added was about 2 days. The addition of sodium metasilicate in the M12 mortar at 24 hours reduced the setting time from 2 days to about 9.5 hours. The addition of CSH silicate seeds in the M13 mortar at 24 hours reduced the setting time from 2 days to about 12 hours. The addition of LDH in the M14 mortar reduced the setting time from 2 days to about 12 hours. By using sodium metasilicate alone, CSH alone or LDH alone, it was therefore possible to obtain a reduced setting time and satisfactory 24 hour resistances.

EXAMPLE 4

Concrete B1 was prepared according to formulation (3) at 20 ° C. Three wastes of about 500 liters each were prepared.

The retarding agent was CHRYSOPIast CER ™. Concrete B1 included 0.35% by weight of dry extract of the retarding agent relative to the mass of cement.

The rheology modifier was Culminai MHPC 20000 P ™. Concrete B1 comprised 0.13% by weight dry solids of the rheology modifier relative to the cement mass.

The superplasticizer was GLENIUM 27 ™. Concrete B1 included 0.40% by weight of GLENIUM 27 ™ solids in relation to the cement mass. The mixes were made in a Pemat type mixer. The three spoils were homogenized by 70 turns in a Fiori mixer truck of 2 m ³ . Three impermeable bags P1, P2 and P3 double jacket were each filled with about 400 liters of concrete B1.

The bags were trucked for 75 minutes, including 15 minutes at an average speed of 1 10 km / h and 60 minutes at an average speed of 80 km / h.

The bags were then kept at rest.

The release of concrete B1 for each bag P1, P2 and P3 was achieved by mixing the concrete and the triggering agent CHRYSOJet RS 38 ™. Surfynol MD20 ™ Defoamer was added simultaneously with the triggering agent.

The method of triggering each bag was as follows:

-the bag was emptied into a bucket;

- the dump was emptied into a Fiori truck of 2 m ³ ;

the concrete in the truck has been homogenized by 70 turns of the top; and

-The triggering agent has been added.

The following trigger method was used:

4 hours after the manufacture of the concrete B1 for the P1 bag, addition of 1.25% by weight of dry extract of CHRYSOJet RS 38 ™ with respect to the mass of cement and 1.5 ml of Surfynol MD20 ™;

-24 hours after the manufacture of the concrete B1 for the P2 bag addition of 0.75% by weight of CHRYSOJet RS 38 ™ dry extract relative to the cement mass and 1.5 mL of Surfynol MD20 ™; and

48 hours after the manufacture of the concrete B1 for the P3 bag, addition of 0.25% by weight of dry CHRYSOJet RS 38 ™ extract relative to the cement mass and 1.5 mL of Surfynol MD20 ™.

The trigger method was used for concrete B1 contained in the bag P2. This concrete was then poured into a formwork for the realization of a parallelepiped wall 90 cm high, 60 cm long and 15 cm thick. The removal of the wall was done after 24 hours.

For each concrete B1 of bags P1, P2 and P3, sagging and compressive strengths were measured at 1 day and 28 days after initiation. The results of these tests are collated in the following table 10: Table 10

Concrete B1 was maintained in the same consistency class (class S4) over 48 hours. No bleeding or settling aggregates was observed for each bag. Bags P1, P2 and P3 were emptied without difficulty into the truck. Concrete B1 flowed by itself without having to vibrate. In addition, the bags P1, P2 and P3 have emptied completely without there remains pile of dough or granules on the walls of the top.

Regardless of the time of onset during the 48 hours following the fabrication of concrete B1, the compressive strength of concrete B1 at 1 day after release was greater than about 2 MPa. It was therefore possible to discard this deadline. Moreover, regardless of the moment of initiation during the 48 hours which followed the manufacture of concrete B1, the compressive strength of concrete B1 at 28 days after the release was greater than 35 MPa.

In addition, the variation of the slump of the concrete B1 was less than 50 mm for at least 45 minutes after the addition of the accelerating agent.

EXAMPLE 5

B2 concrete was prepared according to formulation (4) at 20 ° C. A batch of about 500 liters was prepared. The retarding agent was CHRYSOPIast CER ™. Concrete B2 comprised 0.3% by weight of dry extract of the retarding agent relative to the mass of cement.

The superplasticizer was GLENIUM 27 ™. Concrete B1 comprised 0.3% by weight of GLENIUM 27 ™ solids in relation to the cement mass.

The concrete was mixed in a Pemat kneader and homogenized by 70 turns in a Fiori mixer truck of 2 m ³ . A double-walled bag was filled with approximately 400 liters of B2 concrete.

The bag was transported by truck. The bag was then kept at rest.

The concrete B2 was triggered by mixing the concrete and the CHRYSOJet RS 38 ™ release agent. Surfynol MD20 ™ Defoaming Agent was added simultaneously with the triggering agent. The triggering method was identical to that described for concrete B1.

The triggering method was used 4 hours after the manufacture of concrete B2 by adding 1.25% by weight of dry CHRYSOJet RS 38 ™ extract relative to the cement mass and 1.5 mL of Surfynol MD20 ™.

Sag was measured just prior to initiation and subsidence was measured immediately after initiation and 45 minutes after initiation. The results of these tests are collated in the following table 11:

Table 11

The variation in the slump of concrete B2 was less than 50 mm for at least 45 minutes after the addition of the accelerator agent.

EXAMPLE 6

Concrete B3 was prepared according to formulation (5) at 20 ° C. A batch of about 500 liters was prepared.

The retarding agent was CHRYSOPIast CER ™. Concrete B3 comprised 0.3% by weight of dry extract of the retarding agent relative to the mass of cement.

The rheology modifier was Culminai MHPC 20000 P ™. Concrete B3 comprised 0.13% by weight of dry extract of the rheology modifier relative to the cement mass.

The superplasticizer was GLENIUM 27 ™. Concrete B3 included 0.3% by weight of GLENIUM 27 ™ solids in relation to the cement mass.

The concrete was mixed in a Pemat kneader and homogenized by 70 turns in a Fiori mixer truck of 2 m ³ . A double-walled bag was filled with approximately 400 liters of B3 concrete.

The bag was transported by truck. The bag was then kept at rest.

The B3 concrete was triggered by mixing the concrete and the CHRYSOJet RS 38 ™ release agent. Surfynol MD20 ™ antifoam agent has been added simultaneously with the triggering agent. The triggering method was identical to that described for concrete B1.

The triggering method was used 48 hours after the manufacture of the B3 concrete by adding 0.35% by weight of dry CHRYSOJet RS 38 ™ extract relative to the cement mass and 1.5 mL of Surfynol MD20 ™.

Sag was measured just prior to initiation and compressive strengths at 1 day and 28 days after initiation were measured. The results of these tests are collated in the following table 12:

Table 12

Before after

triggers

is lying

c / 3

C / 3, φ

E .0

E 03

03 03

CL 00

00 CM

LO '03 '03

'03 '03 O O

c c OR ω OR ω

ω ω ω E CD E

E E o ω ω

ω ω c .e ϋ .e

C 3 C 3 03 o C o

C / 3 C / 3 C / 3 C 03

o _ C / 3 c

_ω

^' θ3 ^' θ3 ^' c / 3 ^'

-Φ -0 o c / 3

-Φ o

S Q

B3 220 170 48

The variation in slump of B3 concrete was less than 50 mm for 48 hours. No bleeding or settling of the granular skeleton / aggregates was observed after storage.

In addition, the compressive strength of concrete B3 at 1 day after release was greater than about 9 MPa. It was therefore possible to discard this deadline.

EXAMPLE 7

Concrete B4 was prepared according to formulation (6) at 20 ° C. A batch of about 50 liters was prepared. The retarding agent was CHRYSOPIast CER ™. Concrete B4 comprised 0.3% by weight, expressed as solids, of the retarding agent relative to the cement mass.

The superplasticizer was GLENIUM 27 ™. Concrete B4 included 0.3% by weight, expressed as solids, of GLENIUM 27 ™ in relation to the mass of cement.

Concrete B4 was kept at rest, without agitation.

The release of B4 concrete was achieved using a mixture of the CHRYSOJet RS 38 ™ triggering agent and CSH (X-Seed adjuvant) germs. Surfynol MD20 ™ Defoaming Agent was added simultaneously with the triggering agent. The triggering method was identical to that described for concrete B1.

The triggering method was used 48 hours after the manufacture of concrete B4 by adding 0.2% by mass, expressed as dry extract, of CHRYSOJet RS 38 ™ with respect to the mass of cement, of 0.7% by mass, expressed as dry extract, X-Seed adjuvant relative to the cement mass and 1.5 mL of Surfynol MD20 ™.

Table 12

The slump variation of concrete B4 was less than 50 mm for 48 hours. No bleeding or settling of the granular skeleton / aggregates was observed after storage.

In addition, the compressive strength of concrete B4 at 1 day after release was greater than about 9 MPa. It was therefore possible to discard this deadline.

EXAMPLE 8

An M15 mortar was prepared according to the formulation (1) at 20 ° C. The cement was cement produced by Lafarge from the Le Havre site of the type CEM I 52.5 N according to standard EN 197-1.

An M16 mortar was prepared according to the formulation (1) at 20 ° C except that the cement of the formulation (1) was replaced by 85% by weight of the cement produced by Lafarge from the site of Le Havre type EMC I 52.5 N according to EN 197-1 and 15% by weight of the calcareous filling material of Saint Pierre La Cour.

An M17 mortar was prepared according to the formulation (1) at 20 ° C except that the cement of the formulation (1) was replaced by 85% by weight of cement produced by Lafarge from the site of Le Havre type EMC I 52.5 N according to EN 197-1 and 15% by mass of fly ash from the Carling site.

An M18 mortar was prepared according to the formulation (1) at 20 ° C with the difference that the cement of the formulation (1) was replaced by 85% by weight of the cement produced by Lafarge from the site of Saint Pierre la Court type EMC II 32.5 N according to EN 197-1 and 15% by weight of the calcareous filling material of Saint Pierre La Cour.

An M19 mortar was prepared according to the formulation (1) at 20 ° C with the difference that the cement of the formulation (1) was replaced by 82% by weight of cement produced by Lafarge from the site of Saint Pierre la Court of type CEM II 42.5 N according to EN 197-1 and 18% by mass of the calcareous filling material of Saint Pierre La Cour.

One liter of each mortar M15, M16, M17, M18 and M19 was made.

For mortars M15, M16, M17, M18 and M19, the retarding agent was CHRYSOPIast CER ™. Each mortar M15, M16 and M17 included 0.33% by weight, expressed as dry extract, of the retarding agent relative to the mass of binder (cement + substitute material). Each mortar M18 and M19 included 0.38% by weight, expressed as dry extract, of the retarding agent relative to the mass of binder (cement + substitute material).

For M15, M16, M17, M18 and M19 mortars, the rheology modifier was Culminai MHPC 20000 P ™. Each mortar M15, M16, M17, M18 and M19 comprised 0.1% by weight, expressed as solids content, of the rheology modifier with respect to the binder mass (cement + substitute material).

For the M15, M16, M17, M18 and M19 mortars, the superplasticizer was GLENIUM 27 ™. Each mortar M15, M16 and M17 comprised 0.3% by weight, expressed as solids, of the superplasticizer relative to the mass of binder (cement + substitute material). The M18 mortar comprised 0.35% by weight, expressed as solids, of the superplasticizer relative to the mass of binder (cement + substitute material). Mortar M19 comprised 0.5% by weight, expressed as solids, of the superplasticizer relative to the mass of binder (cement + substitute material).

The accelerator for the M15, M16, M17, M18 and M19 mortars was sodium metasilicate (CHRYSOJet RS 38 ™).

Mortars M 15, M 16, M 17, M 18 and M 19 were kept at rest, without stirring. The triggering method was used 48 hours after the manufacture of mortars M15, M16, M17, M18 and M19 by adding 0.7% by weight, expressed as solids, of CHRYSOJ and RS 38 ™ with respect to the mass of binder ( cement + substitute material).

Sag was measured just prior to initiation and compressive strengths at 1 day and 28 days after initiation were measured. The results of these tests are collated in the following table 13:

Table 13

03

CL 03

CL

E E E E

oo

CM CM

oo ™, 03

LO M

'03 '03

'03 '03 '03 ω g Φ g

C C C o ϋ

C ω ω ω c C

g 03 ω 03 ω ω E E E

'Ϊ́. ω _ω _ω _ω Q. Q.

ο Ε 03 03 03 E -Φ E

<LU LU LU o

o t: o

o

Μ15 CEM I 0% 165 165 150 8.3 48.1

(100%)

Μ16 CEM I Filler 165 150 150 7.4 41

(85%) limestone

(15%)

Μ17 CEM I Ash 130 120 120 10.69 38.1

(85%) flying

(15%)

Μ18 CEM II Filler 155 135 135 35

32.5 limestone

(74%) (26%)

Μ19 CEM II Ash 155 155 135 34

42.5 flying

(82%) (18%)

The 48-hour decrease in spreading was less than 20 mm for the M15, M16, M17, M18 and M19 mortars, which corresponded to a 48-hour spread reduction measured with a cone according to the EN 12350-2 standard. less than 100 mm. Mortars M15, M16, M17, M18 and M19 were therefore satisfactory. In addition, no bleeding or sedimentation of mortars M15, M16, M17, M18 and M19 was observed.

In addition, the compressive strength of mortars M15, M16, M17, M18, and M19 at 1 day after release was greater than about 1 MPa. It was therefore possible to discard this deadline.

Claims

1. Hydraulic composition, comprising:

in which :

the compressive strength of the hydraulic composition is at least equal to 1 MPa 24 hours after the beginning of the setting of the hydraulic composition;

the hydraulic composition, without a retarding agent, belongs to a class of resistance, as defined by the standard EN 206-1, determined for a compressive strength measured 28 days after the manufacture of the hydraulic composition, the hydraulic composition comprising retarding agent belonging to the same strength class determined for a compressive strength measured 28 days after the addition of the accelerating agent.

Hydraulic composition according to claim 1, wherein the accelerating agent comprises a water-soluble salt, a double-layered hydroxide or hydrate seeds.

Hydraulic composition according to claim 1 or 2, wherein the retarding agent comprises a hydroxycarboxylic acid or a hydroxycarboxylic acid salt.

The hydraulic composition of claim 3, wherein the retarding agent comprises a gluconate.

The hydraulic composition according to any one of claims 1 to 4, further comprising from 0.01 to 2% by weight of dry extract relative to the weight of the hydraulic binder of a rheology modifier, which is distinct from the superplasticizer, comprising a compound selected from a viscosing agent, a water retainer, a thresholding agent or a thixotropic agent.

6. Hydraulic composition according to any one of claims 1 to 5, wherein the duration between the end of the workability window of the hydraulic composition and the beginning of the setting of the hydraulic composition is less than 36 hours.

7. A method of manufacturing a hydraulic composition according to any one of claims 1 to 6, comprising the following successive steps:

-mix the hydraulic binder, the retarding agent, the superplasticizer and water to make the hydraulic composition in the fresh state; andadding the accelerating agent to the hydraulic composition in the fresh state to trigger the setting of the hydraulic composition.

The method of claim 7, wherein the hydraulic composition further comprises a rheology modifier comprising a compound selected from a viscosifier, a water retainer or a thresholding agent, the process comprising transporting and / or storing the hydraulic composition in the fresh state without stirring the hydraulic composition before the addition of the accelerating agent.

9. The method of claim 7 or 8, further comprising adding to the hydraulic composition an antifoaming agent with the accelerating agent.

10. Method according to any one of claims 7 to 9, comprising the addition in the hydraulic composition of 0.1 to 10% by weight of dry extract of the accelerating agent relative to the mass of the hydraulic binder.