288 results about "Cement particle" patented technology

The invention discloses a nano material modified alcohol amine grinding aid as well as a preparation method and application thereof, and the preparation method comprises the following steps: firstly, carrying out esterification reaction on alcohol amine and an acid small monomer containing double bonds to generate an esterification product; then, carrying out bulk polymerization on the esterification product and a silane coupling agent KH-570; and finally, combining the bulk polymerization product with the nano-material through a dehydration reaction of a silane coupling agent and hydroxyl on the surface of the nano-material to form the nano-material modified alcohol amine grinding aid. According to the invention, the nano material is directly grafted into the alcohol amine, so that the dispersity of the nano material in the cement grinding process can be effectively optimized, the friction force and energy consumption among cement particles can be reduced, the efficiency and stability of the cement production process can be improved, and the strength and durability of the cement product are improved.

The invention relates to the technical field of concrete, and particularly discloses super-retarded concrete for an ultra-large pile and a preparation method of the super-retarded concrete. The super-retarding concrete for the ultra-large pile is prepared from the following raw materials in parts by mass: 320 to 400 parts of a cementing material, 1820 to 1960 parts of aggregate, 20 to 28 parts of an inorganic-organic hybrid retarding reinforcing agent, 7.2 to 11.6 parts of a polycarboxylate superplasticizer and 85 to 98 parts of water, the inorganic-organic hybrid delayed coagulation enhancer is prepared by carrying out in-situ free radical polymerization reaction on a hydroxyl acrylate monomer, acrylamide and nano silicon dioxide. According to the inorganic-organic hybrid retarding reinforcing agent, a hybrid substance is formed through a chemical bond, an organic phase is chelated with calcium ions to realize retarding and does not excessively inhibit cement particles, inorganic phase nano silicon dioxide has no agglomeration risk, gaps are filled, a stable product is generated to resist alkali erosion, and the super retarding performance and the long-term strength of concrete are both considered; and the service life of the ultra-large pile is prolonged.

The invention discloses a cement-based material mixing state intelligent regulation and control auxiliary agent and a preparation method and application thereof. The auxiliary agent is composed of reversible sulfonation modified degradable starch and acrylic resin containing hydroxyl. The method is characterized in that the sulfonated modified starch plays roles in dispersing and suspending cement particles and gravels and improving uniformity and flowability in the cement-based material mixing and injection molding stages, and the sulfonated starch is stimulated to be reversibly reduced into dialdehyde starch in a cement paste alkaline environment in the curing and curing stage; the molecules are mutually crosslinked to form a three-dimensional network structure, so that the effects of dispersing, suspending, adhering and fixing cement particles and gravels are achieved. Therefore, the prepared cement-based material mixing state intelligent regulation and control auxiliary agent has the intelligent effects of presenting different molecular structures and playing different roles in the stirring, injection molding and curing states, the preparation method is unique, the materials are easy to obtain, the application effect is remarkable, and the good application prospect is achieved.

The invention discloses a super-retarding type polycarboxylic acid water reducing agent and a preparation method and application thereof, and belongs to the field of concrete water reducing agents. The preparation method comprises the following steps: taking acrylic acid AA, isobutenol polyoxyethylene ether HPEG and hydroxyethyl acrylate HEA as monomers, taking mercaptopropionic acid MPA as a chain transfer agent, taking hydrogen peroxide H2O2 and L-ascorbic acid Vc, and mixing in proportion to serve as an initiator; preparing a first and second monomer mixed solution; adding bottom water into the reaction kettle, and carrying out stepwise polymerization reaction; and cooling the reaction liquid, adjusting the pH value, filtering, and discharging to obtain the product. According to the invention, an ester functional monomer hydroxyethyl acrylate HEA is introduced, and a step-by-step polymerization technology is adopted to control the dispersion process of water reducing agent molecules on cement particles, so that the water reducing agent molecules continuously disperse the cement particles within a certain period of time; the problem that the slump loss is too fast due to long-time and long-distance transportation of concrete or transportation in high-temperature weather is effectively relieved.

The invention relates to the technical field of cement-based materials, in particular to a preparation method of a special ultra-high-strength cement-based grouting material for wind power generation, which comprises the following steps of: performing simulation analysis on stress and bonding conditions in a contact area of cement particles and aggregate particles by quantifying the proportion of cement, aggregate and an additive and adopting a discrete element method; gap distribution among particles is adjusted in combination with a genetic algorithm, mechanical behaviors of the particles are refined through application of a discrete element method, the problem of local stress concentration possibly caused by particle arrangement randomness is avoided, microcosmic stress distribution data are continuously mapped through a radial basis function interpolation method, and the stability of the microcosmic stress distribution data is improved. A macroscopic stress distribution model is established by adopting finite element analysis, data support is provided for the crack resistance and bearing capacity design of the material, the comprehensive performance of the cement-based grouting material in the aspects of fatigue resistance, deformation resistance, environmental erosion resistance and the like is improved by optimizing the synergistic effect of a microstructure and macroscopic stress, and the comprehensive performance of the cement-based grouting material in the aspects of fatigue resistance, deformation resistance, environmental erosion resistance and the like is improved. The mechanical stability and the long-term durability are ensured.

The invention relates to the technical field of concrete admixtures in building materials, in particular to a viscosity reduction type polycarboxylic acid water reducer suitable for high-strength concrete and a preparation method of the viscosity reduction type polycarboxylic acid water reducer. The hydrophobic modified unsaturated double-chain polyether macromonomer is prepared from the following components in parts by mass: 20 to 30 parts of unsaturated acid, 200 to 300 parts of hydrophobic modified unsaturated double-chain polyether macromonomer, 10 to 15 parts of phosphate monomer, 2 to 4 parts of oxidizing agent, 1 to 2 parts of reducing agent, 1 to 2 parts of chain transfer agent, 5 to 10 parts of neutralizing agent and 120 to 180 parts of water. According to the invention, the polyether chain can unfold in a pore solution, the steric hindrance effect is further enhanced, cement particles are ensured to be effectively dispersed in a compact space, and meanwhile, the hydrophobic part of the side chain can effectively reduce the surface tension of the pore solution, so that the condition of overhigh viscosity is avoided, and the flowability and constructability of the concrete are improved.

The invention relates to the technical field of polycarboxylate superplasticizers, and discloses a durability-enhanced polycarboxylate superplasticizer and a preparation method thereof.The preparation method comprises the following steps that raw materials such as a polyether macromonomer are prepared, the polyether macromonomer and the like have the requirements for purity and dosage, deionized water and the polyether macromonomer are added into a reaction kettle to form a solution A, and the solution A is prepared; and preparing an initiator solution B with the mass concentration of 10-20% from ammonium persulfate, heating to 60-80 DEG C, stirring, firstly adding 1 / 3 of the initiator solution B to react, then preparing a mixed monomer solution from acrylic acid and the like, dropwise adding the mixed monomer solution and the residual initiator solution B within 2-3 hours, carrying out heat preservation reaction, cooling, and regulating the pH value to 6-8 by using sodium hydroxide to obtain a finished product. The sulfonic acid group of the introduced sodium methallyl sulfonate functional monomer can enhance the electrostatic repulsion between water reducer molecules and cement particles, so that the dispersing performance of the water reducer is improved, the agglomeration of the cement particles can be inhibited to a certain extent, and the fluidity of concrete can be maintained.

The invention discloses a retarder for delaying cement setting time and a preparation method thereof, and belongs to the field of cement admixtures. The retarder is anionic polymer modified chitosan, and the preparation method comprises the following steps: (1) fully dissolving chitosan in a weak acid solution to obtain a chitosan solution; (2) fully dissolving an anionic polymer in a solvent to obtain an anionic polymer solution; and (3) adding the anionic polymer solution into the chitosan solution, fully stirring, carrying out electrostatic adsorption reaction, and centrifuging, washing, drying and crushing after the electrostatic adsorption reaction is finished to obtain the anionic polymer modified chitosan. Chitosan is modified through electrostatic adsorption of an anionic polymer to form a compound, the compound is added into cement, and the coagulation time of the cement is prolonged by utilizing the complexing action of functional groups of the compound on calcium ions and the surface adsorption action on cement particles, so that the construction operability is favorably improved; and the preparation process is simple, and the cost is low.

The invention provides a viscosity reduction type concrete super plasticizer and a preparation method and application thereof.The super plasticizer is solid and is prepared from an unsaturated monomer a, an unsaturated monomer b and an unsaturated monomer c through free radical polymerization under the microwave condition, the unsaturated monomer a is methacrylic acid or methyl alkenyl phosphonic acid monomer, and the unsaturated monomer b is methacrylic acid or methyl alkenyl phosphonic acid monomer. The unsaturated monomer b is a monomer containing a rigid ring, the rigid ring is an aromatic ring or an imidazole ring or a pyridine ring, and the unsaturated monomer c is an unsaturated polyether monomer containing a benzene ring. A methyl group and a rigid ring group are introduced into a main chain of the super plasticizer, so that the rigidity of a polymer is improved, the hydrophobicity is increased, the conformation of the polymer is changed, and a relatively thick water film layer is formed on the surface of cement particles; meanwhile, a branched structure side chain is introduced into the super plasticizer, so that the molecular size of the polymer can be remarkably increased, the steric hindrance effect of the polymer is more outstanding, the dispersing capacity is good, the thickness of a water film layer on the surface of cement can be increased, and the viscosity of concrete is further reduced.

The invention discloses low-hydration-heat iron aluminate cement and a preparation method thereof, and belongs to the technical field of maritime work cement, and the low-hydration-heat iron aluminate cement comprises 70-85 parts of iron aluminate cement clinker, 5-7 parts of a bio-based retarder, 4-8 parts of a nano friction regulator, 3-4.5 parts of a microcapsule dual repair agent, 5-10 parts of gypsum and 15-25 parts of a mixed material. The fucoidan polysaccharide sulfate and calcium ions in a cement hydration product form a complex through sulfate groups in molecules of the fucoidan polysaccharide sulfate, and further hydration of cement particles is prevented, so that the early heat release rate is effectively reduced, temperature cracks are prevented from being generated in a concrete structure, and the stability and durability of the structure are improved. According to the microcapsule dual-repairing agent, the problem of delayed volume expansion of the steel slag powder caused by fluctuation of the content of free calcium oxide is effectively solved through the matching effect of the inner-layer repairing agent and the outer-layer carrier. According to the gradient clinker sintering process, mineral distribution and chemical reaction paths in clinker are optimized, so that the generation amount of cement hydration heat is remarkably reduced, and meanwhile, the thermal stability of slurry is improved.

The invention relates to the technical field of intelligent grouting, in particular to an intelligent grouting method based on real-time permeability monitoring, which comprises the following steps: arranging a pressure monitoring array in a to-be-grouted area, and electrically connecting the pressure monitoring array with a controller; grouting is started, and the time when the grout reaches all the measuring points is obtained; the stratum permeability change condition is calculated; and dynamically adjusting grouting parameters according to the permeability change condition, wherein the grouting parameters comprise grouting pressure, a water-cement ratio and a cement particle size. According to the method, the grouting target is achieved most efficiently, most economically and most safely through the most appropriate grout, and the problems that in a traditional grouting technology, grouting is not uniform, the reinforcing effect is poor, and potential safety hazards are large are solved. And the grouting parameters are dynamically adjusted based on the change of the permeability, it is ensured that proper grout is injected, the construction quality and efficiency are improved, and intelligent development of the grouting technology is further promoted.

The invention relates to low-cost retarded concrete and a preparation method thereof. The low-cost retarded concrete comprises the following components in parts by weight: 24-27 parts of cement, 6-8 parts of blast furnace slag powder, 5-8 parts of fly ash, 70-90 parts of fine aggregate, 2-7 parts of sludge incineration ash, 93-100 parts of coarse aggregate, 0.4-0.6 part of a water reducing agent, 0-0.25 part of a retarder and 12-21 parts of water. When the temperature of the production environment is lower than 30 DEG C, the retarder comprises sodium gluconate; when the temperature of the production environment is higher than or equal to 30 DEG C, the retarder further comprises white sugar. According to the invention, the sludge incineration ash is recycled, phosphate radicals dissolved in the sludge incineration ash are combined with calcium ions generated by cement hydration, and the calcium ions coat the surfaces of cement particles to hinder further hydration of cement, so that the purpose of retarding is achieved, and the cement can be retarded by increasing the mixing amount of the sludge incineration ash and the retarder. The retarded concrete meeting different setting time requirements can be prepared; other components in the sludge incineration ash can be subjected to secondary hydration reaction with calcium hydroxide generated by cement hydration, so that the durability of the concrete can be improved.

The invention provides a viscosity reduction type water reducer as well as a preparation method and application thereof. The water reducer is prepared by the following steps: firstly, alternately polymerizing styrene and maleic anhydride to obtain a low-molecular-weight styrene-maleic anhydride polymer, and then respectively grafting a phosphonic acid monomer and a polyether monomer into a main chain of the styrene-maleic anhydride polymer through reaction, the number average molecular weight of the styrene-maleic anhydride polymer is 1000 to 2000. Through an esterification reaction, a phosphonic acid monomer and a polyether monomer are grafted to a main chain formed by a styrene-maleic anhydride alternating polymer, and a phosphonic acid group and a hydrophobic epoxypropane structural unit are introduced into a water reducing agent structure, so that the surface tension of the water reducing agent is further reduced; the wetting effect and a certain air entraining effect of the water reducing agent on cement particles are improved, the sliding resistance among the cement particles is reduced, and the viscosity of concrete is reduced to a certain extent.

The present invention relates to the technical field of concrete admixtures, and particularly relates to a rapid-dispersing polycarboxylate water reducer and a preparation method thereof. The water reducer is copolymerized from an acetyl-capped polyether macromonomer, acrylic acid, an ester macromonomer and functional monomer C through a copolymerization reaction. The rapid-dispersing polycarboxylate water reducer prepared by using a specific acetyl-capped polyether macromonomer in the present invention has a significantly improved adsorption rate and early adsorption amount on the surface of cement particles, and the later adsorption amount of the water reducer can be maintained at a relatively high level. The net paste dispersion time of the cement using this water reducer is short, and less of this water reducer is required to meet the same initial net paste fluidity requirement. This water reducer has a fast dispersion speed, good dispersion performance and good slump retention performance at low temperatures.

The invention discloses a frost-crack-resistant salinized soil curing agent based on a nano material and a preparation method thereof, and relates to the technical field of soil curing agents. The preparation method of the curing agent comprises the following steps: uniformly stirring and mixing the cement and the basalt fiber to obtain a premix; adding silica fume, nano silicon dioxide and polyacrylamide into the premix, and continuously stirring and uniformly mixing to obtain the frost crack resistant saline soil curing agent based on the nano material. The silica fume and the nano silicon dioxide are used, so that gaps among cement particles can be effectively filled, the porosity is reduced, and the compactness of the solidified soil is improved; after the nano silicon dioxide is hydrophobically modified by the polydimethylsiloxane, a hydrophobic network is formed in the material, and water permeation is further hindered. And meanwhile, due to the reinforcement function of the basalt fibers and the spatial reticular reinforcement structure constructed by polyacrylamide, the cracking resistance of the soil body is enhanced.

The invention provides a high-temperature-resistant oil well cement retarder and a preparation method thereof, and relates to the technical field of cement retarder materials. The high-temperature-resistant oil well cement retarder is prepared from the following materials in parts by weight: 30 to 40 parts of sulfo-siloxane grafted lignosulfonate, 5 to 10 parts of self-repairing microcapsules, 5 to 8 parts of zinc oxide, 2 to 3 parts of hexagonal boron nitride nanosheets, 1 to 2 parts of pH buffering agent, 2 to 4 parts of polycarboxylic acid water reducing agent and 8 to 12 parts of deionized water. According to the high-temperature-resistant oil well cement retarder disclosed by the invention, the temperature resistance of the high-temperature-resistant oil well cement retarder is improved; the phenomena of bulging, core wrapping and the like in a high-temperature experiment are avoided; the dispersion uniformity of the high-temperature-resistant oil well cement retarder on cement particles is improved, and local premature solidification or excessive retarding in cement paste is prevented; the problem that the strength is reduced due to the fact that retarder components are adsorbed on the surfaces of cement particles to hinder formation and growth of hydration products is solved.

The present application relates to the field of concrete technology, and in particular to a non-structural steel slag anti-floating weighted concrete that can replace all aggregates. The anti-floating weighted concrete comprises cement, fine aggregate steel slag, coarse aggregate steel slag and a modifier. The modifier includes a polymer polymerized by methacrylic acid, 4,4'-diaminobenzyl-2,2'-disulfonic acid and n-butyl isobutyrate. The fine aggregate steel slag and coarse aggregate steel slag completely replace conventional sand and gravel fine aggregate and coarse aggregate, which can not only reduce the occupation of land and environmental pollution by industrial waste steel slag, but also reduce the material cost of concrete. The modifier has a highly polar hydrophilic group, which is doped in cement, can efficiently bind to the water molecules inside the concrete, attach to the cement particles bound to the water molecules, disperse the cement particles, improve the workability of the fresh concrete, improve the density of the concrete after solidification, and improve the impermeability, compressive strength, crack resistance and impact resistance of the concrete after solidification.

The invention discloses an air-entraining type viscosity-reducing polycarboxylic acid water reducer and a preparation method thereof, the polycarboxylic acid water reducer is prepared by taking unsaturated polyether macromonomer, unsaturated acid monomer, vinyl polyacetylene monomer and functional monomer as main raw materials through free radical polymerization reaction under the action of an oxidizing agent, a reducing agent and a chain transfer agent. The unsaturated acid monomer is introduced, so that water reducer molecules can be well adsorbed on the surfaces of particles, the electrostatic repulsion effect is exerted, and the particles are further dispersed; the vinyl polyacetylene monomer and the functional monomer are subjected to gradient hydrolysis in alkaline cement paste, carboxyl is gradually released, and the re-adsorption-dispersion effect of water reducing agent molecules on cement particles within a long time is ensured, so that the slump loss is effectively reduced, and the concrete workability is improved. And the process is simple, the raw materials are cheap, large-batch production and manufacturing are facilitated, and the batch concrete matching and selecting requirements are met.

The invention provides a concrete workability improved water reducing agent with a polyphosphate side chain as well as a preparation method and application of the water reducing agent. The water reducing agent is prepared from a phosphate macromonomer and a charged monomer through free radical copolymerization, the structure is characterized in that a side chain contains a large number of P-O bonds and has high ductility, and a main chain adsorption group has a flexible chain segment formed by ester bonds. The side chain segment of the water reducing agent contains a large number of P-O bonds, the hydrogen-bond interaction is stronger than that of the conventional polyether polyol chain segment, the ductility of the side chain in a slurry solution is increased, the thickness of an adsorption layer of the water reducing agent on the surface of cement particles is increased, and the water reducing agent has high dispersity; an electrified monomer with a flexible chain segment is used as an adsorption unit of water reducing agent molecules, the effect of adsorption base embedding caused by curling and folding of a polymer chain segment is avoided, the electrostatic adsorption effect of the water reducing agent molecules on the surfaces of cement particles is effectively enhanced, the cement adaptability is improved, and the sensitivity is reduced.

The invention relates to the technical field of water reducing agents, and discloses a slow-release polycarboxylic acid water reducing agent and a preparation method thereof.The slow-release polycarboxylic acid water reducing agent is prepared by adding polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, a propylene glycol methyl ether acetate chain transfer agent, monoethylene glycol phthalate, hydrogen peroxide, alkenylated silane and water into a stirrer, stirring, adding an initiator, and stirring to obtain a mixture; and finally, obtaining the slow-release polycarboxylic acid water reducer. Quaternary ammonium salt in the slow-release polycarboxylate superplasticizer increases the dispersity to cement particles, so that the surfaces of the cement particles are slightly positively charged, the fluidity of cement paste is increased, the strength of concrete is improved, and silane contained in the slow-release polycarboxylate superplasticizer can deeply permeate into capillary pore walls of the concrete and chemically react with hydrated cement, so that the strength of the concrete is improved. The silane-modified polycarboxylic acid water reducing agent has the advantages that a polysiloxane interpenetrating network structure is formed, the durability of concrete is improved, the content and substitution degree of silane are increased by a hyperbranched structure in the silane-modified polycarboxylic acid water reducing agent, the silane is hydrolyzed firstly in the hydrolysis process of the water reducing agent, and a good slow-release effect is achieved.

The invention relates to the technical field of cement grinding aids, and particularly discloses an efficient composite Portland cement clinker grinding aid and application thereof. The grinding aid comprises a liquid A and a liquid B which are separated from each other. Wherein the solution A comprises a mixed solution of ethylene glycol and water and iron dihydrogen phosphate. Wherein the volume ratio of the ethylene glycol to the water is (3-3.7): 1, and the iron dihydrogen phosphate in the mixed solution is in a saturated state. The solution B comprises a sodium borohydride and / or potassium borohydride solution, a polycarboxylate superplasticizer and modified magnesium oxide powder. Wherein the mass fraction of the sodium borohydride and / or potassium borohydride solution is 3-5%, the mass fraction of the polycarboxylate superplasticizer in the solution B is 12-17%, and the content of the modified magnesium oxide powder is 4.5-7 g / L. The grinding aid disclosed by the invention can effectively eliminate the electrostatic effect of cement particles, reduce re-agglomeration among the particles and improve the dispersity of cement clinker particles, so that the grinding efficiency is improved.

The present application relates to cement product particle grading technical field, specifically to a kind of cement product particle grading device, grading device includes feeding device, grading device, collection device and induced draft fan, feeding device and grading device pipeline intercommunication, induced draft fan import and grading device pipeline intercommunication, induced draft fan outlet and collection device intercommunication, feeding device is used to scatter cement, grading device is used to carry out internal circulation type grading to cement.The feeding device is used to transport cement product, and is sent into grading device for grading treatment, after treatment, through induced draft fan, it is sent into collection device, and fine powder cement particles are collected, coarse powder cement particles still remain in grading device, and flow out from the bottom discharge port, facilitate collection, and the grading device is used to carry out internal circulation to cement, to improve grading efficiency.

The present application relates to the technical field of gypsum board, in particular to water-resistant and moisture-proof paper-faced gypsum board and its preparation process, comprising two layers of modified facing paper and gypsum board core material between the two layers of modified facing paper, characterized in that the gypsum board core material is composed of modified core material slurry, and the raw materials of the modified core material slurry are composed of the following components: gypsum clinker, water, cement particle ball, premixed paste, alkali-free glass fiber, hydrophobic / hydrophilic mixed starch, hydroxypropyl methyl cellulose, coagulant, and silicon oil catalyst. The present application builds a micro-nano titanium dioxide / silane composite hydrophobic coating on the surface of the facing paper to form the first physical water-blocking layer, and introduces silane-modified nanocellulose and emulsified silicon oil into the core to establish a hydrophobic network inside the core material, and the two form a gradient protection structure of surface shielding and internal hydrophobicity. Even if the outer coating is partially worn, the core material can still effectively prevent water diffusion, significantly improving the water resistance reliability in long-term humid environment.

An organic phosphonate retarder, its preparation method and application relate to the technical field of concrete admixtures. The specific preparation method is as follows: Add a hydroxylamine monomer, water, phosphorous acid, and a catalyst into a reaction vessel, dropwise add formaldehyde for reaction, cool the reaction to room temperature, and add liquid alkali to neutralize to a pH of 5 to obtain the organic phosphonate retarder. The hydroxylamine monomer is an organic compound containing both an amino group and a hydroxyl group in its molecular structure. The molar ratio of the active hydrogen in the amino group of the hydroxylamine monomer to phosphorous acid is 1:0.5 - 1, the molar ratio of phosphorous acid to formaldehyde is 1:1 - 1.2, the catalyst accounts for 3 - 10% of the total mass, and the mass of water accounts for 30 - 50% of the total mass. The organic phosphonate retarder prepared by the present invention has both phosphonic acid groups and hydroxyl groups, can simultaneously complex calcium ions in the cement solution to delay the formation of hydration products, and can form a solvation film on the cement particles to hinder the hydration of cement, with a stronger retardation effect.

The invention discloses a dynamic-water dispersion-resistant condensation-controllable viscosity time-varying grouting material, which is prepared from 0.6 to 0.8 part of water, 1 part of a cementing material component and 0.03 to 0.05 part of an additive component. The Portland cement is taken as a main raw material, and the composite anti-dispersing agent is added, so that a polymer film and glue can be formed among cement particles, and the anti-dispersing performance of the slurry is improved; the water reducing agent, the retarder and the sulphoaluminate cement are used for regulating and controlling the hydration process of the cement, so that the fluidity and the setting time of the slurry are regulated and controlled, meanwhile, the structural strength of cement particles is enhanced, and the dispersion resistance of the slurry is further enhanced. According to the invention, by adjusting the production and addition amount of each component, the cement can be prepared, wherein the initial fluidity is 160-220mm, the pumping period is 5-20min, the water initial setting time is 30-120min, the underwater initial setting time is 40-160min, and the 28d compressive strength is greater than 15MPa; the flow velocity of underground water is not greater than 0.6 m / s, and the retention rate is greater than 80%.

This utility model discloses a grouting device for bridge engineering construction, belonging to the field of bridge engineering technology. It includes: a base plate and a mixing tank; a mounting cover fitted onto the upper end of the mixing tank, the mounting cover being located on the upper end of the base plate and internally connected to a drive shaft, the bottom end of the drive shaft extending into the mixing tank. This utility model, through first contact blocks located on the outer sides of multiple support sleeves and multiple second contact blocks at the bottom of the mixing tank, allows the mixing tank to reciprocate axially up and down with the periodic thrust generated at the contact points of the first and second contact blocks when the drive shaft rotates. This enhances the longitudinal convection of the grout and also causes the mixing tank to rotate in the opposite direction to the drive shaft, forming a three-dimensional composite mixing effect. This significantly improves the dispersion efficiency and mixing uniformity of cement particles, effectively shortens the mixing cycle, and thus improves the efficiency of grouting operations, enhancing the applicability and practicality of the equipment under complex working conditions.

A roofing material is provided having an asphalt-coated mat or felt made up of or in combinations of fiberglass, polyester, nylon, cotton, cellulosic fibers or materials, polyethylene, polypropylene, co-polymers, melamine, phenolic, acrylics, polycarbonate, carbon fiber, clay, metallic in woven, non-woven, strands or sheets, styrene compounds, rubber, silk, leather, or wool in a woven, non-woven, or solid form. The surfacing materials can be made up of or in combination minerals, plastic particles or film, metal particles or film, cement particles, clay particles, paints, coatings, glass, ceramics, wood, wood fiber, or composite materials.

The invention provides a super-long slow-release slump retaining agent suitable for low-carbon cement as well as a preparation method and application thereof. The slump retaining agent is obtained by carrying out a Graft From grafting reaction on a prepolymer main chain and a side chain with a block structure, the main chain of the prepolymer is of a polymer structure with a plurality of modifiable hydroxyl groups, and is obtained by free radical polymerization of unsaturated enol monomers in the presence of an initiator and a chain transfer agent; the side chain is obtained by polymerization reaction of a monomer A, a monomer B, a monomer C and a monomer D; the monomer A is hydrophobic alkyl acrylate, the monomer B is unsaturated acid, the monomer C is hydroxyl ester, and the monomer D is polyoxyethylene ether. An ATRP initiator of a main chain initiates generation of a multi-branched side chain structure, a side chain contains carboxylic acid and hydroxyl ester at the same time, an ester bond between the main chain and the side chain can be hydrolyzed to release a side chain slump retaining component, and the released slump retaining component can continue to be hydrolyzed through a small monomer to gradually release adsorption groups; and the cement particles can be continuously and slowly adsorbed on the cement particles so as to prolong the slurry fluidity retention time.

The invention relates to the technical field of polycarboxylate superplasticizer modification, in particular to a method for modifying a polycarboxylate superplasticizer through Ti-SiO2 porous microspheres, the modified polycarboxylate superplasticizer and application. The polycarboxylate superplasticizer is modified by adopting the nano Ti-SiO2 porous microspheres, and the modified polycarboxylate superplasticizer effectively reduces the liquid level tension of slurry, increases the spacing of cement particles and releases more free water, so that the viscosity reduction performance of cement slurry is improved, the mechanical property and durability of a hardened cement material are improved, and the strength of concrete is enhanced. The modified polycarboxylate superplasticizer prepared by adopting the method for modifying the polycarboxylate superplasticizer by adopting the nano Ti-SiO2 porous microspheres, provided by the invention, has relatively high water-reducing rate and relatively good workability and viscosity reduction performance, and the mechanical strength and durability are improved.

The invention discloses a preparation method of a slurry-extracting and gas-retaining concrete admixture, which is characterized in that dodecenyl succinic anhydride, ethanediamine or hexamethylenediamine and caprolactam are used as raw materials, and a carboxyl-terminated polyamide monomer (PAMA) with a long-chain olefin hydrophobic structure is synthesized through amidation and ring-opening reaction. And carrying out free radical copolymerization on the monomer, acrylic acid, a polyether macromonomer (HPEG / TPEG), hydroxyethyl acrylate, hydroxypropyl acrylate and the like in an aqueous solution to prepare a target additive. According to the invention, the self-synthesized PAMA monomer is introduced, and a long-chain hydrophobic structure in molecules of the PAMA monomer can be directionally adsorbed on the surfaces of cement particles to form a stable microscopic hydrophobic region and has a synergistic effect with the acrylate monomer, so that the gas-retaining property and the slurry extraction effect of the concrete are remarkably enhanced, and the problems of bleeding and segregation are effectively solved. The method is simple in process, the product is excellent in comprehensive performance, and the compounding process is simplified.