WO2022018509A1 - Mélange de béton ayant des propriétés statiques et dynamiques améliorées et son procédé de préparation - Google Patents

Mélange de béton ayant des propriétés statiques et dynamiques améliorées et son procédé de préparation Download PDF

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Publication number
WO2022018509A1
WO2022018509A1 PCT/IB2020/062179 IB2020062179W WO2022018509A1 WO 2022018509 A1 WO2022018509 A1 WO 2022018509A1 IB 2020062179 W IB2020062179 W IB 2020062179W WO 2022018509 A1 WO2022018509 A1 WO 2022018509A1
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range
amount
concrete mixture
concrete
fraction
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PCT/IB2020/062179
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English (en)
Inventor
Binod Kumar BAWRI
Saroj BAWRI
Malvika Bawri
Raghunandan KADABA
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Sarod Greenback Llp
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Publication of WO2022018509A1 publication Critical patent/WO2022018509A1/fr

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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
    • 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
    • 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
    • C04B20/10—Coating or impregnating
    • C04B20/1055—Coating or impregnating with inorganic materials
    • C04B20/1066—Oxides, Hydroxides
    • 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
    • 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
    • C04B28/10—Lime cements or magnesium oxide cements
    • C04B28/12—Hydraulic lime
    • 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
    • C04B28/30—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 magnesium cements or similar cements
    • C04B28/32—Magnesium oxychloride cements, e.g. Sorel cement
    • 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 a concrete mixture having enhanced static and dynamic properties and a process for preparing the same.
  • Concrete mixture is a highly consumable and utilizable man-made construction material on earth. Infrastructures such as buildings, roads, airports, dams, ports require the use of concrete. Concrete mixture, is by far a heterogeneous composite, consisting of a bulk skeletal portion containing coarse aggregate, fine aggregate, and a binder portion containing a hydraulic material such as cement, and supplementary cementitious materials, such as fly ash, GGBS, micro silica, metakaolin, etc., held together by water.
  • a heterogeneous composite consisting of a bulk skeletal portion containing coarse aggregate, fine aggregate, and a binder portion containing a hydraulic material such as cement, and supplementary cementitious materials, such as fly ash, GGBS, micro silica, metakaolin, etc., held together by water.
  • Ordinary Portland cement plays a major role to ensure the high strength of the concrete mixture.
  • the ordinary Portland cement poses a great threat to the environment in terms of air pollution, deforestation, and/or soil erosion. Further, the production of the ordinary Portland cement consumes very high amount of energy and produces high amount of CO 2 . Hence, it is always desirable to provide a concrete mixture that minimizes the use of ordinary Portland cement without compromising on the strength of the concrete mixture.
  • the conventional method for increasing the packaging efficiency of the concrete and for producing a closely packed concrete mixture includes mixing binder, fine aggregate materials, and coarse aggregate materials in an optimum percentage.
  • the packaging efficiency of the concrete is low and hence, there exists a need to provide a concrete mixture that has high packaging efficiency thereby and maximize the strength of the construction material.
  • a methodology of making concrete mixture consists of a scientific way of combining the above materials (i.e. coarse aggregate, fine aggregate, and a binder portion containing a hydraulic material such as cement, and supplementary cementitious materials, such as fly ash, GGBS, micro silica, metakaolin, water, etc.).
  • a hydraulic material such as cement
  • supplementary cementitious materials such as fly ash, GGBS, micro silica, metakaolin, water, etc.
  • ITZ layer The Interfacial Transition zone
  • the aggregate phase or the main bulk phase consists of coarse aggregates, usually crushed stones made of hard rock materials such as igneous granite/basalt, limestone, etc.
  • the mortar phase is a uniform combination of the binder material along with the fine aggregate in the matrix.
  • the layer which forms the interface between the aggregate phase and the mortar phase is well known as the ITZ layer, or the Interfacial transition zone layer.
  • the function of the mortar phase is generally to bind the aggregates together in the densest possible manner, so that the resistance offered is higher.
  • the mortar strength by itself is not the limit to which the concrete strength can be attained.
  • Aggregates like granite or Basalt for instance have an individual compressive strength of anywhere around 150-300 MPa.
  • the resistance offered to uni-axial compression is very high, then on reaching a stress of around 150-300 MPa, the aggregates should crack or get crushed, leaving the concrete subject to failure.
  • This is the uppermost limit of the maximum compressive strength the concrete can attain which is a function of the maximum stress to which any of its individual materials may be subject to, such as coarse aggregates in this case.
  • the ITZ layer distributed unevenly throughout the matrix of the concrete, does not allows the mortar phase nor the aggregate phase to reach its full potential of stress handling.
  • the ITZ layer which is in terms of microns is proven through experiments to be the weakest zone in the concrete matrix. There are various reasons for this namely:
  • All structures including concrete structures in the modern times are analyzed and designed for earthquake loads and wind loads, which act horizontally on vertical members of a structural frame.
  • the wind loads are applied on nodes on a frame in the horizontal direction or the earthquake loads are suitably applied, and the frame is analyzed for different load combinations for failure criteria.
  • one conventional method for increasing earthquake resistance of concrete structures includes addition of reinforcing steel in the concrete structures.
  • Another conventional method for increasing earthquake resistance of concrete structures includes providing Tuned Mass Dampers (TMD), like a heavy water tank, a free pendulum of heavy weight etc., on the top of the concrete structure.
  • TMD Tuned Mass Dampers
  • the foundation of the concrete structure is designed under rocking conditions to mitigate the horizontal accelerations due to earthquakes.
  • fibre reinforced concrete Apart from the nature of fibre incorporated, the characteristics of fibre reinforced concrete are said to be affected by the following characteristics of fibre:
  • the present invention in an embodiment provides a concrete mixture having enhanced static and dynamic properties.
  • the concrete mixture comprises coarse aggregates in an amount of 20 to 50 (wt%) of the concrete mixture, fine aggregates in an amount of 15 to 45 (wt%) of the concrete mixture; binder material in an amount of 10 to 25 (wt%) of the concrete mixture; and optionally at least one additive in an amount of 0 to 5 (wt%) of the concrete mixture.
  • the coarse aggregate is having a layer of silica fumes thereupon, an amount of silica fumes being in the range of 0.1 to 5.0 % wt/wt of the coarse aggregate.
  • the concrete mixture further comprises fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm.
  • the silica fumes have a diameter in the range of 1 nano-meter to 10 microns.
  • the present invention in a further embodiment provides a method for preparing the concrete mixture, said process comprises obtaining (a) coarse aggregates having a layer of silica fumes thereupon, an amount of silica fumes being in the range of 0.1 to 5.0 % wt/wt of the coarse aggregate, (b) fine aggregates, (c) binder material, (d) fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, and (e) at least one additive; and mixing the coarse aggregates in an amount in the range of 20 to 50 (wt%) of the concrete mixture, the fine aggregates in an amount in the range of 15 to 45 (wt%) wt% of the concrete mixture, the binder material in an amount in the range of 10 to 25 (wt%) of the concrete mixture, the fibres, and optionally the at least one additive in an amount in the range of 0 to 5 (wt%) of the concrete mixture to obtain the concrete mixture.
  • Figure 1 shows the schematic view of the experimental set-up adopted for testing the concrete mixtures as per the examples of the invention
  • Figure 2(a) shows the attenuation characteristics of the induced shock waves in a beam which is said to provide “ductile response”
  • Figure 2(b) shows the attenuation characteristics of the induced shock waves in a beam which is said to provide a “brittle response”
  • Figure 3 shows a representative view of the concrete mixture having silica fumes coated particles heavily concentrated in the ITZ zone, consuming much of the Ca(OH2) concentration in the zone, making the ITZ layer much stronger;
  • Figure 4 shows the comparison of reduction of the acceleration with time, over a very infinitesimal time period of a fraction of a second, in a single pinged response for the concrete mix without any fibres, concrete mix with solid fibres, and the concrete mix with hollow fibres.
  • compositions comprising a list of ingredients does not include only those ingredients, but may include other ingredients not expressly listed.
  • process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method.
  • the term “strength” or “compressive strength” of concrete is the most common performance measure used by the engineer in designing buildings and other structures.
  • the compressive strength is measured by breaking cylindrical concrete specimens in a compression-testing machine. The compressive strength is calculated from the failure load divided by the cross- sectional area resisting the load and reported in units of pound-force per square inch (psi) in US Customary units or Mega Pascal (MPa) in SI units.
  • the mode average particle diameter as provided herein is understood to be the peak of the particle frequency distribution curve, obtained from PSD analysis.
  • the mode is the highest peak seen in the particle frequency distribution curve.
  • the mode represents the particle size (or size range) most commonly found in the particle frequency distribution curve within 1 standard deviation in the normal distribution curve.
  • the smallest fine and coarse aggregate mode average particle diameter is termed herein as the mode average particle diameter of the particles present in the raw construction material.
  • the smallest fine and coarse aggregate mode average particle diameter thus provides a clear cut idea of lattice void fillers being size of the particle of the raw construction material.
  • the particle-size distribution (PSD) analysis is termed herein as the mathematical expression of finding about the ratio/proportion of various particle size ranges which are present in given raw construction material.
  • volume, area, length, and quantity are used as standard dimensions for determining the particle amount present in the raw construction material.
  • the volume of the raw construction material sample is considered as the easiest dimension and/or way of finding out the ratio of various particles size ranges present in the given raw construction sample.
  • the present invention provides a concrete mixture having enhanced static and dynamic properties, said concrete mixture comprising coarse aggregates in an amount of 20 to 50 wt.% of the composition; fine aggregates in an amount of 15 to 45 wt.% of the composition; and binder material in an amount of 10 to 25 wt.% of the composition.
  • the concrete mixture optionally comprises at least one additive in an amount of 0 to 5 wt.% of the composition.
  • the coarse aggregate has a layer of silica fumes thereupon. In an embodiment of the invention, an amount of silica fumes on the coarse aggregate in the range of 0.1 to 5.0 wt.% of the coarse aggregate.
  • the silica fumes has a diameter in the range of 1 nano-meter to 10 microns.
  • the concrete mixture further comprises fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 0.5 mm to 5mm.
  • the silica fumes for coating on the coarse aggregate preferably has a diameter in the range of 1 nano meter to 1 micron. In an alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate preferably has a diameter in the range of 1 nano meter to 0.1 microns. In still another alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 10 nano meter to 1 micron. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 20 nano meter to 0.5 microns.
  • the silica fumes for coating on the coarse aggregate has a diameter in the range of 50 nano meter to 0.5 microns. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 75 nano meter to 1 micron. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 100 nano meter to 2.5 microns. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 150 nano meter to 500 nano meter.
  • the coarse aggregate comprises two or more fractions that are different from each other in term of their mode average particle size (MAPS).
  • the coarse aggregate comprises a first coarse aggregate fraction having MAPS in the range of 8 to 12 mm, corresponding to the maximum size of about 20 mm; and a second coarse aggregate fraction having MAPS in the range of 3 to 7 mm, corresponding to the maximum size of about 12 mm.
  • the coarse aggregate may comprise a third coarse aggregate fraction having MAPS in the range of 2-4 mm, corresponding to the maximum size of about 6.3 mm, as available in crusher productions of coarse aggregates.
  • an amount of the first coarse aggregate fraction may be in a range of 50 to 70 wt.% of the amount of the coarse aggregate.
  • an amount of the second coarse aggregate fraction may be in a range of 30 to 50 wt.% of the amount of the coarse aggregate.
  • an amount of the third coarse aggregate fraction may be in a range of 10 to 30 wt.% of the amount of the coarse aggregate.
  • the coarse aggregates are large sized filler materials selected from the group comprising of Brick chips (broken bricks), stone chips (broken stones), gravels, pebbles, clinkers, and cinders etc.
  • the fine aggregate comprises two or more fractions that are different from each other in term of their MAPS.
  • the fine aggregate comprises a first fine aggregate fraction having MAPS in the range 1 to 3 mm, corresponding to a maximum size of about 4.75 mm; and a second fine aggregate fraction having MAPS in the range of 0.5 to 2 mm, corresponding to a maximum size of about 4.75 mm.
  • the fine aggregate may comprise a third fine aggregate fraction having MAPS in the range of 0.1 to 1 mm, corresponding to a maximum size of about 2.36 mm.
  • an amount of the first fine aggregate fraction may be in a range of 40 to 100 wt.% of the amount of the fine aggregate.
  • an amount of the second fine aggregate fraction may be in a range of 20 to 80 wt.% of the amount of the fine aggregate.
  • an amount of the third fine aggregate fraction may be in a range of 10 to 50 wt.% of the amount of the fine aggregate.
  • the fine aggregates are small sized filler materials selected from the group of sand, stone screenings, burnt clays, cinders, fly ash, etc.
  • the binder material comprises a spontaneous hydraulic material, and optionally a pozzolanic material, a latent hydraulic material and at least one activator material.
  • an amount of spontaneous hydraulic material may be in the range of 30 to 100 wt.% of the binder material.
  • an amount of latent hydraulic material may be in the range of 0 to 70 wt.% of the binder material.
  • an amount of pozzolanic material may be in the range of 0 to 60 wt.% of the binder material.
  • an amount of activator material may be in the range of 0 to 10 wt.% of the binder material.
  • the spontaneous hydraulic material comprises two or more fractions that are different from each other in term of their MAPS.
  • the spontaneous hydraulic material comprises a first spontaneous hydraulic fraction having MAPS in the range of 70 to 80 microns; and a second spontaneous hydraulic fraction having MAPS in the range of 20 to 30 microns.
  • the spontaneous hydraulic material may comprise a third spontaneous hydraulic fraction having MAPS in the range of 3 to 8 microns.
  • the spontaneous hydraulic material may further comprise a fourth spontaneous hydraulic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first spontaneous hydraulic fraction may be in a range of 40 to 70 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the second spontaneous hydraulic fraction may be in a range of 20 to 40 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the third spontaneous hydraulic fraction may be in a range of 5 to 20 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the fourth spontaneous hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the spontaneous hydraulic material.
  • the spontaneous hydraulic material may be selected from a group comprising of Portland cement, modified Portland cement, or masonry cement, hydraulic hydrated lime, white cement, calcium aluminate cement, silicate cement, phosphate cement, high-alumina cement, magnesium oxychloride cement, oil well cements, and combinations thereof.
  • the latent hydraulic material comprises two or more fractions that are different from each other in term of their MAPS.
  • the latent hydraulic material comprises a first latent hydraulic fraction having MAPS in the range of 70 to 80 microns; and a second latent hydraulic fraction having MAPS in the range of 20 to 30 microns.
  • the latent hydraulic material may comprise a third latent hydraulic fraction having mode average particle size (MAPS) in the range of 3 to 8 microns.
  • the latent hydraulic material may further comprise a fourth latent hydraulic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first latent hydraulic fraction may be in a range of 40 to 70 wt.% of the amount of the latent hydraulic material.
  • an amount of the second latent hydraulic fraction may be in a range of 20 to 40 wt.% of the amount of the latent hydraulic material.
  • an amount of the third latent hydraulic fraction may be in a range of 5 to 15 wt.% of the amount of the latent hydraulic material.
  • an amount of the fourth latent hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the latent hydraulic material.
  • the latent hydraulic material may be selected from a group comprising of blast furnace slag, mechanically modified blast furnace slag, chemically modified blast furnace slag, and combinations thereof.
  • the pozzolanic material comprises two or more fractions that are different from each other in term of their mode average particle size (MAPS).
  • the pozzolanic material may comprise a first pozzolanic fraction having MAPS in the range of 70 to 80 microns; and a second pozzolanic fraction having MAPS in the range of 20 to 30 microns.
  • the pozzolanic material may comprise a third pozzolanic fraction having MAPS in the range of 3 to 8 microns.
  • the pozzolanic material may further comprise a fourth pozzolanic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first pozzolanic fraction may be in a range of 40 to 70 wt.% of the amount of the pozzolanic material.
  • an amount of the second pozzolanic fraction may be in a range of 20 to 40 wt.% of the amount of the pozzolanic material.
  • an amount of the third pozzolanic fraction may be in a range of 5 to 15 wt.% of the amount of the pozzolanic material.
  • an amount of the fourth latent hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the latent hydraulic material.
  • the pozzolanic material may be selected from a group comprising of fly ash, volcanic ash material, quartz material, pond ash, mechanically modified fly ash, chemically modified fly ash, mechanically modified pond ash, chemically modified pond ash, mechanically modified quartz, chemically modified quartz, micro silica, metakaoline and combinations thereof.
  • the activator material may be selected from a group comprising of sodium sulphate, slag sand, lime, and combinations thereof.
  • an amount of the fibre in the concrete mixture is in a range between 0.5 kg/m 3 to 5.0 kg/m 3 of concrete.
  • the fibres may be made of any of steel, polymer, glass, asbestos, carbon, or organic material.
  • the fibre is made of at least one of polyethylene, polypropylene, and polyester, or steel and has tensile strength in a range of 300 N/mm 2 to 2000 N/mm 2 .
  • the fibres are solid. In an alternative embodiment of the invention, the fibres are hollow in yet another alternative embodiment of the invention, the fibres are hollow and have their ends closed and is filled with air or with a fluid. In an embodiment of the invention, the fluid is non-reactive to the fibres. In another embodiment of the invention, the fluid has a viscosity index in the range of 100 to 250. Non-limiting example of the fluid include food grade oils, and other synthetic oils.
  • the fibres are having a layer of silica fumes thereupon, an amount of silica fumes being in the range of 0.1 to 5.0 wt. % of the fibres.
  • the silica fumes has a diameter in the range of 1 nano meter to 10 microns.
  • the silica fumes for coating on the coarse aggregate preferably has a diameter in the range of 1 nano meter to 1 micron. In an alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate preferably has a diameter in the range of 1 nano meter to 0.1 microns. In still another alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 10 nano meter to 1 micron. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 20 nano meter to 0.5 microns.
  • the silica fumes for coating on the coarse aggregate has a diameter in the range of 50 nano meter to 0.5 microns. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 75 nano meter to 1 micron. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 100 nano meter to 2.5 microns. In a further alternative embodiment of the invention, the silica fumes for coating on the coarse aggregate has a diameter in the range of 150 nano meter to 500 nano meter.
  • the concrete mixture further comprises 4 to 8 wt.% of water.
  • the at least one additive is selected from a group comprising of Melamine, Lignosulphonate, Sulphonated Naphthalene Formaldehyde, Polycarboxylate group, micro silica, nano-silica, metakaoline, carbon nanotube (CNT) based additives, and combinations thereof.
  • the invention also provides a process for preparing the aforesaid concrete mixture which has enhanced static and dynamic properties.
  • the method of preparing the concrete mixture comprises obtaining coarse aggregates, fine aggregates, hydraulic material, fibres, and optionally at least one additive.
  • the method of preparing the concrete mixture comprises mixing coarse aggregates in an amount of 20 to 50 wt.% of the concrete mixture, fine aggregates in an amount of 15 to 45 wt.% of the concrete mixture, the binder material in an amount of 10 to 25 wt.% of the concrete mixture, the fibres, and optionally the at least one additive in an amount of 0 to 5 wt.% of the concrete mixture to obtain the concrete mixture.
  • the coarse aggregate has a layer of silica fumes thereupon.
  • an amount of silica fumes on the coarse aggregate in the range of 0.1 to 5.0 wt. % of the coarse aggregate.
  • the silica fumes has a diameter in the range of 1 nano meter to 10 microns.
  • the fibres have a length in the range of 5 mm to 50 mm and internal diameter in the range of 0.5 mm to 5 mm.
  • the concrete mixture further comprises of water in an amount in the range of 4 to 8 wt.% of the concrete mixture.
  • water in an amount in the range of 4 to 8 wt. % of the concrete mixture is added and mixed with the remaining ingredients.
  • the coarse aggregate comprises two or more fractions that are different from each other in term of their mode average particle size (MAPS).
  • the coarse aggregate comprises a first coarse aggregate fraction having MAPS in the range of 8 to 12 mm, corresponding to the maximum size of about 20 mm; and a second coarse aggregate fraction having MAPS in the range of 3 to 7 mm, corresponding to the maximum size of about 12 mm.
  • the coarse aggregate may comprise a third coarse aggregate fraction having MAPS in the range of 2-4 mm, corresponding to the maximum size of about 6.3 mm, as available in crusher productions of coarse aggregates.
  • an amount of the first coarse aggregate fraction may be in a range of 50 to 70 wt.% of the amount of the coarse aggregate.
  • an amount of the second coarse aggregate fraction may be in a range of 30 to 50 wt.% of the amount of the coarse aggregate.
  • an amount of the third coarse aggregate fraction may be in a range of 10 to 30 wt.% of the amount of the coarse aggregate.
  • the coarse aggregates are large sized filler materials selected from the group comprising of Brick chips (broken bricks), stone chips (broken stones), gravels, pebbles, clinkers, and cinders etc.
  • the coarse aggregate having a layer of silica fumes thereupon is obtained by:
  • silica fumes • making a slurry of silica fumes with water, the silica fumes having a diameter in the range of 1 nano meter to 10 microns;
  • the slurry for coating the coarse aggregates has 50 to 300 grams of silica fumes per litre of water.
  • the fine aggregate comprises two or more fractions that are different from each other in term of their MAPS.
  • the fine aggregate comprises a first fine aggregate fraction having MAPS in the range 1 to 3 mm, corresponding to a maximum size of about 4.75 mm; and a second fine aggregate fraction having MAPS in the range of 0.5 to 2 mm, corresponding to a maximum size of about 4.75 mm.
  • the fine aggregate may comprise a third fine aggregate fraction having MAPS in the range of 0.1 to 1 mm, corresponding to a maximum size of about 2.36 mm.
  • an amount of the first fine aggregate fraction may be in a range of 40 to 100 wt.% of the amount of the fine aggregate.
  • an amount of the second fine aggregate fraction may be in a range of 20 to 80 wt.% of the amount of the fine aggregate.
  • an amount of the third fine aggregate fraction may be in a range of 10 to 50 wt.% of the amount of the fine aggregate.
  • the fine aggregates are small sized filler materials selected from the group of sand, stone screenings, burnt clays, cinders, fly ash, etc.
  • the binder material comprises a spontaneous hydraulic material, and optionally a pozzolanic material, a latent hydraulic material and at least one activator material.
  • an amount of spontaneous hydraulic material may be in the range of 30 to 100 wt.% of the binder material.
  • an amount of latent hydraulic material may be in the range of 0 to 70 wt.% of the binder material.
  • an amount of pozzolanic material may be in the range of 0 to 60 wt.% of the binder material.
  • an amount of activator material may be in the range of 0 to 10 wt.% of the binder material.
  • the spontaneous hydraulic material comprises two or more fractions that are different from each other in term of their MAPS.
  • the spontaneous hydraulic material comprises a first spontaneous hydraulic fraction having MAPS in the range of 70 to 80 microns; and a second spontaneous hydraulic fraction having MAPS in the range of 20 to 30 microns.
  • the spontaneous hydraulic material may comprise a third spontaneous hydraulic fraction having MAPS in the range of 3 to 8 microns.
  • the spontaneous hydraulic material may further comprise a fourth spontaneous hydraulic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first spontaneous hydraulic fraction may be in a range of 40 to 70 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the second spontaneous hydraulic fraction may be in a range of 20 to 40 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the third spontaneous hydraulic fraction may be in a range of 5 to 20 wt.% of the amount of the spontaneous hydraulic material.
  • an amount of the fourth spontaneous hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the spontaneous hydraulic material.
  • the spontaneous hydraulic material may be selected from a group comprising of Portland cement, modified Portland cement, or masonry cement, hydraulic hydrated lime, white cement, calcium aluminate cement, silicate cement, phosphate cement, high-alumina cement, magnesium oxychloride cement, oil well cements, and combinations thereof.
  • the latent hydraulic material comprises two or more fractions that are different from each other in term of their MAPS.
  • the latent hydraulic material comprises a first latent hydraulic fraction having MAPS in the range of 70 to 80 microns; and a second latent hydraulic fraction having MAPS in the range of 20 to 30 microns.
  • the latent hydraulic material may comprise a third latent hydraulic fraction having mode average particle size (MAPS) in the range of 3 to 8 microns.
  • the latent hydraulic material may further comprise a fourth latent hydraulic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first latent hydraulic fraction may be in a range of 40 to 70 wt.% of the amount of the latent hydraulic material.
  • an amount of the second latent hydraulic fraction may be in a range of 20 to 40 wt.% of the amount of the latent hydraulic material.
  • an amount of the third latent hydraulic fraction may be in a range of 5 to 15 wt.% of the amount of the latent hydraulic material.
  • an amount of the fourth latent hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the latent hydraulic material.
  • the latent hydraulic material may be selected from a group comprising of blast furnace slag, mechanically modified blast furnace slag, chemically modified blast furnace slag, and combinations thereof.
  • the pozzolanic material comprises two or more fractions that are different from each other in term of their mode average particle size (MAPS).
  • the pozzolanic material may comprise a first pozzolanic fraction having MAPS in the range of 70 to 80 microns; and a second pozzolanic fraction having MAPS in the range of 20 to 30 microns.
  • the pozzolanic material may comprise a third pozzolanic fraction having MAPS in the range of 3 to 8 microns.
  • the pozzolanic material may further comprise a fourth pozzolanic fraction having MAPS in the range of 0.01 to 2 microns.
  • an amount of the first pozzolanic fraction may be in a range of 40 to 70 wt.% of the amount of the pozzolanic material.
  • an amount of the second pozzolanic fraction may be in a range of 20 to 40 wt.% of the amount of the pozzolanic material.
  • an amount of the third pozzolanic fraction may be in a range of 5 to 15 wt.% of the amount of the pozzolanic material.
  • an amount of the fourth latent hydraulic fraction may be in a range of 1 to 5 wt.% of the amount of the latent hydraulic material.
  • the pozzolanic material may be selected from a group comprising of fly ash, volcanic ash material, quartz material, pond ash, mechanically modified fly ash, chemically modified fly ash, mechanically modified pond ash, chemically modified pond ash, mechanically modified quartz, chemically modified quartz, micro silica, metakaoline and combinations thereof.
  • an amount of the fibre in the concrete mixture is in a range between 0.5 kg/m 3 to 5.0 kg/m 3 of concrete.
  • the fibres may be made of any of steel, polymer, glass, asbestos, carbon, or organic material.
  • the fibre is made of at least one of polyethylene, polypropylene, and polyester, or steel and has tensile strength in a range of 300 N/mm 2 to 2000 N/mm 2 .
  • the fibres are solid. In an alternative embodiment of the invention, the fibres are hollow. In yet another alternative embodiment of the invention, the fibres are hollow and have their ends closed and is filled with air or with a fluid. In an embodiment of the invention, the fluid is non-reactive to the fibres. In another embodiment of the invention, the fluid has a viscosity index in the range of 100 to 250. Non-limiting example of the fluid include food grade oils, and other synthetic oils.
  • the fibres are having a layer of silica fumes thereupon, an amount of silica fumes being in the range of 0.1 to 5.0 wt. % of the fibres, the silica fumes has a diameter in the range of 1 nano meter to 10 microns..
  • the fibres are having a layer of silica fumes thereupon is obtained by: making a slurry of silica fumes with water, the silica fumes having a diameter in the range of 1 nano meter to 10 microns.; mixing the slurry and the fibres to obtain wet fibres; and drying the wet fibres to obtain the fibres having a layer of silica fumes thereupon.
  • the slurry for coating the fibres has 50 to 300 grams of silica fumes per litre of water.
  • the at least one additive is selected from a group comprising of Melamine, Lignosulphonate, Sulphonated Naphthalene Formaldehyde, Polycarboxylate group, micro silica, nano-silica, metakaoline, carbon nanotube (CNT) based additives, and combinations thereof.
  • the activator material may be selected from a group comprising of sodium sulphate, slag sand, lime, and combinations thereof.
  • the step of mixing comprises mixing the binder material in an amount in the range of 10 to 25 wt.% of the concrete mixture with water in an amount in the range of 4 to 8 wt.% of the concrete mixture to obtain a slurry.
  • the step of mixing further comprises adding and mixing coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture to the slurry in any sequence to obtain the concrete mixture.
  • the silica fumes have a diameter in the range of 1 nano meter to 10 microns.
  • the fibres are solid or hollow and the fibres are optionally coated with the silica source having a diameter in the range of 1 nano meter to 10 microns.
  • the binder material comprises a spontaneous hydraulic material, and optionally a pozzolanic material, a latent hydraulic material and at least one activator material
  • the step of mixing comprises mixing the spontaneous hydraulic material in an amount in the range of 30 to 100 wt.% of the binder material and water in an amount in the range of 4 to 8 wt. % of concrete mixture to obtain a slurry.
  • the step of mixing further comprises adding and mixing the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, the at least one activator material in an amount in the range of 0 to 10 wt.% of the binder material, the coarse aggregates having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, the fine aggregates in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture to the slurry in any sequence to obtain the concrete mixture.
  • the silica fumes have a diameter in the range of 1 nano meter to 10 microns.
  • the fibres are solid or hollow and the fibres are optionally coated with the silica fumes having a diameter in the range of 1 nano meter to 10 microns.
  • the concrete mixture may be supplied in “ready-mix form” or in “dry- mix form”.
  • the concrete mixture may contain water in an amount in the range of 4 to 8 wt. % of concrete mixture.
  • the dry-mix form is devoid of water. In such case, the desired quantity of water may be added by the user to the dry mix form to obtain the concrete mixture.
  • a first ingredient comprising coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of concrete mixture, and fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture; and a second ingredient comprising binder material in an amount in the range of 10 to 25 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of concrete mixture are supplied.
  • a first ingredient comprising coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, and the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm; and a second ingredient comprising the binder material in an amount in the range of 10 to 25 wt.% of the concrete mixture, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture are supplied.
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising binder material in an amount in the range of 10 to 25 wt.% of the concrete mixture, and the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm are supplied.
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the binder material in an amount in the range of 10 to 25 wt.% of the concrete mixture are supplied.
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, the at least one activator material in an amount in the range of 0 to 10 wt.% of the binder material and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material in an amount in the range of 30 to 100
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material in an amount in the range of 30 to 100 wt.% of the binder material and the at least one activator material in an amount in the range of 0 to
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, the at least one activator material in an amount in the range of 0 to 10 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material in an amount in the range of 30 to 100 wt.% of the binder material, and the latent hydraulic material in an amount in the range of 0
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, the at least one activator material in an amount of in the range of 0 to 10 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material in an amount in the range of 30 to 100 wt.% of the binder material, and the pozzolanic material in an amount in the range of
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material in an amount in the range of 30 to 100 wt.% of the binder material, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, and the at least one activator material in an amount in the range of 0
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the latent hydraulic material in an amount in the range of 0 to 70 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient the spontaneous hydraulic material comprising 30 to 100 wt.% of the binder material, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, and the at least one activator material in an amount in the range of 0 to 10 wt.%
  • a first ingredient comprising the coarse aggregate having a layer of silica fumes thereupon in an amount in the range of 20 to 50 wt.% of the concrete mixture, fine aggregate in an amount in the range of 15 to 45 wt.% of the concrete mixture, the fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5mm, the at least one activator material in an amount in the range of 0 to 10 wt.% of the binder material, and optionally the at least one additive in an amount in the range of 0 to 5 wt.% of the concrete mixture; and a second ingredient comprising the spontaneous hydraulic material 30 to 100 wt.% of the binder material, the pozzolanic material in an amount in the range of 0 to 60 wt.% of the binder material, and the latent hydraulic material in an amount in the range of 0 to 70 wt.%
  • the silica fumes on the coarse aggregate have a diameter in the range of 1 nano meter to 10 microns.
  • the fibres are solid or hollow and the fibres are optionally coated with silica fumes having a diameter in the range of 1 nano meter to 10 microns.
  • the moisture content when the concrete mixture is being supplied in “dry-mix form”, the moisture content does not exceed the threshold permissible moisture levels. In a preferred aspect of the invention, the moisture content is removed from all the ingredients to the maximum possible extent. In a more preferred aspect of the invention, the concrete mixture in “dry-mix form” is in substantially bone-dry condition.
  • the ingredients forming part of the concrete mixture or the concrete mixture are dried or heated. Prior to drying or heating, an amount of moisture contained in (or absorbed by) the ingredients forming part of the concrete mixture is estimated or determined.
  • the amount of moisture contained in (or absorbed by) the ingredients forming part of the concrete mixture is estimated or determined taking into consideration the rate of moisture absorption of the ingredients under the prevailing environmental conditions.
  • the concrete mixture allows for a high-level consumption of calcium hydroxide concentration in the ITZ (Interfacial Transition zone) layer by secondary hydration process, due to a very high concentration of micro silica particles on the aggregate, thus creating a strong interfacial bond.
  • ITZ Interfacial Transition zone
  • incorporation of solid fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm in the concrete mixture leads to improving the static flexural toughness characteristics of concrete member.
  • incorporation of solid fibres in the concrete mixture leads to incorporation of 3-dimensional reinforcement inside the matrix of the concrete architectural structure.
  • incorporation of solid fibres imparts certain amount of flexibility to the concrete architectural structure.
  • the discontinuity includes an interface between the mortar medium and the fibre medium, and an interface between the fibre medium and the mortar medium.
  • the random discontinuities present in all directions inside the concrete structure interact with the waves that propagate through the concrete architectural structure (in response to the concrete architectural structures being subjected to horizontal acceleration waves caused by earthquake) and reflect the waves which leads to partial dampening of waves propagating through the concrete architectural structure.
  • the concrete mixture incorporates hollow fibres having a length in the range of 5 mm to 50 mm and internal diameter in the range of 1 mm to 5 mm, the static flexural toughness characteristics as well as the dynamic properties, such as dampening of acceleration waves inside the concrete member is drastically improved.
  • the discontinuity when hollow fibres are incorporated includes a mortar medium interfacing with a fibre medium, fibre medium interfacing with air medium (or other fluid medium), air medium (or other fluid medium) interfacing with the fibre medium, and fibre medium interfacing the mortar medium. Furthermore, air (or the other fluid medium) which is present within the hollow fibres is not only a very good suppressor of the waves but also drastically improves dynamic properties of the concrete member.
  • the fibres may have a layer of silica fumes thereupon.
  • Silica fumes as provided on the fibres reacts with the calcium hydroxide present in the ITZ layer formed at the interface between the fibre and the mortar and cause secondary hydration process and formation of strong interfacial bond (which leads to depletion of the calcium hydroxide present in the ITZ layer).
  • the silica fumes have a diameter in the range of 1 nano meter to 10 microns.
  • the fibres may be hollow with the ends sealed. By providing hollow fibres having their ends sealed, the probability of the binder (or other additives) getting inside the fibres can be prevented.
  • the hollow fibres are not brought in direct contact with solid binder or other additives that are either solid or in free-flowing liquid state. Instead, the solid binder and other additives are first mixed with water to obtain slurry and subsequently thereof, the hollow fibres are mixed with the slurry.
  • the hollow fibres may be blended along with a suitable dosage of solid polymeric/steel fibres, to create a hybrid system of fibres, for further enhanced static and dynamic performance.
  • a suitable dosage of solid polymeric/steel fibres to create a hybrid system of fibres, for further enhanced static and dynamic performance.
  • Mix 1 A control mix of M40 grade, in which the coarse aggregate do not have a layer of silica fumes.
  • Mix 2 The same concrete mix as above, but where the coarse aggregate has a layer of silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the amount of silica fumes is approximately 0.7% by weight of the coarse aggregate.
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • Mix 3 The same concrete mix as above, but where the coarse aggregate has a layer of silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the amount of silica fumes is approximately 1.87% by weight of the coarse aggregate.
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • Mix 4 The same concrete mix as above, but where the coarse aggregate has a layer of silica source fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the amount of silica fumes is approximately 7.12% by weight of the coarse aggregate.
  • silica source fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • concretes can be made which basically reach the strength levels of the coarse aggregates which are used in the making, and making concrete grades 150 MPa to 200 MPa would be possible with much lesser binder content than ever before, with unprecedented levels of reduction in cost and increase in durability of concrete.
  • Mix 5 A control mix of M40 grade, in which the coarse aggregate has a layer of silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the amount of silica fumes is approximately 0.7% by weight of the coarse aggregate (i.e. Mix 2 was taken as control).
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • Mix 7 The same concrete mix as above, but having 1.0 kg of solid fibres per cubic meter of concrete, wherein the solid fibres have a length of about 25 mm and internal diameter of around 2.5 mm.
  • Mix 8 The same concrete mix as above, but having 1.0 kg of solid fibres per cubic meter of concrete, wherein the solid fibres have a length of about 50 mm and internal diameter of around 5.0 mm.
  • Mix 9 The same concrete mix as above, but having 5.0 kg of solid fibres per cubic meter of concrete, wherein the solid fibres have a length of about 50 mm and internal diameter of around 5.0 mm.
  • Mix 10 The same concrete mix as above, but having 7.0 kg of solid fibres per cubic meter of concrete, wherein the solid fibres have a length of about 70 mm and internal diameter of around 10.0 mm.
  • Concrete beams 150 mm X 150 mm X 150 mm
  • the sample beams are fixed at the bottom.
  • Waves can be made to propagate through the beam by inducing shock at say, the bottom end of the beam.
  • a pendulum comprising a weight of let’s say 1 kg was made to strike a bottom portion of the beam to induce the shock which will propagate throughout the beam.
  • Suitable numbers of accelerometers are incorporated for the measurement of acceleration response of the beam under test, power spectrum, etc.
  • the accelerometer measures stochastic vibrations.
  • at least one accelerometer is placed at the top of the beam.
  • the acceleration data was downloaded from the accelerometer and evaluated on the following parameters: a. The time period for which the shock wave was observed; b. Peak value of acceleration; and c. Average value of the peak acceleration for the experiments that were repeated 20 times.
  • the peak value of the acceleration wave as observed at the second end of the beam which was made of Mix 6, Mix 7, Mix 8, and Mix 9 was less than the peak value of the acceleration wave as observed at the end of the beam which was made of Mix 10 (which has excessive amount of fibres and wherein the fibres have more than the desired length and internal diameter).
  • Mix 11 The same concrete mix as in Mix 5, but having 1.0 kg of hollow fibres per cubic meter of concrete, wherein the hollow fibres have a length of about 5 mm and internal diameter of approximately 1 mm.
  • Mix 12 The same concrete mix as in Mix 5, but having 1.0 kg of hollow fibres per cubic meter of concrete, wherein the hollow fibres have a length of about 25 mm and internal diameter of around 2.5 mm.
  • Mix 13 The same concrete mix as in Mix 5, but having 1.0 kg of hollow fibres per cubic meter of concrete, wherein the hollow fibres have a length of about 50 mm and internal diameter of around 5.0 mm.
  • Mix 14 The same concrete mix as in Mix 5, but having 5.0 kg of hollow fibres per cubic meter of concrete, wherein the hollow fibres have a length of about 50 mm and internal diameter of around 5.0 mm.
  • Mix 15 The same concrete mix as in Mix 5, but having 7.0 kg of hollow fibres per cubic meter of concrete, wherein the hollow fibres have a length of about 70 mm and internal diameter of around 10.0 mm.
  • the acceleration data was downloaded from the accelerometer and evaluated on the following parameters: a. Peak value of acceleration; b. Average value of the peak acceleration for the experiments that were repeated 20 times; and c. The time period for which the shock wave was observed.
  • the peak value of the acceleration wave as observed at the second end of the beams which were made of Mix 11, Mix 12, Mix 13, and Mix 14 was very less than the peak value of the acceleration wave as observed at the end of the beams which were made of Mix 6, Mix 7, Mix 8, and Mix 9, respectively.
  • the beams which were made of Mix 11, Mix 12, Mix 13, and Mix 14 provided a ductile response to the induced shock waves (as shown in Figure 2(a) in that the shock waves were attenuated over a marginally short period of time) while the beams which were made of Mix 6, Mix 7, Mix 8, and Mix 9, respectively provided brittle response (as shown in Figure 2(b) in that the shock waves died abruptly).
  • Mix 16 The same concrete mix as in Mix 5, but having 1.0 kg per cubic meter of concrete of fibres that have their ends closed and is filled with air, wherein the filled fibres have a length of about 25 mm and internal diameter of approximately 2.5 mm.
  • Mix 17 The same concrete mix as in Mix 5, but having 1.0 kg per cubic meter of concrete of fibres that have their ends closed and is filled with food grade oil, wherein the filled fibres have a length of about 25 mm and internal diameter of around 2.5 mm.
  • the acceleration data was downloaded from the accelerometer and evaluated on the following parameters: a. Peak value of acceleration; b. Average value of the peak acceleration for the experiments that were repeated 20 times; and c. The time period for which the shock wave was observed.
  • the peak value of the acceleration wave as observed at the second end of the beams which were made of Mix 16, and Mix 17 was very less than the peak value of the acceleration wave as observed at the end of the beam which was made of Mix 7.
  • the average value of the peak acceleration wave as observed at the second end of the beams which were made of Mix 16, and Mix 17 was less than the average value of the peak acceleration wave as observed at the end of the beam which was made of Mix 7.
  • the beams which were made of Mix 16, and Mix 17 provided a ductile response to the induced shock waves (in that the shock waves were attenuated over a marginally short period of time) while the beam which was made of Mix 7 provided brittle response (in that the shock waves died abruptly).
  • Mix 18 The same concrete mix as in Mix 5, but having 1.0 kg per cubic meter of concrete of solid fibres having silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the solid fibres have a length of about 25 mm and internal diameter of approximately 2.5 mm and, the amount of micro -silica on the solid fibre is about 1.5 wt.% (the wt.% being expressed on the basis of the weight of the solid fibre).
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • Mix 19 The same concrete mix as in Mix 5, but having 1.0 kg per cubic meter of concrete of hollow fibres having silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the hollow fibres have a length of about 25 mm and internal diameter of approximately 2.5 mm and, the amount of micro-silica on the hollow fibre is about 1.5 wt.% (the wt.% being expressed on the basis of the weight of the hollow fibre).
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • Mix 20 The same concrete mix as in Mix 5, but having 1.0 kg per cubic meter of concrete of hollow fibres having their ends closed and being filled with air, wherein the hollow fibres having their ends closed and being filled with air have silica fumes (preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns) thereupon, wherein the hollow fibres having their ends closed and being filled with air have a length of about 25 mm and internal diameter of approximately 2.5 mm and, the amount of micro -silica on the hollow fibres having their ends closed and being filled with air is about 1.5 wt.% (the wt.% being expressed on the basis of the weight of the hollow fibres having their ends closed and being filled with air).
  • silica fumes preferably micro-silica having a diameter in the range of 0.1 microns to about 5 microns
  • the binder used comprises continuous series of different particle sizes having a defined mode average particle diameter which is achieved via various mechanical particle size modification processes.
  • particle sizes having a continuous series of different mode average particle diameter provides compact fillers of lattice void of the particle lattice structure ranging from Micro to Nano level.
  • This mixture provides a perfect particle chemistry to fill the maximum voids of the particle lattice structure and also improves the chemistry related to the early settings and the latter settings of the concrete material.
  • the constituents such as fine aggregate, coarse aggregates, hydraulic material and activators are chosen to have specific particle sizes as well as specific chemical constituents.
  • the chemical modification of the concrete composition enhances the properties contributed by the fine particle size, wherein the activator, such as sodium sulphate, initiates the reaction of the pozzolan material, such as fly ash, with Ca(OH)2 phase released due to primary hydration process, to enhance the early strength of the concrete composition within 1 day of setting.
  • the activator such as sodium sulphate
  • the pozzolan material such as fly ash
  • the coated hollow fibres show much better static behaviour such as residual strength of the fibre reinforced concrete, or the overall flexural toughness, in comparison to un-coated hollow fibres and solid fibre reinforced concretes. This is a very important aspect where the concrete gives enough warning before collapse under static loading conditions, even after the first crack occurs.
  • concretes made with aggregate coated with silica fumes exhibit much higher compressive strengths (and evidently much better durability characteristics due to enhanced ITZ layer) than concretes made with uncoated aggregates.
  • the order of increase in strength and durability is observed to be higher in higher grades of concrete.
  • Figure 4 shows the comparison of reduction of the acceleration with time, over a very infinitesimal time period of a fraction of a second, in a single pinged response for the concrete mix without any fibres, concrete mix with solid fibres, and the concrete mix with hollow fibres.
  • Figure 2(a) and 2(b) shows the comparison of reduction of the acceleration with time, over a very infinitesimal time period of a fraction of a second, in a single pinged response. When magnified, it shows the response spectrum revealing that the damping response is more ductile in nature in case of concrete with hollow fibre, as compared to a more brittle response in case of concrete with solid fibres. This indicates that by introduction of hollow fibres, the member behaves more ductile in nature, which is desired against a brittle one, where the energy transfer is of sudden nature.

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Abstract

La présente invention concerne un mélange de béton ayant des propriétés statiques et dynamiques améliorées, ledit mélange de béton comprenant des granulats grossiers dans une quantité de 20 à 50 (% en poids) du mélange de béton ; des granulats fins dans une quantité de 15 à 45 (% en poids) du mélange de béton, un matériau liant dans une quantité de 10 à 25 (% en poids) du mélange de béton ; et éventuellement au moins un additif dans une quantité de 0 à 5 (% en poids) du mélange de béton ; ledit mélange étant caractérisé en ce que : le granulat grossier est doté d'une couche de fumée de silice, une quantité de fumées de silice étant comprise dans la plage de 0,1 à 2,0 % en poids de du granulat grossier ; les fumées de silice ont un diamètre compris dans la plage de 1 nanomètre à 10 microns, et le mélange de béton comprend en outre des fibres ayant une longueur comprise dans la plage de 5 mm à 50 mm et un diamètre interne dans la plage de 1 mm à 5 mm.
PCT/IB2020/062179 2020-07-22 2020-12-18 Mélange de béton ayant des propriétés statiques et dynamiques améliorées et son procédé de préparation WO2022018509A1 (fr)

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IN202031031282 2020-07-22

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CN114853411A (zh) * 2022-04-20 2022-08-05 同济大学 一种用于3d打印的高阻尼全再生骨料混凝土油墨材料及制备方法

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KR100867250B1 (ko) * 2007-05-15 2008-11-06 현대건설주식회사 비소성 결합재를 포함하는 초고강도 콘크리트 조성물
US20110015306A1 (en) * 2009-07-15 2011-01-20 US Concrete, Inc. Cementitious compositions for decreasing the rate of water vapor emissions from concrete and methods for preparing and using the same
KR20170005669A (ko) * 2015-07-06 2017-01-16 주식회사 포스코건설 실리카계 더스트 혼합물을 포함하는 콘크리트 조성물 및 이를 이용한 콘크리트의 제조방법

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114853411A (zh) * 2022-04-20 2022-08-05 同济大学 一种用于3d打印的高阻尼全再生骨料混凝土油墨材料及制备方法
CN114853411B (zh) * 2022-04-20 2023-03-14 同济大学 一种用于3d打印的高阻尼全再生骨料混凝土油墨材料及制备方法

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