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
  • C04B7/00—Hydraulic cements
  • C04B7/345—Hydraulic cements not provided for in one of the groups C04B7/02 - C04B7/34
• • 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
• • 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
  • C04B28/24—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 alkyl, ammonium or metal silicates; containing silica sols
  • C04B28/26—Silicates of the alkali metals
• • 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

Definitions

• the present invention relates to the field of hydraulically setting materials.
• Hydraulic setting materials such as cement and concrete are known.
• the applications of concrete made from aggregates bound by Portland cement or lime (hydraulic) are numerous (see for example the article "The
• Portland cement particles have dimensions of the order of 50 microns because it is their surface that is mainly active to form the adhesive (silicates, calcium aluminates ...) that binds the aggregates together.
• Portland cement is contaminated with chromium VI of non-negligible toxicity and likely to cause allergies.
• Portland cement On the aesthetic level, Portland cement has a gray color that denatures the appearance of aggregates. The setting speed depends strongly on the temperature and is low below about 5 ° C, a handicap which restricts the activity of the BTP especially in winter.
• the cement paste has a shrinkage while the aggregates are rigid, which generates tensions that can lead to the appearance of cracks.
• Portland cement concrete is made by adding the cement, water, to aggregates. According to their decreasing dimensions, these are commonly called pebbles, chippings (order of 1 cm), sand (order of millimeter), fines and fillers. Aggregates used for the manufacture of concrete and mortar must meet different constraints. Thus, they preferably have a suitable grain size curve to minimize voids and thus the amount of binder needed to make the medium continuous.
• the invention aims to provide a composition having a hydraulic setting similar to cement but does not have one or more of the disadvantages mentioned, including releasing less carbon dioxide.
• component (d) an appropriate amount of water, characterized in that it contains less than 20%, preferably less than 15% and most preferably less than 5% by weight of component (c). Indeed, it has surprisingly been found that a composition comprising the indicated components was likely to take up mass even in the presence of a very small amount of alkali hydroxide.
• the composition comprises 0.1 to 10% by weight of component (c).
• the mass ratio between component (c) and components (a) and (b) is less than 20%, preferably less than 15% and most preferably less than 10%.
• component (a) and (b) is provided by a silico-calcareous aggregate.
• Component (a) or (b) may be or contain a waste.
• component (b) is a siliceous aggregate.
• the composition comprises 10 to 60% by weight of component (a) and component (b), respectively.
• the composition also preferably comprises little water, generally less than 10% by weight and in particular less than 5% by weight.
• the invention relates to a method for preparing a monolithic material, comprising the step of: - preparing a composition according to the invention;
• the invention relates to a monolithic material that can be obtained by the method described. According to a last aspect, the invention aims to use the material thus obtained as a construction or repair material.
• cement refers to a mixture of crushed inorganic materials which form by addition of water a binder paste capable of hardening and binding granular materials together.
• aggregates refers to divided solids of variable size generally derived from nature, for example quarries or sand pits, including powders but also aggregates such as sand, gravel and crushed. Generally, the aggregates used in the context of the invention have an average size of between 0.1 and 20 mm. The chemical reactions involved in making the composition described differ from those involved in the manufacture of a cement concrete
• one of the reagents is soluble and available in solution in ionic form, that is to say in the form of elements of a size of the order of 50 A.
• the solution reacts with the limestone and siliceous aggregates to create links between them.
• the aggregates of the composition include limestone aggregates and siliceous aggregates.
• the aggregates used comprise silica-sand aggregates, which have both silica and limestone. Aggregates generally come from nature and thus contain other elements.
• the aggregates contain few cations other than silicon and calcium, such as in particular aluminum, iron, magnesium, titanium, potassium and sodium.
• the sum of the contents of the cation aggregates other than calcium and silicon, and in particular aluminum is preferably less than 10%, more preferably less than 5% and in particular less than 2% by weight.
• the silica may be in crystalline or amorphous form. When it is crystalline, it can be in particular a quartz or a crystalobalite.
• the soluble reagent is an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide, alone or in admixture. Preferably, it is sodium hydroxide. It may also be reagents releasing the alkali metal hydroxide in situ, such as in particular the carbonates of these metals.
• the amount of water is adjusted to ensure a good hold of the composition.
• the appropriate amount of water depends on several factors, including the size of aggregates and their degree of dryness. In general, sufficient water is added to ensure granulation of the mixture and formation of hydrated compounds, but taking care to avoid excessive amounts leading to seepage.
• the different components are intimately mixed and then shaped. This mixture can be made once or twice.
• the stirring of the mixture is preferably carried out so as to benefit from the thixotropic properties of the mixture (planetary motion, shear forces, etc.).
• the order of introduction of the reagents during mixing does not matter.
• the mixture can then be placed directly, for example in a mold, or between banches, or on a substrate by vibro-compaction.
• Other methods customary for hydraulically setting compositions for example molding, spraying, injection or grout may also be contemplated.
• the composition solidifies by hydraulic setting, which takes place in a time between a few hours and a few days. Hardening can be followed by measurements of mechanical strength.
• Reaction (1) results in in situ formation in the composition of lime and sodium carbonate.
• Lime reacts with silica according to equation (2) to yield a poorly soluble compound, mainly tobermorite.
• Sodium carbonate reacts with calcium carbonate to give a mixed carbonate, which precipitates according to the quantity of water in the form of pirsonnite (2 molecules of water) or of gaylussite (5 molecules of water), which are also poorly soluble.
• composition described requires little or no adjuvants usually used in cementitious compositions, such as accelerators and retarders, anti-clay agents, chromium reducers.
• composition may contain certain additives in order to modify its properties and / or its appearance, such as fillers, reinforcements, pigments, dyes.
• composition does not substantially alter the appearance of the aggregates, thus making the material very aesthetic. Also, this composition is particularly interesting for a mortar type application for coatings and floor coverings. It can also be useful as a grout, in particular by injection into the basement.
• the sample hardens on the surface after a few hours and can be demolded after a few days.
• the sample is evaluated by compressive strength at 28 days and has a compressive strength of 80 MPa.
• the sample is subjected to the X leaching test 30417 described above.
• the pH is less than 12, which is lower than the leaching of a conventional Portland concrete.
• the results of the evaluation are summarized in Table 6.
• Table 1 Composition of the siliceous granules of Chazeuil
• Table 4 composition of siliceous granulose from Meillers
• a hydraulically setting composition was prepared as in Example 2, but adding 312.33 cm 3 NaOH 16.7 N and no water.
• a water-setting composition was prepared as in Example 2, but adding 156 cm 3 of 16.7 N NaOH and no water.
• a water-setting composition was prepared as in Example 2, but adding 52.39 cm 3 of 16.7 N NaOH and no water.
• a hydraulic setting composition is prepared as in Example 2 with 900 g of standardized silica sand certified to ISO 679 (ciosceni Littoral, Leucate, France), 175 g of calcium carbonate, 125 g of silica, predominantly in the form of cristobalite and 100 cm 3 of 10 N NaOH.
• EXAMPLE 8 A hydraulic setting composition was prepared as in Example 7, but with a larger amount of sodium hydroxide. 900 g of standardized silica sand certified to ISO 679 (ciosico du Littoral, Leucate, France), 225 g of calcium carbonate, 105 g of silica predominantly in the form of cristobalite and 175 cm 3 of 10 N NaOH are mixed. found that the compressive strength at 28 days is better when the amount of sodium hydroxide is greater.
• EXAMPLE 9 In order to study the influence of the addition of calcium chloride, a hydraulic setting composition is first prepared as in Example 2 with 900 g of standardized silica sand certified according to ISO 679 (ciosico du Littoral Leucate, France), 175 g of calcium carbonate, 125 g of silica predominantly in the form of cristobalite and 91 cm 3 of 10 N NaOH. The results of the evaluation are summarized in Table 6.
• the concrete composition After mixing for 5 minutes, the concrete composition is introduced into a suitable mold.
• the sample hardens in a few hours and can be demolded in a few days.
• the sample is evaluated in particular by measuring the compressive strength at 8 days and has a compressive strength of 6 MPa.
• the composition After mixing for 5 minutes, the composition is introduced into a suitable mold.
• the sample hardens on the surface in a few hours and can be demolded in a few days.
• the sample is evaluated in particular by measuring the compressive strength at 79 days and has a compressive strength of 90 MPa.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Structural Engineering (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Soil Conditioners And Soil-Stabilizing Materials (AREA)

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• 2006
  • 2006-08-21 FR FR0607425A patent/FR2904972B1/fr active Active
• 2007
  • 2007-08-08 WO PCT/FR2007/001354 patent/WO2008023109A2/fr active Application Filing
  • 2007-08-08 EP EP07823406A patent/EP2069256A2/de not_active Withdrawn
  • 2007-08-08 US US12/438,181 patent/US20090249981A1/en not_active Abandoned
  • 2007-08-08 CA CA002661135A patent/CA2661135A1/fr not_active Abandoned

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