EP3068745A1

EP3068745A1 - Fluidity-retaining agent for hydraulic compositions, compatible with a water-reducing agent of the comb polymer type

Info

Publication number: EP3068745A1
Application number: EP14809482.4A
Authority: EP
Inventors: David Platel; Yves MATTER; Jean-Marc Suau
Original assignee: Coatex SAS
Current assignee: Coatex SAS
Priority date: 2013-11-15
Filing date: 2014-11-12
Publication date: 2016-09-21
Also published as: CN105722804A; WO2015071584A1; US20160289120A1; CA2929307A1; FR3013350B1; FR3013350A1; MX2016006306A

Abstract

The invention relates to the technical field of hydraulic compositions, for example compositions of concrete and mortars. More specifically, the present patent application relates to a fluidity-retaining agent compatible with a water-reducing agent of the hydrophilic comb polymer type.

Description

FLUIDITE RETENTION AGENT FOR HYDRAULIC COMPOSITIONS COMPATIBLE WITH WATER REDUCING AGENT

FIELD OF THE INVENTION Field of the invention

The present invention relates to the technical field of hydraulic compositions, for example concrete and mortar compositions. Such compositions are intended for all construction markets. More specifically, the present patent application relates to additives used in such hydraulic compositions.

Background of the invention

The hydraulic compositions generally comprise various chemical additives for improving their properties. Among these, a chemical agent is generally used whose function is to improve the state of dispersion of the mineral particles within the composition. This chemical agent is indifferently called "dispersing agent", "fluidifying agent", "water reducing agent", "plasticizing agent" or "superplasticizer". This chemical agent makes it possible to reduce the water content of the hydraulic compositions, which makes it possible to improve the performance of the hydraulic compositions, including the mechanical strength.

There is a wide variety of dispersing agents for hydraulic compositions. These agents differ in their chemical composition and the properties they induce in the compositions containing them.

For example, documents WO 2006/028252 and WO 2003/144332 describe the use of dispersing copolymers of small molecular weights.

To evaluate the dispersant properties of the dispersing agent in the hydraulic composition, the slump is measured in accordance with the EN 12350-2 standard. The greater the sag value, the easier the hydraulic composition is. The workability of a concrete is an important property that conditions its implementation, for example for the filling of a formwork. It is evaluated right after its manufacture, as well as at specific times after manufacture, this which makes it possible to evaluate the workability over time, also called retention of fluidity ("slump retention" in English), as well as the limited period of workability after manufacture.

There are several categories of concrete. For each category of concrete, specific handling characteristics are expected.

Among the different categories of concretes, mention may be made of self-compacting concretes (or SCC for "concrete self-compacting") which are characterized by high handling values (> 620 mm and never <500 mm). For such concretes, it is a question of increasing their maneuverability for their implementation, as well as to guarantee a maneuverability for a prolonged time.

Also mentioned ready-mix concrete (BPE), another category of concrete that has maneuverability values of the order of 50 mm to 200 mm. A proposed solution for increasing the workability of the concrete consists in overdosing the quantity of dispersing agents used. This solution, very practical, nevertheless leads to a loss of stability and homogeneity of the formulation, which negatively impacts the performance of the concrete (segregation). Another solution is to use setting retarding agents, in accordance with the standard ADJUVANT NF EN 934-2. As soon as the anhydrous cement has been mixed with the water, which may be additive, the hydration starts and the properties of the paste thus obtained change over time. After a while, the crystals become more important, the mixture has changed viscosity and stiffens. This corresponds to the beginning of taking. The use of setting retarding agents makes it possible to inhibit the step of hydration of the cement when it comes into contact with the other constituents of the concrete or the mortar and / or the step of crystallization of the constituents of the cement. The use of setting retarding agents nevertheless has the major disadvantage of reducing the resistance at young ages of the structures.

The use of fluidity retentive agents is also proposed to ensure maneuverability for a prolonged time. WO 2007/047407, in particular, describes a method for increasing the workability of combining three additives: an initial fluidity increasing agent, a fluidity retaining agent and an agent that controls the response of the agent increasing the initial fluidity when the first two agents are added to said composition.

The document WO 97/48656 describes the use of a copolymer-type agent which confers an initial fluidity on a hydraulic composition such as a cement paste, a mortar or concrete and, moreover, makes it possible to maintain the fluidity of the composition. This concrete mixing agent consists of a copolymer consisting of (a) an ethylenically unsaturated monomer having from 25 to 300 moles of C2-C3 oxyalkylene groups, (b) an ethylenically unsaturated monomer of the alkyl, alkenyl or hydroxyalkyl ester type and optionally (c) an ethylenically unsaturated carboxylic acid or a salt thereof, said copolymer comprising a high proportion of monomers (b). Such a copolymer is presented as allowing an excellent balance between initial fluidity and fluidity retention, these properties being adjusted according to the molecular weight of the copolymer.

EP 2 147 901 discloses a dispersion-maintaining agent for hydraulic compositions, without initial fluidity, comprising structural units based on ethylenically unsaturated carboxylate. This agent does not comprise an ethylenically unsaturated carboxylic acid group which, according to this document, confers an initial fluidity on the copolymer. EP 1 655 272 A1 discloses cement additives useful as superplasticizers which increase the workability of cement. These additives confer initial fluidity and fluidity retention. These additives necessarily consist of the following three monomers: (I) ethylenically unsaturated poly (alkylene glycol) ether monomers having from 25 to 300 units of C2-C3 oxyalkylene groups, (II) monomers alkyl esters with ethylenic unsaturation and comprising from 1 to 4 ethylene / propylene glycol units and (III) monomers comprising two optionally oxyalkylated ethylenic unsaturations. The document WO 2010/064098 (Coatex) describes the use of a combination of comb polymers as an agent improving the workability of an aqueous formulation based on hydraulic binders, one having hydrophilic side chains and the other of chains. hydrophobic sides.

EP 0 612 702 A1 discloses superplasticizer type additives consisting of methacrylic acid monomers, poly (ethylene glycol) monoethyl ether methacrylate and poly (ethylene glycol) dimethacrylate as crosslinking agent. This document gives no indication of the molecular weight of the additives described. None of the solutions presented in these documents are completely satisfactory.

Brief description of the invention

An object of the present invention is to provide a copolymer agent for hydraulic compositions whose essential property fluidity retention.

Another object of the present invention is to provide a copolymer which does not provide initial fluidity when it is within a hydraulic composition.

Another object of the present invention is to provide a fluidity retentive agent which is totally compatible with a water-reducing agent of the comb polymer type having at least one hydrophilic side chain, that is to say to propose an agent fluidity retainer which is miscible in all proportions with such a water reducing agent and which has no impact on the initial fluidity of the formulation at standard doses.

Another object of the present invention is to provide a workability agent which has an optimization of its characteristics of initial fluidity and fluidity retention.

The fluid-retaining agent according to the invention, of particular composition, compatible with a comb-type water-reducing agent having at least one hydrophilic side chain and the handling agent consisting of a combination of this retaining agent. fluidity and a particular water reducing agent make it possible to respond to all of these objects. Another object of the present invention is to provide an additive which makes it possible to obtain a homogeneous composition, that is to say which does not lead to a segregation of the materials within the composition. Detailed description of the invention

Fluid Retention Agent

A first object of the invention consists of a fluidity retentive agent for hydraulic compositions, said agent not being a water-reducing agent, consisting of a copolymer obtained by polymerization:

a) at least one anionic monomer comprising a polymerizable unsaturated functional group and a carboxylic group,

b) at least one macromonomer comprising a polymerizable unsaturated functional group and a polyalkoxylated chain, consisting of at least one alkoxylated unit, for example at least 10 alkoxylated units, and

c) at least one nonionic crosslinking monomer comprising at least two polymerizable unsaturated functional groups,

said copolymer having a molecular weight greater than 400,000 g / mol.

The flow-retaining agent according to the invention is a concrete admixture incorporated at the time of mixing concrete at a dose less than or equal to 5% by weight / weight of the cement content of the concrete, in order to modify the properties of the mixture. fresh and / or hardened condition.

The agent according to the invention makes it possible to extend the handling time of a hydraulic composition, for example a concrete. Furthermore, if it is important to extend the handling time of a concrete, this must not be done at the expense of the performance of the concrete during curing or in the cured state (in particular the initial or final mechanical strengths sought), or the rate of entrained air in the hydraulic compositions.

The fluid retention agent according to the invention is not a water reducing agent or a high water reducing agent.

In the context of the present invention, a "water reducing agent" or a "plasticizer" is an agent which, in accordance with the ADJUVANT standard NF EN 934-2, allows a water reduction for the adjoining concrete> 5% compared to the control concrete. A "high water reducer" or "superplasticizer" is an adjuvant that allows water reduction for adjuvanted concrete> 12% over control concrete. The fluidity retentive agent according to the invention does not meet these characteristics. Thus, the fluid retention agent according to the invention is completely compatible with a water reducing agent, plasticizer or superplasticizer. This makes it possible to formulate the hydraulic compositions adapted to each structure, without having to adjust the amounts of one or the other of the additives to obtain a desired profile of initial fluidity and maintenance of the maneuverability over time.

The flow-retaining agent according to the invention is also not a setting-retarding agent according to the standard ADJUVANT NF EN 934-2. Thus, the agent according to the invention does not affect the hydration stage of the cement when it comes into contact with the other constituents of the concrete or the mortar and / or the crystallization step of the constituents of the cement. It has no influence on resistance at young ages of structures, for example resistance to 1 day or 7 days.

The fluidity-retaining agents according to the invention, with a molecular weight greater than 400 000 g / mol, make it possible to obtain homogeneous compositions, whereas these same agents, with a molecular weight of the order of 100,000 to 150,000 g / mol, , lead to a segregation of materials within the composition. Such a meaning is not acceptable because it is likely to have a negative impact on the performance of the compositions containing them.

The embodiments described below can be combined with each other.

The retention agent according to the present invention is derived from the polymerization of monomers a), b) and c). Each monomer a), b) and c) can be present in the copolymer, alone or in a mixture of two or more entities.

The monomer a) can be in acid form, for example carboxylic acid, and / or in salt form, for example carboxylate.

The copolymer comprises, for example, one or more crosslinking monomers c). According to one embodiment, it comprises a single crosslinking monomer. According to another embodiment, it comprises two crosslinking monomers. The crosslinking monomer (s) is (are) used to generate a copolymer in the form of a three-dimensional network. According to the present invention, a monomer which is a polyunsaturated compound is used as crosslinking monomer c). This compound may comprise two, three or more ethylenic unsaturations. The crosslinking monomer may have a hydrophilic, hydrophobic or amphiphilic character. Examples of these compounds include di (meth) acrylate compounds such as polyalkylene glycol di (meth) acrylate, especially polypropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, di (meth) ) polyethylene glycol acrylate, triethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-butylene glycol di (meth) acrylate, di (meth) acrylate 1,6-hexanediol, neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, but also 2,2'-bis (4- (acryloxypropyloxyphenyl) propane, 2,2'-bis (4- (acryloxydiethoxy-phenyl) propane and zinc acrylate, tri (meth) acrylate compounds such as trimethylolpropane tri (meth) acrylate, tri (meth) acrylate trimethylolethane, tri pentaerythritol (meth) acrylate and tetramethylolmethane tri (meth) acrylate; tetra (meth) acrylate compounds such as ditrimethylolpropane tetra (meth) acrylate, tetra (met) h) tetramethylolmethane acrylate and pentaerythritol tetra (meth) acrylate; hexa (meth) acrylate compounds such as dipentaerythritol hexa (meth) acrylate; penta (meth) acrylate compounds such as dipentaerythritol penta (meth) acrylate; allyl compounds such as allyl (meth) acrylate, diallylphthalate, diallyl itaconate, diallyl fumarate and diallyl maleate; polyallyl sucrose ethers having 2 to 8 groups per molecule, polyallyl pentaerythritol ethers such as pentaerythritol diallyl ether, pentaerythritol triallyl ether and pentaerythritol tetraallyl ether; polyallyl ethers of trimethylolpropane such as diallyl trimethylolpropane ether and triallyl trimethylolpropane ether. Other polyunsaturated compounds include divinyl glycol, divinyl benzene, divinylcyclohexyl and methylenebisacrylamide. In another aspect, the crosslinking monomers may be prepared by an esterification reaction of a polyol with an unsaturated anhydride such as maleic anhydride or itaconic anhydride or by an addition reaction with an isocyanate such as 3 isopropenyl-dimethylbenzene isocyanate. The following unsaturated compounds which crosslink by means of their pendant carboxyl groups may also be used: polyhaloalkanols such as 1,3-dichloroisopropanol and 1,3-dibromoisopropanol; haloepoxyalkanes such as epichlorohydrin, epibromohydrin, 2-methyl epichlorohydrin and epiiodohydrin; polyglycidyl ethers such as 1,4-butanediol diglycidyl ether, glycerin-1,3-diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, bisphenol A- epichlorohydrin epoxy resin and mixtures.

The present invention also relates to a fluidity retentive agent for hydraulic compositions, said agent not being a water-reducing agent (according to the standard ADJUVANT NF EN 934-2) consisting of a copolymer obtained by polymerization of:

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) _n - (OB) _p ] - R _f '(I) in which:

[(EO) _m - (OP) _n - (OB) _p ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from ethoxylated units EO, propoxylated units OP and butoxylated units OB , m, n and p represent, independently of each other, 0 or an integer ranging between 1 and 250 (inclusive), the sum of m, n and p being between 10 and 250,

R _f represents a radical containing a polymerizable unsaturated functional group,

R _f 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

c) at least one nonionic crosslinking monomer comprising at least two polymerizable unsaturated functional groups and an ester group,

said copolymer having a molecular weight greater than 400,000 g / mol as determined by CES. According to one embodiment, said retention agent is a copolymer obtained by polymerization of monomers b), in which R _f represents a radical containing a polymerizable unsaturated functional group and a carboxylic group.

According to one embodiment, said melt-retaining agent is a copolymer obtained by polymerization of monomers b) and c), in which the polymerizable unsaturated functional groups, independently of one another, are chosen from the group consisting of acrylic esters, methacrylic esters, maleic esters, itaconic esters, crotonic esters and a mixture of these esters.

According to one embodiment, said fluidity retentive agent is a copolymer obtained by polymerization of monomers a) selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, acid, and the like. crotonic and a mixture of these monomers.

According to another embodiment, said retention agent is a copolymer obtained by copolymerization of two or more different monomers a). For example, it may be a mixture of acrylic acid monomers and methacrylic acid monomers, a mixture of maleic acid monomers, acrylic acid and methacrylic acid.

According to one embodiment, said retention agent is a copolymer with a molecular weight greater than 400 000 g / mol obtained by copolymerization of:

a) at least one anionic monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid and a mixture of these monomers,

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) _n - (OB) _p ] - R _f '(I) in which:

[(EO) _m - (OP) _n - (OB) _p ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from ethoxylated units EO, propoxylated units OP and butoxylated units OB , m, n and p represent, independently of one another, 0 or an integer ranging between 1 and 250 (inclusive), the sum of m, n and p being between 10 and 250,

R _f represents a radical selected from the group consisting of acrylic esters, methacrylic esters, maleic esters, itaconic esters, croquant esters and a mixture of these esters,

R _f 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

c) at least one nonionic crosslinking monomer comprising at least two radicals selected from the group consisting of acrylic esters, methacrylic esters, maleic esters, itaconic esters, crotonic esters and a mixture of these esters.

According to yet another embodiment, said retention agent is a copolymer obtained by copolymerization of monomers a) chosen from the group consisting of acrylic acid, methacrylic acid and a mixture of these monomers.

According to another embodiment, said retention agent is a copolymer obtained by polymerization of monomers b) and c), in which the polymerizable unsaturated functional groups, independently of one another, are chosen from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters.

According to one embodiment, the retention agent according to the invention consists of a copolymer obtained by polymerization of: a) one or two anionic monomers chosen from the group consisting of acrylic acid, methacrylic acid and a mixture of these monomers,

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) _n - (OB) _p ] - R _f '(I) in which:

Rf represents a radical selected from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters,

Rf 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

c) at least one nonionic crosslinking monomer comprising at least two radicals selected from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters.

According to one embodiment, the flow-retaining agent according to the invention consists of a copolymer obtained by polymerization of:

a) from 0.5 to 40% by weight of at least one anionic monomer comprising a polymerizable unsaturated functional group and a carboxylic group,

b) from 50 to 99% by weight of at least one macromonomer having a formula (I) and

c) from 0.05 to 10% by weight of at least one nonionic crosslinking monomer comprising at least two polymerizable saturable functional groups and an ester group,

the sum of the percentages being equal to 100%.

The anionic monomers according to a) can be used in a mass proportion varying between 0.5 and 40% by weight according to one aspect of the invention, between 5 and 30% by weight according to another aspect of the invention and between 7 and 25% by weight according to still another aspect of the invention, the percentage being based on the total weight of all the monomers which constitute the retention agent according to the invention.

According to one embodiment, the copolymer is obtained by polymerization of 0.5 to 40% by weight of two or more anionic monomers. For example, the copolymer is obtained by polymerizing from 0.5 to 40% by weight of two anionic monomers selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like. tonic acid. By "poly (alkylene glycol)" is meant a polymer of an alkylene glycol derived from an olefinic oxide.

The macromonomers of formula (I) comprise a poly (alkylene glycol) chain. The polyalkylene glycol chains of the copolymer according to the present invention contain a proportion of ethylene-oxys groups, a proportion of propylene-oxys groups and / or a proportion of butylene-oxys groups. The polyalkylene glycol chains according to the present invention may, for example, comprise a major proportion of ethylene-oxys groups in combination with a minor proportion of propylene-oxys groups. Specific examples of alkylene glycol polymers include: polyalkylene glycols having an average molecular weight of 1,000, 4,000, 6,000 and 10,000 g / mol; polyethylenes polypropylenes glycols having a percentage of ethylene oxides of between 20 and 80% by weight and a percentage of propylene oxides of between 20 and 80% by weight.

The macromonomers of formula (I) can be used in a mass proportion varying between 50 and 99% by weight according to one aspect of the invention, between 60 and 95% by weight according to another aspect of the invention and between 70 and 93. % by weight according to still another aspect of the invention, the percentage being based on the total weight of all the monomers which constitute the retention agent according to the invention. The crosslinking monomers can be used in a mass proportion varying between 0.05 and 10% by weight according to one aspect of the invention, between 0.5 and 5% by weight according to another aspect of the invention and between 0.5 and 3% by weight according to still another aspect of the invention, the percentage being based on the total weight of all the monomers which constitute the retention agent according to the invention.

According to one embodiment of the present invention, the flow-retaining agent according to the invention does not contain an ethylenically unsaturated monomer of the alkyl, alkenyl or hydroxyalkyl ester type.

According to another embodiment, the flow-retaining agent according to the invention does not contain an ethylenically unsaturated poly (alkylene glycol) ether monomer having from 25 to 300 moles of C2-C3 oxyalkylene groups.

According to one embodiment of the present invention, in formula (I) above: m represents an integer ranging between 1 and 250 (different from 0) and n and p represent, independently of one another, 0 or an integer ranging between 1 and 250 (inclusive),

the sum of m, n and p being between 10 and 250, for example between 20 and 200 or for example between 40 and 150.

According to another embodiment of the present invention, in formula (I) above:

m and n represent an integer ranging between 1 and 250 (different from 0) and p equals 0,

the sum of m and n being between 10 and 250, for example between 20 and 200 or for example between 40 and 150.

According to another embodiment, in formula (I) above:

m represents an integer ranging between 10 and 250, for example between 20 and

200 or for example between 40 and 150 and

n and p are 0.

The flow-retaining agents according to the invention have a molecular weight greater than 400 000 g / mol. This is an essential feature of the invention.

The flow-retaining agents according to the invention can, according to a first aspect of the present invention, have a molecular weight of between 450,000 and 800,000 g / mol (inclusive), as determined by CES.

The flow-retaining agents according to the invention may, according to a second aspect of the present invention, have a molecular weight greater than or equal to 1 500 000 g / mol, as determined by CES.

The inventors have indeed found that at these molecular weights, that is to say higher than 400 000 g / mol, in addition to the advantageous effect on the handling retention, the concrete or mortar formulations have a high homogeneous appearance, without sedimentation of constituents. This is an advantageous technical effect because in the case of sedimentation, the heavier components of the fresh concrete descend by gravity, resulting in segregation, settling of the concrete and the formation of a film of surface water ("bleeding" in English). On the contrary, the use of agents of lower molecular weight, of the order of 100,000 to 150,000 g / mol for example, leads to segregation of the materials within the composition, which is likely to negatively impact. the performance of concrete or hydraulic compositions containing them.

The flow-retaining agent according to the invention may be in the form of salts, stoichiometric or otherwise, mixed or not and consisting of alkali metals, alkaline earth metals, amines or quaternary ammoniums. According to one embodiment, the flow-retaining agent according to the invention is in acid form.

According to another embodiment, the flow-retaining agent according to the invention is in neutralized form.

According to yet another embodiment, the flow-retaining agent according to the invention is in partially or totally neutralized form.

When in the form of salts, the fluid retention agent according to the invention may in particular be a calcium salt, a sodium salt or a diethanolamine salt.

According to one embodiment, the flow-retaining agent is neutralized with an ion selected from the group consisting of potassium ion, sodium ion, lithium ion, calcium ion, magnesium ion, ammonium ion and a mixture of these ions.

The flow-retaining agent according to the invention is in liquid form.

The additive according to the invention is water-soluble or water-dispersible. Handling agent

Another subject of the present invention relates to a handling agent for hydraulic compositions, consisting of a compatible mixture of the two following additives:

a fluidity retaining agent as defined above and

a water-reducing agent of the dispersant copolymer type obtained by polymerization of: a) at least one anionic monomer having a saturable polymerizable function and a carboxyl group and

b) at least one macromonomer of formula (II): R _d - [(EO) i - (OP) _j - (OB) _k ] - R _d '(II) in which:

[(EO) i - (OP) _j - (OB) _k ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from ethoxylated units EO, propoxylated units OP and butoxylated units OB ,

i, j and k represent, independently of each other, 0 or an integer ranging between 1 to 150 (inclusive), the sum of i, j and k being between 1 and 250,

R _d represents a radical containing a polymerizable unsaturated functional group and

R _d 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

said copolymer having a molecular weight of between 20,000 g / mol and 400,000 g / mol.

The constitutive water-reducing agent of the workability agent according to the invention is a copolymer obtained by polymerization of anionic monomers a) and macromonomers b). It does not include crosslinking monomer.

Alternatively, the water-reducing agent is a copolymer obtained by direct esterification (or grafting or polyesterification) of a polymer (homopolymer or copolymer) containing carboxylic or anhydride functions. For example, reference is made to Coatex WO 2007/132322 which discloses such a method.

Thus, according to an object of the present invention, the handling agent for hydraulic compositions consists of a compatible mixture of the two following additives:

a fluidity retaining agent as defined above and

a water-reducing agent of dispersing copolymer type obtained by functionalization of a homopolymer and / or a copolymer of (meth) acrylic acid by esterification with at least one compound comprising a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, selected from ethoxylated units EO, propoxylated units OP and butoxylated units OB. According to one embodiment, said water-reducing agent is a copolymer obtained by polymerization of macromonomers b) of formula (II) in which the radical R <j is chosen from the group consisting of acrylic esters, methacrylic esters, maleic esters, itaconic esters, crotonic esters and a mixture of these esters.

According to another embodiment, said water-reducing agent is a copolymer obtained by polymerization of macromonomers b) of formula (II) in which the radical Rd is chosen from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters.

According to another embodiment, said water-reducing agent is a copolymer obtained by copolymerization of monomers a) selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, and a mixture of these monomers.

According to one embodiment, said water-reducing agent is a copolymer obtained by copolymerization of monomers a) chosen from the group consisting of acrylic acid, methacrylic acid and a mixture of these monomers.

According to one embodiment of the present invention, in formula (II) above:

i represents an integer ranging between 1 and 250 (different from 0) and

j and k represent, independently of one another, 0 or an integer ranging between 1 and 250 (inclusive),

the sum of i, j and k being between 1 and 250, for example between 10 and 200, or for example between 40 and 150.

According to another embodiment of the present invention, in formula (II) above:

i and j represent an integer ranging between 1 and 250 (different from 0) and k equals 0,

the sum of i and j being between 2 and 250, for example between 10 and 200 or for example between 40 and 150.

According to another embodiment, in formula (II) above: i represents an integer ranging between 1 and 250, for example between 10 and 200 or for example between 40 and 150 and

and k are equal to 0. The anionic monomers can be used in a mass proportion varying between 0.5 and 30% by weight according to one aspect of the invention, between 1 and 25% by weight according to another aspect of the invention and between 2 and 10% by weight according to still another aspect of the invention, the percentage being based on the total weight of all the monomers which constitute the water reducing agent.

The macromonomers of formula (II) comprise a poly (alkylene glycol) chain. The polyalkylene glycol chains of the copolymer according to the present invention contain a proportion of ethylene-oxys groups, a proportion of propylene-oxys groups and / or a proportion of butylene-oxys groups. The polyalkylene glycol chains according to the present invention may, for example, comprise a major proportion of ethylene-oxys groups in combination with a minor proportion of propylene-oxys groups. Specific examples of alkylene glycol polymers include: polyalkylene glycols having an average molecular weight of 1,000, 4,000, 6,000 and 10,000 g / mol; polyethylenes polypropylenes glycols having a percentage of ethylene oxides of between 20 and 80% by weight and a percentage of propylene oxides of between 20 and 80% by weight.

The macromonomers of formula (II) can be used in a mass proportion varying between 70 and 99.5% by weight according to one aspect of the invention, between 75 and 99% by weight according to another aspect of the invention and between 90 and 90% by weight. and 98% by weight according to still another aspect of the invention, the percentage being based on the total weight of all the monomers which make up the water-reducing agent.

The workability agent for hydraulic compositions according to the invention may consist of a compatible mixture of the flow-retaining agent, as defined above, and of the water-reducing agent in the proportions varying between 1: 0, 1 and 1: 10, for example between 1: 0.2 and 1: 3 or between 1: 0.25 and 1: 1.5 or between 1: 0.25 and 1: 1.

The inventors have shown that the fluidity retentive agent makes it possible to extend the handling time of the concrete, in particular when it is added to the composition in combination with the water reducing agent described above. It is a combination of additives having advantageous properties for hydraulic compositions, for example concretes, mortars, glues, coatings or grouts.

Hydraulic composition

In the context of the present invention, the hydraulic composition is an aqueous formulation containing water, at least one hydraulic binder, at least one fluidity-retaining agent according to the invention and at least one water-reducing agent. The hydraulic binder comprises at least one cement, for example a Portland cement. For all practical purposes, aluminous cement type hydraulic binders and a sulfoaluminum calcium cement are also mentioned.

The dosages of the flow control agent according to the invention and the water-reducing agent depend mainly on the amount of hydraulic binders in the hydraulic composition. Most often, they are expressed in additive dry matter relative to the total hydraulic binder (for example cement in concrete and mortar compositions).

According to one embodiment of the present invention, said hydraulic composition comprises, expressed as a percentage by dry weight of said fluid retention agent relative to the dry weight of cement, from 0.05% to 5% of said fluid retentive agent.

According to another embodiment of the present invention, said hydraulic composition comprises, expressed as a percentage by dry weight of said fluid retention agent relative to the dry weight of cement, from 0.1% to 3% of said fluid retentive agent.

According to one embodiment of the present invention, said hydraulic composition comprises, expressed as a percentage by dry weight of said workability agent relative to the dry weight of cement, from 0.05% to 5% of said workability agent.

According to another embodiment of the present invention, said hydraulic composition comprises, expressed as a percentage by dry weight of said workability agent relative to the dry weight of cement, from 0.1% to 3% of said workability agent.

This hydraulic composition is, for example, for the manufacture of a grout, a coating, an adhesive, a concrete or a mortar. This composition may comprise impurities, for example clays. This composition can in particular include latexes, fibers, organic granulates, inorganic aggregates, fillers and / or CaCO ₃ .

Hydraulic compositions, for example concrete and mortar compositions, for which the flow-retaining agent according to the invention may be useful may comprise, as hydraulic binder, different types of cements such as CEM I, CEM II, CEM cements. III, EMC V as described in the standard EN 197-1. Of these, CEM I cements do not have additions. It is nevertheless possible to add to these cements slags, fly ash, calcareous fillers, siliceous fillers. The concrete compositions may be concrete of classes of different strengths such as C20 / 25 to C100 / 115.

According to one embodiment, the hydraulic composition according to the invention comprises from 10 to 90% by weight of hydraulic binder.

According to one embodiment, the hydraulic composition according to the invention comprises, relative to the total weight of the composition:

from 2 to 15% by weight of water,

from 10 to 30% by weight of hydraulic binder comprising a cement,

from 0.05 to 3% by weight of said at least one fluidity-retaining agent and

from 0.05 to 3% by weight of said at least one water-reducing agent.

According to this embodiment, the hydraulic composition according to the invention can also comprise, in addition, from 10 to 60% by weight of sand.

from 2 to 15% by weight of water,

from 10 to 30% by weight of hydraulic binder comprising a cement,

from 0.05 to 3% by weight of said at least one flow-retaining agent,

from 0.05 to 3% by weight of said at least one water-reducing agent,

from 10 to 60% by weight of sand and

from 10 to 60% by weight of one or more gravel (s). The hydraulic composition according to the invention may, in addition, comprise one or more ingredient (s) following:

sand,

gravel,

- aggregates,

fine or ultra-fine fillers, for example calcium carbonate or silica, anti-foam agent,

thickening,

stabilizing,

- biocidal or antibacterial agent,

pH modifying agent and

accelerator agent or retarder.

uses

The present invention also relates to the use of a fluidity retaining agent according to the present invention, and optionally a water reducing agent according to the present invention, for preparing a hydraulic composition comprising water, a hydraulic binder comprising himself a cement. The present invention also relates to the use of a handling agent according to the present invention for preparing a hydraulic composition comprising water, a hydraulic binder itself comprising a cement.

Said hydraulic composition may, for example, be a ready-mixed concrete.

According to one embodiment, said fluid retentive agent and said water reducing agent are introduced separately into said hydraulic composition.

According to another embodiment, said fluidity retentive agent and said water-reducing agent are introduced in the form of a mixture into said hydraulic composition.

The present invention also relates to a copolymer as fluidity retentive agent for hydraulic compositions, said copolymer being obtained by polymerization of: a) at least one anionic monomer comprising a polymerizable unsaturated functional group and a carboxylic group,

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) "- (OB) p] - R _f '(I) in which:

R _f represents a radical containing a polymerizable unsaturated functional group and

R _f 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

said copolymer having a molecular weight greater than 400,000 g / mol.

Finally, the present invention relates to the use, as a handling agent for hydraulic compositions, of a combination of a fluidity-retaining agent and a water-reducing agent, said agents being such that:

1 / the flow-retaining agent is a copolymer obtained by polymerization of:

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) _n - (OB) _p ] - R _f '(I) in which:

R _f represents a radical containing a polymerizable unsaturated functional group and R _f 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

said copolymer having a molecular weight greater than 400 000 g / mol and

2 / the water-reducing agent is a copolymer obtained by polymerization of:

a) at least one anionic monomer having a polymerizable saturated function and a carboxyl group and

b) at least one macromonomer of formula (II):

R _d - [(EO) i - (OP) _j - (OB) _k ] - R _d '(II) in which:

[(OE); - (OP) _j - (OB) _k ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into alternating or random blocks, chosen from ethoxylated units EO, propoxylated units OP and butoxylated units OB,

R _d 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

The embodiments described above concerning the melt-retaining agent and the water-reducing agent are also applicable to this part of the invention. EXAMPLES

The examples below illustrate the preparation of different hydraulic compositions. Measurements of initial fluidity, maneuverability at T45 and T90 (slump) and air capture are carried out on these compositions according to the following protocols.

Measurement of the molecular mass of copolymers

In each of the following examples, the molecular weight of the copolymers according to the invention is determined by Steric Exclusion Chromato graphy (CES).

One such technique uses a WATERS ™ brand liquid chromato graphy instrument with two detectors. One of these detectors combines static dynamic light scattering at an angle of 90 ° C with viscometry measured by a VISCOTEK ™ MALVERN ™ viscometer. The other of these detectors is a WATERS ™ refractometric concentration detector.

This liquid chromatography apparatus is provided with steric exclusion columns appropriately chosen by those skilled in the art in order to separate the different molecular weights of the polymers studied. The liquid phase of elution is an aqueous phase containing 1% of KN0 ₃ .

In a detailed manner, according to a first step, the polymerization solution in the eluent of the CES, which is a 1% solution of KNO ₃ , is diluted to 0.9% dry. Then filtered at 0.2 μιη. 100 μΐ _^ are then injected into the chromatograph (eluent: a 1% solution of KN0 _3).

The liquid chromatography apparatus contains an isocratic pump (WATERS ™ 515) with a flow rate of 0.8 ml / min. The chromatography apparatus also comprises an oven which itself comprises in series the following column system: a precolumn GUARD COLUMN type ULTRAHYDROGEL WATERS ™ 6 cm long and 40 mm internal diameter, a linear column type ULTRAHYDROGEL WATERS ™ 30 cm long and 7.8 mm inside diameter and two columns ULTRAHYDROGEL 120 ANGSTROM WATERS ™ 30 cm long and 7.8 mm inside diameter. The detection system consists on the one hand of a RI WATERS ™ 410 type refractometric detector and on the other hand a double viscometer detector and light scattering at an angle of 90 ° type 270 DUAL DETECTOR MALVERN ™ The oven is heated to a temperature of 55 ° C and the refractometer is heated to a temperature of 45 ° C.

The chromato graphie instrument is calibrated by a single standard of PEO 19k type PolyCAL ™ MALVERN ™.

Measurement of maneuverability at TO, T45 and T90 - concrete

Measurements of the initial fluidity (or maneuverability at TO) and of maneuverability at T45 and T90 are carried out at room temperature, by means of a bottomless cone, of frustoconical shape, made of galvanized steel, called the Abrams cone, according to the EN 12350-2 standard. This cone has the following characteristics:

Upper diameter: 100 + 2 mm,

Lower diameter: 200 ± 2 mm and

Height: 300 ± 2 mm.

The cone is placed on a plate moistened with a sponge.

The cone is then filled with a determined quantity of each of the preparations. The filling lasts 2 minutes. The contents of the cone are packed with a metal rod. · Measurement of maneuverability in TO

As soon as the filling is completed, the cone is lifted vertically, which leads to the collapse of its contents on the plate.

The difference in height (in mm) between the top of the cone and the top of the round cake thus formed after 30 seconds is measured.

• Measurement of maneuverability at T45 and T90

The concrete is allowed to stand for 45 or 90 minutes, the mixture is again kneaded and the maneuverability is measured with the Abrams cone as indicated above.

Measuring air capture

The measurement of air capture (%) is in accordance with EN 12350-7, paragraph 3.3. Measurement of compressive strength

It is measured according to EN 12390-3, paragraph 3. The compressive strength is expressed in MPa. Example 1

In each of the following tests 1-1 to 1-5, a concrete according to EN 480-1 is prepared by mixing with stirring, standardized sand (0/4), cement (CEM I 52.5N Holcim), gravel 4/11 and 11/22, water and possibly an anti-foaming agent. A water-reducing agent and / or a fluid-retaining agent according to the invention is optionally added. The proportions of each constituent are given in Table 1 below.

More specifically, the exemplary water reducing agent in the following Examples 1-2 and 1-5 is a dispersant copolymer consisting of, based on the total weight of the copolymer:

7.4% by weight of methacrylic acid monomers and

96.6% by weight of poly (ethylene-propylene) glycol methacrylate macromonomers with a molecular weight of 3,000 g / mol (46 units of ethylene oxide EO and 15 units of propylene oxide OP, arranged randomly ).

The dispersant copolymer has a molecular weight of between 110,000 and 150,000 g / mol and is partially neutralized with NaOH (pH 3-4.5).

The fluidity retaining agent exemplified in the tests 1-3 to 1-5 below is a copolymer according to the invention, prepared according to the method below.

In a 1 liter reactor equipped with mechanical stirring and oil bath heating, 514.7 g of water are weighed.

In a first container, we weigh:

19.8 g of acrylic acid,

6.7 g of methacrylic acid, 220.1 g of poly (ethylene-propylene) glycol methacrylate macromonomers with a molecular weight of 3,000 g / mol (46 units of ethylene oxide EO and 15 units of propylene oxide OP, arranged randomly) and

1.5 g of poly (ethylene glycol 200) diacrylate.

In a second container (syringe), 1.1 g of 1,8-dimercapto-3,6-dioxaoctane (DMDO) is weighed.

In a third vessel, a solution consisting of 0.9 g of ammonium persulfate and 4.4 g of deionized water is prepared.

The reagents contained in the 3 containers are introduced into the reactor heated to 70 ° C. and with stirring.

The mixture is then cooked for 2 hours at 67 ° C.

The whole is then partially neutralized with 50% sodium hydroxide until pH = 4.5 and diluted to reach a concentration of 40.7% dry matter. The final polymer has the following characteristics: Mw = 695 600 g / mol and Ip = 5.3.

The fluidity retaining agent exemplified is therefore composed of, based on the total weight of the copolymer:

8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

88.7% by weight of poly (ethylene-propylene) glycol methacrylate macromonomers with a molecular weight of 3,000 g / mol (46 units of EO ethylene oxide and 15 units of propylene oxide OP, arranged randomly ) and

0.6% by weight of poly (ethylene glycol 200) diacrylate. Tests 1-1 1-2 1-3 1-4 1-5

Sand (kg) 34.4 34.4 34.4 34.4 34.4

Gravel 4/11 (kg) 15.2 15.2 15.2 15.2 15.2

Gravel 11/22 (kg) 24.2 24.2 24.2 24.2 24.2

Cement (kg) 14 14 14 14 14

Total 87.8 87.8 87.8 87.8 87.8

Reducing agent

0 74 0 0 74 water (g)

% reducing agent

- 0.21 - - 0.21 sec / cement

Retention Agent

0 0 74 74 35 of fluidity (g)

% retaining agent

- - 0.21 0.21 0.10 sec / cement

Water (g) 9,725 7,600 7,600 9,221 7,600

Water reduction - 22% - 22% - 1,1% - 22%

Handling T0 (mm) 205 ΐ ο 30 ΐ ο 240

Handling T45 (mm) 160 90 na na 190

Handling T90 (mm) 60 na na na 120

Air Capture (%) 1.7 3.3 2.7 2 2.1

Resistance 1J (MPa) 10 18 - - 17 na: the workability measured at a previous time is <100 ± 10 mm or the measurement is impossible

Table 1 The set of hydraulic compositions has a homogeneous appearance, without segregation of the constituents. Test 1-1 is a negative control. It illustrates a hydraulic composition without adjuvant, that is to say without water reducing agent and fluidity retaining agent according to the invention. In Run 1-2, the use of the water reducing agent reduces the amount of water by 22% in the hydraulic composition by maintaining an initial fluidity similar to that of the negative control. The water reducing agent can be qualified as a high water reducer in accordance with the standard ADJUVANT NF EN 934-2 according to which is qualified "high water reducer" or "superplasticizer" an adjuvant that allows a reduction of water. water for the adjoining concrete> 12% compared to the control concrete.

Tests 1-3 and 1-4 confirm that the exemplary flow-retaining agent is not a water-reducing agent according to the standard ADJUVANT NF EN 934-2 according to which is qualified as "water-reducing agent" or " plasticizer "an adjuvant that allows a water reduction for the adjoining concrete> 5% compared to the control concrete.

Test 1-5 shows that the combination of a fluid retention agent according to the invention and a high water-reducing agent at the same time allows a water reduction of 22, a good initial fluidity as well as a maintenance of maneuverability over time.

The resistance at the young ages of the formulation according to test 1-5 is similar to that of the control composition (test 1-2) comprising as sole additive a water-reducing agent. It is thus demonstrated that the flow-retaining agent according to the invention is not a set-retarding agent. It is furthermore confirmed that, in accordance with the standard ADJUVANT NF EN 934-2 (Table 3.1), the resistance values of the adjuvanted concretes (tests 1-2 and 1-5) at 1 day are greater than 140% of the value. resistance of control concrete without adjuvant (test 1-1).

Example 2

In each of the following tests 2-1 to 2-3, a concrete according to EN 480-1 is prepared by mixing with stirring, standardized sand (0/4), cement (CEM I 52.5N Holcim), gravel 4/11 and 11/22, water and possibly an anti-foaming agent. We also adds a combination of a water-reducing agent and a flow-retaining agent according to the invention. The proportions of each constituent are given in Table 2 below. More specifically, the water reducing agent exemplified in the tests below is a dispersant copolymer identical to that of Example 1.

Tests 2-1 to 2-4 illustrate various fluidity-retaining agents according to the invention or to the invention. They are prepared according to a procedure similar to that of Example 1 above.

The fluidity retaining agent exemplified in test 2-1 consists of, based on the total weight of the copolymer:

8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

0.6% by weight of pentaerythritol triacrylate. Characteristics of the agent:

Mw = 478,800 g / mol; Ip = 3.6; partial neutralization NaOH; pH = 2.6; ES = 41.7%.

The fluidity retaining agent exemplified in test 2-2 consists of, based on the total weight of the copolymer: 8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

88.4% by weight of poly (ethylene-propylene) glycol methacrylate macromonomers with a molecular weight of 3,000 g / mol (46 units ethylene oxide EO and 15 units of propylene oxide OP, arranged randomly) and

0.9% by weight of dipentaerythritol pentaacrylate. Characteristics of the agent:

Mw = 693,400 g / mol; Ip = 4.5; partial neutralization NaOH; pH = 2.7; ES = 41.9%.

The fluidity retaining agent exemplified in test 2-3 consists of, based on the total weight of the copolymer:

8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

0.6% by weight of trimethylolpropane triacrylate. Characteristics of the agent:

Mw = 142,100 g / mol; Ip = 1.8; partial neutralization NaOH; pH = 5.25; ES = 40.8%.

The fluidity retaining agent exemplified in test 2-4 consists of, based on the total weight of the copolymer:

8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

0.6% by weight of poly (ethylene glycol 200) diacrylate. Characteristics of the agent:

Mw = 100,000 g / mol; Ip = 1.6; partial neutralization NaOH; pH = 5.2; ES = 40.8%.

na: the measured maneuverability at a previous time is <100 ± 10 mm or the measurement is impossible

Table 2

All of the copolymers exemplified in the table allow maintenance of the maneuverability over time.

The flow-retaining agents according to the invention (tests 2-1 and 2-2), with a molecular weight greater than 400 000 g / mol, do not cause segregation of the constituents within the hydraulic composition. On the other hand, copolymers of tests 2-3 and 2-4 cause a segregation of constituents within the hydraulic composition and therefore do not constitute good additives for hydraulic compositions. Tests 2-1 to 2-2 show, moreover, that the combination of the said fluid retention agents according to the invention and a high water reducing agent at the same time allows a good initial fluidity as well as a maintenance maneuverability over time.

Example 3

In the following tests 3-1, 3-2 and 3-3, 3-4, a concrete according to EN 480-1 is prepared by mixing with stirring, standardized sand (0/4), cement (CEM I 52.5N Holcim), gravel 4/11 and 11/22, water and a water-reducing agent and a flow-retaining agent according to the invention are added at two different doses. The proportions of each constituent are given in Table 3 below. Tests 3-1 and 3-2 illustrate a fluid retention agent according to the invention. They are prepared according to a procedure similar to that of Example 1 above.

This agent consists of, based on the total weight of the copolymer:

8% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

0.6% by weight of poly (ethylene glycol 200) diacrylate.

Characteristics of the agent:

Mw = 7,860,000 g / mol; Ip = 5.3; partial neutralization NaOH; pH = 5.7; ES = 26.1%.

Tests 3-3 and 3-4 illustrate a fluidity retaining agent according to the invention. They are prepared according to a procedure similar to that of Example 1 above.

This agent consists of, based on the total weight of the copolymer: 8.1% by weight of acrylic acid monomers,

2.7% by weight of methacrylic acid monomers,

88.6% by weight of poly (ethylene-propylene) glycol methacrylate macromonomers with a molecular weight of 3,000 g / mol (46 units of ethylene oxide EO and 15 units of propylene oxide OP, arranged randomly ) and

0.6% by weight of trimethylolpropane triacrylate.

Characteristics of the agent

Mw = 616,700 g / mol; Partial neutralization NaOH

ES = 26.2%.

Table 3

Claims

1. Fluid retentive agent for hydraulic compositions, said agent not being a water-reducing agent (according to the standard ADJUVANT NF EN 934-2), consisting of a copolymer obtained by polymerization of:

b) at least one macromonomer having a formula (I):

R _f - [(EO) _m - (OP) _n - (OB) _p ] - R _f '(I) in which:

R _f 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms and

said copolymer having a molecular weight greater than 400,000 g / mol, as determined by CES.

The flow control agent according to claim 1, wherein the monomers a) are selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, crylic acid and a mixture of these monomers.

The flow control agent according to claim 1 or 2, wherein the polymerizable unsaturated functional groups of the monomers b) and c), independently of one another, are selected from the group consisting of acrylic esters, methacrylic esters, esters and the like. maleic esters, itaconic esters and crotonic esters.

4. fluidity retaining agent according to one of the preceding claims, consisting of a copolymer obtained by polymerization of:

the sum of the percentages being equal to 100%.

5. Handling agent for hydraulic compositions, consisting of a compatible mixture of the following two additives:

- A fluidity retaining agent according to one of claims 1 to 4 and

b) at least one macromonomer of formula (II):

R _d - [(EO) i - (OP) _j - (OB) _k ] - R _d '(II) in which:

R _d represents a radical containing a polymerizable unsaturated functional group and R _d 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

said copolymer having a molecular weight of between 20,000 g / mol and

400,000 g / mol.

6. Hydraulic composition comprising:

- some water,

a hydraulic binder comprising a cement,

- A fluidity retaining agent according to one of claims 1 to 4 and

a water-reducing agent of the dispersant copolymer type obtained by polymerization of:

a) at least one anionic monomer having a polymerizable unsaturated functional group and a carboxyl group,

b) at least one macromonomer of formula (II):

R _d - [(EO) i - (OP) _j - (OB) _k ] - R _d '(II) in which:

R _d denotes a polymerizable unsaturated function and

R _d 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

7. Use of a fluid retention agent according to one of claims 1 to 4 or a handling agent according to claim 5 for preparing a hydraulic composition comprising water, a hydraulic binder itself comprising a cement .

8. Use of a fluid retention agent according to one of claims 1 to 4 and a copolymer-type water reducing agent obtained by polymerization of:

a) at least one anionic monomer having a polymerizable unsaturated functional group and a carboxyl group and

b) at least one macromonomer of formula (II): R _d - [(EO) i - (OP) _j - (OB) _k ] - R _d '(Π) in which:

R _d denotes a polymerizable unsaturated function and

R _d 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

said copolymer having a molecular weight of between 20,000 g / mol and 400,000 g / mol,

for preparing a hydraulic composition comprising water, a hydraulic binder comprising itself a cement.

9. Use according to claim 8, wherein said fluid retentive agent and said water reducing agent are separately introduced into said hydraulic composition.

Use according to claim 8, wherein said fluid retentive agent and said water reducing agent are introduced as a mixture into said hydraulic composition.

11. Use according to one of claims 7 to 10, wherein said hydraulic composition is a ready-to-use concrete.