26 results about "Cement based composites" patented technology

The application provides a cement-based composite material and a preparation method thereof, and belongs to the technical field of composite material preparation.The application comprises the following steps: step one, preparing heat-conducting and enhanced phase change energy storage microcapsules with uniform and controllable particle sizes; step two, preparing heat-conducting and enhanced phase change energy storage microcapsules with controllable wall thicknesses; and step three, preparing a phase change energy storage cement-based composite material test piece.The application prepares heat-conducting and enhanced phase change energy storage microcapsules with uniform and controllable particle sizes through a microfluidic chip, controls the wall thicknesses of the microcapsules through a layer-by-layer self-assembly method, and finally adds the heat-conducting and enhanced phase change energy storage microcapsules with controllable wall thicknesses into a cement paste, so that the microcapsules are dispersed in the cement paste, and a phase change energy storage cement-based composite material with good heat regulation capacity is prepared.

This invention discloses a testing device and method for tensile deformation of fiber-reinforced cementitious materials, belonging to the field of engineering material testing technology. The testing device mainly includes three parts: a support frame, a lever system, and a specimen mounting system. The main steps of the testing method include: lifting the lever to unload; installing the specimen mounting system, slowly releasing the lever and finely adjusting the position of the tensile specimen to reduce eccentricity and achieve preloading; repeatedly lifting and unloading the lever, and finely adjusting the centering tensile clamp and the tensile specimen; installing the displacement sensor and zeroing it in the unloaded state; adjusting the weight of the lever according to the real-time display value of the force sensor to complete the suspension and precise loading of the tensile specimen. This method applies tensile force to the cement-based composite material through the lever mechanism and performs arbitrary crack propagation evaluation based on the micro-cracks in the cement-based material using digital image processing, which can quantitatively characterize the creep deformation and crack propagation process of cement-based composite materials under continuous tensile load.

The application discloses a kind of unbound post-tensioned prestressed fabricated column foot and post-earthquake rapid repair method, belong to building structure seismic and fabricated steel structure technical field.The column foot includes base plate, steel column, friction layer, strain hardening cement-based composite sleeve, vertical prestressed steel bar and cover plate;The friction layer uses block type structure, and is spliced by several friction layer monomers;Vertical prestressed steel bar is threaded through strain hardening cement-based composite sleeve and cover plate, and is fixed cover plate and applies prestress to vertical prestressed steel bar by disc spring group and anchor nut being set to its top end, realizes the unification of " high seismic, easy construction, fast repair ".The application also discloses the post-earthquake rapid repair method of the column foot, including post-earthquake evaluation, elastic self-resetting, installing temporary support, in-situ jacking, lateral replacement, resetting tensioning and the like steps, using unbound characteristics, without lifting off steel column can be completed in 3-4 hours friction layer replacement.

The application discloses an ultra-early-strength high-anti-cracking cement-based composite material and a preparation method thereof, and belongs to the technical field of building materials. The cement-based composite material comprises cement, aggregate, fiber, water reducing agent, early-strength agent, composite expansion agent, admixture and retarder. The composite expansion agent comprises expansion agent A and coated expansion agent B. The tensile strength of the coating layer of the coated expansion agent B is 1.5-2.0 MPa, and the elongation at break is 5-10%. The cement-based composite material effectively solves the problem of early cracking of ultra-early-strength cement and has high anti-cracking performance.

This invention belongs to the field of building materials technology, specifically relating to a low-carbon cement-based composite material and its preparation method. The components of the low-carbon cement-based composite material of this invention include: silicate cement, fly ash, alkali-modified biochar, and mixing water. The alkali-modified biochar is prepared by a method comprising the following steps: A1, mixing and stirring biochar with an alkaline solution; A2, solid-liquid separation to obtain the alkali-modified biochar; the mass of the alkaline solution in the alkali-modified biochar is 60%-70% of the mass of the biochar; the mixing water is the filtrate obtained from the solid-liquid separation in step A2. This invention, by mixing and stirring biochar with an alkaline solution and then separating the solid and liquid to obtain the alkali-modified biochar, without subjecting the biochar obtained from the solid-liquid separation to any drying or heat treatment, can effectively maintain the active functional groups on the surface of the alkali-modified biochar, which helps to better improve the mechanical properties of the low-carbon cement-based composite material.

The utility model provides a kind of lightweight design of steel ladle structure civil air defence door door leaf, civil air defence door technical field, this civil air defence door door leaf includes panel, the panel back is provided with pouring hollow steel ladle box body structure, and the periphery of panel is provided with the door leaf frame of the fixed connection of pouring hollow steel ladle box body structure;The inside of pouring hollow steel ladle box body structure is provided with reinforcing rib and cement-based composite material material;By setting pouring hollow steel ladle box body structure on panel, and setting reinforcing rib and cement-based composite material material in pouring hollow steel ladle box body structure, while the overall strength and stability of door leaf are strengthened, the weight of door leaf is also effectively reduced, satisfy the dual demand of modern civil air defence engineering to high performance and lightweight, so that civil air defence door door leaf has the advantages, such as convenient transportation and installation, improve the overall efficiency of civil air defence engineering.

Methods of additive manufacturing by spraying and automated spraying devices are provided. The device comprises a feed system and an automated spray head with at least one nozzle in communication with a first supply and a second supply to spray at least one stream comprising fibers and a sprayable cementitious material. A first nozzle may deliver the first sprayed stream comprising fibers, a second nozzle may deliver a second sprayed stream of first sprayable cementitious material, and a third nozzle may deliver a third sprayed stream of second sprayable cementitious material comprising carbon dioxide. The device forms a cementitious component on a target having a first region comprising a reinforced cementitious composite material. There is also a second distinct region comprising a carbonized cementitious material formed from the third sprayed stream comprising the second sprayable cementitious material comprising carbon dioxide.

This invention discloses a lightweight, high-ductility cement-based composite material made of phosphogypsum, belonging to the field of building materials technology. The high-ductility cement-based composite material of this invention comprises the following raw materials in parts by weight: 450-600 parts cement, 150-300 parts fly ash, 100-300 parts silica fume, 400-500 parts lightweight phosphogypsum aggregate, 200-300 parts elastic asphalt sand, 12-18 parts composite fiber, 60-90 parts steel fiber, 20-30 parts water-reducing agent, and 170-200 parts water. The preparation method of the elastic asphalt sand includes the following steps: screening waste asphalt concrete to obtain waste asphalt sand; washing the waste asphalt sand with an organic solvent, drying it, soaking it in industrial oil, and drying it to obtain elastic waste asphalt sand; adding the elastic waste asphalt sand to a mixed solution of water, a silane coupling agent, and anhydrous ethanol, reacting, filtering, and drying to obtain the elastic asphalt sand. The lightweight, high-ductility cement-based composite material of the present invention has the advantages of being lightweight, having low shrinkage, high tensile strength, and high impact strength.

The application discloses a compressed air storage structure and a pressure balance method, and belongs to the technical field of compressed air energy storage. The application comprises a primary support layer arranged on the surface of surrounding rock; a plurality of inverted-arch prefabricated lining units made of an engineering cement-based composite material, the cross section of the inverted-arch prefabricated lining units being in an arc shape protruding towards the inside of the chamber; a closed internal pressure balance cavity is formed between the outer wall of each inverted-arch prefabricated lining unit and the inner wall of the primary support layer; a monitoring unit of the pressure balance system is used for monitoring the air pressure inside the chamber and / or the pressure in the internal pressure balance cavity; a fluid regulating unit is in communication with the internal pressure balance cavity and is used for injecting or discharging fluid medium into the internal pressure balance cavity; a control unit is in signal connection with the monitoring unit and the fluid regulating unit, and is used for controlling the fluid injected or discharged by the fluid regulating unit according to the monitored pressure data, so as to adjust the pressure in the internal pressure balance cavity. The application effectively avoids the problem of concrete lining cracking and failure, and realizes the balance of the internal and external pressures of the chamber.

The application discloses a kind of limestone powder replaces silica fume's ultra-high performance concrete interface enhancement evaluation method, belongs to cement-based composite material proportioning design and performance evaluation technical field.The application first establishes the benchmark cementitious material matrix system containing silica fume, and sets up limestone powder gradient replacement group to silica fume;Through 28d matrix compressive strength to different replacement ratio test piece group is pre-screened with strength, selects representative replacement group;The 100h cumulative heat release of representative replacement group, 28d total porosity, single steel fiber peak pullout load and single fiber pullout work are determined, constructs hydration response coefficient, pore structure density coefficient, peak bearing coefficient and energy dissipation coefficient, establishes the coupling determination method of interface enhancement index IEI and strength constraint coefficient Kc;According to IEI and Kc output candidate enhancement group, optimal replacement group and corresponding replacement ratio.The application can be used for the rapid screening and quantitative design of low-silica fume ultra-high performance concrete cementitious system.

The application relates to the technical field of concrete, and discloses a polymer cement-based composite material and a preparation method and application thereof. According to mass parts, the polymer cement-based composite material comprises the following preparation raw materials: cementitious material 80-120 parts, aggregate 160-240 parts, polymer monomer 1-5 parts, initiator 0.04-0.07 parts, crosslinking agent 0.01-0.03 parts and mixing water 35-55 parts; the polymer monomer is a combination of a sulfonic acid-based vinyl monomer and an acrylic monomer. In-situ copolymerization is carried out by introducing the sulfonic acid-based vinyl monomer and the acrylic monomer, the synergistic effect of sulfonic acid groups and cement hydration products is utilized, the negative influence of pure acrylic monomers on early hydration is significantly relieved, when the sulfonic acid-based vinyl monomer accounts for 30% of the total amount of polymer monomers, the 3-day flexural strength of the material is about 7.5 times that of a pure acrylic monomer system, the 28-day flexural strength is higher than that of the pure acrylic monomer system, and the compressive strength is equivalent, and the defects of traditional modified products, such as toughness increase and strength decrease or early loss, are overcome.

The application discloses a light heat-insulating cement-based composite material, and relates to the technical field of cement-based composite materials, which comprises the following components by weight: 40-60 parts of a cement matrix, 20-35 parts of light aggregate, 5-12 parts of a polymer modifier, and 0.5-0.3 parts of a functional additive; the cement matrix is sulphoaluminate cement or portland cement; the light aggregate comprises hollow glass microbeads with a particle size of 0.1-0.5 mm, expanded perlite with a particle size of 0.5-2 mm and surface-modified aerogel particles; the aerogel particles are silica aerogel or silicon carbide aerogel; the surface area of the aerogel particles is 700-600 m2 / g; the pore size of the aerogel particles is 40-50 nm; the polymer modifier is acrylate-styrene copolymer emulsion; the solid content of the acrylate-styrene copolymer emulsion is 50-45%; the glass transition temperature of the acrylate-styrene copolymer emulsion is -10-15 DEG C; and the functional additive comprises a cellulose ether thickening agent, a polycarboxylic acid water reducing agent and a nano-alumina dispersion liquid.

This application relates to the field of reinforcing materials, specifically disclosing a graphene-calcium carbonate composite material, its preparation method, and its application. The preparation method includes the following steps: S1, adding natural graphite to an aqueous solution of sodium carboxymethyl cellulose and ball milling it under supercritical carbon dioxide conditions to obtain a graphene nanosheet dispersion; S2, adding calcium chloride solution to the graphene nanosheet dispersion, adjusting the pH to 8-11, stirring, and obtaining a mixed solution; S3, adding sodium carbonate solution dropwise to the mixed solution, reacting, then centrifuging, washing with water, and drying to obtain the graphene-calcium carbonate composite material. This application also discloses the application of the graphene-calcium carbonate composite material prepared by the above method in cement-based composite materials. This application has the characteristic of achieving an organic combination of graphene and calcium carbonate, which can better enhance the function of cement-based materials.

The present application belongs to the technical field of engineering cement-based composite materials, and particularly relates to a self-healing cement-based composite material and a preparation method thereof. Raw material composition of the self-healing cement-based composite material comprises Portland cement, fly ash, slag powder, water reducing agent, fiber, SAP and capsule type additive. The capsule type additive comprises an inner core and a silica coating shell layer, and the inner core comprises a silane modified ethylene-acrylic ester-GMA terpolymer and a sodium carbonate activator. The self-healing cement-based composite material of the present application can effectively limit cracking through fiber reinforcement ductility, and further realizes good synergistic self-healing performance through SAP and the capsule type additive. The self-healing cement-based composite material has the advantages of low cost, stable performance and easy industrialization.

This invention belongs to the field of building materials technology and discloses a high-crack-resistant cement-based composite material and its preparation method. The material is composed of silicate cement, activated fly ash, modified titanium gypsum, composite expansion agent, regulating agent, aggregate, and water. During preparation, the raw materials undergo pretreatment, dry mixing, wet mixing, and vibration molding, followed by 3 days of carbonization curing, and then standard wet curing for 28 days. This invention fundamentally solves the imbalance problem in the strength-crack resistance-durability triangle of existing cement-based materials by systematically integrating three core technologies: solid waste activation, two-stage expansion compensation, and synergistic carbonization-wet curing. It overcomes the technical bottlenecks of insufficient timeliness of single expansion sources and low-activity utilization of industrial solid waste, providing a new generation of cement-based composite materials with high performance, high durability, and high environmental friendliness, along with an industrially feasible preparation method.

This invention relates to a high-performance polymer-cement-based composite repair material and its preparation method. The high-performance polymer-cement-based composite repair material, by mass fraction, comprises the following components: 690-710 parts cement; 130-150 parts fly ash; 45-55 parts silica fume; 200-210 parts mixing water; 950-1050 parts fine aggregate; 21-23 parts modified polymer; 9-10 parts expansion agent; 4-5 parts water-reducing agent; 5-6 parts modified fiber; and 0.16-0.18 parts defoamer. This invention utilizes nano-toughened modified polymer and modified fiber. The nano-modified polymer improves the microstructure of the repair material, while the modified fiber limits shrinkage and enhances the crack resistance of the matrix. The synergistic effect of both effectively improves the toughness and mechanical properties of the repair material, ensuring that early cracking does not occur.

This invention discloses a method for evaluating the interfacial reinforcement of ultra-high performance concrete using limestone powder as a substitute for silica fume, belonging to the technical field of cementitious composite material mix design and performance evaluation. The invention first establishes a reference cementitious material matrix system containing silica fume and sets up gradient substitution groups for silica fume using limestone powder. The strength of specimens with different substitution ratios is pre-screened based on the 28-day matrix compressive strength, selecting representative substitution groups. The 100-hour cumulative heat release, 28-day total porosity, peak pull-out load of a single steel fiber, and pull-out work of a single fiber are measured for the representative substitution groups. Hydration response coefficient, pore structure compactness coefficient, peak bearing capacity coefficient, and energy dissipation coefficient are constructed, and a coupled determination method of interfacial reinforcement index (IEI) and strength constraint coefficient (Kc) is established. Based on IEI and Kc, candidate reinforcement groups, optimal substitution groups, and corresponding substitution ratios are output. This invention can be used for the rapid screening and quantitative design of low-silica fume ultra-high performance concrete cementitious systems.

The application belongs to the technical field of cement-based materials, and discloses a high-reflection-high-emission bistable white cement-based composite material and a preparation method thereof; the water-binder ratio of dry mixture and mixing water in the composite material is 0.35-0.45, and the dry mixture comprises the following components in mass fraction: modified white cement clinker 85-100 parts; hollow glass microbeads 3-8 parts; fumed silica 1-3 parts; wherein the raw materials of the modified white cement clinker comprise the following components in mass fraction: white portland cement raw material 100 parts; sodium borate 0.8-2.5 parts; nano titanium dioxide 0.3-1.2 parts; and the raw materials are mixed, ground, sintered and ground again to obtain the modified white cement clinker. The application overcomes the technical problems of multi-scale scattering center instability and infrared radiation channel blockage, thereby guaranteeing the optical performance of high reflection-high emission of the white cement.

The application relates to the technical field of building materials in an extreme highland environment, and particularly discloses a super-early-strength high-strength high-ductility cement-based composite material, a preparation method and application. According to mass fractions, the composite material comprises the following components: cement 64-82 parts, mineral powder 12-16 parts, fly ash microbeads 6.2-8 parts, silica mortar 25-32 parts, limestone powder 8.3-11 parts, early-strength components 6.9-35 parts, sodium lignosulfonate 1.4-7 parts, quartz sand 40-60 parts, rubber particles 0.3-0.7 parts, polyethylene fibers 1.2-1.8 parts, water 17.5-21 parts, water reducing agent 1.2-1.6 parts, expanding agent 7.9-8.7 parts and defoaming agent 0.6-1.0 part. The composite material prepared by the application has the advantages that the 3h compressive strength reaches 13.5-22.8 MPa, the 28d ultimate tensile strain is 5.9-6.3%, the frost resistance grade reaches above F400, and the composite material is particularly suitable for repairing and replacing the expansion joints of roads and bridges in plateau areas.

The application discloses a kind of thermoelectric cement-based prefabricated wall based on 3D printing and manufacturing method, and thermoelectric cement-based prefabricated wall includes wall body, outer surface vertical conductive band, inner surface vertical conductive band, horizontal conductive mesh and conductive terminal;Wall body is integrally formed by N-type thermoelectric cement-based composite material and P-type thermoelectric cement-based composite material by 3D printing;The printing path of 3D printing is set to along the thickness direction of wall, so that continuous material strip from the outer surface to the inner surface of wall is formed in each printing layer, and the continuous material strip constitutes directional heat transfer channel.The application realizes the integration design of heat transfer optimization and thermoelectric conversion, simple structure, adapts 3D printing process, and can be widely applied to building external wall and self-powered component.

This invention provides a design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness, comprising the following steps: assessing the seismic toughness level of the existing masonry structure to determine the seismic toughness improvement target; preliminarily determining the design parameters of the high-ductility cement-based composite material surface layer based on the seismic toughness improvement target; assessing the seismic toughness level of the reinforced masonry structure to confirm whether the seismic toughness improvement target is met, and obtaining the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target based on the confirmation result. The beneficial effects of this invention are: this invention organically combines the quantification of seismic toughness with the reinforcement design scheme, and uses a new high-performance material to establish a reinforcement design method for existing masonry structures to improve the seismic toughness level of existing masonry structures. Therefore, this invention not only considers the improvement of the seismic performance of existing masonry structures, but also the optimization of structural repair time and repair costs.

The application discloses a modified organic fiber material and a preparation method and application thereof.The modified organic fiber material comprises an organic fiber and a calcium silicate hydrate layer on the surface of the organic fiber.The modified organic fiber material has the calcium silicate hydrate layer on the surface, can form a chemical compatible interface layer with a cement hydration product, significantly improves the interface bonding force between the fiber and the cement matrix, and improves the interface bonding performance of the fiber / cement matrix.The modified organic fiber material is used in a fiber reinforced cement-based composite material, improves the fiber pull-out strength, makes the fiber not easy to be pulled out and not easy to slip, has a good fiber reinforcing effect, significantly improves the crack resistance of the cement-based composite material, has good durability of the composite material, and can meet the reliability and industrial application requirements of the high-performance cement-based composite material under long-term service conditions.