Abstract: A method including introducing a well cementing composition into a wellbore, the cementing composition including a pumpable slurry of cement comprising a liquid anti-shrinkage additive including: an aqueous base fluid; a calcined magnesium oxide; and an anti-hydration agent; and allowing at least a portion of the cementing composition to harden. A liquid anti-shrinkage additive for cement including an aqueous base fluid, a calcined magnesium oxide, and an anti-hydration agent.

Abstract: The present invention provides a bidirectional energy-transfer system comprising: a thermally and/or electrically conductive concrete, disposed in a structural object; a location of energy supply or demand that is physically isolated from, but in thermodynamic and/or electromagnetic communication with, the thermally and/or electrically conductive concrete; and a means of transferring energy between the structural object and the location of energy supply or demand. The system can be a single node in a neural network. The thermally and/or electrically conductive concrete includes a conductive, shock-absorbing material, such as graphite. Preferred compositions are disclosed for the thermally and/or electrically conductive concrete.

Abstract: A method for creating multifunctional cementitious composites that provide load-bearing and self-sensing properties. The method involves dispersing conductive nanomaterials (e.g., multi-walled carbon nanotubes) into a polymer (e.g., latex) material from which a thin film is created and deposited (e.g., sprayed) onto aggregates, which after drying, can be incorporated with cementitious materials and desired liquids and cast, along with sufficient number of electrodes, into a form for curing. After curing, the resultant structure can be electrically tested through the electrodes, for structural characteristics, including determination of damage severity and location using back-calculation utilizing electrical resistance tomography (ERT), or electrical impedance tomography (EIT), to generate a spatial resistivity map (distribution).

Abstract: A method for making an admixture in liquid form for concrete includes the step of providing a nanocarbon mixture containing at least two different types of nanocarbon particles, with each type of nanocarbon particle having a predetermined percentage range by mass of the admixture, crushing or grinding the nanocarbon mixture into a carbon powder, and wetting and mixing the carbon powder in a water/surfactant mixture using high energy mixing apparatus. The method can also include blending the nanocarbon mixture with a nano-silica based compound, either before or after the wetting and mixing step. An admixture for concrete includes at least two different types of nanocarbon particles in a water/surfactant mixture having a predetermined percentage range by mass of the admixture. The admixture also includes surfactant and can include a nano-silica based suspension stabilizer having a predetermined percentage range by mass of the admixture.

Abstract: The present invention discloses a micro-nano composite hollow structured nanometer material-modified high-durability concrete material, and according to mass parts, its raw material formula is as follows: cobaltosic oxide, 1000-1500 parts; cement, 1000-1300 parts; dioctyl sebacate, 1000-1500 parts; water, 800-1200 parts; nanocarbon, 1200-1800 parts; nano calcium carbonate, 35-50 parts; sodium silicate, 10-20 parts; micro-nano structured calcium molybdate, 50-80 parts; dipentaerythritol, 60-90 parts; and dioctyl ester 30-60 parts. The present invention enables existing concrete to be improved effectively and stably in terms of shrinkage, cracking resistance and rapid hardening; the synthetic chemical functional material may lower a chloride ion diffusion coefficient of the concrete by more than 50%, cut down shrinkage by more than 30%, and reduce the cracking risk of concrete products by 50%.

Abstract: Disclosed is a method of forming a set cement shape. The method comprises providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; forming the set-delayed cement composition into a shape; and allowing the shaped set-delayed cement composition to set.

Abstract: Methods of using the set-delayed cement slurries and compositions resulting from the combination of the set-delayed cement slurries are also described. A method may comprise providing a first set-delayed cement slurry comprising a pozzolanic cement and/or a Portland cement, water, and a first cement set retarder; providing a second set-delayed cement slurry comprising calcium-aluminate and a second cement set retarder; mixing the first slurry and the second slurry to form a cement composition; and allowing the cement composition to set.

Abstract: A system and related method that provides, but is not limited thereto, a thin structure with unique combination of thermal management and stress supporting properties. An advantage associated with the system and method includes, but is not limited thereto, the concept providing a multifunctional design that it is able to spread, store, and dissipate intense thermal fluxes while also being able to carry very high structural loads. An aspect associated with an approach may include, but is not limited thereto, a large area system for isothermalizing a localized heating source that has many applications. For example it can be used to mitigate the thermal buckling of ship deck plates, landing pad structures, or any other structures subjected to localized heating and compressive forces.

Abstract: A composite cement material is prepared from cement material and carbon nanotubes, wherein the carbon nanotubes are present from about 0.02 wt % to about 0.10 wt % based on weight of cement material. The process for preparing such cement compositions includes sonicating a mixture of a surfactant, water, and carbon nanotubes; and blending the dispersion and the cement material to form a cementitious paste. The process may also include curing the cementitious paste. The composite cement materials are useful in a variety of cement applications where a reduction in nanoscale flaws and fractures is desired.

Abstract: The reaction product of a polyhydroxy compound and borax is used as a cement retarder for slurries introduced into a wellbore. The molar ratio of the polyhydroxy compound to boron, derived from the borax, is from 1:1 to about 4:1. The polyhydroxy compound may be a sugar such as a gluconic acid, gluconate or glucoheptonate or a salt thereof.

Abstract: A method of making a rapid setting lightweight homogeneous foamed fly ash based cementitious aggregate composition with improved compressive strength for products such as panels is disclosed. The method mixes fly ash, alkali metal salt of citric acid, foaming agent for entraining air, optional foam stabilizing agent, a calcium sulfate such as stucco or gypsum, and water. Compositions are also disclosed which include mixtures of fly ash, particularly Class C fly ash alone or in mixtures with Class F fly ash, alkali metal salts of citric acid, foaming agents, a calcium sulfate such as calcium sulfate dihydrate or hemihydrate and an optional portland cement.

Abstract: Disclosed is a system or method for efficiently manufacturing construction materials using carbon nanomaterials. In one or more embodiments, the method comprises creating a blend of carbon nanomaterials, wherein the blend of the carbon nanomaterials includes at least one of a carbon nanofiber, a carbon nanotube, a graphite nanoparticle and an amorphous carbon. The method also includes dispersing the carbon nanomaterials and adding a plasticizer and a sand to the dispersed mixture within 3 minutes. The method also includes adding at least one of water and a cement binding agent to the dispersed mixture after the plasticizer and the sand have been added.

Abstract: A method of treating an offgas includes purifying the offgas to remove particulate matter, water, undesirable gaseous components and inert gases to produce a dried carbon oxide gas feedstock, and converting at least a portion of carbon oxides in the dried carbon oxide gas feedstock into solid carbon. In other embodiments, a method includes passing a dried carbon oxide gas feedstock through a multi-stage catalytic converter. A first stage is configured to catalyze methane-reforming reactions to convert methane into carbon dioxide, carbon monoxide and hydrogen with residual methane. A second stage is configured to catalyze the Bosch reaction and convert carbon oxides and hydrogen to solid carbon and water.

Abstract: Conductive concrete mixtures are described that are configured to provide EMP shielding and reflect and/or absorb, for instance, EM waves propagating through the conductive concrete mixture. The conductive concrete mixtures include cement, aggregate, water, metallic conductive material, and conductive carbon particles and/or magnetic material. The conductive material may include steel fibers, and the magnetic material may include taconite aggregate. The conductive concrete mixture may also include graphite powder, silica fume, and/or other supplementary cementitious materials (SCM). The conductive carbon particles may comprise from about zero to twenty-five percent (0-25%) of the conductive concrete mixture by weight and/or the magnetic material may comprise from about zero to fifty percent (0-50%) of the conductive concrete mixture by weight.

Abstract: Methods and compositions that protect cement compositions from corrosion, particularly from wet carbon dioxide, are provided. A soluble salt additive is provided to react with reaction products generated during the reactions that occur when cement is exposed to wet carbon dioxide. The soluble salt reacts to form an insoluble salt that forms a protective layer on the surface of the cement that protects it from further corrosion from exposure to wet carbon dioxide.

Abstract: Disclosed is a system or method for efficiently manufacturing construction materials using carbon nanomaterials. In one or more embodiments, the method comprises creating a blend of carbon nanomaterials, wherein the blend of the carbon nanomaterials includes at least one of a carbon nanofiber, a carbon nanotube, a graphite nanoparticle and an amorphous carbon. The method also includes dispersing the carbon nanomaterials and adding a plasticizer and a sand to the dispersed mixture within 3 minutes. The method also includes adding at least one of water and a cement binding agent to the dispersed mixture after the plasticizer and the sand have been added.

Abstract: Disclosed is a system or method for efficiently manufacturing construction materials using carbon nanomaterials. In one or more embodiments, the method comprises creating a blend of carbon nanomaterials, wherein the blend of the carbon nanomaterials includes at least one of a carbon nanofiber, a carbon nanotube, a graphite nanoparticle and an amorphous carbon. The method also includes dispersing the carbon nanomaterials and adding a plasticizer and a sand to the dispersed mixture within 3 minutes. The method also includes adding at least one of water and a cement binding agent to the dispersed mixture after the plasticizer and the sand have been added.

Abstract: A vertebroplastic cementitious composition includes a solid phase including Portland cement and a biocompatible additive which is a plasticizer and a hardening accelerant, wherein the amount of additive is between about 1% and about 15% by weight relative to the Portland cement; and an aqueous liquid phase, wherein the ratio of the solid phase to the liquid phase is between about 3 g/ml and about 6 g/ml. Methods of forming such compositions, treatment methods using such compositions and cementitious implants including such compositions are also described.

Abstract: Methods and compositions that protect cement compositions from corrosion, particularly from wet carbon dioxide, are provided. A soluble salt additive is provided to react with reaction products generated during the reactions that occur when cement is exposed to wet carbon dioxide. The soluble salt reacts to form an insoluble salt that forms a protective layer on the surface of the cement that protects it from further corrosion from exposure to wet carbon dioxide.

Abstract: A method for improving the thermal characteristics of cement compositions is provided in which fine resilient graphitic carbon particles (“RGC”) are substituted for a portion of the fine aggregate (typically sand) in the cement formulation. For the purposes of the present disclosure, “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.

Abstract: Cement retarders are based on blends of lignosulfonate compounds, borate compounds and gluconate compounds. The compounds are present in certain ratios that allow the retarders to operate at temperatures and pressures up to and exceeding about 176° C. and 152 MPa. The retarders may also be provided in liquid form, improving their suitability for use at offshore well-site locations.

Abstract: Concrete reinforced with nanostructures and reinforcing concrete methods are provided having cement and dispersion including water, a surfactant, carbon nanotubes having on the external surfaces thereof carbon atoms substituted by atoms of another element or other elements, and carbon nanotubes possessing chemical groups on the surface thereof.

Abstract: Concrete reinforced with nanostructures and reinforcing concrete methods are provided having cement and dispersion including water, a surfactant, carbon nanotubes having on the external surfaces thereof carbon atoms substituted by atoms of another element or other elements, and carbon nanotubes possessing chemical groups on the surface thereof.

Abstract: A thermal neutron shield comprising concrete with a high percentage of the element Boron. The concrete is least 54% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of Boron loaded concrete which includes enriching the concrete mixture with varying grit sizes of Boron Carbide.

Abstract: Resilient graphitic carbon may be an effective lost-circulation control agent for well-cementing compositions. During primary or remedial cementing, the carbon particles may hinder or prevent the egress of the well-cementing composition from the wellbore into subterranean formations via formation fissures or cracks. The carbon particles may also be added to spacer fluids, chemical washes or both.

Abstract: A hydraulic cement comprising a calcium silicate and at least one phosphate compound. The phosphate compound is included in an amount sufficient to react a major portion of the calcium hydroxide that is produced during hydration of the cement to hydroxyapatite or other calcium phosphates. The phosphate compound is preferably a mono-calcium phosphate. The cement is useful in both bio-medical/dental and engineering applications. The calcium hydroxide is reacted by the phosphate to form hydroxiapatite or other calcium phosphate that is co-precipitated with the calcium silicate hydrate to form a composite-like structure on a nano-scale level. The reduced calcium hydroxide content in the set cement increases its strength and reduces its pH. The hydroxiapatite content and the reduced pH render the cement bio-active and suitable for use in medical and dental implants, for example, for replacement bone and tooth material. Due to its high strength, the cement may also be used for structural/engineering applications.

Abstract: A method to render stone, ceramic, or cementitious structures water repellent is disclosed. The method includes the step of contacting the stone, ceramic, or cementitious structures with an alkylphosphonic acid. The alkylphosphonic acid can be dispersed in an aqueous medium and can be at least partially neutralized with ammonia, an amine, or a basic alkali salt.

Abstract: This invention provides a material for vibration damping, said material comprising a composite, said composite comprising a cement matrix, and exfoliated graphite that is distributed in said composite. Said cement is preferably hydraulic cement containing calcium silicate. Said exfoliated graphite exhibits a morphology that enables the physical units of exfoliated graphite to connect mechanically. The proportion of exfoliated graphite in the composite is high enough for the exfoliated graphite to connect mechanically in the presence of cement. The proportion of cement in the composite is high enough for the cement to form a continuous matrix in the composite. This invention also provides a material for vibration damping, said material comprising a composite, said composite comprising a continuous cement matrix and a graphite network, said network being mechanically connected.

Abstract: A process for producing a clinker with a high content of belite, includes (i) introducing a raw meal into a calcination chamber of a cement plant kiln; (ii) calcining the raw meal at a temperature of from 1150° C. to 1375° C.; (iii) measuring the weight per litre of the product of step (ii) and eliminating the product having a weight per litre strictly less than 650 g/litre; (iv) measuring the quantity of SO3 in the product of step (ii) and eliminating the product having a ratio of quantity of SO3 of the decarbonated raw meal/quantity of SO3 in the product of step (ii) less than or equal to 0.75 and greater than or equal to 1.2; (v) measuring the quantity of free lime (CaOl) in the product of step (ii) and eliminating the product having a quantity of free lime strictly greater than 1.5%, percentage by mass of free lime in the product of step (ii).

Abstract: The embodiments herein provide a dental and medical biomaterial and its use for sealing and/or filling the tooth and bone cavities. In the embodiments herein, the calcium salt, calcium oxide, calcium silicate, and calcium phosphate compounds are mixed with a water-base solution, and a bioactive phosphate and calcium enriched mixture is prepared. The mixture comprises high concentration of water-soluble calcium and phosphate, and consequently forms hydroxyapatite during and after setting. The dental/medical biomaterial is biocompatible, antibacterial and capable of forming an effective seal against reentrance of microorganisms into the filled cavity. The biomaterial is compatible to handle and set in an aqueous environment and to stimulate soft/hard tissue healing/generation/regeneration.

Abstract: Exemplary embodiments as disclosed herein are directed to setting and curing accelerators for hydraulic binders, including at least one ester of a polyhydric alcohol with an acid and/or salts thereof, where the acid is a phosphoric acid, phosphorous acid or a C2 to C20 carboxylic acid. Compositions including at least one accelerator as disclosed herein can accelerate the setting and curing of hydraulic binders and mortar or concrete produced therefrom, such as quick-setting cement. Methods for accelerating the setting and curing of hydraulic binders and mortar or concrete produced therefrom are also disclosed.

Abstract: A method of preparing a mortar composition, comprising mixing of mortar materials comprising at least 25 to 45 parts by weight of high-early-strength portland cement, 40 to 60 parts by weight of sand, 0.05 to 0.12 parts by weight of polycarboxylic acid-based powdered water reducing agent, and 10 to 25 parts by weight of water, and not comprising any organic adhesives. Mixing of the mortar materials is achieved by agitating the same in an agitator until agitating load rapidly decreases. The mortar composition prepared in accordance with this invention has excellent ability to infiltrate into the surface to be adhered, and high bonding strength after hardening.

Abstract: Carbon nanomaterials are stabilized and uniformly dispersed in a liquid such as water using a simple procedure. Methylcellulose is added to hot water where it separates and expands with a temperature of about 80-90 degree Celsius. Methylcellulose swiftly dissolves when the water cools down. Carbon nanomaterials are dispersed in a solvent and sonicated. This nanomaterial dispersed solvent is then added to the methylcellulose dispersed water and mechanically stirred. The resulting uniform mixture is up to 90% by weight nanomaterials and is stable for months.

Abstract: Hydraulic cement compositions that include a carbonate compound composition, e.g., a salt-water derived carbonate compound composition containing crystalline and/or amorphous carbonate compounds, are provided. Also provided are methods of making and using the hydraulic cements, as well as settable compositions, such as concretes and mortars, prepared therefrom. The cements and compositions produced therefrom find use in a variety of applications, including use in a variety of building materials and building applications.

Abstract: The present invention is a bioactive endodontic material and its use for filling the tooth and bone cavities. The present invention, by using calcium salt, calcium oxide, calcium silicate, and calcium phosphate compounds as essential constituents, and mixing them with a water base solution, prepares a bioactive calcium and phosphate enriched material. The enriched material (cement) comprises high concentration of water-soluble calcium and phosphate, and immediately forms hydroxyapatite during and after setting. The cement is biocompatible, antibacterial, capable to form an effective seal against reentrance of microorganisms into the filled cavity, compatible to handle and set in an aqueous environment, and able to stimulate hard tissue healing.

Abstract: A high performance multifunctional cementitious nanocomposite material is made by adding a nano admixture to the water used in a conventional cementitious material manufacturing process. The nano admixture is made by dispersing nanomaterials in a solvent and sonicating the mixture, adding a hydrophilic emulsifier, thickener, additive or cellulose derived compound to hot water, where it separates and expands, cooling the water, causing the compound to dissolve, and then adding the solvent and nanomaterial mixture to the water and mechanically mixing. The contact between the nanomaterials and the surrounding matrix changes with applied stress, affecting the volume electrical response of the finished nanocomposite material. By measuring the electrical resistance of the material, its structural health, as well as the stress applied to it, can be monitored. A bridge made with the material is monitored for structural integrity and for the weight, speed, and location of traffic over the bridge.

Abstract: Disclosed embodiments relate to well treatment fluids and methods that utilize nano-particles. Exemplary nano-particles are selected from the group consisting of particulate nano-silica, nano-alumina, nano-zinc oxide, nano-boron, nano-iron oxide, and combinations thereof. Embodiments also relate to methods of cementing that include the use of nano-particles. An exemplary method of cementing comprises introducing a cement composition into a subterranean formation, wherein the cement composition comprises cement, water and a particulate nano-silica. Embodiments also relate to use of nano-particles in drilling fluids, completion fluids, stimulation fluids, and well clean-up fluids.

Abstract: Methods and compositions are provided that may comprise cement, a nano-particle, latex, and water. An embodiment of the present invention includes a method of cementing in a subterranean formation. The method may include introducing a cement composition into the subterranean formation, wherein the cement composition comprises cement, a nano-particle, latex, and water. The method further may include allowing the cement composition to set in the subterranean formation. Another embodiment of the present invention include a cement composition. The cement composition may comprise cement, a nano-particle, latex, and water.

Abstract: Method for cementing a well comprising a hydraulic cement, water, carbon fiber and graphite are provided. The synergy achieved from combining fibers and particulates into the same sample results in a composite slurry with improved electrical properties and easy-to-optimize rheologies. Method for measuring resistivity through casing thanks to the nature of the cement composition is also provided.

Abstract: Carbon nanomaterials are stabilized and uniformly dispersed in a liquid such as water using a simple procedure. Methylcellulose is added to hot water where it separates and expands with a temperature of about 80-90 degree Celsius. Methylcellulose swiftly dissolves when the water cools down. Carbon nanomaterials are dispersed in a solvent and sonicated. This nanomaterial dispersed solvent is then added to the methylcellulose dispersed water and mechanically stirred. The resulting uniform mixture is up to 90% by weight nanomaterials and is stable for months.

Abstract: A setting and curing accelerator for hydraulic binders comprises: Al2(SO4)3 aluminum sulfate, Al(OH)3 aluminum hydroxide and mineral acid in aqueous solution. The setting and curing accelerator preferably comprises: 10-50% of Al2(SO4)3 aluminum sulfate, 5-30% of Al(OH)3 aluminum hydroxide, 0.5-10% of a mineral acid in aqueous solution.

Abstract: The invention relates to the use of lithium glycerophosphate for treating structures made of a cement-based product and having steel rebars, making it possible to inhibit rebar corrosion, to prevent the alkali reaction and to avoid the presence of alkalis and sulfates in the structure.

Abstract: A high performance multifunctional cementitious nanocomposite material is made by adding a nano admixture to the water used in a conventional cementitious material manufacturing process. The nano admixture is made by dispersing nanomaterials in a solvent and sonicating the mixture, adding a hydrophilic emulsifier, thickener, additive or cellulose derived compound to hot water, where it separates and expands, cooling the water, causing the compound to dissolve, and then adding the solvent and nanomaterial mixture to the water and mechanically mixing. The contact between the nanomaterials and the surrounding matrix changes with applied stress, affecting the volume electrical response of the finished nanocomposite material. By measuring the electrical resistance of the material, its structural health, as well as the stress applied to it, can be monitored. A bridge made with the material is monitored for structural integrity and for the weight, speed, and location of traffic over the bridge.

Abstract: Described herein is the use of new cementitious mortars with a high degree of fluidity and short consolidation times in the production of cementitious products by means of pouring in foundry moulds. The mortars used contain water, a fast-setting cement, fluidifiers and/or superfluidifiers, setting regulators, and aggregates having a specific granulometric distribution. The aggregates are made up of two fractions with different grain size such that the ratio between the characteristic grain diameters of the two fractions is comprised between 2.2 and 3.2. The new mortars thus obtained have values of fluidity 2-3 times higher than those of mortars produced with traditional aggregates.

Abstract: Disclosed embodiments relate to well treatment fluids and methods that utilize nano-particles. Exemplary nano-particles are selected from the group consisting of particulate nano-silica, nano-alumina, nano-zinc oxide, nano-boron, nano-iron oxide, and combinations thereof. Embodiments also relate to methods of cementing that include the use of nano-particles. An exemplary method of cementing comprises introducing a cement composition into a subterranean formation, wherein the cement composition comprises cement, water and a particulate nano-silica. Embodiments also relate to use of nano-particles in drilling fluids, completion fluids, simulation fluids, and well clean-up fluids.

Abstract: A hydraulic cement comprising a calcium silicate and at least one phosphate compound. The phosphate compound is included in an amount sufficient to react a major portion of the calcium hydroxide that is produced during hydration of the cement to hydroxyapatite or other calcium phosphates. The phosphate compound is preferably a mono-calcium phosphate. The cement is useful in both bio-medical/dental and engineering applications. The calcium hydroxide is reacted by the phosphate to form hydroxiapatite or other calcium phosphate that is co-precipitated with the calcium silicate hydrate to form a composite-like structure on a nano-scale level. The reduced calcium hydroxide content in the set cement increases its strength and reduces its pH. The hydroxiapatite content and the reduced pH render the cement bio-active and suitable for use in medical and dental implants, for example, for replacement bone and tooth material. Due to its high strength, the cement may also be used for structural/engineering applications.

Abstract: Disclosed embodiments relate to well treatment fluids and methods that utilize nano-particles. Exemplary nano-particles are selected from the group consisting of particulate nano-silica, nano-alumina, nano-zinc oxide, nano-boron, nano-iron oxide, and combinations thereof. Embodiments also relate to methods of cementing that include the use of nano-particles. An exemplary method of cementing comprises introducing a cement composition into a subterranean formation, wherein the cement composition comprises cement, water and a particulate nano-silica. Embodiments also relate to use of nano-particles in drilling fluids, completion fluids, stimulation fluids, and well clean-up fluids.

Abstract: A hydraulic cement for biomedical applications. The cement sets in-situ, hardening when exposed to water to produce nano-dispersed composite of calcium-silicate-hydrate gel mixed with hydroxyapatite. In comparison with prior cements, the composition provides high biocompatibility, high bioactivity and high biomechanical strength, due to the composite structure of the calcium silicate hydrate reinforced with co-precipitated particles of hydroxyapatite. Biocompatibility is also increased due to an absence of aluminum and magnesium in the composition. The cement is suitable for variety of applications, including dental implants, bone fixation, and bone repair.

Abstract: A hydraulic composition of the present invention includes (A) 100 parts by weight of cement having a Blaine specific surface area of 2,500 to 5,000 cm2/g, (B) 10 to 40 parts by weight of fine particles having a BET specific surface area of 5 to 25 m2/g, and (C) 15 to 55 parts by weight of inorganic particles having a Blaine specific surface area which is 2,500 to 30,000 cm2/g and which is larger than that of the cement. The inorganic particles (C) may comprise 10 to 50 parts by weight of inorganic particles (C1) having a Blaine specific surface area of 5,000 to 30,000 cm2/g and 5 to 35 parts by weight of inorganic particles (C2) having a Blaine specific surface area of 2,500 to 5,000 cm2/g.

Abstract: Concrete products and dry concrete mixes comprise cement, acrylic coated carbon fibers, and any optional components such as silica fumes, slag, stone, sand, and/or other aggregates. Preferably, the acrylic coated carbon fibers have a length of about 2½ inches to about 6 inches. A method of reinforcing concrete comprises mixing the cement, the acrylic coated carbon fibers, any optional components (such as silica fumes, slag, stone, sand, and/or other aggregates), and water to form a cement slurry, and letting the slurry set to cure the cement and form bonds between the cement and the carbon fibers, thereby obtaining reinforced concrete.