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
  • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators or shrinkage compensating agents
  • C04B22/0013—Boron compounds
• • 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
  • C04B28/04—Portland cements
• • 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
  • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
  • C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

• the present invention relates to the use of an admixture containing boron in hydraulic compositions comprising a Portland clinker and a mineral addition.
• the main problem of hydraulic compositions comprising a mineral addition as a partial substitution of the Portland clinker is the decrease of mechanical compressive strengths, in particular measured 28 days after the hydraulic composition has been mixed. This decrease is, in particular, due to the reduction of the quantity of clinker relative to the total quantity of binder, given that the binder generally comprises clinker and mineral additions.
• borate An example of an admixture containing boron is borate. Borate is known as a set- retarding agent for hydraulic binders and hydraulic compositions. It is therefore not known as a means to improve the development of mechanical compressive strengths.
• the problem which the invention seeks to solve is to provide a means to improve the mechanical compressive strengths measured 28 days after hydraulic compositions comprising a Portland clinker and a mineral addition have been mixed.
• the present invention relates to a use of an admixture containing boron, which comprises a boron oxide, boric acid or a borate, before or during the mixing, to improve the compressive mechanical strength of a hydraulic composition, comprising a Portland clinker and a mineral addition, said compressive mechanical strength being measured 28 days after the hydraulic composition has been mixed.
• the admixture containing boron is a borate.
• the borate is preferably a borate salt. More preferably, the borate is selected from a metaborate, a tetraborate, a pentaborate, a perborate, a pyroborate and a biborate, even more preferably a metaborate and a tetraborate, most preferably a metaborate.
• the borate comprises a salt of a mono- or di-valent cation. More preferably, the borate comprises an alkali metal salt, an alkaline earth metal salt or a poor metal salt. Most preferably, the borate comprises an alkali metal salt or an alkaline earth metal salt.
• a poor metal is a metal element in the p block of the Periodic Table of Elements, generally aluminium, gallium, indium, thallium, tin, lead and bismuth.
• the cation is selected from sodium, potassium, barium, calcium and strontium.
• the borate is preferably selected from sodium metaborate, potassium metaborate, barium metaborate, calcium metaborate, calcium tetraborate and mixtures thereof.
• the borate is selected from sodium metaborate, potassium metaborate, barium metaborate, calcium metaborate and mixtures thereof.
• the borate comprises barium metaborate.
• the borate is in a hydrated form.
• the admixture containing boron may be added, for example:
• the quantity of admixture containing boron is from 1 to 5 % by mass of B 2 0 3 -equivalent relative to the mass of binder.
• the binder comprises the clinker, the mineral addition and the admixture containing boron.
• the quantity of admixture containing boron is less than or equal to 10 % by mass relative to the mass of binder.
• Portland clinker is obtained by clinkering at high temperature a mixture comprising limestone and, for example, clay.
• a Portland clinker is a clinker as defined in the NF EN 197-1 Standard of February 2001 .
• Calcium sulphate used according to the present invention 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. Calcium sulphate produced as a by-product of certain industrial processes may also be used.
• 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 in the "Cement” NF EN 197-1 Standard of February 2001 , paragraph 5.2.4), calcined shale (for example, as defined in the « Cement » NF EN 197-1 Standard, paragraph 5.2.5), mineral additions comprising calcium carbonate, for example limestone (for example as defined in the" Cement” NF EN 197-1 Standard paragraph 5.2.6) silica fume (for example as defined in 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.
• slags for example as defined in the "Cement” NF EN 197-1 Standard of February 2001 , paragraph 5.2.2
• the mineral addition comprises a pozzolan, a slag, a fly ash or mixtures thereof. More preferably, the mineral addition comprises a fly ash.
• the mineral addition may also comprise a mineral addition comprising calcium carbonate, for example limestone.
• Fly ash generally comprises pulverulent particles contained in fume in thermal power plants fed with carbon. It is generally recovered by electrostatic or mechanical precipitation.
• the fly ash is as described in the EN 197-1 Standard of February 2001
• a fly ash of type V comprises less than 10.0 % by mass of reactive CaO, at most
• the reactive CaO is the total CaO of the binder minus the CaO coming from the CaC0 3 , calculated on the basis of the measured content of C0 2 , and minus the CaO coming from the CaS0 4 , calculated on the basis of the measured content of S0 3 minus the S0 3 carried by the alkali metal salts.
• a fly ash of type W comprises at least 10.0 % by mass of reactive CaO.
• a fly ash of type W which comprises from 10.0 and 15.0 % of reactive CaO also comprises at least 25.0 % by mass of reactive Si0 2 .
• a fly ash of class C comprises at least 50.0 % of Si0 2 + Al 2 0 3 + Fe 2 0 3 , at most 5.0 % of S0 3 and a loss on ignition of at most 6.0 %.
• a fly ash of class F comprises at least 70.0 % of Si0 2 + Al 2 0 3 + Fe 2 0 3 , at most 5.0 % of S0 3 and a loss on ignition of at most 6.0 %.
• a hydraulic binder is a material which sets and hardens by hydration, for example a cement.
• a cement generally comprises clinker and calcium sulphate.
• the clinker may in particular be a Portland clinker.
• the cement may be:
• Portland cement which is generally a cement of type CEM I according to the NF EN 197-1 Standard of February 2001 , in particular Table 1 , page 12 of the Standard;
• a pozzolanic cement which is generally a cement of type CEM IV according to the NF EN 197-1 Standard of February 2001 , in particular Table 1 , page 12 of the Standard; or
• blended cement which is generally a cement of type CEM II, CEM III or CEM V according to the NF EN 197-1 Standard of February 2001 , in particular Table 1 , page 12 of the Standard.
• the hydraulic composition comprises 20 to 80 % by mass of Portland clinker and 80 to 20 % by mass of a mineral addition relative to the mass of clinker and mineral addition.
• a hydraulic composition generally comprises a hydraulic binder and water, optionally aggregates, and optionally admixtures.
• Hydraulic compositions include both fresh and hardened compositions, for example a cement slurry, a mortar or a concrete.
• the hydraulic composition may be used directly on the jobsite in the fresh state and poured into formwork adapted to a given application, used in a pre-cast plant or used as a coating on a solid support.
• the quantity of water is preferably such that the water/binder ratio is from 0.2 to 0.7, more preferably from 0.4 to 0.6.
• the binder comprises the clinker, the mineral additions and the admixture containing boron.
• the aggregates used include sand (whose particles generally have a maximum size
• Dmax less than or equal to 4 mm
• coarse aggregates 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 example one of those described in the EN 934-2, EN 934-3 or EN 934-4 Standards, respectively of September 2002, November 2009 and August 2009.
• the hydraulic composition also comprises an admixture for a hydraulic composition, for example, an accelerator, an air- entraining agent, a viscosity-modifying agent, a retarder, a clay-inerting agent, a plasticizer and/or a superplasticizer.
• a superplasticizer e.g. a polycarboxylate superplasticizer, in particular from 0.05 to 1.5 %, preferably from 0.1 to 0.8 % by mass.
• Clay-inerting agents are compounds which permit the reduction or prevention of the harmful effects of clays on the properties of hydraulic binders. Clay-inerting agents include those described in the patent applications WO 2006/032785 and WO 2006/032786.
• a water reducer is defined as an additive which reduces the amount of mixing water of concrete for a given workability by typically 10 - 15 %.
• Water reducers include, for example lignosulphonates, hydroxycarboxylic acids, glucides and other specialized organic compounds, for example glycerol, polyvinyl alcohol, sodium alumino-methyl-siliconate, sulfanilic acid and casein.
• Superplasticizers belong to a new class of water reducers, chemically different from the older water reducers and capable of reducing water contents by about 30 %.
• the superplasticizers have been broadly classified into four groups: sulphonated naphthalene formaldehyde condensate (SNF) (generally a sodium salt); sulphonated melamine formaldehyde condensate (SMF); modified lignosulfonates (MLS); and others.
• SNF sulphonated naphthalene formaldehyde condensate
• SMF sulphonated melamine formaldehyde condensate
• MLS modified lignosulfonates
• More recent superplasticizers include polycarboxylic compounds, for example, polycarboxylates, e.g. polyacrylates.
• a superplasticizer is preferably a new generation superplasticizer, for example a copolymer containing polyethylene glycol as graft chain and carboxylic functions in the main chain such as a polycarboxylic ether.
• Sodium polycarboxylate-polysulphonates and sodium polyacrylates may also be used.
• Phosphonic acid derivatives may also be used.
• the amount of superplasticizer required generally depends on the reactivity of the cement. The lower the reactivity, the lower the amount of superplasticizer required. In order to reduce the total alkali salt content, the superplasticizer may be used as a calcium salt rather than a sodium salt.
• the components of the hydraulic composition to which the admixture containing boron may be added comprise aggregates, fibres, a hydraulic binder, a slag, silica fume, a fly ash, a mineral addition comprising calcium carbonate, a siliceous filler, a pozzolan, an admixture, the mixing water and/or the pre-wetting water of the aggregates.
• the mixing of the hydraulic composition may be carried out, for example by known methods.
• the binder is prepared during a first step, and the optional aggregates and the water are added during a second step.
• the hydraulic composition may be shaped to produce, after hydration and hardening, a shaped article for the construction field.
• Such shaped articles that comprise a hydraulic composition as obtained according to the process of the invention also constitute a feature of 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 block of concrete, optionally foamed 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, a surfacing (for example of a road or a wall), or an insulating component (acoustic and/or thermal).
• a road system component for example a border of a pavement
• a roof tile for example of a road or a wall
• a surfacing for example of a road or a wall
• an insulating component acoustic and/or thermal
• the Dv97 is the 97 th percentile of the size distribution of the particles, by volume; that is, 97 % of the particles have a size that is less than or equal to the Dv97 and 3 % of the particles have a size that is greater than the Dv97.
• Particle size distributions and particle sizes less than approximately 200 ⁇ are measured using a Malvern MS2000 laser granulometer. Measurements are carried out in ethanol.
• the light source consists of a red He-Ne laser (632 nm) and a blue diode
• the optical model is that of Mie and the calculation matrix is of the polydisperse type.
• the apparatus is calibrated before each working session by means of a standard sample (Sibelco C10 silica) for which the particle size distribution is known.
• Measurements are carried out with the following parameters: pump speed 2300 rpm and stirrer speed 800 rpm.
• the sample is introduced in order to establish an obscuration between 10 and 20 %.
• the measurement is carried out after stabilisation of the obscuration.
• Ultrasound at 80 % is first applied for 1 minute to ensure the de-agglomeration of the sample. After about 30 seconds (for possible air bubbles to clear), a measurement is carried out for 15 seconds (15000 analysed images). Without emptying the cell, the measurement is repeated at least twice to verify the stability of the result and elimination of possible bubbles.
• Particle sizes greater than 200 ⁇ are generally determined by sieving.
• the tested hydraulic composition was a mortar, the formulation of which is described in the various tables herein below.
• the standardized sand was a siliceous sand conforming with the EN 196-1 Standard of April 2006, the supplier of which is Societeirritone concentrate.
• the cement was a CEM I 52.5 R cement having a Dv97 of approximately 19 ⁇ , it came from the Lafarge cement plant of Saint Pierre La Cour.
• the admixture containing boron was:
• the fly ash was fly ash from a thermal power plant in Sundance in the United States having an initial fineness without grinding (FA1 -1 ), a Dv97 of approximately 25 ⁇ (FA1 -2) or a Dv97 of approximately 10 ⁇ (FA1 -3), or fly ash coming from a thermal power plant in Le Havre in France having an original fineness without grinding (FA2-1 ), a Dv97 of approximately 25 ⁇ (FA2-2) or a Dv97 of approximately 10 ⁇ (FA2-3).
• the pozzolans were pozzolans from Cameroon (Pozzl ) or from Mylos in Greece (Pozz2).
• the slag was a slag from Fos Sur Mer in France having an initial fineness without grinding.
• the mineral addition comprising calcium carbonate was limestone commercialised under the brand name of BL200 (Supplier: Omya).
• the mortar was produced according to the procedure described herein below:
• the mechanical compressive strengths were measured 28 days after the hydraulic composition was mixed on samples of hardened mortar in the form of a paving stone with the following dimensions: 40 mm x 40 mm x 160 mm.
• the samples of mortar had been moulded immediately after the preparation of the mortar.
• the mould was attached to a shock table.
• the mortar was introduced into the mould in two layers (each layer of mortar weighing approximately 300 g).
• the first layer of mortar, then the second layer of mortar were placed by 60 shocks on the shock table.
• the mould was removed from the shock table and 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 in a humid enclosure.
• the mould was removed from the enclosure and the sample of hardened mortar was demoulded 24 hours after the hydraulic composition was mixed, 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 the measurement of the mechanical compressive strength.
• the sample of hardened mortar was dried then covered with a damp cloth until the measurement was taken.
• Example 1 Hydraulic compositions comprising fly ash
• Table 1 a and Table 1 b herein below present the tested compositions and the results obtained for the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.
• Table 1a Hydraulic compositions comprising fly ash FA1-1, FA1-2 or FA1-3
• the effect of the admixture containing boron on the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed was better when the fly ash was finer.
• the mechanical compressive strength measured 28 days after the composition of Test 15 was mixed was 28.9 MPa
• the mechanical compressive strength measured 28 days after the composition of Test 14 was mixed was 21 .8 MPa.
• the gain of mechanical compressive strength measured 28 days after the hydraulic composition was mixed was 7.1 MPa for the FA2-1 fly ash, which had a standard fineness.
• the mechanical compressive strength measured 28 days after the composition of Test 19 was mixed was 43.3 MPa
• the mechanical compressive strength measured 28 days after the composition of Test 18 was mixed was 23.6 MPa.
• the gain of mechanical compressive strength measured 28 days after the hydraulic composition was mixed was 19.7 MPa for the FA2-3 fly ash, which had a Dv97 of approximately 10 ⁇ .
• the increase of the mechanical compressive strength measured 28 days after the hydraulic composition was mixed was therefore greater for the finer fly ash.
• the same finding was made for the FA1 fly ash.
• Example 2 Hydraulic compositions comprising pozzolans
• Table 2 herein below presents the tested compositions and the results obtained for the mechanical compressive strengths measured 28 days after the hydraulic compositions were mixed.
• the addition of barium metaborate improved the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.
• the mechanical compressive strength measured 28 days after the composition of Test 2 was mixed was 31 .1 MPa
• the mechanical compressive strength measured 28 days after the composition of Test 1 was mixed was 21 .6 MPa.
• Example 3 Hydraulic compositions comprising slag
• Test 1 was the control composition because the composition tested in this trial did not comprise barium metaborate.
• 28-day Cs is to be understood as the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.
• the addition of barium metaborate improved the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.
• the mechanical compressive strength measured 28 days after the composition of Test 3 was mixed was 42.1 MPa
• the mechanical compressive strength measured 28 days after the composition of Test 1 was mixed was 37.6 MPa.
• Example 4 Hydraulic compositions comprising different admixtures containing boron
• Test 0 was the control composition because the composition tested in this trial did not comprise an admixture containing boron.
• the tested admixtures containing boron were barium metaborate, calcium metaborate, potassium metaborate and sodium metaborate.
• Table 4 herein below presents the tested compositions and the results obtained for the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.
• Hydraulic compositions comprising different admixtures containing boron 28-day Cs is to be understood as the mechanical compressive strengths measured 28 days after the hydraulic composition was mixed.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)

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Citations (6)

• 2012
  • 2012-05-24 FR FR1254755A patent/FR2990939B1/fr not_active Expired - Fee Related
• 2013
  • 2013-05-23 WO PCT/EP2013/060568 patent/WO2013174899A1/fr not_active Ceased

Patent Citations (6)

Non-Patent Citations (2)

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