WO2017044808A1 - Béton haute résistance et faible densité et procédés associés - Google Patents

Béton haute résistance et faible densité et procédés associés Download PDF

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Publication number
WO2017044808A1
WO2017044808A1 PCT/US2016/051047 US2016051047W WO2017044808A1 WO 2017044808 A1 WO2017044808 A1 WO 2017044808A1 US 2016051047 W US2016051047 W US 2016051047W WO 2017044808 A1 WO2017044808 A1 WO 2017044808A1
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WIPO (PCT)
Prior art keywords
lwa
composition
lightweight concrete
concrete composition
settable
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Application number
PCT/US2016/051047
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English (en)
Inventor
Randall Lee Byrd
Original Assignee
Sebastos Technologies, Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Sebastos Technologies, Inc filed Critical Sebastos Technologies, Inc
Publication of WO2017044808A1 publication Critical patent/WO2017044808A1/fr
Priority to US15/808,525 priority Critical patent/US10377669B2/en
Priority to US16/277,362 priority patent/US10759701B1/en
Priority to US17/002,490 priority patent/US11577998B2/en
Priority to US18/165,059 priority patent/US20240043332A1/en

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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/02—Controlling the operation of the mixing
    • B28C7/022—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/02—Controlling the operation of the mixing
    • B28C7/022—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component
    • B28C7/024—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component by measuring properties of the mixture, e.g. moisture, electrical resistivity, density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B14/02—Granular materials, e.g. microballoons
    • C04B14/04—Silica-rich materials; Silicates
    • C04B14/22—Glass ; Devitrified glass
    • C04B14/24—Glass ; Devitrified glass porous, e.g. foamed glass
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00034—Physico-chemical characteristics of the mixtures
    • C04B2111/00103—Self-compacting mixtures
    • 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
    • C04B2111/40—Porous or lightweight materials
    • 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

  • this invention relates to low-density, high-strength concrete that is lightweight, and to related concrete mixes that may be self-compacting and that, among the many multiple uses thereof, may be used for walls, building structures, architectural panels, concrete blocks, insulation (including pipe insulation), poles and beams, roofing, fencing, shotcrete, floating structures, concrete backfill, fire-proofing (structural, sprayed and troweled), precast structures, cast-in-place structures, pipe rack structures, and self-leveling flooring, and includes the methods of manufacturing such items or structures using such a lightweight concrete, and the steps of providing such a lightweight concrete composition and the unmixed components thereof.
  • Concrete is an important building material for structural purposes and nonstructural purposes alike. Concrete, generally speaking, includes cementitious materials and aggregate. There may be one or more types of cementitious material and one or more types of aggregate. Concrete may also include voids and reinforcing materials, such as fiber or steel rod (rebar), wire mesh or other forms of reinforcement. It can have high compressive strength, wear-resistance, durability, and water-resistance, be lightweight, readily formed into a variety of shapes and forms, and be very economical compared to alternative construction materials. The formation process includes the presence of water to permit the cementitious materials to harden and to form bonds with itself, with any aggregate, and with reinforcing materials.
  • rebar steel rod
  • That hydration process which involves some of the water present being used in those chemical reactions, is well- known and -understood.
  • the use or value of concrete as a building material may be limited by a number of factors. Those factors pertaining to finished structures and products include: weight, relatively poor tensile strength, ductility, the inability to readily cut, drill or nail, and poor insulating properties. Those factors pertaining to the concrete before setting include: weight, limited flowability (and/or reduced strength caused by adding water to overcome the same), requirement to vibrate or otherwise compact the concrete to limit voids, segregation of aggregate, and the like. Those factors pertaining to the precursor materials or components supplied for use in making concrete structures or products include: cost, weight, and segregation of aggregate and other materials.
  • Lightweight concretes have been developed to reduce the limiting effect of the weight of, among other things, finished concrete structures and products and uncured concrete.
  • Such lightweight concretes typically involve replacing some or all of the aggregate in a mix with another form of aggregate that is less dense than commonly-used aggregate.
  • Such aggregate may be known as lightweight aggregate (“LWA”).
  • LWCs often have lower strength (such as tensile, compressive, elastic modulus etc.) than a comparable concrete not using LWA, but may have higher strength-to- weight ratios due to the reduced density of the concrete and the weight for a given structure or product.
  • a structural LWC is ordinarily considered to have a density between about 90 - 120 Ib/cu.ft. and a compressive strength from 2500 psi to over 8000 psi. These values may be measured by ASTM C567 and ASTM C39, respectively.
  • a variety of characteristics of the set concrete or its behavior during the manufacturing process can be measured and/or designed into that process. These include tensile strength, compressive strength, elastic modulus, modulus of rupture, plastic density, bulk density, oven-dried density, R-value, coefficient of thermal expansion, crack resistance, impact-resistance, fire resistance, slump, water/cement ratio, paste content by volume, weights, and weight-fractions.
  • the amount or characteristics of the LWA used, or the amount of ordinary aggregate replaced by LWA may be constrained by the need to meet certain minimum characteristics, including but not limited to tensile strength, compressive strength, elastic modulus, flexural strength, or modulus of rupture. Other constraints may include segregation of the LWA within the concrete.
  • Admixtures may be liquid or solid, but are typically liquid unless the mix is to be kept in the dry state, such as for making bagged concrete mix.
  • LWC Low density, higher strengths, higher strength-to-weight ratios, and increased R-value, as well as improved crack resistance, impact-resistance, and fire resistance.
  • Reduction of the density and weight of the concrete offers a variety of advantages, including but not limited to: reduced structure weight and loading in dead loads in buildings and structures; easier and cheaper transportation and handling of the concrete products, lower transportation costs (equipment / fuel); improved thermal insulating properties, fire resistance, and acoustical properties.
  • An embodiment of the present invention includes a self-compacting LWC having a low density, high strength-to-weight ratio, good segregation-resistance, and a high R- value. Another embodiment includes a non-self-compacting LWC having a low density, high strength-to-weight ratio, good segregation-resistance, and a high R-value. An embodiment of the present invention includes a LWC having a high replacement volume, a low weight-fraction of aggregate to total dry raw materials, and highly- homogenous distribution of LWA.
  • An embodiment of the present invention includes a LWC that has a density less than 50% of what is ordinarily found in structural LWC (about 90 - 120 Ib/cu.ft.) while having at least the minimum compressive strength of about 2500 to 3000 psi of a structural LWC or, in another embodiment, at least a minimum compressive strength of about 3000 to 3500 psi.
  • An embodiment of the present invention includes a LWC that has a more moderate replacement volume and weight-fraction of aggregate to total dry raw materials, a highly-homogenous distribution of LWA, and a density between about 50% and 75% of what is ordinarily found in structural LWC (about 90 - 120 lb/cu.ft.), while having at least a minimum compressive strength of about 2500 psi of a structural LWC and up to or above about 150% of that strength.
  • An embodiment of the present invention includes a LWC having a low replacement volume, a high weight-fraction of aggregate to total dry raw materials, a highly-homogenous distribution of LWA, and a density about what is ordinarily found in structural LWC (about 90 - 120 lb/cu.ft.), and a compressive strength of about two or three times the minimum compressive strength (3500 psi) of a structural LWC.
  • That LWC includes a LWA that is composed of one or both of the following types of particles: glass microspheres and polymer beads.
  • Glass microspheres which are substantially less dense than water, are closed- cell, smooth and non-absorptive, and vast majority of the particles are smaller than 115 microns.
  • An embodiment of the invention is a LWC including a LWA composed of glass microspheres between around 0.10 and 0.40 specific gravity ("SG"), and whose size distribution is such that about 90% are smaller than about 115 microns, and about 10% are smaller than about 10 microns, and the median size is in the range of about 30-65 microns.
  • Such glass microspheres may have about a 90% survival rate (i.e. they are not crushed) at pressures ranging from about 250 - 4000 psi or higher.
  • glass microsphere LWA include those in which the density is about 0.15 SG, the median size is about 55 microns, and 80% are between about 25-90 microns. Such glass microspheres have about a 90% survival rate at about 300 psi.
  • Another particular embodiment of the glass microspheres is one in which the density is about 0.35 SG, the median size is about 40 microns, and 80% are between about 10-75 microns, with about a 90% survival rate at about 3000 psi.
  • An embodiment of the invention is a LWC including a LWA composed of a mixture of two or more particular types of glass microspheres, such that the two or more varieties compose all of the LWA in the LWC.
  • An embodiment of the present invention includes a self-compacting LWC mix having a high replacement volume, a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • An embodiment of the present invention includes a non-self-compacting LWC mix having a high replacement volume, a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • Those LWC mixes includes a LWA that is composed of glass microspheres and/or polymer beads, as described above.
  • Embodiments of the LWC and LWC mixes include those in which other aggregates are present in addition to one or more types of LWA.
  • Such ordinary aggregates may include, but are not limited to, sand, and gravel.
  • Embodiments also include LWC including LWA both with reinforcing materials, such as fiber or steel rod (re- bar) or wire mesh or other forms of reinforcing, or without reinforcement.
  • Embodiments of the LWC and LWC mixes include cementitious materials, which may include one or more materials such as hydraulic cements, Portland cements, fly ash, silica fume (fumed silica), pozzolana cements, gypsum cements, aluminous cements, magnesia cements, silica cements, and slag cements. Cements may also be colored.
  • cementitious materials may include one or more materials such as hydraulic cements, Portland cements, fly ash, silica fume (fumed silica), pozzolana cements, gypsum cements, aluminous cements, magnesia cements, silica cements, and slag cements. Cements may also be colored.
  • An embodiment of the present invention includes the steps of preparing a LWC mix having a high replacement volume, a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • An embodiment of the present invention includes the steps of preparing a LWC mix having a more moderate replacement volume and weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • An embodiment of the present invention includes the steps of preparing a LWC mix having a low replacement volume, high weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • Those LWC mixes includes a LWA that is composed of glass microspheres, as described above.
  • a mix may be prepared with liquids for forming concrete therefrom, or as a dry mix, such as for a bagged concrete mix.
  • a wet mix may be prepared, for example, in either a drum-type mixer, a pan-type mixer, or a ribbon mixer.
  • a dry mix may be prepared, for example, in a pan-type mixer.
  • An embodiment of the present invention includes wet mix methods. These include ready mix methods, such as concrete precursor materials prepared and mixed on-site, either for use on-site or for transport, and such as concrete precursor materials forming the unmixed components of a LWC mix, prepared for batching and mixed during transportation. Admixtures may be added during mixing, or during batching.
  • An embodiment of the present invention includes dry mix methods. These include dry concrete precursor materials prepared and mixed or blended on-site, with only dry admixtures if necessary, and bagged or otherwise prepared for sale.
  • An embodiment of the present invention includes manufacturing and mixing processes.
  • Such processes include a concrete manufacturer acquiring concrete precursor materials including water (such as either by purchase or extraction) and any admixtures, preparing batches, weighing or otherwise measuring them individually (or together in such a way as to permit the components to be measured), and providing the unmixed components of a LWC mix, such as by depositing the components into a concrete mixing truck.
  • Such processes also include a concrete manufacturer acquiring concrete precursor materials including water (such as either by purchase or extraction) and any admixtures, preparing batches including weighing the components individually, holding them for delivery, and providing the components, such as by depositing the components into a stationary concrete mixer or other type of mixer.
  • a concrete manufacturer may use the mixed concrete on-site, such as for a structure, or may be a pre-caster.
  • a pre-caster will cast concrete products on- or off-site using molds or forms, but those products are typically transported for use elsewhere. Examples of pre-cast products include but are not limited to concrete blocks, structural beams, and architectural panels.
  • An embodiment of the present invention includes a self-compacting LWC composition having a high strength after curing for 3 days, 7 days and 28 days, and has a low oven-dried density, including embodiments in which that density is below 130, 120, 110, 100, 90, 80, 70, 60, and even 40 Ib./cu.ft., and embodiments at about 40 Ib./cu.ft. in which the compressive strengths are over 1200 and over about 1600 psi at 3-days, over about 1500 psi at 7-days, over about 1750 psi at 4-days, and over about 2750, over about 3100 and over about 3800 psi at 28-days.
  • Embodiments of the present invention at about 40 Ib./cu.ft. include a self-compacting LWC composition for which the strength-to-density ratio is above about 30 and about 40 for the 3-day compressive strength, and above about 30, about 40, and about 50 for the 7-day compressive strength, and above about 45, about 70 and about 80 for the 28-day compressive strength.
  • An embodiment of the present invention including an ordinary aggregate such as sand includes a self-compacting LWC composition having a high strength after curing for 3 days, 7 days and 28 days, and has a low oven-dried density, including embodiments in which that density is above 90, and below 90, 80, 70, and even 60 Ib./cu.ft., including embodiments at or below about 60 Ib./cu.ft. in which the compressive strengths are over about 1700, about 2000 and about 2200 psi at 3-days, over 1800 and about 2750 psi at 7-days, and over about 2500 and about 4000 psi at 28-days.
  • Embodiments also include LWC with an oven-dried density over 60 Ib./cu.ft. in which the compressive strengths are over about 2300, and about 3700 psi at 3-days, over about 2700 and about 4300 psi at 7-days, and over about 3000 and about 4700 psi at 10- days.
  • Embodiments of the present invention at or below about 60 Ib./cu.ft. include a self- compacting LWC composition for which the strength-to-density ratio is at or above about 25 and about 40 for the 3-day compressive strength, at or above about 30 and about 50 for the 7-day compressive strength, and above about 40 and about 70 for the 28-day compressive strength.
  • Embodiments also include a self-compacting LWC composition with an oven-dried density over 60 Ib./cu.ft. for which the strength-to-density ratio is at or above about 30 for the 3-day compressive strength, at or above about 35 for the 7- day compressive strength, and above about 40 for the 10-day compressive strength.
  • An embodiment of the present invention including an ordinary aggregate such as gravel includes a self-compacting LWC composition having a high strength after curing for 7 days and 28 days, and has a low oven-dried density, including embodiments in which that density is about 120, about 100, or below about 80 Ib./cu.ft., and embodiments at about 120 Ib./cu.ft. in which the compressive strengths are over about 4000 and about 5000 psi at 3-days, over about 4000, about 5000 and about 6000 psi at 7-days, and over about 4000, about 5000 and about 7000 psi at 28-days.
  • Embodiments of the present invention at about 120 Ib./cu.ft. include a self- compacting LWC composition for which the strength-to-density ratio is at or above about 35 and about 40 for the 3-day compressive strength, at or above about 40 or 50 for the 7-day compressive strength, and about 50 or 55 for the 28-day compressive strength.
  • Embodiments of the present invention between about 75 and 100 Ib./cu.ft. include a self-compacting LWC composition for which the strength-to-density ratio is at or above about 35 and about 40 for the 3-day compressive strength, at or above about 40 or 45 for the 7-day compressive strength, and about 45 or 50 for the 28-day compressive strength.
  • the above embodiments may also be LWC compositions that are non-self- compacting.
  • FIG. 1 A is a cutaway showing fiber-reinforced LWC.
  • FIG. 1 B is a cutaway showing rebar-reinforced LWC.
  • FIG. C is a cutaway showing wire mesh-reinforced LWC.
  • FIG. 2 displays a relationship between density and thermal resistance at several thickness.
  • FIGS. 3A-3B describes the steps used to mix the concrete during preparation of a concrete composition.
  • FIG. 4 displays the process for making bagged LWC mix.
  • FIG. 5A displays a partially cutaway drum mixer.
  • FIG. 5B displays a pan mixer.
  • FIG. 5C displays a ribbon mixer.
  • FIG. 5D displays a cement truck.
  • FIG. 6 describes the steps at a central-mix facility for mixing a concrete composition or for preparing and providing the components of a concrete composition.
  • FIG. 7A displays an exploded view of a precast mold and product.
  • FIG. 7B displays an in-situ mold and product.
  • FIG. 8A describes the steps for mixing and manufacturing a CMU.
  • FIG. 8B displays a partial cutaway view of a CMU making machine and CMUs.
  • Embodiments of the invention include: (a) a LWA composed of (i) glass microspheres, which are less dense than water, are closed-cell, smooth and non- absorptive, and of which the vast majority of such microspheres are smaller than 105 microns; (ii) polymer beads, which are about as dense as water, are solid, smooth and non-absorptive and having a median size of at least about 150 microns, or (iii) a combination of such polymer beads and such glass microspheres, (b) a wet LWC mix comprising such a LWA; (c) unmixed components of a LWC mix comprising such a LWA; (d) a dry LWC mix comprising such a LWA; (e) a LWC formed of or comprising such a LWA; (f) manufactured or pre-cast products comprising a LWC formed of or comprising such a LWA; (g) the process of preparing batches of components of a LWC mix comprising
  • An embodiment of the present invention includes a self-compacting LWC having a low density, high strength-to-weight ratio, high strength-to-density ratio, good segregation-resistance, and a high R-value.
  • An embodiment of the present invention includes a LWC having a high replacement volume, a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous distribution of LWA.
  • An embodiment of the present invention includes a LWC that has a density about 50%, or even less (as low as about 30 or 35 Ib/cu.ft), as compared to the ordinary value for structural LWC (about 90 - 120 Ib/cu.ft.), and has 28-day compressive strengths of over 1750 psi, over 2000 psi, over 2500 psi and over 3000 psi.
  • Embodiments of the present invention also includes a LWC that has a density that falls at about 1 ⁇ 2 to 3 ⁇ 4 the ordinary value for structural LWC (about 90 - 120 lb/cu.ft.), and has 28-day compressive strengths of over 2500 psi, and over 4000 psi.
  • Embodiments of the present invention also includes a LWC that has a density that falls in about the same range as the ordinary value for structural LWC (about 90 - 120 lb/cu.ft.), and has 28-day compressive strengths of over 5000 psi, and over 7000 psi.
  • a LWA of an embodiment of the invention comprises glass microspheres, which are less dense than water and preferably substantially much less dense, are closed-cell, substantially resistant to volumetric change (or dimensional change) under pressure, smooth and non-absorptive, and vast majority of the microspheres are smaller than 115 microns.
  • the glass microspheres may range between around 0.10 and 0.60 specific gravity ("SG"), and have a size distribution such that about 90% are smaller than about 115 microns, and about 10% are smaller than about 9 microns, and the median size is in the range of about 18-65 microns.
  • Such glass microspheres may have about a 90% survival rate (i.e. they are not crushed) at pressures ranging from about 250 - 28000 psi.
  • the LWC is substantially free of either all of, or some of, such non-dimensionally and non-volumetrically stable materials such as aerogels and foamed particles and foams incorporating air bubbles such as those formed by including air entrainment admixtures.
  • microspheres and the materials in which they are utilized can have their isostatic crush strength measured.
  • the crush strength distribution gets revealed by analyzing the volume change as the pressure increases.
  • Such data gets analyzed by using a metric commonly referred to as the "survival rate" to which the apparent pore volume stays intact.
  • Sphere size and wall strength determine the crush strength. Owing to the irreversible nature of crushing, the entrapment can be up to 100%.
  • the glass microsphere LWA include one in which the density is about 0.15 SG, the median size is about 55 microns and some 80% are between about 25-90 microns (and some 10% each are smaller than about 25 microns and larger than about 90 microns). Such 0.15 SG glass microspheres have an approximate 90% survival rate at about 300 psi.
  • Another particular embodiment of the glass microspheres is one in which the density is about 0.35 SG, the median size is about 40 microns, and 80% are between about 10-75 microns (and some 10% each are smaller than about 10 microns and larger than about 75 microns), with such 0.35 SG microspheres having an approximate 90% survival rate at about 3000 psi.
  • microspheres can be as large as 300 microns.
  • glass microspheres are typically smooth, but the surface could be etched, such as by acid-washing or other methods. Without being bound by any particular theory, it is believed that etching the surface of the glass microspheres may permit better adhesion between the cementitious materials and the microspheres, leading to greater strength, crack-resistance and other benefits. Doing so may also permit or encourage reaction between the glass microspheres and the cementitious materials.
  • hollow glass microspheres may have the following approximate characteristics. (The "80% between” column also reflects that some 10% each are smaller than the lower value and larger than the larger value.):
  • a LWA having a higher crush strength is generally stronger.
  • a LWA may be composed of a mixture of two or more particular types of glass microspheres, such that the two or more varieties compose all of the LWA in the LWC.
  • This mixed LWA may have the advantage of enabling the concrete design to meet certain density and/or strength or strength-to-weight targets that would difficult with just one LWA.
  • Embodiments of the LWC and LWC mixes also include those in which other aggregates are present, in addition to one or more types of LWA.
  • ordinary aggregates include sand, gravel, pea gravel, pumice, perlite, vermiculite, scoria, and diatomite; concrete aggregate, expanded shale, expanded slate, expanded clay, expanded slag, pelletized aggregate, tuff, and macrolite; and masonry aggregate, expanded shale, clay, slate, expanded blast furnace slag, sintered fly ash, coal cinders, pumice, scoria, pelletized aggregate and combinations of the foregoing.
  • Other ordinary aggregates that may be used include but are not limited to basalt, sand, gravel, river sand, river gravel, volcanic sand, volcanic gravel, synthetic sand, and synthetic gravel.
  • the LWC is free or substantially free of porous glass spheres (i.e., glass spheres having a porous surface). In another embodiment, the LWC is free or substantially free of porous glass spheres that lack a hollow vacuum center.
  • the number of types of LWA is from 1-n
  • the number of types of ordinary aggregates is 1-m
  • the f_wA + fAgg values reflect either the weight fraction of that component or its volume fraction, as appropriate.
  • the volume and weight of the total aggregate can be described in the following manner:
  • Agg T LWAi + LWA 2 + ... LWA n + Aggi + Aggi + ... LWA m [02]
  • LWA and AGG values reflect either weight of that component or its volume, as appropriate.
  • these calculations may be simplified thusly:
  • Embodiments of the LWC and LWC mixes include cementitious materials.
  • the LWC and LWC mixes include a hydraulic cement, Portland cement, including a Type I, Type l-P, Type II, Type l/ll (meeting both Types I and II criteria) or Type III Portland cement, fly ash, and silica fume. These cementitious materials undergo a chemical reaction resulting in the formation of bonds with itself and other cementitious materials present, with any aggregate, and with reinforcing materials.
  • Such exemplary cement types are as defined in ASTM C150, and may be generally described as having the following particulary appropriate uses: Type I (general), Type l-P (blended with a pozzolan, including fly ash), Type IA (air-entraining Type I), Type II (general - with need for moderate sulfate resistance or moderate heat of hydration), Type IIA (air-entraining Type II), Type III (with need for high early strength), and Type MIA (air-entraining Type III).
  • Portland cements are powder compositions produced by grinding Portland cement clinker, a limited amount of calcium sulfate which controls the set time, and up to 5% minor constituents (as allowed by various standards).
  • Portland cements are powder compositions produced by grinding Portland cement clinker, a limited amount of calcium sulfate which controls the set time, and minor constituents (as allowed by various standards).
  • the specific gravity of Portland cement is typically about 3.15.
  • the cement includes a HOLCIM brand Type l/ll Portland cement component, in particular HOLCIM St. Genevieve Type l/ll.
  • Fly ash is a cementitious material that is a byproduct of coal combustion. Pulverized coal is burned in the presence of flame temperatures of to 1500 degrees Celsius. The gaseous inorganic matter cools to a liquid and then solid state, forming individual particles of fly ash.
  • Types of fly ash include Class C and Class F. Based upon ASTM C618, Class F fly ash contains at least 70% pozzolanic compounds (silica oxide, alumina oxide, and iron oxide), and Class C fly ash contains between 50% and 70% of these compounds. Such fly ash can reduce concrete permeability, with Class F tending to have a proportionately greater effect. Class F fly ash also protects against sulfate attack, alkali silica reaction, corrosion of reinforcement, and chemical attack. The specific gravity of fly ash may range from 2.2 to 2.8.
  • fly ash as a cementitious material reacts with water present in the mix. Fly ash is believed to improve workability of the cement mixture once mixed with water. In addition, use of fly ash holds down manufacturing costs, as it is less expensive by weight than either cement or microspheres.
  • BORAL brand Class F Fly Ash is used, with an SG of 2.49.
  • MRT Labadie brand Class C Fly Ash is used, with an SG of 2.75.
  • Silica fume is a cementitious material that is a powdered form of microsilica. Silica fume, as a cementitious material reacts with the calcium hydroxide in the cement paste present in the mix. It is believed to improve strength and durability of the concrete product, by increasing the bonding strength of the cementitious materials in the concrete mix and reducing permeability by filling voids in among cement particles and the LWA (such as the glass microspheres). Silica fume can have an SG of around 2.2. In one embodiment of the invention, EUCON brand MSA is used, with an SG of 2.29.
  • the LWA for example the glass microspheres
  • the amount of cementitious materials considered to be present in a mix should account for that capability.
  • a way to account for it is by evaluating the effective mass of cementitious materials (CMEFF) where that value is experimentally derived to capture the effect of the LWA present in the mix on the workability of the mix and strength of the concrete.
  • Mc is the mass of the cement
  • MSF is the mass of the silica fume
  • MFA is the mass of the fly ash
  • MLWA represents the mass(es) of the one or more LWAs present
  • ⁇ is a scaling factor for the effective cementitious mass of that LWA
  • the amount of water in the wet mix will depend in many instances on the desired water-to-cement (W/CM) ratio and amount of cement or cementitious materials in the concrete mix.
  • W/CM water-to-cement
  • a lower W/CM ratio results in stronger concrete but also in a lower slump value and reduced workability and ability for the wet concrete mix to flow.
  • More water is usually used in mixing concrete than is required merely for workability. But thinning the paste reduces its strength.
  • Admixtures can be used to reduce the amount of water needed for workability, but at the cost of increased manufacturing costs due to the expense of the admixtures.
  • a minimum W/CM ratio is 0.22 to permit sufficient hydration for the concrete to set properly.
  • W/CM ratios can range upward therefrom to about 0.40, from about 0.57-0.62, about 0.68 or above, and at levels ranging between any of the values stated above.
  • a higher W/CM ratio can be tolerated in multiple instances, including when the concrete's design strength and strength-to-weight ratios are higher.
  • a higher ratio is also tolerable in the event the glass microspheres are reacting with cementious materials, allowing for a portion of such glass microspheres to be used in the cementious material calculations, thereby lowering the W/CM ratio.
  • the W/CM ratio accounts for all water (here potable water), excluding water in any admixtures. This ratio is calculated by dividing the weight of that water by the total weight of all cementitious materials. That ratio can also be calculated by dividing the weight of that water by CMEFF, the effective weight of the cementitious materials.
  • embodiments of the invention could also include LWC 1 including reinforcing materials, such as fiber 2 or steel rod (re-bar) 3 or wire mesh 4, and LWC mixes including reinforcing materials, such as fiber, as well as the processes of preparing and/or batching them.
  • LWC 1 including reinforcing materials, such as fiber 2 or steel rod (re-bar) 3 or wire mesh 4
  • LWC mixes including reinforcing materials, such as fiber, as well as the processes of preparing and/or batching them.
  • a fundamental function of reinforcing materials is to increase tensile strength and resist tensile stresses in portions of the concrete where cracking as well as other structural failures might otherwise occur.
  • inclusion of fiber in a concrete mix can help reduce plastic shrinkage and thermal cracking and to improve abrasion resistance, as well as flexural characteristics of concrete products. Fiber is believed to bond with the concrete.
  • Suitable fibers may include glass fibers, silicon carbide, PVA fibers aramid fibers, polyester, carbon fibers, composite fibers, fiberglass, steel fibers and combinations thereof.
  • the fibers or combinations thereof can be used in a mesh or web structure, intertwined, interwoven, and oriented in any desirable direction, or non- oriented and randomly-distributed in the LWC as shown in FIG. 1A, or LWC mix.
  • a short, small diameter, monofilament PVA (polyvinyl alcohol) fiber is used, which meets ASTM C-1116, Section 4.1.3 (at 1.0 Ib/cu.yd).
  • a particular example of such fiber is a NYCON brand PVA RECS15, having an 8-denier (38 micron) diameter, 0.375" (8mm) length, about 1 .3 (or 1 .01 ) SG and a tensile strength of 240 kpsi (1600 Mpa) and a flexural strength of 5,700 kpsi (40,000 Mpa).
  • the fiber amount may be adjusted to provide desired properties to the concrete.
  • An embodiment of the LWC mix may include admixtures to improve the characteristics of the mix and/or the set concrete.
  • Such admixtures can include an air entrainment admixture, a de-air entrainer admixture, a superplasticizer (or high range water reducer), a viscosity modifer (or rheology-modifier), a shrinkage reducer, an expansive agent, latex, superabsorbent polymers, a hydration stabilizer (or set retarding admixture) or any combination of any of the foregoing.
  • the admixtures may also include colorants, anti-foam agents, dispersing agents, water-proofing agents, set-accelerators, a water-reducer (or set retardant), bonding agents, freezing point decreasing agents, anti-washout admixtures, adhesiveness-improving agents, air or any combination of any of the foregoing.
  • the admixture(s) may be determined on a weight basis (e.g. in ounces or lbs.), based on the amount per 100 lbs of cementitious materials.
  • Such admixtures typically form less than one percent by weight with respect to total weight of the mix (including water), but can be present at from amounts below 0.1 to around 2 or 3 weight percent, or at amounts therebetween or at higher amounts, such as around 3 to 5 weight percent or around 4 to 6 weight percent or higher or by ounces per 100 lbs. of cement material.
  • admixtures may be present in ranges from zero to about fifty (and much higher for certain types, such as latex) including ranges from 0-5, 5-10, 5- 5, 15-20, 5-25, 20-30, 25-35, 30-40 and 40-50 fl. oz. / 100 lbs. of cementitious materials. By lbs. per 100 lbs.
  • admixtures may be present in ranges from zero to about fifty (and much higher for certain types, such as latex) including ranges from 0-5, 5-10, 5-15, 15-20, 15-25, 20-30, 25-35, 30-40 and 40-50 fl. oz. / 100 lbs. of cementitious materials.
  • Exemplary plasticizing agents include, but are not limited to, polyhydroxycarboxylic acids or salts thereof, polycarboxylates or salts thereof; lignosulfonates, polyethylene glycols, and combinations thereof.
  • a superplasticizer permits concrete production with better workability but with a reduced amount of water, assists in forming flowable and self-compacting concrete.
  • Exemplary superplasticizing agents include alkaline or earth alkaline metal salts of lignin sulfonates; lignosulfonates, alkaline or earth alkaline metal salts of highly condensed naphthalene sulfonic acid/formaldehyde condensates; polynaphthalene sulfonates, alkaline or earth alkaline metal salts of one or more polycarboxylates; alkaline or earth alkaline metal salts of melamine/formaldehyde/sulfite condensates; sulfonic acid esters; carbohydrate esters; and combinations thereof.
  • EUCON brand SPC is used, which is a polycarboxylate-based superplasticizer.
  • BASF brand Glenium 7500 is used.
  • An air entrainment admixture assists in forming small or microscopic air voids in the set concrete that results from a favorable size and spacing of air bubbles in the concrete mix. This helps protect the concrete from freeze/thaw cycle damage. It also improves W/CM ratio, resistance to segregation of components, workability, resistance to de-icing salts, sulfates, and corrosive water.
  • An exemplary air entrainment admixture meets ASTM C260.
  • Euclid Chemical AEA-92 is used.
  • the LWC is free or substantially free of an air entrainer.
  • a de-air entrainer admixture acts to reduce the entrained air (or plastic air content). This helps to mitigate the reduced strength caused by entrained air (i.e. the volume comprising air lacks the strength of cement or aggregate) and also reduces the need to overdesign the concrete or object due to that decrease in strength.
  • Air may be present in the mix from a number of sources, including: air entrained as a result of other admixtures (such as polycarboxylate based high-range water reducers); air entrained with aggregate; and air mechanically mixed into the mix. Admixtures may also increase the effect caused by the other two sources.
  • Exemplary air detrainers include but are not limited to those based upon tributyl phosphate in a range of about 3.0 to about 7.0 weight percent, and acetic acid in a range of about 1 .0 to about 5.0 weight percent, and is sold commercially as BASF brand PS 1390 (or MasterSure 1390). PS 1390 may be applied at about 0.2-3.0 oz. or about 0.2-1.0 oz., both per 100 lbs. of the cementitious materials.
  • air detrainers suitable for achieving reduction in air pores are products based on polyalkylene oxides, such as adducts of ethylene oxide or propylene oxide with alcohols or phenols; phosphates such as tributyl phosphate or triisobutyl phosphate, phthalates such as dibutyl phthalate, siloxanes such as polydimethylsiloxane, or phosphates of ethoxylated fatty alcohols, such as ethylene oxide stearyl phosphate.
  • Suitable air detrainers are described in U.S. Patent Publication No. 2002/0132946 and U.S. Patent No. 6,545,067, both of which are incorporated by reference.
  • a viscosity modifier (or rheology-modifying admixture), promotes formation of self-consolidating concrete by modifying the rheology of concrete, specifically by increasing the viscosity of the concrete while still allowing the concrete to flow without segregation of aggregate or other materials in the mix.
  • the increased viscosity permits small particles, including LWA such as the glass microspheres, to remain suspended in the mix, rather than segregating by sinking or floating or rising to the top.
  • An exemplary admixture meets ASTM C494 Type S.
  • Exemplary viscosity modifiers include but are not limited to those based upon or including 5-chloro-2-methyl-2H-isothiazol-3-one, and is sold commercially as GRACE brand V-MAR 3.
  • V-MAR 3 may be applied at about 4-16 oz. per 100 lbs. of the cementitious materials.
  • Other exemplary viscosity modifiers include but are not limited to those based upon or containing quinolone, sodium hydroxide / [1 ,1'-Biphenyl]-2-ol, sodium salt (1 :1 ) (or sodium sulfate) and is sold commercially as EUCON brand AWA.
  • AWA may be applied at about 10-32 oz. per 100 lbs. of the cementitious materials.
  • exemplary viscosity modifiers include but are not limited to those based upon or containing [1 ,1'-Biphenyl]-2-ol in a range of about 0 to about 0.2 weight percent or about 0.1 to about 1 .0 weight percent, and ethylene glycol in a range of about 0 to about 1.0 weight percent or about 0.5 to about 1.5 weight percent, and sulfuric acid, and is sold commercially as BASF brand MasterMatrix VMA 362.
  • VMA 362 may be applied at about 2-14 oz. per 100 lbs. of the cementitious materials.
  • a shrinkage reducer (or surface-tension reducing admixture or shrinkage reducing admixture) reduces shrinkage during the curing process caused by drying, which can create tensile stresses and induce cracking.
  • the shrinkage reducer may operate by decreasing the surface tension of the water in the composition, thereby reducing the capillary tension created by water menisci in pores within the composition.
  • Suitable shrinkage reducers include but are not limited to those based upon neopentyl glycol, alklyene glycol (such as 1 ,6-hexanediol, 1 ,5-pentanediol, 1 ,4-pentanediol, and 2- methyl-2,4-pentanediol), or a secondary and/or tertiary dihydroxy C3-C8 alkane, such as 2-methyl-2,4-pentadiol (hexylene glycol).
  • alklyene glycol such as 1 ,6-hexanediol, 1 ,5-pentanediol, 1 ,4-pentanediol, and 2- methyl-2,4-pentanediol
  • 2-methyl-2,4-pentadiol hexylene glycol
  • Another exemplary shrinkage reducer is based upon a mixture of propylene oxide, 1 ,4-dioxane, and ethylene oxide and is sold commercially as BASF brand MasterLife SRA 20.
  • Another exemplary shrinkage reducer is based upon propylene glycol, and may be applied at about 1.0-1.5 lbs. per 100 lbs. of the cementitious materials or about 1.15 lbs. per 100 lbs. of the cementitious materials.
  • Other shrinkage reducers can reduce shrinkage during the curing process by causing the concrete to expand during that process. This induces a compressive stress to offset tensile stresses caused by drying shrinkage.
  • Such shrinkage reducers may also include an expansive agent.
  • One exemplary admixture includes, by weight, 30-60% poly ethylene glycol mono butyl ether, 15-40% 2-(2-(2-Butoxyethoxy)ethoxy)ethanol, 15-40% tetra ethylene glycol mono butyl ether, 15-40% glycol ether solvent, and 0.1 -1 % sodium hydroxide, and has an SG of about 1 .002, and is sold commercially as EUCON brand SRA-XT. SRA-XT may be applied at about 1 lb. per 100 lbs. of the cementitious materials in air entrained applications, and up to 2 lbs. per 100 lbs. of the cementitious materials in non-air entrained applications.
  • An expansive agent could be also be used separately from the shrinkage reducer, or with it. Differing materials may serve as expansive agents, but they have in common the ability to cause an expansion of the concrete during curing. This may be accomplished by carrying out particular chemical reactions during the curing process.
  • expansive agents include calcium oxide (CaO) and calcium sulfo-aluminate ((CaO) 4 (Al2O3)3(SO3).
  • CaO expansive agent produces a calcium hydroxide platelet crystal system based on calcium aluminate/calcium hydroxide; in particular, lime (CaO) is transformed into calcium hydroxide (Ca(OH)2).
  • Calcium sulfo- aluminate with lime and anhydrite (CaSO 4 ), are converted into ettringite.
  • Calcium oxide and calcium sulfo-aluminate are appropriate for use with reinforced concrete.
  • One exemplary admixture includes, by weight, over 60% calcium oxide (CaO), 15-40% fly ash, 3-7% Portland cement, 3-7% sodium lignosulfate and under 1 % crystalline silica / silica sand, and has an SG of about 3.15, and is sold commercially as Euclid Chemical brand Conex. Conex may be applied at about 3-6 weight percent of the cementitious materials to reduce shrinkage and at about 6-10 weight percent of the cementitious materials to compensate for shrinkage. Calcium oxide may also be applied at about 10 lbs. per 100 lbs. of cementitious materials.
  • An admixture may combine a shrinkage reducer and an expansive agent.
  • Conex and SRA-XT are used together.
  • Another such admixture includes MgO that has been lightly burnt (between 750-1200 °C) with a shrinkage reducing agent and a super absorbent polymer, where the shrinkage reducing agent is present by weight as about 7-25%, 13-25%, or 17.5-25% of the MgO and the super absorbent polymer is present as about 0-7% of the MgO (or at 0.1 -12% or 2-7% with W/CM ratios less than or equal to 0.38), and is sold commercially as a free-flowable powder as Premier Magnesia brand PREVent-C.
  • PREVent-C may be applied may be applied at about 5 weight percent of the cementittous materials.
  • Latex increases bonding within the concrete, reduces shrinkages and increases workability and compressive strength. Latex is a polymer, and Euclid Chemical FLEXCON and BASF brand STYROFAN are examples.
  • Superabsorbent polymers can improve curing of the concrete, including by providing internal water curing, that is by serving as an internal reservoir of water that is not part of the mix water (thus keeping water/cement ratio down). That internal water is usable for the curing process to promote curing (and, thus strength) and mitigate against shrinkage (which may induce cracking). Reducing the mix water can also reduce slump during the curing process.
  • Superabsorbent polymers are a form of polymer that can absorb large volumes of water relative to their dry volume, swell, and then reversibly release that water and shrink. Polyacrylic acids are an example. They may be used with lower water/cement ratios (such as below 0.45 or below 0.42 or lower).
  • a hydration stabilizer (or set retarding admixture) permits concrete production with better predictability by retarding the setting of the concrete to permit time for activities such as mixing, transport, placing and finishing. By reducing the need to add water (thereby decreasing the W/CM ratio) to delay setting during these activities, a water-reducer can improve strength and reduced permeability.
  • An exemplary admixture meets ASTM C494 Type D, and in one embodiment is EUCON brand STASIS, and in another embodiment is BASF brand Delvo.
  • a water-reducer (or set retardant) permits concrete production with better predictability by retarding the setting of the concrete to permit time for activities such as mixing, transport, placing and finishing.
  • a water-reducer can improve strength and reduce permeability.
  • Exemplary water reducers include lignosulfonates, sodium naphthalene sulfonate formaldehyde condensates, sulfonated melamine-formaldehyde resins, sulfonated vinylcopolymers, urea resins, and salts of hydroxy- or polyhydroxy-carboxylic acids, a 90/10 w/w mixture of polymers of the sodium salt of naphthalene sulfonic acid partially condensed with formaldehyde and sodium gluconate and combinations thereof.
  • An example of a water-reducer is EUCON brand NR.
  • the concrete composition can include the above components at above any of the lower levels of weight percent indicated in Table II, below any of the higher levels indicated, or at levels within the ranges indicated.
  • Polymer beads (SG ⁇ 1 .06) 20-30 0-50
  • Higher-density / higher-strength forms of the concrete composition can also include the above components at above any of the lower levels of weight percent indicated in Table IIA, below any of the higher levels indicated, or at levels within the ranges indicated.
  • Microspheres (SG 0.15) 0.0 0-11
  • Microspheres (SG 0.35) 0-2.5 0-15
  • Total cementitious content is a measure of density of the cementitious materials in the wet mix concrete, and may be measured in pounds per cubic yard. In embodiments of the invention, the total cementitious content ranges from around 660 to around 700 lbs., around 750 lbs. and around 800 lbs, and around 825 lbs or below. Higher values tend to correlate with higher-strength concretes. In other embodiments, such as those including sand and/or coarse aggregate, the total cementitious content is about 800 lbs. and ranging from around 750 lbs. to around 825 lbs.
  • the paste content by volume is a percentage measure of the non-aggregate content of the wet mix (including cementitious materials, water, and the plastic air content of that mix).
  • the paste content by volume together with the total volume displaced the aggregates is equal to 100%.
  • the paste content by volume is about 50%, ranging from 49.1 % to 50.6%, or higher with an increase in density.
  • the paste content by volume is about 40% or about 50% ranging from 35% to 55%, or lower with an increase in density.
  • the replacement volume of the LWA is the volume percentage displaced by the LWA in the wet mix, whether it is a single type of LWA or a mix of more than one type. In a mix having no ordinary aggregate (for instance, sand), the replacement volume is the volume percentage displaced by the LWA.
  • VR may be about 50%, ranging from 49.6% to 53.4%, for mixes with no ordinary aggregate, around 10%, 30% or 40% (as density drops), and ranging from about 10% to about 43%, for mixes including sand, and around 17% or 30-35% (as density drops), and ranging from about 16% to about 37%, for mixes including coarse aggregates (and possibly sand).
  • VR may also be at other levels ranging between any of levels stated above.
  • Fresh concrete has certain characteristics of interest, including slump, plastic air content, workability and plastic density.
  • Slump is an important measure of the workability of a concrete mix. Slump is a measure of how easily a wet mix flows. Slump is measured in inches, and may be measured according to ASTM C143. Neither particularly high nor particularly low values are inherently preferable. Extremely low-slump applications include the manufacture of concrete blocks and other products. Low-slump applications include circumstances in which early form removal is necessary or desired, or when the concrete must otherwise be immediately self-supporting (or nearly so - "0" slump) such as troweled-on applications. Normal-slump applications includes circumstances in which pumpability is critical, such as when concrete must be pumped. In embodiments of the invention, slump ranged from about 5 to almost 40, including values around 5, 6, 8, 22, 25, 28, 32, and 38.
  • Plastic air content is a measure of the percentage of the volume of the wet mix that constitutes air entrained in the mix, and may be measured according to ASTM C231 .
  • a desirable target plastic air content may range from about 5.0% to 6.5%. In embodiments of the invention, the value ranged from 4.0% to 1 3.0%. In other embodiments of the invention, the value ranged from 2.4% to 2.8%, 4.0% to 6.0%, and 4.0% to 8.0% and even might be as low 2%, 1 % or about 0%.
  • Plastic density is a measure of the density of the wet mix, and may be measured according to ASTM C138. In embodiments of the invention, the value ranged from around 50 Ib./cu.ft. to around 55 Ib./cu.ft., including about 52 Ib./cu.ft, for lighter weight compositions, and around 70 Ib./cu.ft., including about 69 Ib./cu.ft., 74 Ib./cu.ft., 88 Ib./cu.ft. and 125 Ib./cu.ft, for heavier weight compositions. For embodiments of the invention including coarse aggregrate, such as gravel, the value ranged from around 85 Ib./cu.ft.
  • composition elements were present in an amount effective to achieve a target density in said cured composite of not more than those densities.
  • Cured concrete has many characteristics of interest, including bulk density, oven-dried density, thermal conductivity and insulation value (or R-value), permeable porosity, modulus of rupture, compressive strength, elastic modulus, tensile strength, resistance to fire and combustibility, freeze / thaw resistance, drying shrinkage, chloride ion penetrability, abrasion resistance, the ring test, and CTE (coefficient of thermal expansion).
  • Compressive strength is a measure of the ability of the concrete to resist compressive loads tending to reduce its size until its failure, and may be measured according to ASTM C39. Higher compressive strength and strength-to-weight are an advantage with the invention because less weight reduces costs. This is the case, for example, in applications such as transportation and dead loads. Concrete compressive strength increases as the concrete ages, at least up to a point, and the hydration process (the chemical reaction within the cementitious materials) continues. Tests may be carried out at, for instance, 3, 4, 7, 14, and 28 days or even longer, as well as at other intervals.
  • the measured values ranged as follows: 3-day: about 1100, about 1300, about 1700, about 2200 psi, about 2300 psi, about 3800 psi, about 2900 psi, about 4400 psi, and about 5000 psi; 4-day: about 1900 psi; 7-day: about 1300, about 1400, about 1600, about 1900, about 2600 and about 2750 psi, about 4400 psi, about 3200 psi, about 5100 psi, about 6000 psi, about 4700 psi; 10-day: about 3100 psi, about 4800 psi; 14-day: about 3000 psi; 28-day: about 2500 psi, about 2800, about 3300, about 4000, about 3400 psi, about 1770 psi, about 1750 psi, about 3800 psi, about 7000 psi, about
  • Elastic modulus is a measure of the concrete's tendency to be deformed elastically when a force is applied to it, and may be measured according to ASTM 649. Like compressive strength, elastic modulus increases as the concrete ages. Tests may be carried out at, for instance, 3, 7 and 28 days or even longer or at other intervals.
  • the measured values ranged as follows: 3-day: about 400, about 500, about 650, about 850, about 1350, 2100 and about 3400 kpsi; 7-day: about 500, about 550, about 600, about 650, about 800, about 900, about 1400, about 2300 and about 3500 kpsi; 10-day: about 1400 and 2900 kpsi; 14-day: about 800 kpsi; 28-day: about 800, about 850, about 900, about 600, about 700, about 1100, about 550, about 1600, about 2400 and about 4200 kpsi and higher.
  • Tensile strength is a measure of the maximum stress that the concrete can withstand while being stretched or pulled before failing or breaking, and may be measured by ASTM C496. Like compressive strength, tensile strength increases as the concrete ages. Tests may be carried out at, for instance, 3, 7 and 28 days or even longer or at other intervals.
  • the measured values ranged as follows: 3-day: about 130, about 140, about 160, about 200, about 230, about 300, about 320, about 420 and about 530 psi; 7-day: about 180, about 200, about 230, about 240, about 300, about 330, about 460, about 365 and about 640 psi; 14-day: about 360 psi; 28-day: about 260, about 235, about 260, about 300, about 340, about 420, about 390, about 480, and about 620 psi and higher.
  • Modulus of rupture is a measure of the concrete's ability to resist deformation under load, and may be measured according to ASTM C78. In embodiments of the invention, the measured values at 28 days ranged as follows: about 300, about 330, about 350, about 270, about 410, about 450, about 610, and about 910 psi and higher.
  • Oven-dried density is a measure of the density of a structural lightweight concrete, and may be measured according to ASTM C567. In embodiments of the invention, the measured values ranged as follows: about 36, and from about 39 to 42 lb/cu.ft., and about 55-60 lb/cu.ft., as well as about 75-80 lb/cu.ft., about 100 lb/cu.ft, and about 120 Ib/cu.ft.
  • R-value is a measure of the insulating effect of a material. Where thickness (T) is in inches, and thermal conductivity CT is in (Btu-in.)/(hr-°F-sq.ft), R-value is defined as T / CT. CT and R-value each have a non-linear relationship with the oven-dried density of concrete; the relationship is an inverse one for R-value. This relationship is depicted in FIG. 2, which displays the approximate thermal resistance (in R-value) for oven-dried concretes at 4", 5" and 6" thickness. R-value may be influence by actual moisture content and the thermal conductivity of the material used in the concrete.
  • R-values are about: 4" block: 0.80; 8" block: 1 .11 ; 12" block: 1 .28.
  • the R-values are (at the listed density, in Ib/cu.ft.) at 1 " thickness: 60: 0.52; 70: 0.42; 80: 0.33; 90: 0.26; 00: 0.21 ; 120: 0.13.
  • R-value for embodiments of the invention based upon measured and expected oven-dry density, are expected to be (at the listed density, in Ib/cu.ft.) at 1 " thickness: 40: 1 .06; 60: 0.75; 70: 0.56; 90: 0.43; 100: 0.37; 110: 0.25 and higher.
  • Bulk density may be measured according to ASTM 642.
  • the permeable pores percentage may be measured according to ASTM 642.
  • the resistance to fire may be measured according to ASTM E 36.
  • the combustibility may be measured according to ASTM E119.
  • Freeze / thaw resistance may be measured according to ASTM C666, and is a measure of the concrete's resistance to cracking as a result of enduring freeze / thaw cycling.
  • Drying shrinkage may be measured according to ASTM C157, and is a measure of the percentage of volumetric reduction in size caused by the drop of the amount of water in the concrete as it dries. It can be measured as 'moist' at 7 days, and as 'dry' at 28 days.
  • Chloride ion penetrability may be measured according to ASTM C1202, and is a measure of the ability of the concrete to resist ions of chloride to penetrate. In embodiments of the invention, the measured values ranged as follows (in coulumbs): about 133 to 283.
  • Abrasion resistance may be measured according to ASTM C779, and is a measure of the ability of the concrete's surface to resist damage from abrasion. In embodiments of the invention, the measured values ranged as follows (in inches): about 0.032 to 0.036 and may be lower or higher.
  • the ring test may be measured according to ASTM C1581 , and is a measure of the ability of the concrete to resist nonstructural cracking. In embodiments of the invention, the measured values ranged as follows (in days): about 10.1 to 16.2 and may be and higher.
  • CTE is the coefficient of thermal expansion and may be measured according to AASHTO T 336. In one embodiment of the invention, the measured value was (in in./in./°F): 5.70 x 10 e .
  • This LWA was composed of 3M brand S35 glass microspheres having a SG of about 0.35, a median size of about 40 microns and a microsphere size distribution such that about 80% are between about 10-75 microns, and with about a crushing strength 90% survival rate at about 3000 psi. Then, if the mix included an air entrainment admixture, the air entrainment admixture was added in step 120 together with about 80% of the water by weight to the lightweight aggregate in mixer 6. The air entrainment admixture was Euclid Chemical AEA-92. If the mix did not, about 80% of the water by weight was added in step 125 to the lightweight aggregate in mixer 6.
  • step 130 while adding water, mixer 6 was run slowly at first, and then on full once enough of the water had mixed with the LWA to reduce dust formation. Mixer 6 is then run until stopped (step 135). Thereafter, the fibers were added to mixer 6 in step 140. The fibers were NYCON brand PVA RECS15 8mm fibers. Mixer 6 was run for about a minute in step 145. As there is no sand or coarse aggregates in these mixes, in step 160 the cementitious materials and remaining admixtures (as listed on Table III) were added with the remaining (about 20%) water. The cementitious materials were HOLCIM brand Type l/ll cement, BORAL brand Class F fly ash and EUCON brand MSA silica fume.
  • step 170 and 180 mixer 6 was run for about 3 minutes and thereafter, mixer 6 was stopped to permit the mix to rest for about 3 minutes. While mixer 6 was not running in step 190, mixer blades (paddles) 10 were cleaned off. Mixer 6 was run for about 2 minutes in step 200. At this point, the mix was tested in step 210 for compliance with target slump and target measured air indicated in Table III as target values after any adjustments, if any. If a mix did not comply, such mix was adjusted as required in step 220 to meet target slump and target measured air. If the measured air was too high, de-air entrainment admixture was added in step. 225.
  • step 230 If a mix was adjusted, then mixer 6 was run in step 230 for about 2 minutes, and the mix was again tested (see step 210) for compliance with target slump and target measured air. If it did not comply, the steps above were repeated. If a mix did comply, then the process of preparing the batch, mixing the batched materials, and forming the wet concrete mix was complete (step 240).
  • This LWA was composed of 3M brand S15 glass microspheres having a SG of about 0.15, a median size of about 55 microns and a microsphere size distribution such that about 80% are between about 25-90 microns, and with about a crushing strength 90% survival rate at about 300 psi. Then, if the mix included an air entrainment admixture, the air entrainment admixture was added in step 120 together with about 80% of the water by weight to the lightweight aggregate in mixer 6. The air entrainment admixture was Euclid Chemical AEA-92. If the mix did not, about 80% of the water by weight was added in step 125 to the lightweight aggregate in mixer 6.
  • step 130 while adding water, mixer 6 was run slowly at first, and then on full once enough of the water had mixed with the LWA to reduce dust formation. Mixer 6 is then run until stopped (step 135). Thereafter, the fibers were added to mixer 6 in step 140. The fibers were NYCON brand PVA RECS15 8mm fibers. Mixer 6 was run for about a minute in step 145. As there is no sand or coarse aggregates in these mixes, in step 160 the cementitious materials and remaining admixtures (as listed on Table VIII) were added with the remaining (about 20%) water. The cementitious materials were HOLCIM brand Type l/ll cement, BORAL brand Class F fly ash and EUCON brand MSA silica fume.
  • step 170 and 180 mixer 6 was run for about 3 minutes and thereafter, mixer 6 was stopped to permit the mix to rest for about 3 minutes. While mixer 6 was not running in step 190, the mixer blades (paddles) 10 were cleaned off. Mixer 6 was run for about 2 minutes in step 200. At this point, the mix was tested in step 210 for compliance with target slump and target measured air indicated in Table VI as target values after any adjustments, if any. If a mix did not comply, such mix was adjusted as required in step 200 to meet target slump and target measured air. If the measured air was too high, de-air entrainment admixture was added in step 225.
  • step 230 If a mix was adjusted, then mixer 6 was run in step 230 for about 2 minutes, and the mix was again tested (see step 210) for compliance with target slump and target measured air. If it did not comply, the steps above were repeated. If a mix did comply, then the process of preparing the batch, mixing the batched materials and forming the wet concrete mix was complete (step 240).
  • this LWA was composed of 3M brand S15 glass microspheres having a SG of about 0.15, a median size of about 55 microns and a microsphere size distribution such that about 80% are between about 25-90 microns, and with about a 90% crushing strength survival rate at about 300 psi.
  • this LWA was composed of 3M brand S35 glass microspheres having a SG of about 0.35, a median size of about 40 microns and a microsphere size distribution such that about 80% are between about 10-75 microns, and with about a crushing strength 90% survival rate at about 3000 psi.
  • step 120 the air entrainment admixture was added in step 120 together with about 80% of the water by weight to the lightweight aggregate in mixer 6.
  • the air entrainment admixture was Euclid Chemical AEA-92. If the mix did not, about 80% of the water by weight was added in step 125 to the lightweight aggregate in mixer 6.
  • step 130 while adding water, mixer 6 was run slowly at first, and then on full once enough of the water had mixed with the LWA to reduce dust formation. Mixer 6 is then run until stopped (step 135). Thereafter, the fibers were added to mixer 6 in step 140.
  • the fibers were NYCON brand PVA RECS15 8mm fibers.
  • Mixer 6 was run for about a minute in step 145. These mixes include sand but no coarse aggregates, so in step 150 the sand was added, followed by step 160, adding cementitious materials and remaining admixtures (as shown in Table XIII) with the remaining (about 20%) water.
  • the cementitious materials were HOLCIM brand Type l/ll cement, BORAL brand Class F fly ash and EUCON brand MSA silica fume.
  • the other aggregate was Meyer McHenry sand.
  • steps 170 and 180 mixer 6 was run for about 3 minutes and thereafter, mixer 6 was stopped to permit the mix to rest for about 3 minutes. While mixer 6 was not running, in step 190, the mixer blades (paddles) 10 were cleaned off.
  • Mixer 6 was run for about 2 minutes in step 200. At this point, the mix was tested in step 210 for compliance with target slump and target measured air indicated in Table IX as target values after any adjustments, if any. If a mix did not comply, such mix was adjusted as required in step 220 to meet target slump and target measured air. If the measured air was too high, de-air entrainment admixture was added in step. 225. If a mix was adjusted, then mixer 6 was run in step 230 for about 2 minutes, and the mix was again tested (see step 210) for compliance with target slump and target measured air. If it did not comply, the steps above were repeated. If a mix did comply, then the process of preparing the batch, mixing the batched materials and forming the wet concrete mix was complete (step 240).
  • Aggregate SG 0.35 microspheres and coarse aggregate, with or without sand
  • This LWA was composed of 3M brand S35 glass microspheres having a SG of about 0.35, a median size of about 40 microns, and a microsphere size distribution such that about 80% are between about 10-75 microns, and with about a crushing strength 90% survival rate at about 3000 psi. Then, about 80% of the water by weight was added in step 125 to the lightweight aggregate in mixer 6. In step 130, while adding water, mixer 6 was run slowly at first, and then on full once enough of the water had mixed with the LWA to reduce dust formation. Mixer 6 is then run until stopped (step 135). Thereafter, the fibers were added to mixer 6 in step 140. The fibers were NYCON brand PVA RECS15 8mm fibers.
  • Mixer 6 was run for about a minute in step 145. These mixes include coarse aggregates and some include sand, so in step 150 the sand was added if in the mix design, and in step 155 the coarse aggregate was added, followed by step 160, adding cementitious materials and remaining admixtures (as shown in Table XVIII) with the remaining (about 20%) water.
  • the cementitious materials were HOLCIM brand Type l/ll cement, BORAL brand Class F fly ash and EUCON brand MSA silica fume.
  • the other aggregates were Meyer McHenry sand and Vulcan McCook CM-11 and Martin Marietta #8 coarse aggregates.
  • step 170 and 180 mixer 6 was run for about 3 minutes and thereafter, mixer 6 was stopped to permit the mix to rest for about 3 minutes. While mixer 6 was not running, in step 190, the mixer blades (paddles) 10 were cleaned off. Mixer 6 was run for about 2 minutes in step 200. At this point, the mix was tested in step 210 for compliance with target slump and target measured air indicated in Table XII as target values after any adjustments, if any. If a mix did not comply, such mix was adjusted as required in step 220 to meet target slump and target measured air. If the measured air was too high, de-air entrainment admixture was added in step 225.
  • shrinkage reducing admixtures which may reduce strength by about 10%. Accordingly, based upon predictions relying upon the experimentally-determined values, one may estimate a range of compressive strength values expected for a variety of concrete mixes that may or may not include such an admixture. These are found in Table XXIII below.
  • An embodiment of the invention may be prepared as a dry mix, such as for a bagged concrete mix.
  • a bagging facility acquires bags and concrete precursor materials including cementitious materials, aggregates, dry admixtures, and reinforcing materials. Materials may be purchased or extracted.
  • the precursor materials are prepared, including with any pre-mixing such as of dry admixtures.
  • the precursor materials are blended in a continuous process.
  • the dry mix is then bagged. As shown in FIG. 4, these steps include steps 300 and 310, acquire bags and any necessary Portland cement, class F fly ash, silica fume, sand, glass microspheres, dry admixtures, and reinforcing materials.
  • step 320 is to prepare cementitious materials, aggregates, dry admixtures, and reinforcing materials for blending
  • step 325 carry out any necessary pre-mixing of the acquire materials.
  • step 330 blend all necessary materials in a continuous process.
  • step 340 place blended dry mix into bags, and 350 seal the bags.
  • cement mixer is a device that homogeneously combines the materials being mixed, such as cementitious materials, aggregate, water, and any other additives or reinforcing materials, to form a concrete mix.
  • cement mixer there are both stationary and mobile concrete mixers.
  • twin-shaft mixers which includes both pan mixers 6 and planetary (or counter-current) mixers, and which typically is used for batches between about 1-4 cu.yd.
  • drum mixers 12 which includes both reversing drum mixers and tilting drum mixers.
  • Drum mixers are suitable for the ready mix market as they are capable of high production speeds and are capable of producing in large volumes (batches between about 4-12 cu.yd. or more). All such mixers are charged for a batch of concrete by pouring the dry and wet components into the pan 7 or drum 13, either while it is stationary or in motion, and in a sequence determined by the concrete design.
  • a motor 8 typically electric or gas/diesel-powered, drives a shaft 9 which directly or indirectly rotates and mixes the concrete mix, typically by paddle 10 or by friction and the material being carried along by the drum or by screw 14 in a drum mixer.
  • the mixed concrete is mixed by truck 15, and delivered, in the same manner as with stationary mixers.
  • Batch plants are example of a drum mixer that is stationary, although components of the plant may be tractor-trailer mounted, transported to a location and assembled for use, and then disassembled and moved.
  • FIG. 5C another form of stationary mixer is the ribbon mixer 27 having hopper 28, outlet 29, body 30, blade assembly 31 , ribbon blade 32, shaft 33 and supports 34.
  • Blade assembly 31 is driven by driver 35 (typically electric or gas/diesel- powered) via shaft 33.
  • driver 35 typically electric or gas/diesel- powered
  • Such a mixer is charged by pouring the dry and wet components into the hopper 28, either while blade assembly 31 is stationary or in motion, and in a sequence determined by the concrete design. Rotation of blade assembly 31 and thereby ribbon blade 32, causes mixing of the charged materials.
  • the latter includes concrete transport trucks (“cement-mixers” or “in-transit mixers”) as shown in FIG. 5D for mixing concrete and transporting it to the construction site.
  • trucks 15 have a powered rotating drum 13 the interior of which has a spiral blade 14.
  • Rotating drum 13 in one direction pushes the concrete deeper into drum 13.
  • Drum 13 is rotated in this (the “charging”) direction while truck 15 is being charged with concrete, and while the concrete is being transported to the building site.
  • Rotating drum 13 in the other (the “discharge”) direction causes the Archimedes screw-type arrangement to discharge or force the concrete out of drum 13 onto chute 16.
  • Examples of other mixers include: concrete mixing trailer, portable mixers, metered concrete trucks (containing weighed and loaded but unmixed components for mixing and use on-site), V blender, continuous processor, cone screw blenders, screw blenders, double cone blenders, planetary mixers, double planetary, high viscosity mixers, counter-rotating, double and triple shaft, vacuum mixers, high shear rotor stator, dispersion mixers, paddle mixers, jet mixers, mobile mixers, Banbury mixers, and intermix mixers.
  • truck 15 is charged from a batch plant with the as-yet unmixed components of a concrete mix, including dry materials, water and other additives and/or reinforcements, in a sequence determined by the concrete design, with the rotation of drum 13 mixing the concrete during transport to the destination.
  • truck 15 is charged from a batch plant at a concrete manufacturing plant (or "central mix” plant), with a concrete mix that has already had the dry materials, water and other additives and/or reinforcements added in a sequence determined by the concrete design, and already mixed before loading. In this case, rotation of drum 13 mixing the concrete during transport to the destination maintains the mix's liquid state until delivery.
  • drum 13 is operated in the discharge direction to force the wet mix onto chutes 16 used to guide the mix directly to the job site.
  • the job site may include other machines used to move or process the wet mix, such as a concrete placer or paving machine. If the use of chute 16 does not permit the concrete to reach the necessary location, concrete may be discharged into a concrete pump, connected to a flexible hose, or onto a conveyor belt which can be extended some distance (typically ten or more meters).
  • a pump provides the means to move the material to precise locations, multi-floor buildings, and other distance prohibitive locations. Examples of pumps include a mobile concrete pump, which accepts for instance ready mix concrete, delivered by dump truck or concrete mixing truck.
  • Such a mobile pump can place concrete at the desired position during the construction process using a pipe mounted on a movable boom.
  • a stationary concrete pump which operates similarly except that the pipe is stationary and mounted primarily vertically up the side of a structure during the construction process to provide concrete at the desired location.
  • Embodiments of the present invention include different processes for preparing and supplying concrete for end use.
  • a central-mix facility may prepare and mix the concrete itself. This mix process is described in reference to FIG. 6.
  • Step 400 is acquiring concrete precursor materials including water, cementitious materials, aggregates (including LWAs, sand and gravel), admixtures, and reinforcing materials. This may be done, for example, by purchase or extraction.
  • the acquired materials are prepared, including any premixing.
  • the individual materials are measured, step 420, typically by weight or volume and, in step 430, formed into batches of individual components.
  • the concrete precursor materials are charged into a concrete mixer (dry, step 440, and water, step 450), typically a drum type, and mixed by operating the drum in step 460.
  • the resultant wet mix may be either used for charging, in step 470, a concrete mixing truck or dump truck, or used on-site, in step 480, by discharging it into a pump or delivery apparatus.
  • a concrete mixing truck 15 or dump truck may be owned or controlled by the central-mix facility or by a third-party.
  • Such a third-party may be a builder or general contractor, or a contractor supplying such a party.
  • use on-site may include machinery to place the concrete mix for a structure or building or use of the mix for pre-casting.
  • on-site use includes forming structural beams, architectural panels, sound barriers, blast walls, stadium seating, trench backfill around piping/conduit, insulated roofing, walls, tilt-wall panels, buildings, communication tower buildings, and many other uses typical of normal concrete.
  • a central-mix facility prepares the concrete precursor materials but delivers or provides those materials to another party for mixing.
  • This mix process is also described in reference to FIG. 6.
  • Step 400 is acquiring concrete precursor materials including water, cementitious materials, aggregates (including LWAs, sand and gravel), admixtures, and reinforcing materials. This may be done, for example, by purchase or extraction.
  • the acquired materials are prepared, including any premixing.
  • the individual materials are measured, step 420, typically by weight or volume, in step 430, and formed into batches of individual components.
  • the concrete precursor materials are then used for charging a concrete mixing truck (dry, step 490, and water, step 500), or pre-measured bags.
  • a concrete mixing truck then performs the mixing of the concrete in step 510, and delivers and discharges it as required in steps 520 and 530. Delivery may include to the site of a building or other structure under construction.
  • a concrete mixing truck may be owned or controlled by, for instance, a builder or general contractor, or a contractor supplying such a party.
  • precast concrete is a construction product produced by casting concrete in a reusable mold 20 or "form,” curing it in a controlled environment, transporting to the construction site and placing the precast item 21 where needed. This is in contrast to standard concrete manufacturing in which the wet mix is poured into site-specific forms 22 in-place and cured in-place to create an item 21. Pre- casting may also involve casting concrete in a reusable mold 20 on-site, curing it in a controlled environment, and transporting it within the construction site to where it is needed.
  • items 21 made by pre-casting include but are not limited to concrete blocks, structural beams, double-tees, architectural panels, sound barriers, blast walls, tilt-wall panels, electric and light poles, bridge deck panels, fire-proofing, fencing, cement board, concrete roofing tiles, and floating platforms.
  • an uncured composition may be applied to a structure or material as fire-proofing, either by troweling or spraying the composition onto the structure or material, and allowed to cure. In this case a desired slump is low slump.
  • an uncured composition may be formed around a structure, structural element, or material as fire-proofing, in which a steel structural element (e.g. a beam) is placed partly within a mold (or the mold placed around it), the mold filled with the composition (as disclosed herein) and allowed to cure. These processes can occur in-situ or elsewhere, such as a precasting facility.
  • precast (or "dry cast") manufacture of products, including concrete blocks involves providing extremely low-slump concrete (almost zero), with a low W/CM ratio (about 0.22 or lower).
  • LWC mixes described herein that do not include coarse aggregate would be expected to be acceptable for making concrete blocks, with the modifications of removing admixtures and reducing water to form to extremely low-slump concrete (almost zero), with a low W/CM ratio (about 0.22).
  • Mixes including polymer or copolymer beads, or polymer or copolymer beads with glass microspheres, may be acceptable, and are also disclosed.
  • An admixture could be used as a wetting agent for form removal.
  • the mixing process steps are, as shown in FIG. 8A and with reference to FIG. 5C, is to first prepare equipment in step 600, and then, in steps 605 and 610, weigh any dry ingredients and liquid ingredients.
  • step 615 place all lightweight aggregate into hopper 28 of ribbon mixer 27, while it is running. Other mixers may be acceptable.
  • steps 620 and 625 place all cement and all water into hopper 28 of ribbon mixer 27, while it is running.
  • step 630 run ribbon mixer 27 for about an additional minute.
  • the LWC mix may be conveyed to block machine 40 at a measured flow rate in step 635 and placed into a reusable mold 41 for a concrete block in step 640.
  • Mold 41 includes outer mold box 42 into which the LWC mix is place and one or more mold liners 43. Liners 43 determine the outer shape of the block and the inner shape of the block cavities.
  • Such molds may be used for form different sizes and shapes of concrete blocks, such as those having 4", 8" or 12" thickness, or having two or three "cores" 44 (i.e. the hollow portion) or no core (i.e. solid blocks).
  • step 645 one or more mold liners 43 are inserted into the LWC mix inside of outer mold box 42 to form cores 44.
  • step 650 the concrete mix in mold 41 is subjected to high compression and vibration. However, the vibration required may be lower than ordinary concrete mixes. Due to the low slump, compression and vibration, and aided by the low density (that is, the reduced per-block mass), block 45 is quickly able to stand unsupported.
  • Blocks 45 are pushed down and out of the molds. And block 45 is then set aside for curing in step 665, following which the block may be transported to a construction site or sold for further sale.
  • Curing may include steam-curing, moisture-curing or other processes to develop desirable concrete properties. Reducing the per-block mass may reduce the manufacturing time by reducing the time required for compression and vibration, and the time before forms can be removed.
  • Example 23 and test results for compressive strength, and exemplary ranges in Example 24 of such a concrete are shown in Table XXIV: Table XXIV:
  • the structural concrete blocks made met or exceeded design strengths.
  • R-value (a measure of the insulating effect of a material) were established by testing thermal conductivity of two specimens of a LWC per ASTM C177.
  • the specimens were formed from a LWC mix according to Example 5.
  • the specimens were (L/W/T in in.) 11.97 x 12.04 x 2.05 and 11.93 x 12.03 x 2.04, and had, respectively a dry density (in Ib/cu.ft.) of 41 .0 and 40.9.
  • Thermal conductivity CT (in (Btu-in.)/(hr-°F- sq.ft)) was 1.15. Calculated R-value results are presented below in Table XXV.
  • a LWA of an embodiment of the invention may also comprise small beads formed of a plastic, such as a copolymer.
  • These polymer beads may have roughly the density of water, are typically solid, closed, preferably insoluble, non-porous, substantially resistant to volumetric change under pressure, heat-resistant, smooth and non-absorptive.
  • the polymer beads made be composed of a polymeric material, such as polymers of styrene, ethylinylbenzene, divinylbenzene or any combination of any of the foregoing.
  • the beads may be made of copolymers such as styrene copolymers and styrene-ethylvinylbenzene-divinylbenzene terpolymers.
  • Suitable beads include those described in U.S. Patent Publication No. 2015/0011439 (also published as U.S. Patent Nos. 8,466,093, 8,278,873, 8,455,403, 8,088,718, 702,125, and 7,803,740), each of which is hereby incorporated by reference.
  • the polymeric beads are polymeric nanocomposite spherical beads such as those described in U.S. Patent Publication No. 2015/0011439.
  • the polymer nanocomposite spherical beads may comprise a polymer matrix (such as a rigid thermoset polymer) and nanofiller particles.
  • the polymer matrix is a thermoset polymer matrix, such as a styrene-ethylvinylbenzene-divinylbenzene terpolymer.
  • the nanofiller particles are preferably dispersed throughout the bead. Suitable nanofiller particles include, but are not limited to, carbon black, fumed silica, fumed alumina, carbon nanotubes, carbon nanofibers, cellulosic nanofibers, fly ash, polyhedral oligomeric silsesquioxanes, natural nanoclays, synthetic nanoclays any combination of any of the foregoing.
  • the beads may include 0.001 to 60 volume percent of nanofiller particles.
  • the polymeric beads have a specific gravity of about 1 or greater, for example, a specific gravity of from about 1 to about 1 .5 or from about 1 to about 1 .2.
  • suitable polymeric beads include, but are not limited to, Alpine drilling beads available from Alpine Specialty Chemicals of Houston, TX, and Sun Lubra-Glide beads (available from Sun Drilling Products Corp. of Belle Chasse, LA) and any combination of the foregoing.
  • the beads have a diameter ranging from 0.1 mm to 4 mm.
  • polymer beads may have a rough or irregular surface, or be irregular in shape.
  • Commercial polymer beads are typically smooth, but the surface could be etched, such as by acid-washing or other methods. Without being bound by any particular theory, it is believed that etching may permit better adhesion between the cementitious materials and the polymer beads, leading to greater strength. Doing so may also permit or encourage reaction between the polymer beads and the cementitious materials.
  • An embodiment of the present invention includes an optionally-self-compacting LWC mix having a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties.
  • That LWC mix includes a LWA that is composed of polymer beads, as described above.
  • the polymer beads may be in more than one size. These include both fine or coarse sizes.
  • the polymer beads may have a median particle size of, as an example, about 100-500 microns.
  • the median size may be about 300 microns, greater than about 150 microns, and greater than about 250 microns but less than about 350 microns.
  • substantially all of the polymer beads have a particle size between about 100-500 microns.
  • the coarse size the polymer beads may have a median particle size of, as an example, about 350-1000 microns.
  • the median size may be about 675 microns, greater than about 500 microns, and greater than about 650 microns but less than about 750 microns.
  • substantially all of the polymer beads have a particle size between about 350-1000 microns.
  • the polymer beads' median size may be substantially greater than that of the microspheres.
  • the polymer beads (and the polymer forming them) may range between around 0.8 and about 1 .4 SG, between around 1 and about 1 .5 SG, or as low as between about 0.6-0.9, or between about 0.95-1.15, or between about 1 .02-1 .15, with exemplary densities of 0.9, 1 .06, 1.10 and 1.2 SG.
  • the beads have about neutral buoyancy relative to water.
  • Such polymer beads can remain stable at temperatures up to 425 °F, 450 °F, or even 525 °F.
  • Such polymer beads may resist deformation at over about 15,000, 20,000 and 25,000 psi hydrostatic pressure.
  • the LWC and LWC mixes include the polymer beads disclosed above as the LWA either as the sole LWA or in conjunction with other forms of
  • LWA as described herein for example 3M brand S15 glass microspheres having a SG of about 0.15, or 3M brand S35 glass microspheres having a SG of about 0.35 and other microspheres including those disclosed herein having other densities
  • the polymer bead and glass microsphere varieties of LWA may compose all of the LWA in the LWC or LWC mix or may compose all of the aggregate mix. In compositions having target oven-dried densities below 55 Ibs./cu.ft., it is expected that polymer beads would be combined with one or more type of glass microspheres to meet that low density.
  • their weight percentage of the composition may range from about 20% or below, to over 75%, with particular embodiments including weight percentages of about: 30%, 50%, 65%, and 70%, and ranges including from about 20-30%, about 45-55%, and about 60-75%.
  • their weight percentage of the composition may range from about 5% or below, to over 50%, with particular embodiments including weight percentages of about: 10%, 20%, 40%, and 50%, and ranges including from about 5- 15%, about 15-25%, and about 35-45%.
  • the polymer beads' median size may be substantially greater than the other LWA.
  • the LWA includes polymer beads and glass microspheres where the ratio of the median sizes of the polymer beads and the glass microspheres is at least about 3; in others it is at least about 4, 5, 8 10, 12 and 15.
  • the LWA includes polymer beads and glass microspheres where the ratio of the weights (or equivalently the weight percentages) of the polymer beads to that of the glass microspheres may be between about 0.3-6, about 0.5, about 1 , about 4, about 3.25, ranges of about 3-4, about 2-5, and about 6-9.
  • the ratio of the volume of the glass microspheres to that of the polymer beads may be between about 0.3-6, about 0.5, about 1 , about 1 .5, about 2, about 4 and about 6, ranges of about 0.5-2, and about 2-5.
  • An advantage of LWC mixes using polymer beads as the LWA is that having an SG close to that of water reduces their tendency to segregate.
  • Using polymer beads as the LWA may also reduce or eliminate the segregation of mix components by density. By reducing or eliminating segregation, one may reduce or eliminate the use of viscosity modifier admixtures designed to alter the mix viscosity. It is expected that viscosity modifier admixtures may still be important or necessary if glass microsphere LWA is used with polymer beads.
  • Aggregate SG 1.06 polymer beads with or without SG 0.15 microspheres, and with or without sand or coarse aggregate
  • step 115 all of the LWA is placed into mixing pan 7 of a Hobart type pan mixer 6 (see FIG. 5B).
  • This LWA is composed of polymer beads made of a copolymer having an SG of about 1 .06. Either fine or coarse polymer beads could be used, and in some instances additional LWA composed of 3M brand S15 glass microspheres having a SG of about 0.15, a median size of about 55 microns and a microsphere size distribution such that about 80% are between about 25-90 microns, and with about a crushing strength 90% survival rate at about 300 psi. Other forms / sizes of microsphere LWA could be used.
  • about 80% of the water by weight is added in step 125 to the lightweight aggregate in mixer 6.
  • mixer 6 is run slowly at first, and then on full once enough of the water had mixed with the LWA to reduce dust formation.
  • Mixer 6 is then run until stopped (step 135). Thereafter, if utilized, the fibers are added to mixer 6 in step 140.
  • the fibers could be NYCON brand PVA RECS15 8mm fibers.
  • Mixer 6 is run for about a minute in step 145.
  • Such mixes may include coarse aggregates and may include sand, so in step 150 the sand is added if in the mix design, and in step 155 the coarse aggregate was added if in the mix design, followed by step 160, adding cementitious materials and remaining admixtures (as shown in Table XXVI) with the remaining (about 20%) water.
  • the cementitious materials are HOLCIM brand Type l/l I cement, and if present, could be BORAL brand Class F fly ash and EUCON brand MSA silica fume.
  • the other aggregates, if present, could be Meyer McHenry sand and either Vulcan McCook CM-11 or Martin Marietta #8 coarse aggregates.
  • steps 170 and 180 mixer 6 is run for about 3 minutes and thereafter, mixer 6 was stopped to permit the mix to rest for about 3 minutes. While mixer 6 was not running, in step 190, the mixer blades (paddles) 10 are cleaned off.
  • Mixer 6 is run for about 2 minutes in step 200.
  • step 210 the mix is tested in step 210 for compliance with target slump and target measured air indicated in Table XII as target values after any adjustments, if any.
  • Target measured air plastic air
  • step 240 the process of preparing the batch, mixing the batched materials and forming the wet concrete mix is complete.
  • Such exemplary mixes may also include one or more of the disclosed admixtures and reinforcing materials (e.g. fibers) in amounts consistent with those disclosed for other embodiments of the invention or in other amounts.
  • admixtures may be present in amounts of 0-50 fl. oz. / 100 lbs. of cementitious materials, such as 0-5, 5-10, 5-15, 15-20, 15-25, 20-30, 25-35, 30-40 and 40-50 fl. oz. / 100 lbs. of cementitious materials. Inclusion thereof may slightly alter the weight percentages described above; thus those disclosed are approximate.
  • LWC mixes using such polymer beads may be formed and used to form structures and objects using the disclosed methods and materials from the resulting LWC as already disclosed for mixes or LWC using microspheres elsewhere in this application.
  • Embodiments of the LWC and LWC mixes include those in which other aggregates are present in addition to one or more types of LWA. Such ordinary aggregates may include, but are not limited to, sand and gravel. Embodiments also include LWC including LWA both with reinforcing materials, such as fiber or steel rod (re- bar) or wire mesh or other forms of reinforcing, or without reinforcement.
  • An embodiment of the present invention using such polymer beads includes a self-compacting LWC composition expected to have a high strength after curing for 3 days, 7 days and 28 days, and has a low oven-dried density.
  • the result after curing is a lightweight concrete object (such as the structures or objects disclosed herein), comprising a cured, matrix composite.
  • I he composition elements are present in an amount effective to achieve a target density in said cured composite of not more than about: 125 Ib./cu.ft., 100 Ib./cu.ft., 75 Ib./cu.ft., 60 Ib./cu.ft., 50 Ib./cu.ft., and 40 Ib./cu.ft. or below.
  • Aggregate SG 0.35 microspheres, with or without sand and/or coarse aggregate
  • Modifier MasterMatrix 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
  • precast (or "dry cast") manufacture of products, including concrete blocks involves providing extremely low-slump concrete (almost zero), with a low W/CM ratio (about 0.22 or lower) and a LWA including polymer beads, or polymer beads combined with glass microspheres.
  • LWC mixes described herein that do not include coarse aggregate would be expected to be acceptable for making concrete blocks, with the modifications of removing admixtures and reducing water to form to extremely low-slump concrete (almost zero), with a low W/CM ratio (about 0.22).
  • An admixture could be used as a wetting agent for form removal.
  • Example 41 and exemplary ranges in Examples 42-43 of such a concrete, are shown in Table XXXIII:
  • a bagging facility prepares the concrete precursor materials for bagging and delivery and/or sale of bagged dry concrete (blended or mixed). These steps include acquiring bags and concrete precursor materials including cementitious materials, aggregates, dry admixtures, and reinforcing materials. This may be done, for example, by purchase or extraction. A continuous process is used, in which the individual materials are measured by weight, blended, deposited into bags, which are sealed, and then sold and/or provided for sale. See FIG. 4.
  • Another embodiment of the invention is a concrete mix (and the corresponding concrete) in which the measured entrained air is very low, including levels of below about 4%, about 3%, about 2%, about 1 % and about 0%, as measured following substantially complete mixing.
  • air is allowed to be, or is intentionally, entrained during mixing to volumetrically expand the concrete mix. This has beneficial effects of creating a larger volume of concrete and may improve other characteristics such as resistance!*) cracks a ⁇ d ⁇ reeze/thaw " cycle damage, W/cnvTratTo, reslsla ⁇ nce to segregation of components, workability, as well as resistance to de-icing salts, sulfates, and corrosive water.
  • Adding entrained air also results in a drop in strength of the cured concrete. This may result in the concrete mix having to be designed for a higher strength to compensate, resulting in extra material costs (e.g. cement and admixtures).
  • that level of entrained air can drop as a result of activities associated with the use of the mix, such as pumping (in which increased pressure on the mix forces out entrained air) and delays resulting from transportation or awaiting use of the mix. This results in a loss of design volume that can reduce the beneficial effects of the designed levels of entrained air and reduce profitability.
  • a design mix may have to use an elevated level of entrained air to overcome these concerns.
  • a closed-cell and non-absorptive particle is suitable for displacing a volume within the mix to provide the advantage of the entrained air without the disadvantages.
  • particles that are dimensionally (or volumetrically) stable and that substantially resist change of volume under pressure that displacement eliminates or reduces the need or utility for entrained air to serve that function.
  • particles such as glass microspheres serve that function, resulting in a similarly expanded but stronger concrete.
  • Those particles would be expected to form (as VR) about 5%-25% or more of the concrete mix by volume.
  • Other useful ranges of VR may include about 1 %-6%, about 6%-20%, about 6%-15%, and about 8%-12%.
  • Low-density microspheres may be preferable, for example those having S.G. 0.125 or 0.15, where the lower strength of such particles would be of lesser concern, or much higher density microspheres, for example those having S.G. of even 0.5 or 0.60 or 0.65, or even polymer beads, where the higher strength of such particles would be of value such as in concrete having ordinary density, high strength, and which is used in instances where lightweight concrete is not required but crack-resistance is desirable (such as in foundations or roads).
  • Such concrete can be expected to have compressive strengths ranging upward from 3000 psi, to 4000, 5000, 6000, 7000, 7000, 9000 and 10000 psi and above, as well as at densities greater than 120 Ib./cu.ft.
  • One mix expected to be appropriate, for example, is one having the general proportions of that in Example 2 ⁇ .
  • Such concrete mixes could be expected to be prepaTecT Tn accordance with the steps set forth in FIGS. 3A-3B, and products or structures made therefrom in accordance with the steps set forth above.
  • LWC mixes according to embodiments of the invention may also be used to form concrete roofing tiles, which may take various forms. Concrete roofing tiles are useful as they are hail-resistant and fire-proof, and provide good insulation. However, a roof composed of ordinary concrete roofing tiles is substantially heavier than the shingle / composition roof that is usually originally provided, and for which homes are typically designed to support. Concrete roofing tiles formed of LWC according to embodiments of the invention would be lighter and more readily installed, while still providing other advantages. LWC mixes described herein that do not include coarse aggregate would be expected to be acceptable for making concrete roofing tiles, with the potential modification of removing some or all of the admixtures and by reducing water to form to extremely low-slump concrete (almost zero), with a low W/CM ratio (about 0.22).
  • the mixing process steps are, as shown in FIG. 8A and with reference to FIG. 5C, with regard to concrete block manufacturing.
  • One method of making concrete roofing tiles is by supplying the LWC mix to the intake of an extruding machine, which extrudes an elongated sheet.
  • a cutting tool cuts the elongated sheet at the appropriate lengths to form the individual concrete roofing tiles.
  • the concrete roofing tiles are set aside for curing, following which they may be transported to a construction site or sold for further sale. Curing may include steam-curing or other processes to develop desirable concrete properties.
  • LWC mixes according to embodiments of the invention may also be used to form cement board.
  • Cement board is a combination of cement and reinforcing elements, and are typically formed into 4'x8' or 3'x5' sheets of 1 ⁇ 4" or 1 ⁇ 2" thickness or thicker. They are useful as wall elements where moisture resistance, impact-resistance, and/or strength are important. Typical reinforcing elements include cellulose fiber or wood chips.
  • the cement material may also be formed between two layers of a fiberglass mesh or fiberglass mats. Ordinary cement board is, however, relatively heavy and more difficult to cut. Cement board formed of LWC according to embodiments of the invention would be lighter and more readily cut and installed. LWC mixes described herein that do no indude coarse aggregate would be expected to be acceptable for makTr ⁇ cemeni board.
  • the mixing process steps are, as shown in FIG. 8A and with reference to FIG. 5C, with respect to concrete block manufacturing.
  • One method of making cement board is by supplying the LWC mix to the intake of a sheet extruding machine, which extrudes an elongated sheet.
  • a cutting tool cuts the elongated sheet at the appropriate lengths to form the individual sheets of cement board.
  • the cement board sheets are set aside for curing, following which they may be transported to a construction site or sold for further sale. Curing may include steam-curing or other processes to develop desirable concrete properties.
  • An embodiment of the present invention includes using a LWC composition or dry mix in applying shotcrete.
  • a shotcrete process is one by which a concrete mix is conveyed by pressurization through a hose and pneumatically applied to a surface, while simultaneously being compacted during the application step. Typically, the mix is applied over some form of reinforcements, such as rebar, wire mesh or fibers.
  • dry mix or wet mix There are two variants: dry mix or wet mix.
  • the dry mix process includes providing the dry mix components (e.g. cementious materials, dry admixtures, and LWA) in the respective appropriate ratios, mixing the dry mix components, loading the dry mix components in a storage container, using pneumatic pressure to convey the dry materials out of that container and via a hose to a nozzle.
  • the wet mix process includes providing the mix components (e.g. water, cementious materials, dry admixtures and LWA) in the respective appropriate ratios, mixing the mix components to form a concrete composition, loading the composition in a storage container, pumping the composition out of that container and via a hose to a nozzle.
  • the mix components e.g. water, cementious materials, dry admixtures and LWA
  • LWC according to embodiments of the invention may be readily cut with an ordinary wood saw, without needing a concrete or stone blade. This is so for those LWC in which all aggregate is LWA as described herein and does not include other ordinary aggregates such as sand. Moreover, a person may easily drive an ordinary nail meant for wood-construction into LWC made according to embodiments of the invention, without needing specially-hardened or carbide-tipped nails, and without needing a naif gun or explosive nail driver and/or drill. Moreover, the surface of a LWC according to embodiments of the invention may be paintable (paint-ready), such as for the interior or exterior of a home, or an architectural panel. Paint-ready, in this instance, requires that a surface be free of voids.
  • LWC according to embodiments of the invention is expected to have substantially greater insulating properties (higher R-value, lower thermal conductivity) than ordinary concrete. This is based upon the understood relationship between density and conductivity. However, LWC according to embodiments of the invention has a much greater strength-to-weight (and -density) ratio, and thus can insulate better for a given mass and weight.
  • the LWA (specifically in the case of the glass microspheres) is much less dense even than water, is the lowest-density component, and has the natural tendency to float to the top of a mix.
  • a primary one is that it can cause uneven properties of the concrete product or structure, resulting in visual deficiencies (i.e. visible aggregate maldistribution). Uneven properties might mean a portion of the product or structure having an excessively high concentration of LWA, thus displacing cementitious materials, might be weaker than designed.
  • LWC and LWC mixes according to embodiments of the invention have highly-homogenous mix properties, such that the mix density varies by less than 15%, less than 10%, and less than 1 %.
  • mix design largely prevents the LWA from segregating within the mix. This was revealed by pouring a sequence of about seven test samples (according to ASTM C192) from a mix over time (about 5-10 minutes), and testing their respective densities (according to ASTM C567). In this case, densities measured were extremely similar, differing among themselves by only about 1 %. This results in the LWA remaining substantially homogenous and unsegregated upon pouring from the mixer and prior to curing, and permits the LWA to be substantially evenly distributed within the composition following curing.
  • An embodiment of the present invention includes a LWC having a strength-to- weight ratio substantially greater than that typically found in structural LWC, in which the ratio might be (expressed as compressive strength-to-density) about 2500 psi ⁇ 90 ⁇ Ib/cu.ft. (about 27.8) up to about 6000 psi / 120 Ib/cu.ft. (about 50).
  • Embodiments of the present invention include LWC mixes having 28-day compressive strength-to-density ratios about 81.3 (3310 psi / 40.7 Ib/cu.ft.), about 71 .2 (2800 psi / 39.3 Ib/cu.ft.), about
  • Embodiments of the present invention include LWC mixes having 7-day compressive strength-to-density ratios of about 29.8 (3625 psi / 121.5 Ib/cu.ft.), 40.5 (1580 psi / 39.0 Ib/cu.ft.), 31 .2 (1890 psi / 60.5 Ib/cu.ft.), 50.6 (2757 psi / 54.5 Ib/cu.ft.),
  • This ratio may also be calculated using tensile strength values or elastic modulus or modulus of rupture This ratio is preferably calculated using strengths or moduli from tests at 28 days or longer, but may also be calculated using tests carried out earlier in the curing process. Such ratios calculated using 28-day values are expected to be better, as the strength values can be expected to increase with age.
  • An embodiment of the present invention includes a LWC having a high strength- replacement-volume factor ("Sv"). This value is calculated by multiplying the compressive or tensile strength by the replacement volume of the LWA (VR, volume percentage displaced by the LWA in the wet mix). Or it may be calculated by multiplying the elastic modulus or modulus of rupture by VR. This is a measure of strength of the concrete combined with the density-reducing effect reflected by VR, in which a higher value is better.
  • Sv strength- replacement-volume factor
  • Svc (based upon 28-day compressive strengths) ranges from about 870 to about 2000 psi, and includes these values: 1678, 1754, 1422 and 2010 psi (mixes in which the only aggregate is a LWA comprising glass microspheres) and from about 270 to about 1000 to about 1770 psi, and includes these values: 268, 1003, 6 5, and 1771 psi (mixes in which either or both sand and a coarse aggregate were present in addition to a LWA comprising glass microspheres).
  • SVT (based upon 7-day tensile strengths) ranges from about 90 to about 115, and includes these values: 89.5, 101 .8, 114.5, 94.32 psi (the first three being mixes in which the only aggregate is a LWA comprising glass microspheres). In embodiments of the invention, SVT (based upon 28-day tensile strengths) ranges from about.
  • ITiese values 1187 136.2, 156.5, and 180.7 psi (mixes in which the only aggregate is a LWA comprising glass microspheres) and from about 20 to about 175 psi, and includes these values: 23.8, 112.1 , 153.5, and 176.7 psi (mixes in which either or both sand and a coarse aggregate were present in addition to a LWA comprising glass microspheres).
  • SVA (based upon the 28-day elastic modulus) ranges from about 270 to about 460 kpsi, and includes these values: 273.9, 344.5, 421 .6, 405.6, and 458.1 kpsi (mixes in which the only aggregate is a LWA comprising glass microspheres) and from about 160 to about 770 kpsi, and includes these values: 158.7, 373.8, 462.8, 598.1 , and 767.3 kpsi (mixes in which either or both sand and a coarse aggregate were present in addition to a LWA comprising glass microspheres).
  • SVA (based upon the 7-day elastic modulus) ranges from about 250 to about 315 kpsi, and includes these values: 248.5, 254.5, 273.9 and 314.4 kpsi (the first three being mixes in which the only aggregate is a LWA comprising glass microspheres).
  • This factor is preferably calculated using strengths or moduli from tests at 28 days or longer, but may also be calculated using tests carried out earlier in the curing process.
  • An embodiment of the present invention includes a LWC mix having a low weight-fraction of aggregate to total dry raw materials (FAD). This is a measure of the density-reducing effect of using the embodiments of the LWA as described above, and in particular the lower-density glass microspheres such as the SG 0.15 microspheres.
  • FAD ranges from about 10 to about 75, and includes these values: 30.32, 29.74%, 29.71 %, 30.01 %, 30.06%, 13.95%, 14.37%, and 13.85% (mixes in which the only aggregate is a LWA comprising glass microspheres; those falling below 15% included SG 0.15 microspheres and less fly ash) as well as 42.08% and 42.06% (each mixes in which sand is included in the aggregate with a LWA comprising glass microspheres). Other mixes with large amounts of sand or gravel had substantially higher values.
  • An embodiment of the present invention includes a dry LWC mix having a a low weight-fraction of aggregate to total dry raw materials, and highly-homogenous mix properties, and which forms LWC having a low-density, low thermal conductivity, high strength-replacement-volume factor, a high strength-to-weight ratio, and a high strength- to-density ratio.
  • That LWC mix includes embodiments that use an LWA, which LWA may include glass microspheres and/or polymer beads, as described above.
  • An embodiment of the present invention includes a self-compacting wet LWC mix comprising such a LWA and having such properties.
  • An embodiment of the present invention includes the process of preparing batches of components of a LWC mix (wet or dry) comprising such a LWA.
  • An embodiment of the present invention includes the unmixed components of a LWC mix comprising such a LWA.
  • An embodiment of the present invention includes the process of mixing a LWC mix comprising such a LWA.
  • An embodiment of the present invention includes the process of providing unmixed components of a LWC mix comprising such a LWA for mixing.
  • An embodiment of the present invention includes the process of preparing dry LWC mix comprising such a LWA in a continuous process for bagging.
  • An embodiment of the present invention includes a LWC formed of or comprising such a LWA having a low-density, low thermal conductivity, high strength- replacement-volume factor, a high strength-to-weight ratio, and a high strength-to- density ratio.
  • An embodiment of the present invention includes manufactured or pre-cast products comprising a LWC formed of or comprising such a LWA having such characteristics.

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Abstract

L'invention concerne une composition de béton haute résistance et faible densité qui est à la fois auto-compactante et légère, présentant une faible fraction en poids d'agrégat par rapport à un total de matières premières sèches, et une distribution très homogène d'un agrégat léger non-absorbant et à cellules fermées, tel que des microsphères de verre ou des billes polymères copolymères ou une combinaison de celles-ci, et les étapes consistant à fournir la composition ou les composants. Les bétons légers formés à partir de celle-ci présentent une faible densité, des rapports résistance-poids élevés et une valeur R élevée. Le béton présente une résistance similaire à celle généralement rencontrée dans du béton de structure léger mais à une densité séchée dans un four aussi faible que 40 livres/pied cube. À la densité rencontrée généralement dans du béton de structure léger, le béton présente une résistance supérieure et, à la résistance rencontrée généralement dans du béton de structure léger, une densité inférieure. De tels rapports résistance-densité varient approximativement entre une valeur supérieure à 30pieds cubes/pouces carrés et une valeur supérieure à 110 pieds cubes/pouce carré, une résistance à la compression à 28 jours variant d'environ 3 400 à 8 000 psi.
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US16/277,362 US10759701B1 (en) 2015-09-09 2019-02-15 Low-density high-strength concrete and related methods
US17/002,490 US11577998B2 (en) 2015-09-09 2020-08-25 Low-density high-strength concrete and related methods
US18/165,059 US20240043332A1 (en) 2015-09-09 2023-02-06 Low-density high-strength concrete and related methods

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CN113360828A (zh) * 2021-05-19 2021-09-07 黄子 一种新型lwc大规模碳沉降计算模型的构建方法及应用
CN114250796A (zh) * 2021-12-30 2022-03-29 北京铁科特种工程技术有限公司 用于应急施工和位移监控的复合材料锚固件及施工方法
EP3991933A1 (fr) * 2020-11-02 2022-05-04 Rosetta Hardscapes, LLC Système et procédés de démoulage de blocs de béton et de réinsertion d'inserts de moule
CN114477862A (zh) * 2020-10-27 2022-05-13 成都岷江混凝土有限公司 一种高抗裂混凝土生产方法
CN114564056A (zh) * 2022-02-21 2022-05-31 蚌埠市鹏慈农业科技有限公司 一种种植大棚智能控制系统
CN118063150A (zh) * 2024-04-19 2024-05-24 淮南东辰固废利用有限公司 一种煤矸石轻细集料混凝土及其浮体

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CN114564056A (zh) * 2022-02-21 2022-05-31 蚌埠市鹏慈农业科技有限公司 一种种植大棚智能控制系统
CN118063150A (zh) * 2024-04-19 2024-05-24 淮南东辰固废利用有限公司 一种煤矸石轻细集料混凝土及其浮体

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