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
  • C04B7/32—Aluminous cements
  • C04B7/326—Calcium aluminohalide cements, e.g. based on 11CaO.7Al2O3.CaX2, where X is Cl or F
• • 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
  • C04B28/06—Aluminous cements
  • C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
• • 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
  • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
  • C04B40/06—Inhibiting the setting, e.g. mortars of the deferred action type containing water in breakable containers ; Inhibiting the action of active ingredients
  • C04B40/0641—Mechanical separation of ingredients, e.g. accelerator in breakable microcapsules
  • C04B40/065—Two or more component mortars
• • 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
  • C04B7/32—Aluminous 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
  • 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
  • C04B2111/00724—Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
• • 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 invention relates to a cement composition and in particular to such a composition for use in the production of concrete like materials for filling cavities in underground mines and like purposes.
• Compositions of the invention comprise two slurries to be mixed together.
• the invention is based on the realisation that by selecting specific phases for the cement component of one slurry certain advantages result in terms of cost and efficiency.
• compositions to form a hardened cement comprising two slurries to be mixed together, the first slurry comprising water and a cement component comprising ferrite and C 12 A 7 or C 11 A 7 CX 2 (where X is a halogen atom) and a reactive source of silica, and the second slurry comprising water, beta anhydrite, calcium oxide and/or calcium hydroxide.
• the cement phase of the first slurry comprises a mixture of ferrite, ("C 4 AF") and C 12 A 7 (these formulae are in cement industry nomenclature).
• C 4 AF ferrite
• C 12 A 7 these formulae are in cement industry nomenclature.
• ferrite embraces other phases based on C2
• the ferrite and C 12 A 7 preferably make up about 50%, most preferably 65% to 85% by weight of the cement component.
• C 12 A 7 may be replaced by C 11 A 7 CX 2 where X is a halogen atom.
• the cement component will be made from a mineral clinker in known manner.
• the reactive source of silica is preferably a ground granulated blast furnace slag.
• the blast furnace slag may be of any known type and derived from any source.
• the particle size may vary widely but should be related to that of the particles of the cement component.
• the slag has a specific surface area of about 3000 to about 6000 cm 2 /g.
• the reactive source of silica may be provided by other ingredients in whole or in part such as pozzolans, pulverised fly ash, silica fume or other glassy mixtures of lime and silica.
• the reactive source of silica is preferably present in a weight ratio of 0.1 to 0.6 silica source per 1 part cement component. Sufficient should be present to ensure that strength regression does not occur after admixture of the two slurries. If more of the reactive source of silica is present, the strength of admixture will be too low to provide early pack support for an underground road.
• Suitable retarders include polysaccharides, glucose, fructose, lactose, sucrose and the like.
• Suitable suspending agents include cellulose ethers, polymers such as polyacrylamides and polyethylene oxides and polyacrylates; gums such as guar gum, xanthan gum or gum acacia; starch, hectorite, bentonite, attapulgite and the like.
• the second slurry contains calcium sulphate in the form of beta anhydrite because other forms of calcium sulphate when used alone do not give satisfactory results. Hydrated forms such as Plaster of Paris or gypsum both give strengths which are too low during the initial stages of the setting process and gamma-anhydrite hydrates very rapidly in water and gives similar results to the hydrated forms.
• the beta anhydrite is preferably present in the second slurry so that when the slurries are mixed it will be present relative to the cement component in a ratio of from 3:7 to 4:1 by weight.
• the quantity of calcium oxide or calcium hydroxide which is used. Too little results in inade ⁇ uate strength develonment but it is also poss ible to add too much with the result that the strength after one week is poor.
• the quantity used will be dependent on the quantity and nature of each of the other constituents which is present but in general good results are obtained when the quantity of calcium oxide and/or calcium hydroxide is from about 4 to about 8% by weight based on the weight of the cement component.
• the calcium oxide may be incorporated as such or as a latent source of lime such as Ordinary Portland cement.
• beta anhydrite it may be desirable to include a proportion of a suitable partially water soluble calcium sulphate such as gypsum (CaSO 4 2H 2 O), or hemihydrate (CaSO 4 1/2H 2 O), in order to increase the strength developed by the composition.
• a suitable partially water soluble calcium sulphate such as gypsum (CaSO 4 2H 2 O), or hemihydrate (CaSO 4 1/2H 2 O)
• the quantity of such calcium sulphate is preferably in the range of about 1 to about 6% by weight.
• the slurries may include other known additives such as accelerators of which sodium carbonate in a weight ratio of about 0.5 to about 3% relative to the cement component is an example.
• the present invention includes a dry powder comprising a cement component comprising at least one cement phase which has a C:A ratio greater than unity and a reactive source of silica, the cement phase being preferably ferrite and/or C 12 A 7 ; and a slurry comprising the dry powder and water.
• a first powder was made by mixing together: a high alumina
• ratios are selected so that the slurries can have a
• a method of producing a hardened cement containing ettringite comprising mixing the slurries defined above and allowing the mixture to harden.
• a bentonite clay in the second slurry as a suspension agent, both for the components of the second slurry and for the whole composition when the two slurries are mixed together.
• the quantity of bentonite used will be in the range of from 10.0 to 25.0% by weight based on the weight of beta anhydrite present.
• the quantity of lithium carbonate is preferably up to 0.5 by weight based on the weight of cement component.
• a second powder was made by mixing together: beta anhydrite 74.75
• Each powder was thoroughly mixed with water at 20oC in a water:sclids ratio of 2.5:1 to form a slurry. After 5 minutes the two slurries were intermixed by pouring from one bucket to another six times. The mixed slurries were then poured into insulated 100 mm cube moulds to simulate
• a comparative mixture was made up using the same slurries but following the teaching according to GB patent 2123808 B but including 20 parts relative to the HAC of the blast furnace slag used above.
• the HAC comprised (normalised to 100g):

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

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (9)

Cited By (4)

Families Citing this family (13)

Citations (5)

Family Cites Families (11)

• 1988
  • 1988-09-20 GB GB8822060A patent/GB2223488B/en not_active Expired - Lifetime
• 1989
  • 1989-09-14 EP EP89910901A patent/EP0396671A1/en not_active Ceased
  • 1989-09-14 BR BR8907093A patent/BR8907093A/pt unknown
  • 1989-09-14 AU AU43247/89A patent/AU624430B2/en not_active Ceased
  • 1989-09-14 US US07/476,372 patent/US5096497A/en not_active Expired - Fee Related
  • 1989-09-14 WO PCT/GB1989/001078 patent/WO1990003346A1/en not_active Ceased
  • 1989-09-18 CA CA 611693 patent/CA1331632C/en not_active Expired - Fee Related
  • 1989-09-18 IN IN836DE1989 patent/IN176280B/en unknown
  • 1989-09-20 ZA ZA897181A patent/ZA897181B/xx unknown

Patent Citations (5)

Non-Patent Citations (5)

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