649 results about "Properties of concrete" patented technology

Hundreds of thousands of concrete bridges, buildings etc. and hundreds of billions of tons of concrete require characterization throughout the process from manufacture to pouring and curing and on throughout service life. The characterization may relate to initial concrete properties, projected concrete properties, framework removal, corrosion, failure etc. Accordingly, a variety of measurements such as water content, electrical resistivity, and half-cell corrosion potential for example would be beneficially implemented as easy to use field test equipment or embedded sensors allowing lifetime monitoring to be performed rather than discrete assessments when issues become evident.

This invention is a prestressed concrete pole and its construction method. The pole is of a conicity at 1:75, with holes for cables. It can be a single pole or sectional fabricated. The pole is made by reinforce bar cage centrifugal casting. The reinforce bar cage is composed by vertical main bars and normal bars fixed on supporting and positioning loops, and binding outside by helix wire. Two end plates are installed to the pole ends to fix the mail bars. After installed the end plates and before centrifugal casting, pull the plates with 1000-1900KN power, and steaming the concrete to grade over C60, then loose the power. In case of sectional fabricated, the sections are connected to each other through bolts.

Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

The invention discloses a production technology of ecological concrete. The production technology comprises the steps of preparing an ecological cementing material by using construction waste clay bricks, and preparing recycled aggregate by using construction waste concrete; uniformly mixing cement and the ecological cementing material, then adding part of water, natural fine aggregate and recycled fine aggregate, stirring to form slurry, then adding natural coarse aggregate, recycled coarse aggregate, the rest water and a pumping aid, and stirring to prepare C30-C40 strength grade ecological concrete. By adopting the production technology of the ecological concrete, provided by the invention, useful components of construction waste are effectively used, the waste is turned into wealth, resources are saved, and the recycling of the construction waste resources is realized; the prepared ecological concrete is comparative with normal concrete in performance, is low in production cost, and can be largely applied to general construction engineering.

The invention provides a super slump type polycarboxylate water reducing agent for bored pile concrete. The water reducing agent is in a liquid state and comprises the following ingredients: sodium oleate, water reducing type polycarboxylate plasticizer, slump type polycarboxylate plasticizer, hydroxyethylidene diphosphonic acid, 2-acrylamide-2-methylpropanesulfonic acid/itaconic acid/acrylic acid terpolymer, hydroxypropyl methyl cellulose or hydroxyethyl methyl cellulose, air entraining agent and triisopropanolamine. The super slump type polycarboxylate water reducing agent for bored pile concrete provided by the invention has the following beneficial effects that by using the super slump type polycarboxylate water reducing agent, the bored pile concrete is good in homogeneity, the static bleeding rate of the bored pile concrete can be generally less than 1%, stable working performance can be maintained within a long time span, meeting the working property of concrete after 0.5-5.0h can be met by adjusting the formulation and dosage and improving the compressive strength ratio of the concrete, and the 28 d strength can be more than 130% of that of benchmark concrete. The invention further provides a preparation method of the super slump type polycarboxylate water reducing agent for bored pile concrete.

The invention relates to a surface coating type reinforced concrete corrosion inhibitor. The surface coating type reinforced concrete corrosion inhibitor comprises the components as follows: 15 to 40 wt% of a non-ionic surface active agent with HLB (Hydrophile Lipophile Balance) value more than 10, 5 to 30 wt% of a cosurfactant, 1 to 20 wt% of water insoluble organic inhibitor, and 20 to 50 wt% of water, wherein the cosurfactant is selected from organic alcohol or organic amine. The preparation method comprises the steps of mixing the non-ionic surface active agent, the cosurfactant and the water insoluble organic inhibitor, and agitating along with heating unit the mixture is completely molten, and then agitating along with water adding until the mixed liquid is turned into a clear state from a muddy state, thus obtaining the product. The preparation method provided by the invention is simple; the prepared product can be applied to surface treatment of the constructed concrete structure; and the prepared product has superior infiltration capacity, can effectively prevent the reinforcement surface from being eroded by chloride salt and sulfate, and has no adverse effect to the performance of the concrete.

The system for measuring permeation properties of concrete and porous materials includes a chamber having an upper plate, a lower plate, and a plurality of support members, the chamber being configured for holding a specimen. A plurality of supply tubes and a plurality of discharge tubes are in fluid communication with the chamber. A gas flow measurement assembly is in fluid communication with the chamber, the gas flow measurement assembly having a first pressure gauge and a gas flow meter. A water flow measurement assembly is in fluid communication with the chamber, the water flow measurement assembly having a second pressure gauge and a water flow meter. A gas cylinder is in fluid communication with the one of the plurality of supply tubes. The system may be used to measure gas permeability, water permeability, porosity, and absorption of concrete and other porous materials.

The invention discloses a concrete internal curing agent. The concrete internal curing agent is super absorbent resin which has intelligent water absorption and water release functions and stably exists in concrete for a long term. The concrete internal curing agent comprises deionized water, sodium hydroxide, acrylic acid, a water-soluble initiator, a water-soluble crosslinking agent and natural grafted skeleton kaolin which is calcined kaolin. The concrete internal curing agent disclosed by the invention is environmentallyenvironment-friendly, high-efficiency and convenient to use; the addition amount of the concrete internal curing agent is small; raw materials for preparation are low in cost; and by adopting the concrete internal curing agent, the water consumption of fresh mixed concrete can be obviously reduced, the concrete property is improved, and the service life of the concrete is prolonged.

The invention discloses a method for preparing a polycarboxylate water reducing agent by a normal-temperature mixing process. A polyether macromonomer, a redox, acrylic acid, an unsaturated third monomer, a chain transfer agent and water are mixed once at normal temperature to prepare the polycarboxylate water reducing agent. The method disclosed by the invention adopts a one-time mixing mode; in a synthesis process, a pump circulation device only runs in a pre-dissolving macromonomer, and the device is closed after the pre-dissolved reducing agent component is fed. The traditional production method adopts an elevated tank dropping mode to produce the polycarboxylate water reducing agent, and the production is performed in a reaction kettle, so that the equipment cost input is relatively high. In the method disclosed by the invention, a one-time mixing process is adopted creatively, and the method is performed in a normal-temperature way without needing a heat source, so that the production period is short, the energy consumption is low, and the synthesis process does not need a stirring device, a professional for monitoring and an enamel reaction kettle device; the concrete performance of the synthesized polycarboxylate water reducing agent is equivalent to that of the water reducing agent synthesized by the traditional process, a favorable reference basis is provided for workshop-style water reducing agent production, and the polycarboxylate water reducing agent has obvious advantages.

The invention provides application of temperature-sensitive hydrogel in improvement of the anti-dry-shrinkage cracking property of concrete. The concrete is prepared from the temperature-sensitive hydrogel, cement, aggregates and water. A preparation method of the concrete comprises the steps that firstly, the temperature-sensitive hydrogel is prepared; secondly, the aggregates and the water are blended to be uniform; lastly, the temperature-sensitive hydrogel and the water are added, the materials are blended to be uniform, and then the concrete can be prepared. The adopted homemade temperature-sensitive hydrogel is lightly-crosslinked macromolecules which can be polymerized to form a film after releasing water, no hole can be reserved in the cement concrete, and other properties of the cement concrete are not affected while the anti-cracking property of the concrete is improved. The initial volume water content of the concrete is increased along with increasing of the mixing amount of the temperature-sensitive hydrogel, and it is shown that the water storage capacity of the concrete is enhanced by mixing the temperature-sensitive hydrogel; the water absorption rate of the concrete is decreased along with increasing of the mixing amount of the temperature-sensitive hydrogel, and it is shown that the connectivity of capillary pores in the concrete is reduced by mixing the temperature-sensitive hydrogel.

The invention discloses a concrete expanding agent with triple expansion sources and a preparation method of the concrete expanding agent. The high-performance concrete expanding agent provided by the invention contains calcium oxide, calcium sulfate, calcium sulphoaluminate, magnesium oxide and surfactant. Expansion rate change of the expanding agent and shrinking percentage change of the cement have an adaptive trend, and therefore, after using the expanding agent, the concrete is stable in strength performance, and the performances of the cement or the concrete can be stable for a long time.

The invention provides a clay inhibitor combined with a polycarboxylic water reducer for use, which comprises cationic nitrogen-containing low molecular weight copolymers; a preparation method of the clay inhibitor comprises the following step: a quaternary ammonium cationic monomer a, a monomer b containing primary amine, secondary amine or tertiary amine and a cross-linking monomer c are subjected to free radical copolymerization reaction in an aqueous solution, so that the clay inhibitor is obtained. Under the condition of relatively high mud content, the clay inhibitor can effectively ensure or improve the initial dispersive capacity and dispersion maintaining capability of the polycarboxylic water reducer, and meanwhile, the setting time, gas content, strength and other properties of concrete are not affected.

The invention relates to building material engineering, and aims at providing a preparing method of nano-modified high permeability resistant concrete. The preparing method comprises the steps of conducting dry stirring on cement, sand, gravel, fly ash, blast-furnace slag powder and silica fume, and mixing the mixture evenly; mixing a nanometer additive, a water reducing agent and water which accounts for half the weight evenly, and adding the nanometer additive, the water reducing agent and the water which accounts for half the weight into the mixture for stirring; then adding the water which accounts for the other half the weight and continuing to conducting mixing; conducting discharging, and putting the new mixture into molds; conducting maintenance according to a conventional maintenance mode after removing the molds to obtain the nano-modified high permeability resistant concrete. According to the preparing method of the nano-modified high permeability resistant concrete, the limitation of the influence of a single mineral component on the performance of the concrete is solved, through the combination of the multifunctional composition, the effect of function superposition and synergy is achieved, the composite multifunctional composition can effectively optimize the concrete structure grain composition, and by optimizing the internal pore structure of the concrete, the aim of improving the permeability resistance is achieved. The grain composition optimization is conducted on the concrete structure by utilizing the nanometer additive, the high activity and the microcrystal nuclear effect of nano-particles are given full play to at the same time, and the permeability resistance of the concrete structure is improved.

The invention relates to a mix proportion design and optimization method of machine-made sand self-compacting concrete. The method comprises the following steps: 1) determining the mass of coarse aggregate, the apparent density of the coarse aggregate and the bulk density of the coarse aggregate in a powder material, machine-made sand grains and unit volume concrete; 2) obtaining the use mount ofthe coarse aggregate and the volume of mortar according to performance requirements and the extra coefficient of the mortar; 3) determining a water-binder ratio according to design strength; 4) assuming the volume ratio of a net paste volume to the machine-made sand grains and calculating the mass of cement, the mass of the machine-made sand grains and the mass of mixing water; 5) adjusting the use amount of an additive in the machine-made sand self-compacting concrete according to the workability of the concrete; 6) optimizing a mix proportion meeting requirements on concrete performance according to an excellent-inferior coefficient. Compared with the prior art, the mix proportion design and optimization method has the advantages of simple steps, small calculation amount, wide application, workability and strength and the like.

The invention discloses a preparation method of nano-photocatalytic admixture for cement-based material, comprising the following steps: nanometer titanium dioxide mixed crystal is mixed with active carbon according to the weight ratio of 1:1-2 for 1-2 hours to obtain nano-photocatalytic material loaded with active carbon; then, the nano-photocatalytic material loaded with active carbon, dispersible emulsion powder, water reducer and polypropylene fiber are mixed according to the weight ratio of 1:0.2-0.3:0.04-0.06:0.004-0.006 for 1-2 hours. The invention has simple preparation technology, and prepared nano-photocatalytic admixture for cement-based material has long-term and stable photocatalytic function, and can improve flow property, adhesive property and anti-cracking property of concrete. The nano-photocatalytic admixture not only can be mixed with cement to obtain photocatalytic cement paste which is cement-based photocatalytic paint convenient to paint, but also can be mixed with cement and sand to prepare cement mortar to form cement-based photocatalytic coating with certain thickness on the concrete surface.

The invention discloses a plant-fiber-loading-microbe self-repairing cement-based material. The plant-fiber-loading-microbe self-repairing cement-based material is prepared from a bacillus alcalophilus pasteurii bacterial solution, plant fibers and a nutrient solution, wherein the nutrient solution is prepared from maltodextrin, cottonseed cake meal, yeast extract powder and sodium citrate. The plant-fiber-loading-microbe self-repairing cement-based material disclosed by the invention has the following advantages that microbes can be preserved in a cement matrix for a long time in a high survival rate manner, so that the cement matrix can achieve life-time self-repairing in time of service; the adding of plants does not affect mechanical properties of concrete and can enhance the pull resistance and toughness of the concrete; the plants can release the microbes in time when cracks are generated; and the natural plants are wide in source, and the required plants do not need special complicated process treatment, so that the cost is low, and the plant-fiber-loading-microbe self-repairing cement-based material has environment-friendliness and economical efficiency.

The invention discloses graded sand high-strength reactive powder concrete and a preparation method thereof. The reactive powder concrete is prepared from the following raw material components in parts by weight: 1 part of cement, 0.2 part of crude quartz sand, 0.8 part of medium sand, 0.2 part of fine sand, 0.3 part of silica fume, 0.02 part of a water reducing agent, 0.23 part of water, 0.0075 part of normal-temperature steel fibers and 0.02 part of high-temperature steel fibers, wherein the particle size of the fine sand is 0.16 to 0.315 mm, the particle size of the medium sand is 0.30 to 0.60 mm, the particle size of the crude sand is 0.60 to 1.25 mm, and the volume of the steel fibers is 0.075 percent or 2 percent of that of all the materials. According to the preparation method disclosed by the invention, quart sand with three particle sizes is selected to increase the aggregate packing degree; specific optimized gradation is provided, and a proper amount of steel fibers are doped to improve the tensile strength of a matrix; the proper amount of a cementing material is optimized, so that the workability of the reactive powder concrete is improved; the prepared reactive powder concrete has excellent performance; and the preparation method is simple.

The invention belongs to the field of highways and city roads, in particular to a method for testing the property of low-carbon asphalt and low-carbon asphalt mixtures. The method comprises the following steps of: respectively calculating bulk density of a compact-molded Marshall sample at different temperatures, and using mixture and compaction temperature of the low-carbon asphalt and low-carbon asphalt mixtures at the maximum bulk density as mixture and compression temperature of the low-carbon asphalt mixtures; testing the aging property of the low-carbon asphalt and low-carbon asphalt mixtures, which comprises the following steps of: preparing asphalt samples according to the regulations, and testing the natures of the asphalt samples including needle penetration, viscosity, softening points, ductility and the like before a test of heating a film; adjusting a baking oven to be horizontal so that a rotary disc can rotate on a horizontal plane at a certain speed, enabling a position of a thermometer to be equal to the distance of the centre and the edge of the rotary disc, placing a sample-accommodating utensil on the rotary disc in the baking oven when the temperature in the baking oven reaches 120DEG C, timing when the temperature in the baking oven rises again to 120 DEG C and keeping the temperature; and testing the natures of the asphalt samples including needle penetration, viscosity, softening points, ductility and the like after the aging is completed. Through basic detection of two properties, the method can more objectively evaluate the basic property of the low-carbon asphalt and low-carbon asphalt mixtures and can ensure that the property of the designed low-carbon asphalt concrete can meet the requirement of national current specifications.

The invention discloses high-performance concrete and a preparation method thereof. The high-performance concrete is prepared from, by weight, 350-390 parts of cement, 900-1020 parts of coarse aggregates, 540-600 parts of fine aggregates, 160-180 parts of water, 190-230 parts of an admixture and 10-14 parts of an additive, wherein the coarse aggregates comprise 50-70% of recycled aggregates and 30-50% of broken stone; the recycled aggregates are subjected to S1 acid treatment, S2 mortar treatment and S3 emulsion treatment in sequence. After the recycled aggregates are subjected to S1 acid treatment, S2 mortar treatment and S3 emulsion treatment in sequence, cracks are well repaired, therefore, the compressive strength and other properties of concrete prepared by using the method are closeto the properties of the concrete with natural aggregates, and the anti-penetrability performance of the concrete is even better than that of concrete without recycled aggregates.

Disclosed is device for measuring the variation of the concrete volume. The device is characterized in that the top point (1-1) of bracket (1) contacts the bottom end surface (2-1) of the balance bar (2) middle part; the weight (6) is jointed on the right end of the balance bar (2); the upper end of the hanger (5) is connected on the left end of the balance bar (2); the concrete sample (8) is equipped with sealing rubber film (4) and set in the hanger (5), and dipped in the liquid 3-1 in the container (3); the base of the pulling sensor (7) is connected on the right end top surface of the bracket (1); the detecting end (7-1) of the pulling sensor (7) is connected on the right end bottom surface of the balance bar (2); the thermometer (9) is dipped in the liquid (3-1).

The invention provides a concrete material in-high-temperature compression testing machine and an in-high-temperature compression testing method. The concrete material in-high-temperature compression testing machine comprises loading equipment for applying pressure on a concrete test-piece, heating equipment for heating the concrete test-piece, and a displacement acquisition device for measuring the deformation of the concrete test-piece. According to the concrete material in-high-temperature compression testing machine, the heating equipment and the loading equipment for concrete testing are skillfully combined together, and are assisted by the displacement acquisition device, so that a comprehensive testing system capable of being used for concrete test-piece in-high-temperature compression testing is formed, synchronization of heating and loading is realized, a concrete environment in high temperature due to fire can be truly simulated, a test result obtained by performing a concrete material test through the concrete material in-high-temperature compression testing machine is very close to actual compressive property of concrete in high temperature due to fire, and a guarantee is provided for researching high temperature performance and fire resistance of a concrete material.

The invention discloses a non-linear optimization method for mix proportion of concrete. The non-linear optimization method is carried out according to the following steps: firstly, establishing a neural network model for predicting the performance of concrete; secondly, determining the target and constraint conditions of an optimization model for mix proportion; thirdly, establishing the optimization model for mix proportion by virtue of a particle swarm optimization algorithm; and fourthly, carrying out particle reduction, namely, respectively reducing optimal fitness values obtained by calculation and positions of the optimal fitness values into the lowest cost value and the corresponding mix proportion of concrete and completing the method. The non-linear optimization method has the beneficial effects that (1) the non-linear prediction model of the performance of concrete and the non-linear optimization model of the mix proportion are established; (2) the problem of over-fitting control in the non-linear prediction of the performance of concrete is solved; and (3) the global optimization of the mix proportion of concrete is achieved and the optimization efficiency is relatively high.