CLINKER

The present invention relates to the use of a polymer comprising a first unit with a base of phosphorus and a second polyoxyalkylene unit in hydraulic binders comprising a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker, for example a belite- calcium-sulfoaluminate-ferrite clinker (BCSAF).

Belitic sulfoaluminous clinkers are clinkers having a low content of alite or not having alite. Alite is one of the « mineralogical phases » (called « phases » in the rest of the description) of known clinkers of the Portland type. Alite comprises tricalcium silicate Ca ₃ Si0 ₅ (which can also be designated by C ₃ S or 3(CaO) ^« (Si0 ₂ ) as explained herein after).

The process for production of belitic sulfoaluminous clinkers is such that these clinkers present the advantage of significantly reducing emissions of C0 ₂ compared to the production of known clinkers of the Portland type.

Clinkers and hydraulic binders comprising calcium sulfoaluminate are known. It is however difficult to prepare, from such clinkers or binders, hydraulic compositions which have, for example, sufficiently long fluidity retention to allow the hydraulic composition to be used in good conditions. The properties of such clinkers are affected by the main phases and the additional minor phases which are present in the clinker, as well as their respective quantities. The properties of these clinkers are also affected by the presence of secondary elements in the clinker and their respective quantities. The interaction between these different factors makes it virtually impossible to predict the properties of a clinker from only knowledge of its chemical composition, the phases which are present and the respective quantities of these phases. The facility of production of a clinker, the grinding facility of a clinker to obtain a hydraulic binder and the various chemical and mechanical properties of a hydraulic composition comprising the binder may all be affected.

The chemical formulae in the field of hydraulic binders are often expressed in the form of sums of the oxides they contain: hence, tricalcium silicate, Ca ₃ Si0 _5, can also be written as 3CaOSi0 ₂ . It is to be understood that this does not mean that the oxides have an existence as such in the hydraulic binder.

The formulae of the oxides commonly found in the field of hydraulic binders are also abbreviated by a single letter as follows:

C represents CaO,

A represents Al ₂ 0 ₃ ,

F represents Fe ₂ 0 ₃ , S represents Si0 ₂ ,

$ represents S0 ₃ ,

M represents MgO, and

T represents Ti0 ₂ .

One problem of hydraulic binders and compositions comprising a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker, is fluidity retention over time, which is to say, keep a spread substantially constant over time.

Solutions exist to improve fluidity retention of hydraulic compositions with a base of Portland clinker, but most of these solutions do not work with a sulfoaluminous clinker, in particular belitic sulfoaluminous clinker. As described above, a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker, has a different chemical effect that Portland clinker and it is not possible to predict whether an efficient solution with a Portland clinker will work with a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker.

On another hand, most solutions known to improve fluidity retention of hydraulic compositions with a base of Portland clinker have the disadvantage of increasing the setting time and sometimes reducing the compressive mechanical strength, in particular 24 hours after mixing.

In order to meet user requirements, it has become necessary to find a means of improving the fluidity retention of hydraulic binders comprising a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker, whilst maintaining sufficient compressive mechanical strength 24 hours after mixing to remove formwork, preferably greater than or equal to 2 MPa, more preferably greater than or equal to 4 MPa.

Therefore the problem the invention seeks to solve is to provide a means of improving the fluidity retention of hydraulic binders comprising a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker, whilst maintaining sufficient compressive mechanical strength 24 hours after mixing to remove formwork, preferably greater than or equal to 2 MPa, more preferably greater than or equal to 4 MPa.

Unexpectedly, the inventors have shown that it is possible to use a polymer comprising a first unit with a base of phosphorus and a second polyoxyalkylene unit to improve the fluidity retention of hydraulic binders comprising a sulfoaluminous clinker, in particular a belitic sulfoaluminous clinker.

In the present description, including the accompanying claims, the term « one » is to be understood as « one or more ».

The present invention relates to the use of a polymer as a fluidizer for a hydraulic binder comprising a sulfoaluminous clinker, preferably a belitic sulfoaluminous clinker, the polymer comprising in molar percentages: at least 25 % of a first unit with a base of phosphorus; and

more than 40 to 65 %, preferably from 41 to 65 %, more preferably from 45 to 65 %, of a second polyoxyalkylene unit, for example polyoxyethylene (POE) and/or polyoxypropylene (POP);

the polymer comprising at least 30 % of units comprising a negative charge; and more than 50 % of the units comprising a negative charge being a first unit with a base of phosphorus.

The polymer used according to the present invention is preferably a non-cross- linked polymer, preferably having a molar mass of 10 000 to 400 000 Daltons.

Preferably, the quantity of the first unit with a base of phosphorus is greater than or equal to 30 % in molar percentages.

Preferably, the quantity of the first unit with a base of phosphorus is less than or equal to 35 % in molar percentages.

Preferably, the first unit with a base of phosphorus of the polymer used according to the present invention is of the following general formula (I)

in which:

R ¹ , R ² , R ³ , identical or different, are each a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms or a phenyl group;

m is 0, 1 or 2;

n is 0 or 1 ;

W is an oxygen atom or a NH group;

p is 0 or 1 ;

q is an integer comprised from 0 to 500;

R ⁴ is a linear or branched alkyl group having 2 to 20 carbon atoms; and

R ⁵ is a group of the general formula (III): OR ¹¹

P OR ¹¹ ( ^m )

0

in which R ¹¹ is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms or a mono-, di- or tri-valent cation;

or R ⁵ is a group of the general formula (IV):

R ¹²

/ (IV)

(CH ₂ ) _t — N

(CH ₂ ) _U P(0)(OR ^{1 1} ) ₂

in which R ¹¹ is as described above in relation to formula (III);

t and u, identical or different, are each an integer comprised from 0 to 18, and R ¹² is a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms or a group of the general formula (V):

(CH ₂ ) _V P(0)(OR ¹³ ) ₂ ( ^V )

in which v is an integer comprised from 0 to 18; and

R ¹³ is a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms or a or a mono-, di- or tri-valent cation.

R ¹ preferably represents a hydrogen atom;

R ² preferably represents a hydrogen atom;

R ³ preferably represents a methyl group;

R ⁴ preferably represents an ethylene group;

R ⁵ preferably represents a group of the general formula (III);

W preferably represents an oxygen atom.

When R ⁵ represents a group of formula (IV) and R ¹² represents a group of formula

(V), u and v are preferably identical.

The monovalent cations represented by R ¹¹ and R ¹³ include the quaternary ammoniums. The preferred monovalent cations include those of Group I in the Periodic Table of Elements, for example sodium and potassium. The preferred divalent cations include those of Group II in the Periodic Table of Elements, for example magnesium and calcium.

R ¹¹ and R ¹³ preferably represent identical cations.

The symbol q preferably represents an integer comprised from 1 to 300, more preferably from 10 to 250, even more preferably from 10 to 150.

The polymer used according to the present invention can comprise one or more different first units with a base of phosphorus. Preferably, the second polyoxyalkylene unit of the polymer used according to the present invention is of the following general formula (II):

in which:

R ⁶ , R ⁷ , R ⁸ , identical or different, are each a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, a phenyl group or a group of the general formula -COOR ¹¹ , wherein R ¹¹ is as described above in relation to formula (III); r is 0, 1 or 2;

s is an integer comprised from 0 to 500;

X is an oxygen atom or a NH group;

R ⁹ is a linear or branched alkyl group having 2 to 20 carbon atoms; and

R ¹⁰ is a hydrogen atom, or a linear or branched alkyl group having 1 to 20 carbon atoms.

The symbol s preferably represents an integer comprised from 1 to 300, more preferably from 10 to 250, even more preferably from 10 to 150.

R ⁶ preferably represents a hydrogen atom;

R ⁷ preferably represents a hydrogen atom;

R ⁸ preferably represents a methyl group;

R ⁹ preferably represents an ethylene group;

R ¹⁰ preferably represents a hydrogen atom or a methyl group; and/or

X preferably represents an oxygen atom.

The second polyoxyalkylene unit may for example be selected from:

the esters and diesters of unsaturated monomers of mono- or di-carboxylic acid described above having an alcohol function with 1 to 30 carbon atoms; the amides and diamides of the unsaturated monomers of monocarboxylic or dicarboxylic acid described above having an amine function with 1 to 30 carbon atoms; the esters and diesters of unsaturated monomers of mono- or di-carboxylic acid having an ester group of alkoxy (poly(alkylene glycol)), obtained for example by the addition to the alcohols and amines described above of 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms; the amides and diamides of unsaturated monomers of mono- or di-carboxylic acid having an ester group of alkoxy (poly(alkylene glycol)), obtained for example by the addition to the alcohols and amines described above of 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms;

the esters and diesters of unsaturated monomers of mono- or di-carboxylic acid described above, having a functional glycol group having 2 to 18 carbon atoms or having a chain of poly(alkylene glycol) comprising 2 to 500 units per chain as described above; the amides and diamides of unsaturated monomers of mono- or di-carboxylic acid described above, having a functional glycol group having 2 to 18 carbon atoms or having a chain of poly(alkylene glycol) comprising 2 to 500 units per chain as described above; or

the esters and diesters of unsaturated monomers of mono- or di-carboxylic acid described above, having a functional glycol group having 2 to 18 carbon atoms or having a chain of poly(alkylene glycol) comprising 2 to 500 units per chain as described above; the amides and diamides of unsaturated monomers of mono- or di-carboxylic acid described above, having a functional glycol group having 2 to 18 carbon atoms or a chain of poly(alkylene glycol) comprising 2 to 500 units per chain as described above.

The polymer used according to the present invention may comprise one or more different second polyoxyalkylene units.

Preferably, the polymer used according to the present invention has a molecular mass of 15 000 to 250 000 Daltons, more preferably from 20 000 to 150 000 Daltons, even more preferably from 20 000 to 100 000 Daltons.

Preferably, the polymer used according to the present invention comprises, in addition to the first unit with a base of phosphorus and the second polyoxyalkylene unit, a third unit.

Preferably, the molar ratio first unit with a base of phosphorus/third unit is greater than 2, more preferably greater than 3.

The suitable groups for introduction of the third unit in the polymer used according to the present invention include:

unsaturated groups of mono- or di-carboxylic acid, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid or citraconic acid, their alkyl ester or aryl ester derivatives comprising 1 to 30 carbon atoms, and their ester derivatives having anti-oxidising properties, for example: Name Formula

2,2,6,6-tetramethyl-4-piperidinyle HN ^v

methacrylate

0

2-(4-benzoyl-3-hydroxyphenoxy)

ethyl acrylate

0

2-(3-(2H-benzotriazol-2yl)-4- hydroxyphenyl)ethyl methacrylate

4 allyloxy 2 hydroxybenzophenone anhydrides of di-carboxylic acids, for example maleic and itaconic anhydride;

salts of carboxylic acids with, for example, mono- or di-valents metals, quaternary ammonium or organic amines;

sulfonic acids, for example vinylsulfonate, (meth)allylsulfonate, 2-(meth)-acryloxy- ethylsulfonate, 3-(meth)acryloxy-propylsulfonate, 3-(meth)acryloxy-2-hydroxy- propylsulfonate, 3-(meth)acryloxy-2-hydroxy-propylsulfophenyl ether, 3-(meth)-acryloxy- 2-hydroxy-propyloxysulfobenzoate, 4-(meth)acryloxy-butylsulfonate, I (meth)acrylamido- methylsulfonic acid, (meth)acrylamidoethylsulfonic acid, 2-methylpropanesulfonic (meth)acrylamide acid and styrenesulfonic acid, or salts thereof of mono- or di-valent metal, quaternary ammonium or organic amines;

vinylaromatic groups, for example styrene, 'omethylstyrene; vinyltoluene and p- methylstyrene;

alkanediols mono(meth)acrylates, for example 1 ,4-butanediol mono(meth)acrylate, 1 ,5-pentanediol mono(meth)acrylate, and 1 ,6-hexanediol mono(meth)acrylate;

unsaturated amides, for example methacrylamide, (meth)acrylalkylamide, N- methylol(meth)acrylamide and N,N-dimethyl(meth)acrylamide; unsaturated groups with a base of cyanide, for example (meth)acrylonotrile and o chloro-acrylonitrile;

unsaturated esters, for example vinyl acetate and vinyl propionate;

unsaturated amines, for example aminoethyl (meth)acrylate, methylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dibutylaminoethyl (meth)acrylate amd vinylpyridine;

divinyl aromatic groups, for example divinylbenzene;

cyanurates, for example triallyl cyanurate;

allylic groups, for example (meth)allylic alcohol and glycidyl (meth)allylic ether; silanes;

derivatives of siloxane for example

polydimethylsiloxane-propylaminomaleamic acid,

polydimethylsiloxane-aminopropyleneaminomaleamic acid,

polydimethylsiloxane-bis-(propylaminomaleamic acid),

polydimethylsiloxane-bis-(dipropyleneaminomaleamic acid),

polydimethylsiloxane-(1 -propyl-3-acrylate),

polydimethylsiloxane-(1 -propyl-3-methacrylate),

polydimethylsiloxane-bis-(1 -propyl-3-acrylate),

polydimethylsiloxane-bis-(1 -propyl-3-methacrylate);

the silyl derivatives, for example

methacrylate 3-(trimethoxysilyl)propyl,

methacrylate 3-[tris(trimethylsiloxy)silyl]propyl,

methacrylate 3-(triethoxysilyl)propyl,

methacrylate 3-[tris(triethylsiloxy)silyl]propyl,

acrylate 3-(trimethoxysilyl)propyl,

acrylate 3-[tris(trimethylsiloxy)silyl]propyl,

acrylate 3-(triethoxysilyl)propyl,

acrylate 3-[tris(triethylsiloxy)silyl]propyl;

groups of formula -Si(R) _x (OR) _y wherein the R are alkyl groups, preferably from Ci to C ₆ , x is an integer from 0 to 2 and y is an integer comprised from 1 to 3, the sum of x and y being equal to 3 in order to meet the valence of the silicon.

The polymer according to the present invention may comprise one or more different third units.

Preferably, the polymer according to the invention comprises at most 10 % of the third unit in molar percentage.

Preferably, the third unit is selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, salts of carboxylic acid with the mono- or di-valent metals, quaternary ammonium or organic amines, unsaturated amides, silyl derivatives and mixtures thereof.

According to a preferred variant of the invention, the polymer used according to the invention may comprise at least one first unit of formula (I), at least one second unit of formula (II) and at least one third unit, selected from unsaturated sulfonic acids for example vinylsulfonate, (meth)allylsulfonate, 2-(meth)acryloxy-ethylsulfonate, 3- (meth)acryloxy-propylsulfonate, 3-(meth)acryloxy-2-hydroxypropylsulfonate, 3- (meth)acryloxy-2-hydroxypropylsulfophenyl ether, 3-(meth)acryloxy-2- hydroxypropyloxysulfobenzoate, 4-(meth)acryloxy-butylsulfonate, (meth)acrylamidomethylsulfonic acid, (meth)acrylamidoethylsulfonic acid, 2- methylpropanesulfonic (meth)acrylamide acid, styrenesulfonic acid, or their salts of monovalent, divalent metals, quaternary ammonium or their salts of organic amine.

According to another preferred variant of the invention, the polymer used according to the invention may comprise at least one first unit of formula (I), at least one second unit of formula (II) and at least one third unit, said third unit being selected from the unsaturated carboxylic acids, for example the unsaturated monomers of mono- or di-carboxylic acid, for example acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, and their salts of monovalent, divalent metals, quaternary ammonium or their salts of organic amine. According to this variant, the preferred third unit is methacrylic acid.

According to another preferred variant of the invention, the polymer used according to the invention may comprise at least one first unit of formula (I), at least one second unit of formula (II) and at least one third unit selected from the silyl derivatives.

According to another variant of the invention, the polymer used according to the invention may comprise at least one second unit of formula (II), at least one first unit of formula (I) having a radical R ₅ of formula

and at least one third unit.

The third unit may be selected from those mentioned herein above.

Preferably, the polymer used according to the invention does not comprise a cross-linking unit.

Preferably, the polymer used according to the invention does not comprise a unit from monomers selected from the following examples: • polyalkylene glycol di(meth)acrylates, for example triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polyethylene glycol polypropylene glycol di(meth)acrylate;

• multi-functional methacrylates, for example hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tri(meth)ylolpropane dimethacrylate;

• polyalkylene glycol dimaleates, for example triethylene glycol dimaleate and polyethylene glycol dimaleate.

Preferably, the polymer used according to the invention does not comprise a unit from monomers selected from the following examples:

R ¹³ O

I SI

CH ₂ - C - CO - (OR ¹⁴ )m2 -O - P -OM ⁵

CH ₂ - C - CO - (OR ¹ 3 - O

I

R ^l5 with R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , M, m2 and m3 as defined in patent application n°EP 1 975 136.

A polymer is generally presented in the form of a solution comprising different macromolecules, in particular in the case of non-controlled radical polymerisation. The polymer used according to the present invention, or a salt thereof, can present a variation of composition. This means that the distribution (in other words the respective quantities) of the first and the second units and optionally third units in the polymer can vary from one macromolecule to the other.

On the other hand, the polymer used according to the present invention can have a block, random, alternating or gradient structure.

Preferably, the quantity of polymer used according to the present invention is from 0.01 to 5 %, more preferably from 0.02 to 3 %, even more preferably from 0.05 to 2 %, % expressed as dry mass relative to the mass of binder. The binder comprises the clinker, optionally calcium sulphate and optionally a mineral addition.

The polymer used according to the present invention can be prepared by any known method. In particular, it can be prepared by copolymerisation of one or more monomers in the presence of a suitable catalyst or by introduction on a polymer of one or more types of side groups. This last process is also called post-grafting.

For example, the polymer used according to the present invention can be prepared by radical polymerisation of the first units of formula (I), the second units of formula (II) and optionally third units, by controlled radical polymerisation of these same groups, in the presence of a transfer agent and/or a suitable trigger, or by polymerisation of the main chain, then post grafting the phosphorus side units and/or polyoxyalkylene, and/or optionally the third unit. The post-grafting may be carried out by reaction between the main chain and an alcohol or an amine carrying the side groups.

Preferably, the polymer used according to the present invention is prepared by radical polymerisation. By way of a transfer agent, it is possible to use any agent known to the person skilled in the art, for example thioglycolic acid, MPSA (sodium salt of mercapto-propane sulfonic acid) or mercapto-ethanol. The trigger may be selected from compounds known to the person skilled in the art, for example thermal triggers with a base of azoic compounds.

The sulfoaluminous clinker used according to the present invention generally comprises up to 80 %, preferably up to 60 %, more preferably up to 50 %, of calcium sulfoaluminate. Preferably it comprises at least 10 %, more preferably at least 20 % of calcium sulfoaluminate. Calcium sulfoaluminate, also known by the name of ye'elimite, is of the general formula C ₄ A ₃ $.

The sulfoaluminous clinker preferably also comprises belite. Belite is of the general formula C ₂ S. The minimum quantity of belite is generally at least 15 %, preferably at least 20 %, more preferably at least 30 %. The maximum quantity of belite is preferably at least 75 %, more preferably at least 70 %, even more preferably at least 60 %. In this case the sulfoaluminous clinker is a belitic sulfoaluminous clinker.

Preferably, the belite is partially or totally crystallized in the form α'. More preferably, at least 50 %, for example at least 80 %, in particular 85 to 100 %, by mass of belite is crystallized in the form α'.

The sulfoaluminous clinker preferably also comprises calcium aluminoferrite. The calcium aluminoferrite has a general formula of C ₂ A _X F _(1-X) , wherein X is from 0.2 to 0.8. The quantity of calcium aluminoferrite is preferably at least 5 %, more preferably at least 10 %, even more preferably at least 15 %.

In the case where the sulfoaluminous clinker comprises calcium sulfoaluminate, belite and calcium aluminoferrite, it is a clinker of the belite-calcium-sulfoaluminate- ferrite type (BCSAF).

The sulfoaluminous clinker preferably comprises, by mass relative to the total mass of sulfoaluminous clinker:

from 5 to 30 % of a calcium aluminoferrite phase;

from 10 to 35 % of a calcium sulfoaluminate phase; and

from 40 to 75 % of a belite phase. The sulfoaluminous clinker may also comprise from 0.01 to 10 % of at least one of the minor phases selected from calcium sulphate, metal alkali sulphate, perovskite, calcium aluminate, gehlenite, free lime, periclase, CnS ₄ B, Ci ₂ A ₇ , MAo _.2 F _{1 8} , C ₂ AS, CA, ferroperovskite, ternesite and/or a vitreous phase.

The total percentages of calcium aluminoferrite, calcium sulfoaluminate, belite and the minor phases are preferably greater than or equal to approximately 97 %, more preferably greater than or equal to approximately 98 %, even more preferably greater than or equal to approximately 99%, for example approximately 100 %.

Preferably, the sulfoaluminous clinker comprises:

from 10 to 25 % of a calcium aluminoferrite phase;

from 15 to 30 % of a calcium sulfoaluminate phase;

from 45 to 70 % of a belite phase; and

from 0.01 to 5 % of at least one of the minor phases.

More preferably, the, sulfoaluminous clinker comprises:

from 15 to 25 % of a calcium aluminoferrite phase;

from 20 to 30 % of a calcium sulfoaluminate phase;

from 45 to 60 % of a belite phase; and

from 0.01 to 5 % of at least one of the minor phases.

Pure belite has a general formula of 2(CaO) ^« (Si0 ₂ ), (i.e. C ₂ S); pure calcium sulfoaluminate has a general formula of 4(CaO)'3(AI ₂ 0 ₃ HS0 ₃ ), (i.e.C ₄ A ₃ $). The belite, the calcium sulfoaluminate, the ferroperovskite, the ternesite and the other additional phases of the general formulae given herein above can also comprise substitution elements.

Each phase listed in the clinker according to the present invention is crystalline (except the vitreous phase) and has its own X-ray diffraction spectrum. The quantity of phases in the clinker is generally determined by X-ray diffraction using analyses of the Rietveld type. The vitreous phase is not crystalline and therefore does not have a characteristic profile to X-ray diffraction. The quantity of the vitreous phase is generally determined from the complete spectrum by X-ray diffraction of the clinker.

The sulfoaluminous clinker according to the present invention may comprise the

C ₂ AS phase (generally less than 5 %), the CA phase (generally less than 10 %), the C ₃ FT phase (generally less than 3 %) and/or the Ci ₂ A ₇ phase (generally less than 3 %). These phases are generally inert.

Preferably, the clinker comprises from 5 to 13 %, more preferably from 9 a 13 %, of iron expressed as Fe ₂ 0 ₃ .

The iron in the clinker according to the invention can be found in at least one of the following phases: the ferroperovskite phase (comprising calcium, aluminium, silicon, magnesium and iron, and characterised by X-ray diffraction peaks (2-theta) at 33.2°, 47.7° and 59.4° using a CuKa'1 wave length having a wave length of 0.15406 nm, the calcium aluminoferrite phase having a general formula of C2A _X F _(1-X) , wherein X is from 0.2 to 0.8; the calcium aluminoferrite phase having a general formula of C4AI ₀ .1 FL9 (which is generally orthorhombic); the magnesium aluminoferrite phase having a general formula of MA0.2F1.8; and the C ₃ FT phase.

The sulfoaluminous clinker according to the invention generally comprises from 2 to 10 % of sulphur expressed as S0 ₃ . Preferably the sulfoaluminous clinker does not comprise a C ₃ S phase.

Preferably, the clinker comprises from 0.2 to 3 %, more preferably from 0.2 to 2 %, for example from 1 to 2 %, of boron expressed as boric anhydride.

The clinker according to the present invention may comprise, in the main phases and/or in the other phases, one or more of the secondary elements selected from sodium, potassium, titanium, manganese, strontium, zirconium, phosphorus and mixtures thereof. The total quantity of secondary elements in the sulfoaluminous clinker is preferably less than or equal to 19 %, more preferably less than or equal to 15 %.

The secondary element in the sulfoaluminous clinker according to the present invention is generally present in the following quantities:

from 0 to 5 %, preferably 0.01 to 2 %, more preferably 0.02 to 1 .5 %, for example 0.02 to 1 % of sodium expressed as equivalent sodium oxide,

from 0 to 5 %, preferably 0.1 to 2 %, more preferably 0.2 to 1 .5 %, for example 0.2 to 1 % of potassium expressed as equivalent potassium oxide,

from 0 to 7 %, preferably 0 to 5 %, more preferably 0 to 3 % of phosphorus expressed as equivalent phosphorus pentoxide.

Preferably, the composition according to the invention comprises sodium and potassium as secondary elements.

According to a variant, the sulfoaluminous clinker used according to the present invention may comprise as its main phases, in % by mass relative to the total mass of clinker:

(i) from 15 to 36 % of a belite phase;

(ii) from 37 to 56 % of a calcium sulfoaluminate phase; and

(iii) from 1 to 28 % of a ferroperovskite phase, comprising calcium, aluminium, silicon, magnesium and iron, and characterised by X-ray diffraction peaks (2-theta) at 33.2°, 47.7° and 59.4° using CuK _Q . X-rays with a wave length of 0.15406 nm;

the clinker comprising: from 3 to 15% of iron expressed as Fe ₂ 0 ₃ ; and from 0.2 to 5 % of boron expressed as boric anhydride

According to another variant, the sulfoaluminous clinker used according to the present invention may comprise as its main phases, in % by mass relative to the total mass of clinker:

(i) from 36 to 53 % of a calcium sulfoaluminate phase; and

(ii) from 31 to 50 % of a belite phase;

the clinker comprising: less than 3 % of iron expressed as Fe ₂ 0 ₃ ; and from 0.2 to 5 % of boron expressed as boric anhydride.

The sulfoaluminous clinker can, for example, be obtained according to the process described in patent application WO 2006/018569.

The sulfoaluminous clinker can also be produced according to a process which comprises the clinkering of sources of calcium, silicon, sulphur, alumina, magnesium, iron and boron capable of providing the phases described herein above, via clinkerisation preferably at a temperature of 1 150°C to 1400°C, more preferably from 1200°C to 1325°C.

The sulfoaluminous clinker according to the invention may, for example, be produced in the following manner:

a) prepare a raw meal comprising a raw material or a mixture of raw materials capable of forming, via clinkerisation, the phases as described herein above;

b) mix the raw meal obtained in step a) with at least one additive supplying a secondary element as described herein above, in such quantities that, after clinkerisation, the total quantity of secondary elements, expressed as described herein above, is less than or equal to 19 % by mass relative to the total mass of sulfoaluminous clinker; and

c) burn the mix obtained in step b), for example, at a temperature of 1 150°C to

1400°C, preferably from 1200°C to 1325°C, for example for a minimum of 15 minutes in a sufficiently oxidising atmosphere to avoid the reduction of the calcium sulphate into sulphur dioxide.

Preferably, the suitable raw materials for the process according to the present invention or step a) of the process described herein above may come from quarries or result from an industrial process and comprise:

a source of silicon, for example a sand, a clay, a marl, fly ash, ash from the combustion of coal, a pozzolan or silica fume;

a source of calcium, for example a limestone, a marl, fly ash, ash from the combustion of coal, a slag, a pozzolan or residue from the calcination of household waste; a source of alumina, for example a clay, a marl, fly ash, ash from the combustion of coal, a pozzolan, bauxite, red mud from alumina (in particular alumina sludge coming from industrial waste during the of extraction of alumina), laterite, anorthosite, albite or feldspar;

a source of sulphur;

a source of magnesium;

a source of iron, for example an iron oxide, a laterite, a slag from a steel plant or iron ore; and

a source of boron.

The source of boron according to the invention comprises, for example, colemanite (di-calcium hexaborate pentahydrate), borax or boric acid, preferably colemanite. The source of boron can come from quarries or result from an industrial process.

The raw meal can also comprise calcium sulphate, for example gypsum, calcium sulphate hemihydrate (a or β) or anhydrous calcium sulphate.

The preparation of the raw meal of step a) can be carried out by mixing the raw materials. The raw materials can be mixed in step a) by putting them in contact, optionally comprising a grinding step and/or a homogenisation step. The raw materials of step a) may optionally be dried before step a) or calcined before step a).

The raw materials may be added in sequences, in the main inlet of the kiln, and/or in other inlets of the kiln. Furthermore, combustion residue can also be integrated in the kiln.

Preferably, the suitable raw materials to carry out step b) of the process described herein above are:

a source of boron, for example borax, boric acid, colemanite or any other compound containing boron: the source of boron can come from quarries or result from an industrial process;

a source of magnesium, for example a magnesium salt;

a source of sodium, for example a sodium salt;

a source of potassium, for example a potassium salt;

a source of phosphorous, for example a phosphorous salt;

or mixtures thereof.

The suitable raw materials to carry out step b) in said process are in a solid form (for example powder), or a semi-solid form or liquid form.

Step c) is a clinkering step, wherein, according to the invention it is a burning step.

Clinkering is to be understood according to the invention as the reaction between the chemical elements of step b), which results in the formation of the phases of the sulfoaluminous clinker according to the present invention. This step can be carried out in a typical cement kiln (for example a rotary kiln) or in another type of kiln (for example a passage continuous kiln).

Preferably, the clinkering takes place for a minimum of 20 minutes, more preferably for a minimum of 30 minutes, even more preferably for a minimum of 45 minutes.

The term « sufficiently oxidising atmosphere » is to be understood as, for example, the atmosphere, but other sufficiently oxidising atmospheres may be suitable.

A hydraulic binder is a material which sets and hardens by hydration. A hydraulic binder generally comprises a clinker, calcium sulphate and optionally a mineral addition.

A sulfoaluminous clinker may be co-ground with calcium sulphate to produce a cement. The calcium sulphate used includes gypsum (calcium sulphate dihydrate, CaS0 ₄ .2H ₂ 0), hemi-hydrate (CaS0 ₄ .1/2H ₂ 0), anhydrite (anhydrous calcium sulphate, CaS0 ₄ ) or a mixture thereof. The gypsum and anhydrite exist in the natural state. It is also possible to use calcium sulphate which is a by-product of certain industrial processes.

Preferably, the hydraulic binder according to the invention comprises from 0.1 to 40 %, more preferably from 0.1 to 20 %, even more preferably from 0.1 to 10 % of calcium sulphate, % by mass relative to the total mass of hydraulic binder.

Preferably, the hydraulic binder further comprises a mineral addition. Mineral additions are, for example, slags (for example as defined in the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.2), natural or artificial pozzolans (for example as defined in the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.3), fly ash (for example as defined by the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.4), calcined shales (for example as defined by the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.5), mineral additions with a base of calcium carbonate, for example limestone (for example, as defined by the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.6), silica fume (for example as defined by the "cement" NF EN 197-1 Standard of February 2001 , paragraph 5.2.7), metakaolins, biomass ash (for example rice husk ash) or mixtures thereof.

Preferably, the mineral addition comprises a pozzolan, a slag, fly ash or mixtures thereof. The mineral addition can also comprise a mineral addition comprising calcium carbonate, for example limestone. Preferably, the hydraulic binder comprises 0.1 to 70 %, more preferably 0.1 to 50 %, even more preferably 0.1 to 30 % of mineral additions, % by mass relative to the total mass of hydraulic binder.

Preferably, the hydraulic binder comprises from 30 to 99.8 % of a clinker according to the present invention; from 0.1 to 40 % of calcium sulphate; and from 0.1 to 69.9 % of mineral additions; the total percentages being greater than or equal to 97 %.

It is to be understood that by replacing part of the clinker with a mineral addition it is possible to reduce the emissions of carbon dioxide (produced during the production of the clinker) by reducing the quantity of clinker, whilst obtaining the same mechanical strengths.

A hydraulic composition generally comprises a hydraulic binder and water, optionally aggregates and optionally admixtures. The hydraulic compositions include both fresh and hardened compositions, for example a cement slurry, a mortar or a concrete. The hydraulic composition can be used directly on the job site in a fresh state and poured into formwork adapted to a target application, used in a pre-cast plant or used as coating on a solid support.

The quantity of water is preferably such that the effective water / binder ratio is from 0.2 to 1 .2, more preferably from 0.3 to 0.8.

Aggregates used include sand (whose particles generally have a maximum size (Dmax) of less than or equal to 4 mm), and gravel (whose particles generally have a minimum size (Dmin) greater than 4 mm and preferably a Dmax less than or equal to 20 mm).

The aggregates include calcareous, siliceous, and silico-calcareous materials. They include natural, artificial, waste and recycled materials. The aggregates may also comprise, for example, wood.

The hydraulic composition may also comprise an admixture for a hydraulic composition, for example an accelerator, an air-entraining agent, a viscosity-modifying agent, a clay inertant, a plasticizer and/or a superplasticizer.

Clay inertants are compounds which permit the reduction or prevention of the harmful effect of clays on the properties of hydraulic binders. Clay inertants include those described in WO 2006/032785 and WO 2006/032786.

The term superplasticizer as used in the present description and the accompanying claims is to be understood as including both water reducers and superplasticizers as described in the Concrete Admixtures Handbook, Properties Science and Technology, V.S. Ramachandran, Noyes Publications, 1984.

According to an embodiment, the hydraulic composition comprises an alkanolamine. Preferably, the alkanolamine comprises triethanolamine (TEA), diethanolamine (DEA), tetrakis-hydroxyethyl-ethylenediamine (THEED) or methyl-diethanolamine (MDEA).

Even more preferably, the alkanolamine comprises diethanolamine or methyl- diethanolamine.

The mixing of the hydraulic composition may be carried out, for example according to known methods.

According to an embodiment of the invention, the binder is prepared during a first step, and the optional aggregates and water are added during a second step.

The polymer used according to the present invention may be added, for example:

- at the same time as and/or in the mixing water;

- directly to at least one of the components of a hydraulic composition before adding the mixing water; or

- during the mixing.

The polymer can be used in a liquid form, for example in the form of a solution, in particular an aqueous solution, or in a solid form, for example powder.

The hydraulic composition can be shaped to produce, after hydration and hardening, a shaped object, for the construction field. The invention also relates to such a shaped object, which comprises a hydraulic binder as used according to the invention. Shaped articles for the construction field include, for example, a floor, a screed, a foundation, a wall, a partition wall, a ceiling, a beam, a work top, a pillar, a bridge pier, a masonry block of concrete, a pipe, a post, a stair, a panel, a cornice, a mould, a road system component (for example a border of a pavement), a roof tile, surfacing (for example of a road or a wall), or an insulating component (acoustic and/or thermal).

In the present specification including the accompanying claims, percentages, unless otherwise specified, are by mass.

The percentages of the phases are determined by known methods, for example by X rays using a Rietveld analysis. Quantitative analysis of clinker is carried out by Rietveld analysis of the X-ray diffraction spectrum of this clinker. The clinker sample to be analysed is finely ground to provide a sample, all the particles of which pass through a 63μηι sieve. Reference X-ray diffraction spectra of the crystalline phases present in the sample to be analysed (except for the vitreous phase which does not have a well- defined spectrum) are obtained from pure samples of these phases. In order to quantify the amount of each crystalline phase and of the vitreous phase, an X-ray diffraction spectrum of a pure crystalline phase not present in the sample to be analysed is obtained for use as a reference standard. Suitable reference materials include rutile, quartz and corundum. The percentage of each crystalline phase and of the vitreous phase in a sample of clinker is then calculated from the X-ray diffraction spectrum of the sample using the Rietveld analysis, the reference spectra of each pure phase and the spectrum of the standard reference material, which is generally rutile. The calculation method described in the European Patent No. 1260812 may be used. Because the power of the X-ray source in an X-ray diffractometer could weaken with the age of the source, it may be desirable to measure the diffraction spectra of the standard reference phase and of the pure crystalline materials when the spectrum of the sample to be analysed is measured.

Measurement of the quantity of chemical elements in the clinker according to the present invention is generally carried out using X-ray fluorescence spectroscopy. The results are generally expressed in terms of oxides of each element.

The Dv90 is the 90 ^th percentile of the size distribution of the particles, by volume; that is, 90% of the particles have a size that is less than or equal to Dv90 and 10% of the particles have a size that is greater than Dv90.

The following non-restrictive examples illustrate embodiments of the invention.

EXAMPLES

The tested hydraulic composition was a mortar, the formulation of which is described in the various tables herein below.

The sand was:

Sand 1 : a 0/1 sand from the Lafarge quarry at Saint Bonnet; and

Sand 2: a 1/5 sand from the Lafarge quarry at Saint Bonnet.

The cement was a cement comprising 8 % by mass of anhydrite, 2 % by mass of hemihydrate and 90 % by mass of a sulfoaluminous clinker of the belite-calcium- sulfoaluminate-ferrite type (BCSAF) relative to the mass of total clinker. The BCSAF cement had a chemical composition and the following characteristics, the figures being expressed, unless otherwise specified, in mass percentages:

In the table above, the total of the values of the chemical composition can be different from 100%: the variations relative to 100% result from small inaccuracies in the analytical values. The polymers used according to the present invention were:

- Polymer 1 : a polymer comprising 60 mol.% of MMPEG and 40 mol.% of MeGP;

- Polymer 2: a polymer comprising 55 mol.% of MMPEG and 45 mol.% of MeGP; and

- Polymer 3: a polymer comprising 50 mol.% of MMPEG and 50 mol.% of MeGP

- Polymer 4: a polymer comprising 65 mol. % of MMPEG, 25 mol. % of MeGP and 10 % mol. % of AM.

MMPEG was a poly(ethylene glycol) methyl ether methacrylate, (CAS n°: 26915- 72-0) having a molar mass of 2080 g/mol (supplier: Aldrich).

MeGP was a 2-hydroxyethyl methacrylate ester phosphoric acid (CAS n°: 52628-

03-2) having a molar mass of 210 g/mol (supplier: Aldrich).

AM was a methacrylic acid (CAS n°: 79-41 -4) having a molar mass of 86 g/mol. The other admixtures were:

Admixture 1 : a known fluidity retention agent for Portland cements, commercialized under the brand name of Chrysofluid® Optima 206

(supplier: Chryso);

Admixture 2: a known fluidity retention agent for Portland cements, commercialized under the brand name of Glenium 27 (supplier: BASF); - Admixture 3: a polymer having 40 mol.% of MMPEG and 60 mol.% of MeGP; - Anti-foaming agent: an admixture with a base of ethoxylated acethylenediol commercialized under the brand name of Surfynol MD20 (supplier: Air Products).

The polymers used according to the present invention and Admixture3 were produced in the laboratory, under an aspirating hood, according to the following procedure:

weigh the monomers and the transfer agent (mercapto-ethanol; CAS n°: 60-24-2; supplier: Aldrich) in a beaker;

weigh the trigger in aqueous solution at 10% dry extract (2,2'-Azobis(2- methylpropionamidine) dihydrochloride; CAS n°: 2997-92-4; brand name: Vazo 50; supplier: Aldrich) in another beaker;

weigh the quantity of water (approximately 1 10 g) in a 4-neck flask: 1000 ml_; place a cooling agent on the flask and put cold water into circulation (having a temperature less than 20°C);

begin stirring at 500 rpm and heat to reach the target temperature of 80°C ± 2°C; degass with nitrogen for 30 minutes;

when the initial temperature is reached, simultaneously begin to add the monomers, the transfer agent and the trigger by activating two separate pumps connected to each beaker and adjusted in order to obtain a flow of monomers, transfer agent and trigger in 90 minutes;

after 5 minutes of polymerisation, flush with nitrogen gas;

when the flows of monomers, transfer agent and trigger are finished, leave at the target temperature for 30 minutes;

stop the heating and leave to cool;

when the temperature is less than 30°C, neutralise the polymer by adding a base (NaOH a 50 % dry extract) until reaching a pH of 6 to 7, which corresponds to a neutralisation of approximately 70 % of the anionic units;

filter to 80 μηη and condition.

Each of the tested mortars comprised:

720 g of BCSAF cement;

1425 g of Sandl ;

705 g of Sand2;

2.5 % of an anti-foaming agent by dry mass relative to the dry mass of admixture;

an effective water / cement ratio of 0.55; and

a total volume of 1 .5 litres.

The mortar was produced according to the procedure described below:

introduce the sands in the vessel of a Perrier mixer;

from 0 to 30 seconds, begin mixing at low speed (60 rpm) and introduction of the pre-wetting water in 30 seconds;

from 30 seconds to 1 minute: mix the sands and the pre-wetting water;

from 1 minute to 5 minutes: leave the mix to rest;

at 5 minutes (= TO), introduce the cement;

from 5 minutes to 6 minutes: mix at low speed;

from 6 minutes to 6 minutes and 30 seconds: introduce the mixing water comprising all the admixtures whilst maintaining the mixing at low speed;

from 6 minutes and 30 seconds to 8 minutes 30 seconds: mix at high speed (140 rpm).

The measurement of the compressive mechanical strengths 24 hours after the mixing was carried out on samples of hardened mortar in the shape of a brick with dimensions: 40 mm x 40 mm x 160 mm.

The samples of mortar were moulded in polystyrene moulds 120 minutes after TO as described above. The mortar was introduced into the mould in two layers (each layer of mortar weighing approximately 300 g) and each layer was tamped 30 times. The mould was levelled to remove excess mortar. A plate of glass of 210 mm x 185 mm and 6 mm thickness was placed on the mould. The mould, covered by the glass plate was placed at ambient temperature (approximately 20°C) and 65 % relative humidity. The mould was removed from the enclosure and the sample of hardened mortar was demoulded 24 hours after the mixing, then it was submerged in water at 20°C ± 1 °C. The sample of hardened mortar was removed from the water 15 minutes maximum before measurement of the compressive mechanical strength. The sample of hardened mortar was then covered with a damp cloth whilst waiting for the measurement.

For the measurement of the compressive mechanical strength 24 hours after mixing, an increasing load was applied on the lateral sides of the sample of hardened mortar, at a speed of 2 400 N/s ± 200 N/s, until the sample broke.

For measurement of fluidity retention, the spread of the mortars was measured at several time periods (5, 15, 30, 60, 90 and 120 minutes) using an Abrams mini-cone with a volume of 800 ml_. The dimensions of the cone were as follows:

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 cone was placed on a dried glass plate and filled with fresh mortar. It was then levelled. The lifting of the cone caused the mortar to slump onto the glass plate. The diameter of the disk of mortar obtained was measured in millimetres +/- 5 mm according to 4 different directions. The average of these diameters corresponded to the spread of the mortar.

Between each spread measurement, the mortar was mixed for 30 seconds at low speed (60 rpm) in a Perrier mixer, then it was stored to rest, covered by a damp cloth.

Example 1 : Effect of the polymer used according to the present invention on fluidity retention and compressive strengths 24 hours after mixing

The effect of the polymer used according to the present invention on fluidity retention and compressive mechanical strength 24 hours after mixing was tested on several hydraulic compositions and was compared to controls.

Table 1 below presents the tested compositions and the results obtained for fluidity monitoring and compressive mechanical strengths 24 hours after mixing. Dosage of Spread (mm

Sc admixture

Admixture 5 15 30 60 90 120 24h

(mass%

min min min min min min (MPa) dry/binder)

Control 0 - 0.00 100 - - - - - 16

Control 1 Admixture 1 0.28 230 180 160 140 1 10 - <1

Control 2 Admixture 2 0.28 270 255 210 160 150 - <1

Control 3 Admixture 3 0.22 240 235 225 190 160 100 17

Mortar 1 Polymer 1 0.51 220 225 230 245 260 255 15

Mortar 2 Polymer 2 0.46 250 280 265 270 265 265 17

Mortar 3 Polymer 3 0.28 235 250 235 225 215 215 17

Mortar 4 Polymer 4 0.65 135 1 10 180 310 335 325 16

Mortar 5 Polymer 4 1.00 245 210 210 330 330 330 8

Sc 24h means the compressive mechanical strengths 24 hours after the mixing.

According to Table 1 herein above, when comparing the mortars comprising a polymer as used according to the present invention (Mortarl to Mortar5) and the control, not comprising such a polymer (ControlO), the addition of a polymer as used according to the present invention improved fluidity retention whilst maintaining sufficient compressive mechanical strengths 24 hours after the mixing to remove the formwork, here greater than or equal to 8 MPa.

Moreover, none of the three control admixtures gave both good fluidity retention and satisfactory compressive strengths 24 hours after the mixing. Formwork cannot be removed when the compressive mechanicals strengths are less than 1 MPa.