Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
  • C04B28/04—Portland cements
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • 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
  • C04B14/022—Carbon
  • C04B14/024—Graphite
• • 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
  • C04B28/14—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 calcium sulfate cements
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00439—Physico-chemical properties of the materials not provided for elsewhere in C04B2111/00
  • C04B2111/00465—Heat conducting materials
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00663—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like
  • C04B2111/00706—Uses not provided for elsewhere in C04B2111/00 as filling material for cavities or the like around pipelines or the like
• • 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
  • C04B2111/90—Electrical properties
  • C04B2111/94—Electrically conducting 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

• the present disclosure is directed to methods for improving the thermal and electrical properties of cement compositions and to formulations for cements having such properties and, more particularly to such methods and formulations in which fine resilient graphitic carbon particles are added to the formulations.
• Electrically conductive and/or thermally transmissive cements are useful for a number of purposes, such as, but not limited to, heated pavement systems, indoor or outdoor heated/cooled flooring systems, heat dissipation in power plants or mechanical operations, and heat dissipation in structural systems.
• a method for improving the thermal and electrical characteristics of cement compositions in which fine resilient graphitic carbon particles ("RGC") are substituted for a portion of the fine aggregate (typically sand) in the cement formulation.
• RGC fine resilient graphitic carbon particles
• fine is intended to describe particulates having a mesh size of less than about 8 mesh, or a particle size of less than about 2.38 mm, or, more preferably when referring to RGC, a mesh size of less than about 16 mesh and a particle size of less than about 1 .19 mm.
• “Resilient” is intended to describe graphitic carbon particles that exhibit a rebound of at least about 20% after compression to 10,000 psi.
• RGC may be substituted for up to 100 vol% (or 100 wt%) of the fine aggregate in the dry-constituent concrete composition or, more preferably up to about 75 vol% (or approximately 64 wt%) of the fine aggregate in the dry-constituent mortar composition.
• the RGC may comprise synthetic graphite, thermally treated calcined petroleum coke, or a combination thereof.
• the cement mixtures to which the RGC is added may be the Portland cement formulations defined by ASTM C150, (particularly Types I, II, III and V), oil well cements (as defined by API and including Portland-type cements), and floor leveling gypsum-based cements (such as those sold by USG Corporation under the LEVELROCK® trademark and Maxxon Corporation under the GYP-CRETE® trademark).
• formulations are provided for cement compositions that include RGC as part or all of the fine fraction.
• dry-constituent concrete compositions in accordance with the disclosure include: RGC: 0.5wt%-32.3 wt%; coarse aggregate: 5.2 wt%-71 .0 wt%; fine aggregate/sand: 0 wt% (full replacement by RGC)-88.6 wt%; and cement (Portland Type l/ll): 15.7 wt%-23.2 wt%.
• dry-constituent mortar compositions in accordance with the disclosure include: RGC: 0.5wt%-37 wt%; coarse aggregate: 0 wt%; fine aggregate/sand: 0 wt% (full replacement by RGC)-76.2 wt%; and cement (Portland Type l/ll): 23.3 wt%-40.0 wt%.
• the formulations may include a fly ash fraction as replacement for a portion of the cement of from 3.1 wt%-4.6 wt% for concrete, and of from 4.7 wt% to 8.0 wt% for mortar. Further aspects will become apparent upon reference to the following detailed description.
• Fig. 1 is a table setting forth the wt% of the various cement compositions prepared in connection with the testing reported below
• the present invention relates cement/concrete formulations with a resilient graphitic carbon addition that imparts superior thermal conductivity, electrical resistivity, without degradation of mechanical performance. Because of the excellent thermal and electrical conductivity, cement/concrete products with resilient graphite addition may be used to help dissipate or conduct thermal energy by itself or with the incorporation of energy source (for example an electric heating element or metal pipe to transport fluids).
• energy source for example an electric heating element or metal pipe to transport fluids.
• Resilient graphite may be produced by thermal treatment of calcined petroleum coke through a proprietary continuous fluid bed reactor technology.
• RGC particles are considered resilient if they rebound by at least 20%, and preferably by at least 35%, after applying a compaction pressure of 10,000 psi. More preferably, the resiliency values of the RGC product are greater than 100%.
• Resiliency may be determined by use of a press by which pressure is applied to an un-compacted sample of material and released. More specifically, a test cylinder or die is loaded with a dry and free flowing amount of the material to be tested. The test cylinder is then mounted onto a press. Pressure is applied by the press to the sample (to 10,000 psi) and the height of the compacted sample (h 0 ) within the test cylinder is measured. The pressure is then released and the rebounded height of the sample in the test cylinder ⁇ h r ) is measured at 10 minutes after pressure is released, and then again at 20 minutes to make sure that the sample has stabilized. The resiliency (%) is then calculated as 100 x (fr ,- 1 ).
• the cement portion of the mixtures may comprise various different types of cements.
• the cement fractions of the mixtures comprised Portland cement, as defined by ASTM C 150. Tables 1 and 2 below, set forth the typical primary phases and chemical composition of Portland cement.
• Type I Portland cement is known as common or general purpose cement. When referring to Portland cement, it is generally assumed that Type I is being referred to unless another type is specified. Type I Portland cement is commonly used for general construction, especially when making precast and precast- pre-stressed concrete that is not to be in contact with soils or ground water.
• the typical phase compositions of this type are: 55% (C 3 S), 19% (C 2 S), 10% (C 3 A), 7% (C 4 AF), 2.8% (MgO), 2.9% (SO 3 ), 1 .0% (H 2 O and CO 2) , and 1 .0% (free CaO).
• Type II Portland cement is intended to have moderate sulfate resistance, with or without moderate heat of hydration.
• the typical phase composition is: 51 % (C 3 S), 24% (C 2 S), 6% (C 3 A), 1 1 % (C 4 AF), 2.9% (MgO), 2.5% (SO 3 ), 0.8% (H 2 O and CO 2 ), and 1 .0% (free CaO).
• a limitation on the Type II composition is that the (C 3 A) shall not exceed eight percent, which reduces its vulnerability to sulfates.
• Type II cements are comparably priced, Type II is used as a general purpose cement, and the majority of Portland cement sold in North America meets this specification.
• Type III Portland cement has relatively high early strength.
• the typical phase composition is: 57% (C 3 S), 19% (C 2 S), 10% (C 3 A), 7% (C 4 AF), 3.0%( MgO), 3.1 % (S0 3 ), 0.9% (H 2 0 and C0 2 ), and 1 .3% (free CaO).
• Type III is similar to Type I, but ground finer. Some manufacturers make a separate clinker with higher C 3 S and/or C 3 A content, but this is increasingly rare, and the general purpose clinker is usually used, ground to a specific surface typically 50-80% higher than Type I. The gypsum level may also be increased a small amount.
• Type III cement is commonly used for precast concrete manufacture, where high 1 -day strength allows for a fast turnover of molds, in emergency construction and repairs, and in construction of machine bases and gate installations.
• Type IV Portland cement is generally known for its low heat of hydration.
• the typical phase composition for Type IV cement is: 28% (C 3 S), 49% (C 2 S), 4% (C 3 A), 12% (C 4 AF), 1 .8% (MgO), 1 .9% (SO 3 ), 0.9% (H 2 O and CO 2 ), and 0.8% (free CaO).
• the percentages of (C 2 S) and (C 4 AF) are relatively high and (C 3 S) and (C 3 A) are relatively low.
• a limitation on Type IV cement is that the maximum percentage of (C 3 A) is seven, and the maximum percentage of (C 3 S) is thirty-five. This causes the heat given off by the hydration reaction to develop at a slower rate. However, as a consequence, the strength of the concrete develops slowly. After one or two years the strength is higher than the other types after full curing.
• Type IV cement is used for very large concrete structures, such as dams, which have a low surface to volume ratio.
• Type V Portland cement is used where sulfate resistance is important.
• the typical phase composition for Type V cement is: 38% (C 3 S), 43% (C 2 S), 4% (C 3 A), 9% (C 4 AF), 1 .9% (MgO), 1 .8% (S0 3 ), 0.9% (H 2 0 and C0 2 ), and 0.8% (free CaO).
• Type V cement has a very low (C 3 A) content, which accounts for its high sulfate resistance.
• the maximum content of (C 3 A) allowed is five percent for Type V Portland cement.
• Another limitation is that the (C 4 AF) + 2(C 3 A) fraction cannot exceed twenty percent.
• Type V cement is used in concrete that is to be exposed to alkali soil and ground water sulfates which react with (C 3 A) causing disruptive expansion. While generally unavailable in many places, its use is common in the western United States and Canada.
• Type V Portland cement has mainly been supplanted by the use of ordinary cement with added ground granulated blast furnace slag or tertiary blended cements containing slag and fly ash.
• Types la, I la, and Ilia Portland cements have the same composition as Types I, II, and III. They differ in that Types la, lla, and Ilia additionally include an air- entraining agent ground into the mix. The air-entrainment must meet the minimum and maximum optional specification found in the ASTM manual. These types are generally only available in the eastern United States and Canada.
• Types ll( H) and ll(MH)a have compositions similar to Types II and lla, but with moderate heat of hydration. (These cements were added to ASTM C-150 in 2009.)
• RGC may also be combined with self-leveling cements (typically including gypsum) and oil well cements in accordance with the present disclosure to obtain improved thermal and electrical characteristics.
• self-leveling cements typically including gypsum
• oil well cements in accordance with the present disclosure to obtain improved thermal and electrical characteristics.
• compositions include: RGC, coarse aggregate, fine aggregate/sand, cement, and, optionally, fly ash in the wt% proportions indicated in Table 3.
• the formulations may also include water reducing and/or air entraining admixtures.
• a series of concrete mixes were prepared in accordance with ASTM C192 in which RGC was substituted for a portion of the fine aggregate (sand) fraction.
• RGC fine aggregate
• Fig. 1 eight samples were prepared (Samples A-H), with two samples (Samples A and F) being control samples, in which the fine aggregate did not include any RGC.
• Each sample included cement, coarse aggregate, fine aggregate (RGC and sand), and water.
• the RGC and sand had similar gradation, as set forth in ASTM C778 for standard sand, with a minor amount of the material finer than #100 mesh.

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

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