EP4161883A1 - Coulis pour l'injection de cables de precontrainte et procede d'installation d'un cable comprenant un tel coulis - Google Patents
Coulis pour l'injection de cables de precontrainte et procede d'installation d'un cable comprenant un tel coulisInfo
- Publication number
- EP4161883A1 EP4161883A1 EP21737703.5A EP21737703A EP4161883A1 EP 4161883 A1 EP4161883 A1 EP 4161883A1 EP 21737703 A EP21737703 A EP 21737703A EP 4161883 A1 EP4161883 A1 EP 4161883A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- grout
- geopolymer
- metakaolin
- fly ash
- sodium silicate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
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- 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
- C04B32/00—Artificial stone not provided for in other groups of this subclass
- C04B32/02—Artificial stone not provided for in other groups of this subclass with reinforcements
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- 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
- C04B28/006—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 mineral polymers, e.g. geopolymers of the Davidovits type
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
- B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
- B28B23/04—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members the elements being stressed
- B28B23/046—Post treatment to obtain pre-stressed articles
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- 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
- C04B12/00—Cements not provided for in groups C04B7/00 - C04B11/00
- C04B12/005—Geopolymer cements, e.g. reaction products of aluminosilicates with alkali metal hydroxides or silicates
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- 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
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/04—Silica-rich materials; Silicates
- C04B14/10—Clay
- C04B14/106—Kaolin
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- 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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/06—Combustion residues, e.g. purification products of smoke, fumes or exhaust gases
- C04B18/08—Flue dust, i.e. fly ash
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- 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, shrinkage compensating agents
- C04B22/06—Oxides, Hydroxides
- C04B22/062—Oxides, Hydroxides of the alkali or alkaline-earth metals
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- 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
- C04B7/00—Hydraulic cements
- C04B7/24—Cements from oil shales, residues or waste other than slag
- C04B7/243—Mixtures thereof with activators or composition-correcting additives, e.g. mixtures of fly ash and alkali activators
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
- E04C5/10—Ducts
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/12—Mounting of reinforcing inserts; Prestressing
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- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00034—Physico-chemical characteristics of the mixtures
- C04B2111/00146—Sprayable or pumpable mixtures
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- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
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- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
- C04B2111/26—Corrosion of reinforcement resistance
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- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/70—Grouts, e.g. injection mixtures for cables for prestressed concrete
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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
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- 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 field of reinforcements for construction works. It relates more particularly to the grout injected into conduits of prestressing cables and to the method of manufacturing this grout as well as to the method of installing a structural cable comprising the installation of a conduit and the injection. of a grout in the duct.
- Prestressing cables generally consist of a bundle of reinforcements, most often made of steel, the tensioning of which makes it possible to exert the prestress.
- the reinforcements are arranged in a tubular conduit (generally formed in a sheath) filled with a protective material after tensioning.
- the prestressing cables can be placed inside (embedded in the structure to be stressed) or outside the concrete (the cables are anchored to the structure only by their anchors at the ends).
- the post-stress of the concrete is obtained in the first place by the concreting of a structure (for example a beam) comprising a conduit (for example a sheath) empty of reinforcements. Reinforcements are then threaded into this conduit and then tensioned.
- a grout is injected into the sheath in order to ensure the durability of the cables on the one hand, in particular by protecting them from corrosion, in order to transmit the forces to the concrete of the structure, in the case of internal prestressing and adherent to concrete on the other hand.
- a grout is generally composed of a mixture based on cement and water, the mixture being sufficiently fluid to fill the duct and coat the bundle of reinforcements without leaving a vacuum.
- Cement is a hydraulic binder, ie capable of setting in water.
- a classic cement comes under the form of a very fine powder which, when mixed in water, forms a paste which sets and gradually hardens over time.
- An example of a well-known classic cement is Portland cement. The hardening of cement is due to the hydration of certain mineral compounds.
- the basic composition of current cements is a mixture of silicates and calcium aluminates, resulting from the combination of lime (CaO) with silica (S1O2), alumina (AI2O3), and oxide iron (Fe203).
- the necessary lime is supplied by limestone rocks, alumina, silica and iron oxide by clays. These materials are found in nature in the form of limestone, clay or marl and contain, in addition to the oxides already mentioned, other oxides and in particular Fe202, ferric oxide.
- the water-cement suspension that is to say the mixture based on cement and water, is always added to improve fluidity and delay setting; this mixture is called a cement grout.
- the prestressing cables 10 often have a path of sinuous shape comprising high points 12 and low points 13, the prestressing force exerted by the cable 10 being directed downwards. in the vicinity of high points and vice versa. At these high points 12, one can observe an absence of grout in contact with the reinforcements of the cable 10 and the presence of air and / or of aqueous solution or of particles less dense than the cement, which can promote corrosion. reinforcements.
- the absence of grout results from a lack of stability of the grout or from infill imperfections in the injection operation.
- the lack of stability of the grout results in a phenomenon of segregation of the grout in the duct, by sedimentation (solid deposit) or filtration (water rising along the reinforcements), which can consequently lead to a bleeding phenomenon.
- the injection of the grout into the duct must be done without entraining or trapping air in the duct, particularly in the high points or behind the anchors.
- the grout, once hardened must be chemically stable and protective vis-à-vis the steel constituting the cables during the service life of the structure.
- the grout for its injection, the grout must be sufficiently fluid to be pumped and conveyed in the hoses, the conduits and must remain stable and homogeneous before and during the setting. It is therefore necessary to control bleeding.
- the fluidity of the grout is a critical point that is difficult to control due to the inconstancy of the production of the cement, climatic variations during the injection operations, the application pressures exerted, the kinematics of progression of the grout in the duct, filtration through the fittings etc.
- the fluid grout is a suspension of cement grains dispersed in a large quantity of water containing adjuvants, the roles of which are generally to thin and delay the setting of the mixture.
- the cement sets by a phenomenon of hydration, in which water is the main reagent, which triggers a crystallization reaction. There is always excess water in the grout.
- the grouts are dosed with a mass ratio of water relative to the cement which is of the order of 0.34 to 0.40 while the water content necessary for the hydration of the cement particles is only about 0.17. If the suspension is stable, the excess water turns into microporosities distributed, during setting, in the hardened material.
- Another alternative is to replace the cement grout with a grout of alternative composition. It is for example known from document FR2623492A1 a cement slurry comprising a mineral filler such as for example sand.
- a mineral material can also be considered.
- This type of material is stable in liquid form and requires only a small amount of water compared to a cement grout intended for injection.
- These are products of the poly (silico-oxo-aluminate) type, commonly called a “geopolymer”. Due to the absence of cement in a geopolymer grout, the hydration reaction of the mixture is not involved in the setting and hardening of the grout. This avoids the problems due to the massive presence of water in the grout.
- This type of material is known for example from document FR2949227A1.
- the geopolymer grout disclosed by this document offers the rheological performance and mechanical resistance defined by specifications in which, at 28 days depending on its manufacture, the compressive strength of the grout must be greater than 30 MPa.
- this material does not meet the usual criteria of fluidity necessary for injection of the grout.
- This fluidity is usually measured according to a standardized test described in European standard “NF EN 445” relating to the flow time through a Marsh cone with a 10 mm diameter nozzle, which must theoretically remain less than or equal to 25. seconds, 5 hours after mixing the grout (equivalent to a viscosity of 0.5 Pa.s).
- the grout must be able to be injected into a conduit intended to contain tensioned reinforcements. It is known from document FR2713690A1 a method for the injection of a grout. However, this process is specifically developed for a cement grout and therefore cannot be used for a geopolymer grout.
- the grout proposed by the invention therefore aims to solve the problems encountered in grouts known among those which set, whether it is cement grout or geopolymer grout.
- the grout disclosed by the present invention aims in particular to solve the problems caused by both the presence of water in the cement grout, and the lack of fluidity of the existing geopolymer grouts.
- the invention provides a geopolymer grout for the protection of prestressing reinforcements, the geopolymer grout comprising metakaolin, fly ash and an activator mixture, the activator mixture comprising sodium hydroxide and sodium silicate, in wherein the Na2O: SiO2 molar ratio of the sodium silicate is between 0.40 and 0.70. In particular, the Na 2 O: SiO 2 molar ratio of the sodium silicate is between 0.51 and 0.60.
- the sodium silicate may also have a water content by weight of between 52.1% and 72.1% and the activator mixture have a water content by weight of less than 65%.
- the activator mixture may also have a water content by mass of between 40% and 65%.
- the mass water content is between 56% and 63%.
- the metakaolin: fly ash: alkaline silicate solution: sodium hydroxide mass ratio can be 1: 1: 2-3: 0.15-0.35.
- the metakaolin fly ash: alkaline silicate solution: sodium hydroxide mass ratio can further be 1: 1: 2.4-2.6: 0.19-0.23.
- the geopolymer grout can also have a pH of between 13 and 14.
- the geopolymer grout may also have a bleeding of the aqueous reaction solution of less than 0.5% of the total mass of the grout.
- the BET specific surface (Brunauer, Emmett and Teller theory) of metakaolin alone or of a mixture comprising metakaolin and fly ash may be greater than or equal to 25 m 2 / g and preferably greater than or equal to 30m 2 / g.
- the invention also provides a method of manufacturing a geopolymer grout, the geopolymer grout comprising metakaolin, fly ash and an activator mixture, the activator mixture comprising sodium hydroxide and sodium silicate, the Na2O: SiO2 molar ratio of the sodium silicate being between 0.40 and 0.70, wherein the manufacturing process comprises an activation step in which the metakaolin and the fly ash are activated by the activator mixture in order to 'obtain a polymerization of the whole.
- the manufacturing process can further comprise a preliminary step of homogenizing the metakaolin and the fly ash.
- the manufacturing process can further comprise a mixing step during which the activator mixture is mixed with the metakaolin and the fly ash.
- water is added at the start of the mixing step, the amount of water added being between 1% and 4% by weight of the geopolymer slurry.
- the added water is only useful to improve the fluidity of the grout. Water is in fact not necessary for the polymerization step, which reduces its use to a minimum. Compared to the quantities of metakaolin, fly ash and activator mixture required for the manufacture of the grout, the water thus represents a marginal quantity, thus avoiding the risks associated with the quality and stability during the setting of the grout.
- the metakaolin alone or a mixture comprising the metakaolin and the fly ash is ground in order to obtain a BET specific surface area greater than or equal to 25 m 2 / g and preferably greater than or equal to 30 m 2 / g.
- the invention also provides a method of installing a structural cable, comprising:
- the injection of a geopolymer grout into the pipe and in which the geopolymer grout comprises metakaolin, fly ash and an activator mixture, the activator mixture comprising sodium hydroxide and sodium silicate, the molar ratio Na20: Si02 of the sodium silicate being between 0.40 and 0.70.
- the installation method may further comprise, before the injection of the geopolymer grout into the duct, a mixing of the geopolymer grout for 2 to 5 minutes with an energy of about 9 kilojoules per liter, thus obtaining an equivalent fluidity to the Marsh cone with a 10 mm diameter nozzle between 25 seconds and 35 seconds.
- the installation method may further comprise, during the injection of the geopolymer grout into the conduit, the use of a hose, the hose having an internal diameter greater than 25 mm and a length limited to 100 m.
- the grout is pumped during the injection, the pumping rate of the grout being between 0.5 m 3 / h and 1.5 m 3 / h.
- FIG. 1
- FIG. 1 is a block diagram illustrating an example of a prestressing cable.
- the geopolymer grout according to the invention is a mineral material in stable liquid form, the formulation of which does not contain or only very little free water. It is more precisely a product of the Poly "silico-oxo-aluminate" or (-Si-0-Al-0) n type (for which n is the degree of polymerization).
- This geopolymer grout is particularly advantageous for the protection of prestressing cables in their conduit. Indeed, this geopolymer grout guarantees better filling of the duct and better coating of the reinforcements while having no harmful effect with regard to the prestressing reinforcement.
- the geopolymer grout mainly comprises powders, referred to as a filler element, and a liquid activator mixture.
- the charging elements are metakaolin and fly ash.
- Metakaolin is also called calcined kaolin.
- Metakaolin is a dehydroxylated alumina silicate of general composition Al203.2SÎ202.
- Metakaolin is, for example, a powdered product marketed under the name Argical 1200®, the composition of which is detailed in the following table [Table 1]. [0036] [Table 1]
- metakaolin with the trade name Argical 1200® [0037]
- the metakaolin used is finely ground. More precisely, metakaolin has a BET specific surface area greater than 15 m 2 / g. Preferably, the BET specific surface is greater than 25 m 2 / g. For example, the BET specific surface of metakaolin is greater than 30 m 2 / g.
- Metakaolin makes it possible in particular to obtain a smoother grout than with a conventional cement, by limiting the deposits of mineral salts on the surface of the cement (also called “efflorescence”).
- metakaolin makes it possible to improve the mechanical compressive strengths and to reduce the viscosity of the geopolymer grout obtained.
- an increase in the share of metakaolin relative to the share of fly ash leads to an increase in the mechanical strength and viscosity of the grout.
- metakaolin is elongated and irregular in shape while fly ash is spherical in shape
- grinding metakaolin improves its stacking properties with fly ash, resulting in an increase in the share of metakaolin among the charging elements.
- metakaolin is a component that requires little energy for its extraction compared to ordinary cement, which makes the manufacture of geopolymer grout environmentally attractive.
- metakaolin is obtained by calcining kaolinite (natural clay), which can be carried out at low temperature (between 600 ° C and 800 ° C) compared to the manufacture of a cement which requires a chemical combination of clay and limestone at very high temperature (around 1450 ° C).
- kaolinite natural clay
- Fly ash is class F fly ash. More specifically, the fly ash used comes from the combustion of pulverized coal in the boilers of thermoelectric power stations, by collection in electrostatic dust collectors. For example, the ashes flywheels used are marketed under the trade name “Silicoline ®”. Fly ash makes it possible in particular to improve the workability of the grout and the mechanical performance thereof in the long term.
- the fly ash used can be finely ground.
- the fly ash has a BET specific surface area greater than 15 m 2 / g.
- the BET specific surface is greater than 25 m 2 / g.
- the BET specific surface area of fly ash is greater than 30 m 2 / g.
- the fineness of the fly ash grinding improves the mechanical compressive strengths of the geopolymer grout obtained.
- the activator mixture comprises sodium hydroxide, sodium silicate and water.
- the activator mixture makes it possible to initiate the chemical reactions by breaking chemical bonds of the elements of metakaolin and fly ash, in order to form an amorphous gel then to start the polymerization reaction and to polymerize the whole in order to obtain the geopolymer whose three-dimensional structure contains the Si-O-Al bond.
- Sodium silicate is an alkaline silicate solution. More precisely, sodium silicate has an Na 2 O: SiO 2 molar ratio of between 0.40 and 0.70. For example, the molar ratio is preferably between 0.51 and 0.60. For example, the molar ratio is between 0.55 and 0.59. According to another example, the molar ratio is 0.57.
- the sodium silicate has a water content by mass of between 52.1% and 72.1%. For example, sodium silicate comprises 62.1% of its weight in water.
- Sodium hydroxide is in the initial form of sodium hydroxide tablets.
- the sodium hydroxide tablets are incorporated into the sodium silicate solution, according to the sodium hydroxide: sodium silicate mass ratio of 8.53: 100.
- 85.3g of soda are incorporated into 1000g of sodium silicate solution.
- the basic nature of the soda increases the pH of the geopolymer grout, which helps protect the reinforcements against corrosion.
- the grout has a pH of between 13 and 14.
- the geopolymer grout has a pH of between 13.3 and 13.5.
- the geopolymer grout has a pH close to 13.4.
- the aqueous solution of the penetrant testing has a basic pH included in the ranges detailed above.
- the penetrant water therefore does not cause corrosion of the reinforcements.
- the grout may have an aqueous solution bleeding of less than 0.5% of the total mass of the grout.
- Soda also makes it possible to obtain adequate Na / Si or Na / Al molar ratios, which makes it possible to obtain a geopolymer grout of chemical formulation meeting the desired criteria.
- the activator mixture further comprises water.
- Water is understood here to mean water which is added in addition to the water entering into the composition of the sodium silicate solution. Therefore, the water described here is not part of the water making up sodium silicate and is therefore excluded from the range of 52.1% to 72.1% by weight of sodium silicate water by weight discussed above.
- the added water represents less than 4% by total mass of the geopolymer grout.
- total mass of geopolymer grout is meant the mass of the grout comprising metakaolin, fly ash, sodium hydroxide, sodium silicate and added water. For example, the added water represents between 1% and 4% of the total mass of geopolymer grout.
- the added water represents between 1 and 2% of the total mass of the geopolymer grout, and preferably 1.86%. According to yet another example, the added water represents between 3 and 4% of the total mass of the geopolymer grout, and preferably 3.64%. This quantity remains marginal compared to the total mass of the geopolymer grout.
- the activator mixture has a water content by mass of less than 65%.
- the mass water content takes into account the water contained in the sodium silicate as such and the water added to the sodium silicate and the sodium hydroxide. Therefore, the mass content here is a ratio of the mass of water contained in the sodium silicate and the water added to the total mass of the activator mixture (i.e. sodium silicate, hydroxide sodium and added water).
- the activator mixture has a water content by mass of between 40% and 65%, and for example between 56% and 63%.
- the activator mixture has a mass water content between 58% and 59% According to another example, the activator mixture has a water mass content of between 59% and 60%
- the addition of water to the activator mixture makes it possible to improve the fluidity of the geopolymer grout while reducing only to a limited extent the mechanical resistance after setting and hardening, the latter always respecting the criterion according to which the resistance the compression of the grout must be greater than 30 MPa at 28 days.
- the geopolymer grout of the invention has the advantage of causing very limited bleeding and better homogeneity of the grout given the small amount of water incorporated. In addition, this small amount of water results in the absence of filtration in the bundle of reinforcements constituting the cable. The small amount of water added also results in a porosity of the geopolymer grout much lower than a porosity of the cementitious grout of the prior art. For example, the porosity of the geopolymer grout detailed here has a porosity at least six times lower than the porosity of a cement grout. In addition, the kinetic progression of injection of the geopolymer grout into the duct is facilitated and the grout coats the reinforcements more easily than does a conventional cement grout, which prevents the appearance of air pockets (or bubbles). occluded.
- the geopolymer grout is manufactured according to the process detailed below, comprising certain alternatives.
- the metakaolin and the fly ash are homogenized in a mechanical mixer.
- the metakaolin alone (that is to say without the fly ash) is ground in order to obtain a BET specific surface area greater than or equal to 25 m 2 / g and preferably greater than or equal to 30 m 2 / g.
- metakaolin is ground using a grinder.
- the mill used can be a ring mill or a ball mill.
- the load elements (that is to say the metakaolin and the fly ash) are ground in order to obtain a BET specific surface area greater than or equal to 25 m 2 / g and preferably greater than or equal to 30 m 2 / g.
- metakaolin In the case of a ball mill, for example a mass of 5 kg of metakaolin is introduced, which is ground for 12 hours at a speed of 39 revolutions per minute. Depending on the grinding time, different BET specific surfaces are obtained for metakaolin, some examples of which are grouped together in the following table [Table 2].
- Table 2 illustrates the grinding of 5 kg of metakaolin by a ball mill at a speed of 39 revolutions per minute.
- the sodium silicate solution in which the sodium hydroxide tablets are incorporated is then prepared. For example, a dose of 85.3 g of soda is incorporated per 1000 g of sodium silicate solution. The mixture is stirred until the soda tablets are completely dissolved. Then, in a kneading step, the activator mixture is kneaded with the metakaolin and the fly ash. This step allows to obtain a polymerization of the whole and therefore the geopolymer grout.
- the mixture of metakaolin and fly ash is introduced into the activator solution.
- the whole is then mixed enough to guarantee deflocculation of the mixture (homogeneous mixture without lumps)
- the water is then added to the whole.
- the addition of water makes it possible to thin the mixture so as to obtain a geopolymer grout having a fluidity at the cone of Marsh (with 10 mm diameter nozzle) between 25 seconds and 35 seconds, and for example 30 seconds.
- water is added before mixing the whole.
- water is added during mixing.
- the instant during which water is added during the mixing step does not modify the rheological properties and the mechanical resistance of the geopolymer grout.
- the added water does not participate in the polymerization of the whole. In other words, water is not a reactive component of the polymerization step. The addition of water to the mixture is therefore independent of the polymerization.
- the assembly is then kept at rest for 90 seconds.
- the geopolymer grout prepared has the characteristics grouped together in the following table [Table 3].
- the geopolymer slurry has a metakaolin: fly ash: alkaline silicate solution: sodium hydroxide ratio. 1: 1: 2-3: 0.15-0.35.
- the mass ratio is 1: 1: 2.4-2.6: 0.19-0.23.
- the mass ratio is 1: 1: 2.489: 0.212.
- the method of installing a structural cable mainly comprises the placement of a conduit containing at least one reinforcement as well as the tensioning of the reinforcement, then the injection of a geopolymer grout into the conduit.
- the geopolymer grout is mixed in order to obtain sufficient fluidity, measured with a Marsh cone according to the NF EN 445 standard of between 25 seconds and 45 seconds.
- the geopolymer grout is kneaded for 2 to 5 minutes (eg 4 minutes) with an energy of about 9 kilojoules per liter.
- Mixing is carried out for example by a turbo-type mixer making it possible to disperse in the mixture an energy of approximately 9 kilojoules per liter.
- This mixing is an important step of the injection process because it makes it possible to improve the fluidity in the same way, in other words to reduce the flow time measured with the Marsh cone.
- the geopolymer mixture before turbo-mixing may have a flow time greater than 50 seconds, while the turbo-mixing described above makes it possible to reduce it to a value of between 25 and 45 seconds (viscosity values of between 0.5 and 0.9 Pa.s). These flow time values may remain greater than the usual criterion of standard NF EN 445 (time less than or equal to 25 seconds) without preventing the injection of the grout.
- the geopolymer grout is injected into the conduit by a flexible.
- the hose has, for example, an internal diameter greater than 25 mm.
- the internal diameter of the hose is greater than 35 mm.
- the hose has a length for example limited to 100 m.
- the geopolymer grout is injected, for example, by means of a pump (nominal pressure 25 bar) with a pumping rate of between 0.5 m 3 / h and 1.5 m 3 / h.
- the geopolymer grout remains stable (that is to say homogeneous by absence of segregation). Indeed, no bleeding is observed around and through the reinforcements constituting the cable. In comparison with a cement grout, any risk associated with a poor hydration reaction, and in particular the production of an unstable grout, is therefore avoided here.
- After setting and hardening of the geopolymer grout one can find in cavities or bubbles a resurgence of aqueous solutions whose pH is between 13 and 13.5 and representing less than 0.5% by mass of grout.
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- Curing Cements, Concrete, And Artificial Stone (AREA)
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Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR2005925A FR3111134B1 (fr) | 2020-06-05 | 2020-06-05 | Coulis pour l’injection de cables de precontrainte et procede d’installation d’un cable comprenant un tel coulis |
PCT/FR2021/051007 WO2021245359A1 (fr) | 2020-06-05 | 2021-06-03 | Coulis pour l'injection de cables de precontrainte et procede d'installation d'un cable comprenant un tel coulis |
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EP4161883A1 true EP4161883A1 (fr) | 2023-04-12 |
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EP21737703.5A Pending EP4161883A1 (fr) | 2020-06-05 | 2021-06-03 | Coulis pour l'injection de cables de precontrainte et procede d'installation d'un cable comprenant un tel coulis |
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Country | Link |
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US (1) | US20230212073A1 (fr) |
EP (1) | EP4161883A1 (fr) |
JP (1) | JP2023529635A (fr) |
KR (1) | KR20230021698A (fr) |
AU (1) | AU2021283736A1 (fr) |
CA (1) | CA3185982A1 (fr) |
FR (1) | FR3111134B1 (fr) |
MX (1) | MX2022015389A (fr) |
WO (1) | WO2021245359A1 (fr) |
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DE2710011A1 (de) * | 1977-03-08 | 1978-09-14 | Schaefer Horst | Verfahren zur herstellung von spannbetonkonstruktionen mit nachtraeglichem verbund |
FR2623492B1 (fr) | 1987-11-23 | 1990-04-13 | Electricite De France | Perfectionnements aux mortiers injectables |
FR2713690B1 (fr) | 1993-12-10 | 1996-02-23 | Freyssinet Int Stup | Perfectionnements aux procédés et dispositifs de mise en Óoeuvre des coulis de ciment à injecter dans des gaines de précontrainte. |
FR2717465B1 (fr) * | 1994-03-21 | 1996-04-26 | Rhone Poulenc Chimie | Coulis d'injection pour enrober une armature, notamment une armature de précontrainte. |
FR2762864B1 (fr) | 1997-05-02 | 1999-07-23 | Freyssinet Int Stup | Element de gaine pour cable de precontrainte |
DE202004007409U1 (de) * | 2004-05-08 | 2005-09-15 | Dywidag Systems Int Gmbh | Korrosionsgeschütztes Zugglied, insbesondere Spannglied für Spannbeton ohne Verbund |
FR2949227B1 (fr) * | 2009-08-21 | 2013-09-27 | Laboratoire Central Des Ponts Et Chaussees | Ciment geopolymerique et son utilisation |
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2020
- 2020-06-05 FR FR2005925A patent/FR3111134B1/fr active Active
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2021
- 2021-06-03 CA CA3185982A patent/CA3185982A1/fr active Pending
- 2021-06-03 KR KR1020237000246A patent/KR20230021698A/ko active Search and Examination
- 2021-06-03 MX MX2022015389A patent/MX2022015389A/es unknown
- 2021-06-03 JP JP2022574586A patent/JP2023529635A/ja active Pending
- 2021-06-03 WO PCT/FR2021/051007 patent/WO2021245359A1/fr active Application Filing
- 2021-06-03 AU AU2021283736A patent/AU2021283736A1/en active Pending
- 2021-06-03 US US18/000,734 patent/US20230212073A1/en active Pending
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CA3185982A1 (fr) | 2021-12-09 |
WO2021245359A1 (fr) | 2021-12-09 |
JP2023529635A (ja) | 2023-07-11 |
FR3111134A1 (fr) | 2021-12-10 |
AU2021283736A1 (en) | 2023-01-19 |
US20230212073A1 (en) | 2023-07-06 |
FR3111134B1 (fr) | 2023-06-30 |
MX2022015389A (es) | 2023-03-15 |
KR20230021698A (ko) | 2023-02-14 |
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