Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/243—Phosphorus-containing polymers
  • C04B24/246—Phosphorus-containing polymers containing polyether side chains
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
  • C04B20/02—Treatment
  • C04B20/026—Comminuting, e.g. by grinding or breaking; Defibrillating fibres other than asbestos
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
  • C04B2103/52—Grinding aids; Additives added during grinding

Definitions

• the invention refers to a method of preparing a cement for concrete or mortar, the method comprising a step of adding a diphosphonate dispersing agent.
• Concrete is a very used construction material with high strength and good durability. In addition to sand/aggregates and water, it also contains Portland cement which produces strength-forming phases by solidifying and curing in contact with water. Portland cement is one of the most important binders worldwide.
• Admixtures such as superplasticizers are suitable fluidizing ones. But mitigating the rheology of fresh concrete using admixtures has drawbacks such as the need for high admixture dosage, retardation of the setting time.
• admixtures are added to Portland cement during the concrete mixing phase, either in the mixing water or at the same time as the different components including water to avoid partial or total loss of their fluidizing effect.
• the problem that the current invention solves is to reduce the dosage of admixture while maintaining the positive effect on fresh concrete viscosity. This lower dosage also translates into less retardation of the setting times.
• the purpose of the invention is to provide a method of producing a cement for concrete and mortar with a reduced carbon dioxide footprint.
• the inventors have shown that adding diphosphonate type admixture during the preparation of the cement allows the use of the admixture at a low dosage in concrete or mortar.
• the present invention is directed to a method of preparing a cement, the method comprising a step of adding a diphosphonate dispersing agent.
• the cement is prepared by grinding together cement components or by mixing pre-ground cement components.
• the diphosphonate dispersing agent is mixed with the cement components before or during the step of mixing or grinding of the cement components.
• the step of mixing or grinding is performed at a temperature above 80°C.
• the cement comprises Portland clinker.
• the cement further comprises a pozzolanic material selected from blast furnace slag, fly ash, calcined clays, natural or synthetic pozzolans, burnt oil shale, recycled expanded aggregates, recycled glass, or mixtures thereof.
• a pozzolanic material selected from blast furnace slag, fly ash, calcined clays, natural or synthetic pozzolans, burnt oil shale, recycled expanded aggregates, recycled glass, or mixtures thereof.
• the cement comprises a filler, preferably selected from limestone, precipitated calcium carbonate, concrete demolition waste, or mixtures thereof, and even more preferably limestone, or mixtures thereof.
• a filler preferably selected from limestone, precipitated calcium carbonate, concrete demolition waste, or mixtures thereof, and even more preferably limestone, or mixtures thereof.
• the cement comprises from 0 to 90 wt. % of filler and/or pozzolanic material expressed by weight relative to the weight of cement.
• the diphosphonate dispersing agent corresponds to compound of the formula (1): in which: -R is a hydrogen atom or a monovalent hydrocarbon group with 1 to 18 carbon atoms and optionally one or more hetero atoms;
• the Rj are similar or different and represent an alkylene for example ethylene, propylene, amylene, octylene or cyclohexene or an arylene, for example styrene or methylstyrene, the R; optionally comprising one or more hetero atoms;
• - Q. is a hydrocarbon group with 2 to 18 carbon atoms and optionally one or more hetero atoms;
• - A is an alkylidene group with 1, 2, 3, 4 or 5 carbon atoms
• Rj are similar or different and may be selected from:
• ⁇ B designating an alkylene group carrying 2 tol8 carbon atoms
• n is a number greater than or equal to 0;
• - "y" is an integer from 1 to 3;
• N and the Rj can form together one or more cycles, this or these cycles further being able to contain one or more other hetero atoms.
• the disphosphonate dispersing agent corresponds to a compound of formula (2) or of formula (3): in which: -M is a linear or branched hydrocarbon group (optionally in dendrimers) optionally comprising one or more hetero atoms (O, N, S); optionally of different natures;
• - Q. is a hydrocarbon group with 2 to 18 carbon atoms and optionally one or more hetero atoms;
• p is the number of groups [M] carried by Q, p ranges from 1 to 10;
• - "y" is an integer ranging from 1 to 3.
• the cement comprises from 0.02 to 2 wt. % of disphosphonate dispersing agent, in % expressed by weight of disphosphonate dispersing agent relative to the weight of cement.
• a cationic polymer is added during the cement preparation, preferably at a dosage of more than 0 wt. % to 3 wt. %, in % expressed by weight of cationic polymer relative to the weight of cement.
• the method comprises the steps of: al) mixing the diphosphonate dispersing agent, the cement components and the cationic polymer; a2) grinding the mixture of step al) to the desired fineness to obtain the cement; a3) collecting the cement.
• the step a2) is performed to obtain a cement having a Blaine specific surface ranging from 2500 to 15 000 cm 2 /g.
• steps al) and/or a2) are performed at a temperature above 80°C and preferably at most at a temperature of 140°C.
• steps al) and a2) are concomitant.
• Another aspect of the invention relates to a cement for concrete or mortar obtained by the method as described above. Another aspect of the invention concerns the use of a cement obtained by the method of as described above, for producing concrete or mortar.
• the present invention is directed to a method of preparing a cement for concrete or mortar, the method comprising a step of adding a diphosphonate dispersing agent.
• the cement is prepared by grinding together the cement components or by mixing pre-ground cement components.
• the diphosphonate dispersing agent can be added to cement components before, during or after the step of mixing or grinding of the cement components.
• the step of mixing or grinding is performed at a temperature above 80°C, generally above 90°C or 100°C and preferably at most at a temperature 140°C, generally at most 130°C or at most 120°C.
• the method of the invention is based on the surprising result that when a diphosphonate dispersing agent is added during the preparation of a cement for concrete or mortar then the total amount of dispersing agent needed in concrete or mortar can be reduced. Then, the method of the invention allows the preparation of a cement having lowered Portland clinker amount and suitable performance in concrete and mortar applications, especially in terms of rheology and water demand.
• the method of the present invention renders possible to reduce the amount of dispersing agent in mortar or concrete composition comparing to a composition where the dispersing agent is added at the stage of mixing with water; the amount of Portland clinker in the cement.
• the cement is provided in dry form.
• the residual water content of the cement is less than 2 % by weight (also abbreviated wt. %), preferably less than 1 wt. %, more preferably less than 0,5 wt. %.
• the water content may be the result of a mixture of a dry cement with a small amount of dispersing agent or a cationic polymer that is provided in liquid form. It must be noticed that due to the reaction capacity of the cement any residual water will be converted into hydrates during transport and storage.
• a small amount of liquid admixture such as a dispersing agent or a cationic polymer, may be mixed with a particulate cement in different ways in order to obtain a homogenous mixture.
• the liquid admixture may be added to the cement at the entry of a mill, such as a ball mill or vertical mill, in which a coarse binder (typically clinker, gypsum and supplementary cementitious materials) is ground together with the admixture to obtain a cement as fine powder homogeneously mixed with the admixture.
• the cement comprises Portland clinker and a source of calcium sulfate.
• the cement is as defined in the standard NF-EN-197-1 of April 2012 or in the standard NF-EN- 197-5 of May 2021.
• the cements defined in these standards are grouped in 6 different families: CEM I, CEM II, CEM III, CEM IV, CEM V and CEM VI.
• the cement can also be a CEM I, CEM II, CEM III, CEM IV, CEM V or a CEM VI to which mineral components are further added in a second preparation step.
• Calcium sulphate used according to the present invention includes gypsum (calcium sulphate dihydrate, CaSO ⁇ F O), hemi-hydrate (CaSO4.1/2H2O), anhydrite (anhydrous calcium sulphate, CaSC ) or a mixture thereof. Calcium sulphate produced as a by-product of certain industrial processes may also be used. Preferably, the calcium sulphate content ranges from 0% to 5% by weight of the cement.
• the mineral component can be a pozzolanic material, a filler, or mixtures thereof.
• the cement comprises a pozzolanic material selected from blast furnace slag, fly ash, calcined clays, natural or synthetic pozzolans, burnt oil shale, recycled expanded aggregates, recycled glass, or mixtures thereof.
• a pozzolanic material selected from blast furnace slag, fly ash, calcined clays, natural or synthetic pozzolans, burnt oil shale, recycled expanded aggregates, recycled glass, or mixtures thereof.
• Blast furnace slag is advantageously as defined in the European NF EN 197-1 Standard of April 2012, paragraph 5.2.2.
• Fly ash is advantageously as defined in the European NF EN 197-1 Standard of April 2012, paragraph 5.2.4.
• Calcined clay is advantageously as defined in European NF EN 197-1 Standard of April 2012, paragraph 5.2.5.
• Natural or synthetic pozzolans are advantageously as defined in the European NF EN 197-1 Standard of April 2012, paragraph 5.2.3.
• the filler is advantageously an inert mineral filler.
• the filler is selected from limestone, precipitated calcium carbonate, concrete demolition waste, or mixtures thereof, and even more preferably limestone.
• Limestone is also called ground calcium carbonate.
• Limestone is preferably as defined in the European NF EN 197-1 Standard paragraph 5.2.6.
• one well adapted limestone filler is Betocarb HP provided by OMYA.
• cement includes the mineral components.
• the cement comprises from 15 to 99% of Portland clinker, preferably from 20 to 98% of Portland clinker, expressed by weight relative to the weight of cement.
• the cement comprises from 15 to 90% of Portland clinker, preferably from 20 to 80% of Portland clinker, more preferably from 20 to 65% of Portland clinker, more preferably from 20 to 55% of Portland clinker, expressed by weight relative to the weight of cement.
• the cement comprises, from 0 to 90% of pozzolanic material, preferably from 10 to 70% of pozzolanic material expressed by weight relative to the weight of cement.
• the cement comprises from 0 to 90% of filler, preferably from 10 to 70% of filler expressed by weight relative to the weight of cement. Even more preferably the cement comprises from 35 to 55% of filler.
• the cement comprises a Portland clinker, a source of calcium sulfate, from 0 to 90% of a pozzolanic material, and from 0 to 90% of filler, expressed by weight relative to the weight of cement.
• a diphosphonate dispersing agent is added during the preparation of the cement.
• the diphosphonate dispersing agent corresponds to compounds having following Formula (1): in which:
• -R is a hydrogen atom or a monovalent hydrocarbon group with 1 to 18 carbon atoms and optionally one or more hetero atoms;
• the Rj are similar or different and represent an alkylene for example ethylene, propylene, amylene, octylene or cyclohexene or an arylene, for example styrene or methylstyrene, the R; optionally comprising one or more hetero atoms;
• - Q. is a hydrocarbon group with 2 to 18 carbon atoms and optionally one or more hetero atoms;
• - A is an alkylidene group with 1, 2, 3, 4 or 5 carbon atoms
• Rj are similar or different and may be selected from:
• ⁇ B designating an alkylene group carrying 2 tol8 carbon atoms
• n is a number greater than or equal to 0;
• - "y" is an integer from 1 to 3;
• N and the Rj can form together one or more cycles, this or these cycles further being able to contain one or more other hetero atoms.
• N stands for nitrogen.
• the compounds or the salts of the compounds according to Formula (1) may be used.
• the salts of the compounds according to formula (1) may be stoechiometric or not, mixed or not, and are constituted with alkali metals, alkali earth metals, amines or quaternary ammoniums.
• R is a hydrogen atom, a methyl group, an ethyl group or a nonylphenol group. More preferably, R is a hydrogen atom;
• - Ri groups are selected from ethylene and propylene. Preferably, all R; groups are ethylene. When the majority or all of the R; groups are ethylene, the water-soluble or water-dispersing character of the compounds is increased;
• the Q. group comprises 2 tol2 carbon atoms, and preferably 2 to 6 carbon atoms.
• Q. is selected from ethylene, cyclo-hexene or n-hexene
• a group carries 1 to 3 carbon atoms.
• A is methylene group;
• Rj group which is optionally in salt form, is selected from the -CF -POsh and CzF NfCI- POaF h groups.
• Rj represents the -CH2-PO3H2 group;
• n ranges from 1 to 10000, preferably from 1 to 500, more preferably from 1 to 250;
• the dispersing agent is a diphosphonate compounds having following compound of formula (2):
• the compounds according to Formula (1) or (2) are preferably sodium, calcium or diethanolamine salts.
• the diphosphonate compounds correspond to the admixture CHRYSO Fluid Optima 100 marketed by Chryso.
• the cement preferably comprises from 0.02 to 2 wt. %, preferably from 0.05 to 1.5 wt. %, more preferably from 0.1 to 1 wt. % of disphosphonate dispersing agent.
• the quantity is in % expressed by dry weight of disphosphonate dispersing agent relative to the weight of cement.
• the water reducing agent advantageously corresponds to compounds having following Formula (3): in which:
• -M is a linear or branched hydrocarbon group (optionally in dendrimers) optionally comprising one or more hetero atoms (O, N, S); optionally of different natures;
• - Q. is a hydrocarbon group with 2 to 18 carbon atoms and optionally one or more hetero atoms;
• p is the number of groups [M] carried by Q, p ranges from 1 to 10;
• - "y" is an integer ranging from 1 to 3.
• N stands for nitrogen
• a cationic polymer can be also added during the cement preparation.
• the cationic polymer can be mixed with the cement components before, during, or after the step of mixing or grinding of the cement components.
• the cationic polymer has a cationic charge density strictly greater than 0.5 meq/g, preferably greater than 1 meq/g and more preferably greater than 2 meq/g.
• the cationic polymer in the composition has preferably a cationic charge density less than 10.
• the cationicity is measured at a pH strictly below 7.
• the cationic polymer in the composition has a molecular weight expressed by an intrinsic viscosity less than 1 dl/g, preferably less than 0.8 dl/g and more preferably less than 0.6 dl/g.
• the cationic polymer in the composition has preferably a molecular weight expressed by an intrinsic viscosity above 0.1.
• the cationic polymer is water-soluble.
• the polymer can have a linear, comb or branched structure, preferably a linear structure or a comb structure.
• the cationic polymer preferably comprises groups selected from phosphonium group, pyridinium group, sulphonium group, quaternary amine group and combination thereof.
• quaternary amine groups are preferred.
• the polymer can comprise tertiary amine groups or imine groups which are quaternized by protonation in an acidic medium, i.e. at a pH ⁇ 7.
• the cationic groups can be located on the main chain or on the side groups of the polymer.
• the cationic polymer is preferably a comb-polymer comprising polyoxyalkylenated groups as side groups.
• the cationic polymer can be obtained directly by a known polymerization process, such as radical polymerization, polycondensation or polyaddition, post-synthetic modification of a polymer, as disclosed in W02006/032785, W02007/090948 and W02011/107704.
• a known polymerization process such as radical polymerization, polycondensation or polyaddition, post-synthetic modification of a polymer, as disclosed in W02006/032785, W02007/090948 and W02011/107704.
• grafted natural polymers for example cationic starches.
• the polymer can be obtained by polymerization of monomers including cationic monomers, their precursors, and their combination.
• Cationic monomers are preferably selected from diallyldialkylammonium salts, quaternized dialkylaminoalkyl (meth)acrylates, (meth)acrylamides N-substituted by a quaternized dialkylaminoalkyl, and their combinations.
• Suitable precursors of cationic monomers are specifically monomers carrying amine or imine groups. The nitrogen can be quaternized after polymerization in a known way as disclosed in W02006/032785, W02007/090948 and W02011/107704.
• the polymerization can further be carried out with non-ionic monomers, preferably comprising a short chain, more preferably comprising from 2 to 6 carbon atoms.
• non-ionic monomer is selected from methoxypolyethylene glycol (meth)acrylate, acrylamide, N-vinylpyrrolidone, hydroxyethyl (meth)acrylate, N-vinyl-N-methylacetamide, alkyl (meth)acrylates and combination thereof.
• Anionic monomers can also be present, provided that the polymer finally obtained remains cationic overall.
• cationic polymers are: polyvinylamines.
• the quaternized polyvinylamines can be prepared as described in Patent US 5,292,441; polymers of the polyethyleneimine type are also appropriate. The latter are quaternized by protonation; polymers obtained by polycondensation of epichlorohydrin with a mono- or dialkylamine, in particular methylamine or dimethylamine. Their preparation has been described, for example, in Patents US 3,738,945 and US 3,725,312.
• the unit of the cationic polymer obtained by polycondensation of dimethylamine and epichlorohydrin can be represented as follows: polymers of the polyacrylamide type modified by Mannich reaction, for example polyacrylamide N-substituted by a dimethylaminomethyl group; polymers obtained by polycondensation of dicyandiamide and formaldehyde. These polymers and their process of preparation are described in Patent FR 1 042 084; polymers by condensation of dicyandiamide with formaldehyde in the presence of:
• C) an ammonium derivative.
• the polymers obtained by condensation of dicyandiamide with formaldehyde, optionally in the presence of other compounds, in particular of a polyalkylene glycol (A), of a polyalkoxylated polycarboxylate (B) and/or of a quaternization agent (C) are advantageously prepared as disclosed in W02006/032785, page 6, line 21 to page 7, line 11 et page 8, lines 10 to 14, and page 9 lines 14-15, and page 10, line 3 to page 11, line 6, herein included by reference.
• the polyalkylene glycol (compound A) is preferably a compound of formula (III): R 7 -O-[R 6 -O] n -R8 (III) in which:
• Rs is a C1-C4 alkyl group, preferably an ethyl and/or propyl group;
• R 7 and Rs are, independently of one another, a hydrogen atom or a C1-C4 alkyl group, preferably a methyl group; and n is a number from 25 to 1 000.
• it can be polyethylene glycol, polypropylene glycol, an ethylene oxide/propylene oxide copolymer or a mixture of these different compounds.
• it is polyethylene glycol.
• the molecular weight, Mw, of compound A is preferably from 1 000 to 35 000 g/mol.
• the polyalkoxylated polycarboxylate (compound B) is a comb polymer which comprises a main hydrocarbon chain to which both lateral carboxylic groups and alkoxylated groups are connected, in particular groups of propylene oxide (PO), ethylene oxide groups (EO) and/or combinations thereof.
• the lateral groups may be ionic or non-ionic. It is preferably a compound having the following formula (II):
• Ri and R2 are, independently of each other, a hydrogen atom or a methyl group
• Rs and R4 are, independently of each other, an C1-C4 alkylene group, preferably an ethylene or propylene group or one of the combinations thereof;
• R 5 is a hydrogen atom or an Ci-C4alkyl group preferably a methyl group; m is a whole number from 2 to 100; p is a whole number from 2 to 100; and q is a whole number from 2 to 100.
• the level of ester of the compound B may be from 10 to 60% and in particular from 20 to 40%.
• the ammonium derivative (compound C) has as main role that of increasing the ionic nature of the polymer by introducing cationic functional groups.
• the ionic nature of the polymer contributes greatly to its solubility in water and to its affinity for clays, especially for swelling clays.
• ammonium ion of the ammonium derivative is of following formula (IV):
• the Rg groups are identical or different and correspond to H or to a Ci-Cs alkyl group.
• Mention may be made, as examples of appropriate ammonium derivatives, of ammonium halides, for example ammonium chloride, ammonium bromide and ammonium iodide, ammonium sulphate, ammonium acetate, ammonium formate, ammonium nitrate or ammonium phosphate, ammonium formate being preferred.
• the cement preferably comprises from 0 to 3 wt. %, preferably from more than 0 wt. % to 1 wt. %, preferably from 0.05 wt. % to 1 wt. % of cationic polymer, more preferably from 0.1 wt. % to 1 wt. % of cationic polymer, expressed by dry weight of cationic polymer relative to the weight of cement.
• the method of preparing a cement comprises a step of adding a diphosphonate dispersing agent.
• the cement is prepared by grinding together the components of the cement or by mixing pre-ground cement components.
• the components of the cement are the components recited in the definition of cement above .
• the diphosphonate dispersing agent, as defined above can be mixed with the cement components before, during, or after the step of mixing or grinding of the cement components.
• the diphosphonate dispersing agent, as defined above is mixed with the cement components before or during the step of mixing or grinding of the cement components.
• the method comprises the steps of: al) mixing diphosphonate dispersing agent, cement components and optionally cationic polymer; a2) grinding the mixture of step al) to the desired fineness to obtain the cement; a3) collecting the cement.
• dispersing agent is added during the cement preparation, in particular during the grinding step, there is later on no loss of fluidizing effect compared to a concrete where the dispersing agent is added with mix water.
• the grinding step a2) is generally performed in a cement mill.
• a cement mill is the equipment used to grind the hard, nodular clinker from the cement kiln into the fine cement powder. Most cement, currently ground in ball mills and also vertical roller mills operated in closed or open circuit, can be used.
• the milling unit may further comprise a particle separator to normalize the particle size of the ground mixture.
• step a2) the dispersing agent and the cement components are ground to the desired fineness to obtain the cement.
• the fineness of the ground cement at the output of step a2) may be expressed in terms of Blaine Specific Surface, as determined according to the determination of fineness standard NF EN 196-6 of December 2018.
• the grinding step a2) is advantageously conducted so that the cement at the end of step a2) has a Blaine specific surface ranging from 2500 to 15000 cm 2 /g-
• the Blaine specific surface of the cement at the end of step a2) is ranging from 3000 to 10000 cm 2 /g.
• the cement has advantageously a mean diameter, Dv50, ranging from 2 pm to 50 pm, preferably from 2 pm to 30 pm.
• Dv50 is the 50 th percentile of the size distribution of the particles, by volume; that is, 50% of the particles have a size that is less than or equal to Dv50 and 50% of the particles have a size that is greater than Dv50.
• a part of pre-ground cement components having the desired fineness can be added after the grinding step a2).
• the whole part of cement components is ground during step a2) with dispersing agent.
• a part of dispersing agent can be added during the grinding step a2) of the cement preparation.
• the whole part of dispersing agent is added during the grinding step a2). Accordingly, step al) and a2) are concomitant.
• Cationic polymer as defined above, can further be added. Cationic polymer can also be added during co-grinding, i.e. at step al) and/or step a2). If cationic polymers are used, the dispersing agents and cationic polymers can be added separately to cement components. Alternatively, the dispersing agents and cationic polymers are mixed prior to be added to cement components.
• Step al) and/or step a2) are advantageously performed at a temperature above 80°C, generally above 90°C or 100°C and preferably at most at a temperature 140°C, generally at most 130°C or at most 120°C.
• step a3) the cement is collected generally at the exit of the cement mill.
• the diphosphonate agent is ground together with Portland clinker and calcium sulfate to form a first Portland cement that is then blended with mineral components in a subsequent step.
• the invention is also directed to a cement comprising the cement components as described above, the diphosphonate dispersing agent as described above and optionally a cationic polymer as described above.
• the invention is also directed to a cement obtained by the method described above.
• the cement is preferably in a dry powder form.
• the invention is directed to the use of a cement obtained by the method described above for producing mortar or concrete. Preparing a concrete or a mortar
• the invention is also directed to a method for preparing a concrete or a mortar, comprising the following steps: a) providing a cement as disclosed previously; then b) mixing the cement of step a) with aggregates and water.
• step a) of providing the cement comprises steps al), a2) and a3) as described herein.
• the cement can be stored for long times after having been pre-manufactured.
• providing the dispersing agent and eventually a cationic polymer as a dry component of the cement reduces potentially the number of components to be mixed together at the jobsite.
• only three types of components need to be mixed on site, namely the cement, the aggregates (including sand and/or gravels) and water.
• additional admixture preferably of other type, is further mixed at the jobsite.
• crete refers to a composition comprising cement and aggregates which in presence of water forms a paste which sets and hardens by means of hydration reactions and processes and which, after hardening, retains its strength and stability even under water.
• the composition is usually called “mortar”.
• concrete is as defined in standard EN 197-1 of April 2012.
• the terms “concrete” and “concrete composition” will have the same meaning in the present disclosure.
• water used with regard to the concrete composition preferably relates to the water added for mixing and the water of the admixtures, such as the water of water reducing agent.
• the cement of the present invention lowers the water content introduced in step b).
• any known aggregates suitable for the preparation of concrete may be used for the present invention.
• the aggregates have advantageously a maximum size of 32 mm.
• the aggregates can comprise or consist of sand. Any known sand suitable for the preparation of concrete is suitable for the present invention.
• the sand has advantageously a maximum size of 5 mm, preferentially 4 mm.
• the sand has advantageously a minimum size of 0 mm or of 0.063 mm.
• the sand is a siliceous sand such as quartz sand, a calcined or non-calcined bauxite sand, a silica-calcareous sand or mixtures thereof.
• the mass ratio of the quantity of sand to the quantity of gravel is preferably from 1.5:1 to 1:1.8, more preferably from 1.25:1 to 1:1.4, even more preferably from 1.2:1 to 1:1.2.
• the concrete composition will advantageously comprise: at least 10% of the cement; and up to 90 % of aggregates, the percentages corresponding to proportions relative to the total dry volume.
• the principle of the spread measurement consists in filling a truncated spread measurement cone with the mortar cement to be tested, then releasing the said composition from the said truncated spread measurement cone in order to determine the surface of the obtained disk when the cement has finished spreading.
• the truncated spread measurement cone corresponds to a reproduction at the scale Y2 of the cone as defined by the NF P 18-451 Standard, 1981.
• the truncated spread measurement cone has the following dimensions: top diameter: 50+/-0.5 mm; bottom diameter: 100+/-0.5 mm; and height: 150+/-0.5 mm.
• the entire operation is carried out at 20° C.
• the spread measurement is carried out in the following manner:
• the strength is measured by preparing cement mortars. The detailed protocol is described in the European cement Standard EN 196-1 (September 2016), the only difference is that water to cement content is of 0.35 instead of 0.5. Polystyrene moulds are used instead of steel moulds. The test is carried out at 20°C.
• cement components comprise Portland cement and a filler.
• CEM I is either the CEM I 52,.5R produced at the cement plant of Sete was used, or the CEM I 52.5N produced at the cement plant of Saint Pierre la Cour. These cement compositions are according to the cement standards EN 197-1 of April 2012 and contains less than 5 wt. % of minor constituents, less than 5 wt. % Gypsum, and at least 95 wt. % Portland clinker;
• CEM II is CEM ll-B/M (LL-V) 32, 5R from Saint Pierre La Cour plant comprising 80 wt. % Portland cement and 20 wt. % limestone.
• the filler added to the mixes is ground calcium carbonate (GCC) from Fos sur Mer (supplied by Lafarge), Betocarb HP Saint Beat (supplied by Omya) and Calfiller La Hunaudiere (supplied by Faco).
• GCC ground calcium carbonate
• Cement 1 comprise 46 wt. % of CEM I 52.5R from Sete and with 54 wt. % of GCC (Fos).
• Cement 2 comprise 63 wt. % of CEM II and 37 wt. % of GCC (Calfiller)
• Cement 3 comprise 46 wt. % of CEM I 52.5N from Saint Pierre la Cour and with 54 wt. % of GCC (Betocarb HP).
• 0100 is a commercial diphosphonate based water reducing agent provided by Chryso under the commercial name Chryso Optima 100.
• ME3925 is a commercial diphosphonate based water reducing agent provided by MBCC under the commercial name MasterEase 3925.
• 0224 is a commercial PolyCarboxylate Polyalkylene as water reducer provided by Chryso under the commercial name Chryso Optima 224. 0224 is not a dispersing agent based on phosphonate type compounds.
• FL2250 is a cationic polymer provided by SNF, polycondensate of epichlorohydrin and dimethylamine, having a cationic charge density of 7.3 meq/g and an intrinsic viscosity of 0.04 dl/g under the commercial name FL2250.
• FL2250 has a solid content of: 55 %-wt.
• WATER tap water is used.
• the cement is prepared by mixing together in a lab ball mill preheated at 100°C, the cement components 1, 2 or 3 as defined above, a dispersing agent, and a cationic polymer if any, in a lab ball mill pre-heated at 100°C. Then the mixture is ground at 100°C. After, 500 revolutions are operated, the mill is emptied, and the cement is collected. Tests are done after 24h cooling at 20°C. The fineness of the CEM I cement is 4870 cm 2 /g-
• the mortars prepared according to process A are prepared as described in the standard EN 196-1 (September 2016), the only difference is that water to cement content is of 0.35 instead of 0.5.
• a comparative cement is prepared by mixing the cement components of cements 1, 2, or 3 as defined above in a lab ball mill pre-heated at 100°C. Then the mixture is ground at 100°C. After, 500 revolutions are operated, the mill is emptied, and the cement is collected. Tests are done after 24h of cooling at 20°C. The fineness of the cement is 4870 cm 2 /g.
• the mortars prepared according to process A are prepared as described in the standard EN 196-1 (September 2016), the only difference is that water to cement content is of 0.35 instead of 0.5.
• the dispersing agent, and cationic polymer if any, are added with water during the preparation of the mortar. Results
• Mortars are prepared with Cement 3, using the processes A and B described above. Content of dispersing agent, method of preparation and results are provided in table 1 below.
• Table 1 Mortars 1 and 3 prepared using method A are in accordance with the invention and mortars 1 to 4 prepared using method B are comparatives.
• results in table 1 illustrates that when the cement components are mixed with a dispersing agent during cement preparation (0100 and ME3925), for example during the grinding step, then the slump flow of the mortar composition is improved (1A vs IB; 2A vs 2B).
• results in table 1 demonstrates also that a method where the cement components are mixed with a dispersing agent during cement preparation (0100 and ME3925), for example during the grinding step, allows the use of a lower dosage of dispersing agent while maintaining a similar slump flow (1A vs 2B; 3A vs 4B).
• results in table 1 shows that a dispersing agent not in accordance with the invention, i.e. polyCarboxylate polyalkylene, results in a decrease of the slump flow. This decrease reflects that dispersing agent such as 0224 lose their fluidizing effect when present during cement preparation, in particular during grinding operation.
• Mortars are here prepared with Cement 1. Mortars are prepared with a weight ratio of Water efficient with cement components 1 of 0.35. All mortar compositions contain also 0.30 wt. % of FL2250 as cationic polymer.
• Mortars 6 to 8 prepared using method A are according to the invention and mortars 6 to 8 prepared using method B are comparatives.
• Mortars 6A, 7A and 8A are according to the invention, i.e., 0100 and FL2250 are added during cement preparation, in particular mixed and ground with cement components.
• Mortar 6B, 7B and 8B are comparative, i.e., 0100 and FL2250 are added with the water mix to prepare the mortar
• Results in table 2 demonstrates that when the cement components are mixed with the dispersing agent and also a cationic polymer, for example during the grinding step, then the slump flow of the mortar is improved while the compressive strength is similar or even greater.
• Mortars are prepared with Cement 2, using the processes A and B described above.
• the mortar compositions further contain 0.22 wt. % of FL2250 as cationic polymer, expressed as weight percentage of the amount of cement. Content of dispersing agent and method of preparation are provided in the table below.
• Mortars 9 to 11 prepared using method A are according to the invention and mortars 9 to 11 prepared using method B are comparatives.
• Results in table 3 illustrates that the effect of the invention is obtained for different Portland cement.
• adding the dispersing agent and the cationic polymer during cement preparation for example during the grinding step, improves the slump flow of the mortar while the compressive strength is similar or even greater.

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• Organic Chemistry (AREA)
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• 2023
  • 2023-12-15 EP EP23833086.4A patent/EP4634129A1/de active Pending
  • 2023-12-15 WO PCT/EP2023/086086 patent/WO2024126798A1/en not_active Ceased

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