839 results about "Cement based composites" patented technology

A method of making a rapid setting lightweight cementitious composition with improved compressive strength for products such as boards is disclosed. The method mixes fly ash, alkali metal salt of citric acid and lightweight aggregate with water. Compositions which include fly ash, alkali metal salts of citric acid and lightweight aggregate are also disclosed.

The invention provides a cement-based composite material used for a 3D printing technology as well as a preparation method and application thereof. The cement-based composite material is prepared from the following raw materials based on the total weight of the composite material: 33%-40% of cement, 0%-8% of inorganic powder, 32%-38% of tailing machine-made sand, 2.5%-3% of a high-molecular polymer, 0.1%-0.5% of a water reducing agent and 16.7%-20% of mixing water; a composite thickening time control agent, a thixotropic agent, a volume stabilizer and the like are added into a mixture to prepare an inorganic composite material; and then the inorganic composite material can be directly pumped into a 3D printer for building to be applied to construction. The cement-based composite material is an inorganic material and the materials are easily available; a lot of industrial waste materials can be used; therefore, the cement-based composite material is low in cost, energy-saving and environment-friendly; the condensation time can be flexibly controlled, and the material has super early strength, good caking property and strong stability; the requirements of 3D printing construction continuity of the building and the building strength are met so that the house building has good global stability and use safety; and the application and popularization of 3D printing technology can be greatly promoted.

The invention relates to an oxidized graphene and graphene reinforced cement based composite material and a preparation method thereof. The oxidized graphene and graphene reinforced cement based composite material comprises the oxidized graphene, the graphene, a dispersing agent, a thickening stabilizer, a water reducer, a defoaming agent and a cement matrix, the mass ratio of the total mass of the oxidized graphene and the graphene to the cement matrix is (0.0005-0.5):1, and the mass ratio of the total mass of oxidized graphene and the graphene to the dispersing agent to the water reducer to the thickening stabilizer to the defoaming agent is 1:(0.05-10):(0.1-20):(0.1-20):(0.05-5). In the composite material, the oxidized graphene and the graphene are dispersed in the cement matrix uniformly; compared with the traditional cement material, the tensile strength, rupture strength and conductivity of the composite material are all improved remarkably; and the composite material has more excellent mechanical property and electrical property, and is applicable to the field of multifunctional construction materials.

The invention provides a cement-based composite material for powder-bonding three-dimensional (3D) printing. The material is prepared from the following components in parts by weight: 1 part of cement, 0-5 parts of sand, 0-5 parts of a mineral admixture, 0-0.2 part of an expanding agent, 0-0.2 part of a toughening agent, 0-0.2 part of mineral pigment, 0.1-0.5 part of water, 0-0.25 part of polymer emulsion, 0.001-0.05 part of an additive and 0-0.03 part of fibers, wherein the cement is selected from one or a mixture of more in silicate cements, sulphoaluminate cement, high belite sulphoaluminate cement, aluminate cement, fluoroaluminate cement, aluminosilicate cement, phosphate cement or magnesium oxide cement; the additive is selected from one or a mixture of more in a water reducing agent, an early strength agent or a coagulating regulating agent. After being contacted with water, the cement-based composite material can be hardened, thus not needing a great deal of polymer adhesive; the cement-based composite material is rapid and controllable in hardening speed; the cement-based composite material is small in deformation in the hardening process, thus being suitable for a powder-bonding 3D printing technology. The invention also provides a method for carrying out powder-bonding 3D printing by using the cement-based composite material.

The invention provides a preparation method of novel core-shell type cement-based high-strength lightweight aggregate. A cement-based composite material (cement and an admixture) is used as a main cementing material of a shell material, a pelletizing process is adopted for surrounding a shell outside a lightweight core material, and the high-strength lightweight aggregate can be successfully prepared after curing is performed for a certain period of time. The prepared light aggregate has the advantages of high specific strength, good grain shape and good heat preservation and heat insulation, and can realize certain specific functions, such as heat storage, sound insulation and wave absorption. A production process of the high-strength light aggregate comprises the steps of mixing powder, uniformly stirring, spraying liquid to form pellets, curing (steam curing and moisturizing) and screening. According to the preparation method, the problems of great production energy consumption, complex process and serious pollution of the aggregate produced by a traditional sintering process or the problems of relatively large packing density, insufficiently high strength and insufficiently high product quality of unburned ceramsite products are solved.

The present invention provides a carbon nano-tube reinforcing cement-based composite material and the preparing method thereof, which relates to an inorganic non-metal fiber-reinforced cement-based composite material and the preparing method thereof. The invention settles the problem that the carbon nano-tube is hard to uniformly dispersed in the cement substrate, and the carbon nano-tube reinforcing cement-based composite material of the invention is mainly composed of carbon nano-tube, dispersing agent, thickening stabilizing agent, cement blending material, superplasticiser, antifoaming agent and cement; the method of the invention comprises the following steps: slowly injecting the continuous phase mixed liquid of the thickening stabilizing agent into the carbon nano-tube disperse phase mixed liquid; adding the cement mixing material, mixing to uniform, heating and ultrasonic agitating, then vacuum discharging the bubble; then adding into the mixed liquid of the superplasticiser and the water for mixing to uniform, further eliminating the bubble with the antifoam agent; at last adding cement for mixing to uniform, adding the slurry into the oil mould and jolt ramming for molding; mode removing and standard maintaining to the prescribed lifetime. The carbon nano-tube in the product prepared by the method of the invention is uniformly dispersed in the cement substrate. The mechanical property and conductivity of the product is increased for several times.

The invention relates to a cement-based composite material and a pressure sensor made of the same. The problems that the cement-based composite material has poor electrical resistivity and stress sensing ability because carbon fibers are not uniformly dispersed in a matrix, the pressure sensor is poor in stability and low in sensitivity and the like are solved. The graphene oxide/carbon fiber cement-based composite material is composed of functional components, cement, a dispersing agent, a water reducing agent, a defoaming agent, fine aggregates and other mineral admixtures, wherein the functional components include graphene oxide and carbon fibers, graphene oxide accounts for 0.01-5% of the total mass of a cementing material, and the carbon fibers account for 0.01-5% of the total mass of the cementing material. The graphene oxide/carbon fiber cement-based composite material disclosed by the invention has the advantages of high strength, good durability, few porosity defect, good compactness and the like; the pressure sensor has the advantages of stable initial electrical resistivity, high stress sensing ability, high sensitivity, good stability and the like; and the cement-based composite material is superior to a cement-based composite material which only takes the carbon fibers, graphene oxide, carbon black or steel slag and the like as a conductive phase.

The invention discloses a cellulose fiber internal curing-based ultra-high-performance cement-based composite material and a preparation method thereof. The cellulose fiber internal curing-based ultra-high-performance cement-based composite material comprises the following components in weight percentage: 20.3-40.5% of cement, 8.1-25.3% of active mineral admixture, 32.5-60.8% of fine aggregate, 3.3-9.8% of micro-fine steel fibers, 0.03-0.05% of cellulose fibers, 5.6-8.6% of water and 0.3-0.6% of efficient admixture. According to the technical scheme of the ultra-high-performance cement-based composite material and the preparation method thereof, the advantages of good slurry workability, high breaking strength, low early hydration speed of cement-based materials, small early shrinkage and deformation amount, high overall hydration degree and the like are realized compared with the prior art. Meanwhile, the later compressive strength of cement-based materials is less affected by cellulose fibers. Therefore, the mechanical property and the durability during the later period are improved.

The invention relates to a lightweight high-strength cement based composite material. The grain composition of a multivariate cementing material and grain composition of aggregate are optimized, anddue to use of additives such as water reducing agent and thickener, the material can obtain high compressive strength of over 20MPa while obtaining the unit weight which is significantly lower than that of common concrete. The material has the technical advantages that the compressive strength of 28d standard curing is greater than or equal to 20MPa when the unit weight is smaller than or equal to 1650kg/m<3>; the requirements of the construction liquidity can be met by grain composition of the optimized gel material and the grain composition of the aggregate; the hardened material has a dense surface, and has excellent endurance performances such as anti-permeability, carbonation resistance, resistance to chloride ion erosion and the like.

The invention relates to a graphene oxide modified cement-based composite material and a preparation method thereof. The graphene oxide modified cement-based composite material is prepared by mixing graphene oxide, polyvinyl alcohol fibers (PVA), cement, flyash, water, quartz sand, a polycarboxylate superplasticizer, a shrinkage reducing agent, a polymer and a defoaming agent according to a certain proportion. Compared with the prior art, the graphene oxide modified cement-based composite material has the advantages that the cement-based composite material has the advantages of higher compressive strength and breaking strength, low shrinkability, high toughness, high ductility, and the like compared with common ECC (engineered cementitious composite) and is especially suitable for repair and reinforcement of building structures with complex contours.

The invention relates to a preparation method of a graphene oxide modified polycarboxylic acid type water-reducer. A polycarboxylic acid type water-reducer is a novel efficient water-reducer following a naphthalene type water-reducer, a melamine water-reducer and an amino sulfonic acid based water-reducer, but the mechanical property of concrete cannot be obviously improved by adding the polycarboxylic acid type water-reducer. The preparation method comprises the steps of preparing graphene oxide with natural flake graphite, sodium nitrate, concentrated sulfuric acid and potassium permanganate as raw materials; carrying out ultrasonic dispersion on the graphene oxide; and then adding the polycarboxylic acid type water-reducer with a certain proportion to form an intercalation compound of the graphene oxide and the polycarboxylic acid type water-reducer. With the adoption of the modified water-reducer, on the basisthat the existing water-reducing rate is kept, the flexural strength and the compressive strength of a cement-based composite are obviously strengthened, the relevant raw materials are easily obtained, a preparation technology is reasonable, pollution in a preparation process is little, the performance of products is excellent, and the graphene oxide modified polycarboxylic acid type water-reducer is suitable for industrial production.

The invention discloses a high-ductility cement-based composite material for repairing a hydraulic concrete structure. The cement-based composite material is prepared from the following components in parts by mass: 20 to 60 parts of cement, 0 to 80 parts of fly ash, 0 to 80 parts of pulverized slag powder, 5 to 10 parts of light-weight calcium powder, 1 to 5 parts of nanometer SiO2, 25 to 40 parts of a fine aggregate, 20 to 40 parts of water, 0.1 to 1 part of a water reducing agent and 0.5 to 2.5 parts of polyvinyl alcohol fibers. According to the high-ductility cement-based composite material for repairing the hydraulic concrete structure, the air content of a mixture is 7 to 10 percent; at the 28-day age, the uniaxial tensile strain is greater than or equal to 5.0 percent, the cube compressive strength is greater than or equal to 60MPa, the frost resistance is greater than or equal to F500, the sulfate corrosion resistance is greater than or equal to KS300, the chloride ion penetration resistance DRCM is less than or equal to 2.0*10<-12>m<2>/s, and the tensile bonding strength with base structure concrete is greater than or equal to 5.0MPa. Under the condition of not mixing any air-entraining agent, preservative or thickening agent, the high-ductility cement-based composite material for repairing the hydraulic concrete structure provided by the invention has high durability, enhanced capability in synergistically acting with an existing structure and a remarkable repairing and reinforcing effect.

The invention discloses a quick-hardening high-early strength concrete-based composite material for a maritime work, which mainly comprises the following components in parts by weight: 100 parts of magnesium oxide, 25-50 parts of phosphate, 5-15 parts of retarder, 0.5-3.5 parts of siloyl group moisture repellent, 10-20 parts of flyash, 0-5 parts of glass fibre, 150-350 parts of sea sands and 25-50 parts of seawater. The invention takes the sea sands without desalting treatment as aggregate and the seawater as mixing water, thereby fully utilizing island resources such as sea sands, seawater, and the like, greatly reducing traffic capacity, saving cost. In addition, the invention has the advantages of quick setting and hardening, high early strength, good seawater erosion capability, and the like, thereby being widely applied to quick repatching and building in projects such as island roads, landingstrips, docks, and the like.

The invention relates to a method for checking and measuring the distortion of cement-based composite material caused by force. A conducting film as sensor, which is composed of short-cut carbon fiber, graphite power and adhesion agent, is coated on the surface of specimen of cement-based composite material. Circuit signal collector in bridge type is adopted in the invention. With the specimen ofcement-based composite material being forced, loaded and impacted, uneven distortion and cracking in the specimen of cement-based composite material can be detected by checking and measuring variation of voltage and current caused by the variation of resistance of said conducting film.

The invention relates to a cement base composite wave-adsorption material and relative preparation, belonging to the cross technique field between materials science and microwave technique. The invention is characterized in that the invention uses organic and inorganic hollow wave-transmission balls with low dielectric constant to fill a cement base to improve the resistance match of the base, and coat an uniform conductive coat on the surface of the wave-transmission balls, and stuffs wave absorber or the like to improve the adsorption of base on electromagnetic wave. The inventive wave-adsorption material is in single-layer or dual-layer structure, while the match layer and adsorption layer of dual-layer structure are respectively stuffed with wave-transmission balls or wave absorber in different ratios to gradually change the resistance, and the two layers are combined tightly to improve the wave adsorption. The invention has the advantages of that the improved resistance match and gradual structure can absorb electromagnetic wave in wide frequency range, the light wave-transmission balls can reduce the specific weight of material, and the wave-transmission balls are packed by cement slurry to improve the stability and durability of material.

The invention provides a high-ductility cement-based composite material. The high-ductility cement-based composite material is prepared with the following raw materials by weight: 71.8-85 parts of base material, 12.9-25.2 parts of water, 0.89-2.67 parts of fiber and 0.11-1.23 parts of admixture, wherein the fiber is composed of two or more of polypropylene fiber, polyvinyl alcohol fiber, polyethylene fiber, aromatic polyamide fiber and glass fiber; the weight ratio between the polypropylene fiber, the polyvinyl alcohol fiber, the polyethylene fiber, the aromatic polyamide fiber and the glass fiber, and the total fiber is 15-89.5%, 0-68.4%, 0-75.6%, 0-73.5%, and 0-56.4% respectively. The high-ductility cement based composite material is high in compressive strength and low in preparation cost; the compressive strength can be up to higher than 50.5 MPa; the preparation cost is reduced to 15-50% of that of the prior art. The invention further provides a preparation method of the high-ductility cement based composite material.

The invention discloses a high toughness cement-based material-nonmetal fiber rib composite structure. According to the structure, a high toughness cement-based material is adopted as a base material, nonmetal fiber rib is adopted as directional reinforcing rib; the high toughness cement-based material comprises the following components in percentage by weight: 35% of cement, 45-55% of fly ash, 5-10 % of silicon ash and 5-10% of metakaolin; high-strength short fiber is one or more out of polyvinyl alcohol fiber, polyethylene fiber, carbon fiber and aramid fiber; the nonmetal fiber rib is carbon fiber reinforced plastic rib, aramid fiber reinforced plastic rib, glass fiber reinforced plastic rib or basalt fiber reinforced plastic rib. The invention further discloses applications and an application method of the high toughness cement-based material-nonmetal fiber rib composite structure. The high toughness cement-based material and the nonmetal fiber rib are utilized to reinforce the reinforced concrete structure, so that the bearing capacity and the durability of the structure are increased and the aging speed of the structure is reduced.

Disclosed is reactive powder concrete mixed with slag, which is a novel engineering material with super-high intensity and super-high durability, particularly cement-based composite material having super-high property prepared and formed via using all kinds of industrial residue as reactive powder. Corresponding to Portland cement, proportion by weight of all composites of the concrete is: the Portland cement holding 1 part, the slag holding 0.40-0.60 part, silicon powder holding 0.20-0.35 part, quartz flour holding 0.20-0.35 part, river sand holding 1.20-1.60 parts, water holding 0.20-0.28 part and a water reducing agent holding 0.02-0.03 part.

The invention belongs to the technical field of material science and engineering and particularly relates to a functional porous cement based composite material and a preparation method thereof. The composite material is prepared from the following raw materials: cement, aggregates, water, additives and a catalyst in a ratio of (1-1.2):(0.5-0.6): (0.2-0.8):(0-0.04):(0-0.2), wherein the content of the catalyst is not zero and the catalyst is a compound of titanium dioxide and graphene oxide. The invention provides the functional porous cement based composite material which not only has a separating function, but also has the characteristics of being photocatalytic, pollution-resistant and self-cleaning. The functional porous cement based composite material is simple in preparation process and low in cost and has wide application prospect in the technical industry of environmental protection and management.

The invention discloses a preparation method of cationic surfactant modified fly ash, which comprises the following steps of: firstly performing pretreatment and hydroxylation treatment on the surface of fly ash to obtain hydroxylated fly ash to obtain a grafting point; then modifying the fly ash by use of a coupling agent; and finally performing grafting reaction with a cationic surfactant polyacrylamide to obtain cationic surfactant modified fly ash. According to the preparation method disclosed by the invention, the polyacrylamide is grafted on the surface of the fly ash, and the adsorption property of the grafted fly ash is greatly changed; particularly the fly ash is applied to a cement-based composite material, and the fracture resistance of the cement-based composite material is obviously improved; and the preparation method disclosed by the invention has the advantages of low reaction temperature, mild conditions, simple after-treatment and low industrialization cost.

The present invention discloses a pressed cement composite material, which relates to a cement composite material; the present invention is to solve the shortcoming in the existing pressed cement material that: the sense ability for the force-electricity coupling effect is much lower, the existing method is influenced by the humidity greatly, and the base polarization is easy to influence the test of the electricity signal. The present invention consists of a function component and cement material; the function component is a nickel powder or a mixture between the nickel powder and one or more than one material including carbon cellulose, carbon, graphite and steel residual; the cement material is a glue material or a composite material between the glue material and the bone material; thereinto, the function component occupies between 1 percent and 80 percent in the total weight; and the rested is the cement material. The sense ability of the pressed cement composite material in the present invention is much higher; the sensitivity can reach to more than hundred or thousand, which is higher than the sensitivity of the existing pressed cement composite material with the function component including carbon cellulose, carbon and steel residual and so on. Besides, the force-electricity coupling effect for the material is much smaller by the humidity; the test of the electricity signal is not easy to be influenced by the base polarization.