309results about How to "Small slump loss" patented technology

The invention discloses a mud-proof slump-retaining type polycarboxylate superplasticizer with low shrinkage and high adaptability and a low-temperature preparation method thereof. The polycarboxylatesuperplasticizer is mainly prepared by the following steps: carrying out free radical polymerization on 4-hydroxybutylvinyl polyoxyethylene ether, unsaturated carboxylic acid, an unsaturated amide-type monomer, dipolyethylene glycol maleate, an unsaturated quaternary ammonium cationic monomer, an oxidizing agent, a catalyst, a reducing agent, a chain transfer agent and deionized water at 5-15 DEGC through an aqueous solution, regulating pH value by adding a sodium hydroxide solution, and supplementing water. The preparation method of the invention has advantages of low-temperature production, no heat source, simple equipment, no pollution, short reaction time and high production efficiency. The prepared mud-proof slump-retaining type polycarboxylate superplasticizer endows concrete withgood workability, good adaptability, low shrinkage and high strength, has excellent mud-proof slump-retaining property, and greatly reduces construction difficulty.

The invention relates to a method for preparing a modified aliphatic high-efficiency water-reducing agent by utilizing lignosulfonate, belonging to the field of concrete water-reducing agents. The invention adopts acetone and formaldehyde as condensation monomers and lignosulfonate as a modifying agent and carries out sulfonating and condensation reactions under an alkaline condition to produce anovel high-efficiency concrete water-reducing agent. The preparation method of the novel high-efficiency concrete water-reducing agent comprises the following steps: (1) adding a sulfonating agent, acetone and water to a reactor, increasing the temperature to 25-65 DEG C and reacting for 0.1-1.5 hours; (2) dipping part of formaldehyde solution for 0.25-2.5 hours, increasing the temperature to 70-95 DEG C and reacting for 1-6 hours; and (3) decreasing the temperature to below 60 DEG C, adding the lignosulfonate and the rest of the formaldehyde solution to the reactor, using an alkaline regulator to regulate a pH value of the system to be 8.0-14.0, increasing the temperature to 70-98 DEG C, reacting for 1-5 hours and decreasing the temperature before discharging. The modified aliphatic high-efficiency water-reducing agent is suitable for producing commercial concrete which has similar color as normal concrete and has smaller collapsed slump loss. By adjusting the process, such as proportioning raw materials, and the like and effectively utilizing the lignosulfonate, the invention not only decreases the product cost, but also lessens environmental pollutants and has favorable industrialized prospects.

The invention discloses a mud-resistant polycarboxylic acid water reducer. The mud-resistant polycarboxylic acid water reducer is prepared from the following components: vinyl polyoxyethylene ether, sodium p-styrenesulfonate, an acrylic acid and acrylamide compounds as monomers as well as an alkaline neutralizer, an initiator and a molecule modulator as auxiliary materials through copolymerization. The mud-resistant polycarboxylic acid water reducer disclosed by the invention is high in water-reducing rate, small in slump loss, good in mud-resistant effect, free of formaldehyde pollution in a production process, and especially adapts to sand concrete with relatively high mud content.

The invention relates to an unsaturated polyether monomer, a comb-like branched copolymer cement dispersant prepared by the monomer, and preparation methods of the monomer and the dispersant. The unsaturated polyether monomer has the general formula (I), wherein R1 is H or -CH3; X is a linking group selected from -CH2-, -CH2CH2-, -OCH2CH2-, -OCH2CH2CH2CH2-; AO is ethylene oxide group and / or propene oxide group; l, m and n are all repeating units of AO; and the sum of l, m and n is an natural number of 10 to 50. The dispersant has the following chemical structure (VI), wherein x, y and z represent mole percentages of three structural units in the copolymer, and the sum of x, y and z is 100%. Preferably, x is 10% to 50%, y is 40% to 80% and z is 0% to 30%. The preparation method of the dispersant is simple and does not need organic solvents or complex esterification. The dispersant is advantageous in low dosage, good dispersibility and small slump loss.

The invention discloses a polycarboxylic retarding high-performance water reducing agent used for preparing concrete of middle and low strength grade. According to the weight percentage of the effective solid content, the water reducing agent comprises 9-15% of low air-entrained mother liquor, 0.5-3.0% of retarder, 0.01-0.03% of foam stabilizer, 0.03-0.10% of air-entraining agent, 0.02-0.08% of thickener, 0.05-0.20% of activator and the balance of water. The preparation method comprises the following steps of: weighing all compositions by the weight percentage of each effective solid content, putting and slowly mixing the compositions in a reaction kettle for 10-30min, thus obtaining the concrete. By adjusting the proportion of all compositions, the polycarboxylic retarding high-performance water reducing agent can meet the usage requirements of the concrete of middle and low strength grade (C15-C40), has the advantages of wide doping range, high water reducing ratio, good retarding effect, low chlorine and alkali content, low concrete shrinkage ratio, greenness, environmental protection and the like, and can prepare the green and economic high-performance concrete.

The invention relates to high-strength lightweight aggregate concrete and a preparation method thereof, and belongs to the technical field of building material concrete. The lightweight aggregate concrete is prepared from the following raw materials in parts by weight: 105-118 parts of cement, 180-185 parts of light coarse aggregate, 120-125 parts of fine aggregate, 65-70 parts of mineral admixtures, 9-24 parts of modified polypropylene fiber, 3.4-3.8 parts of concrete admixtures and 65-70 parts of water. The preparation method comprises the following steps that the raw materials are weighed according to the formula ratio, the light coarse aggregate is added into water accounting for one half of the total water amount for pre-wetting for 45-60 minutes, then the fine aggregate is added, stirring is carried out for 1-2 minutes, the cement, the mineral admixtures and the modified polypropylene fiber are continuously added, uniform stirring is carried out, then the concrete admixtures andthe rest water are added, and uniform stirring is carried out so as to obtain the high-strength lightweight aggregate concrete. The high-strength lightweight aggregate concrete and the preparation method thereof have the advantages that the strength is high, and the quality is stable.

The invention relates to dry powder of active powder concrete and a use method of the dry powder. The dry powder comprises the following components by weight percent: 25%-55% of concrete, 5%-20% of blending stock, 30%-60% of fine aggregate, 5%-20% of micro powder, 2-5% of super plasticizing agent powder, 1-3% of air entraining agent powder, 0.2-1% of defoamer powder, and 0%-25% of fibers. According to the invention, through industrial production, water, of which the weight is 5%-10% of the weight of the dry powder, is added into the products on site, a conventional stirring technology and equipment are used for uniformly stirring, and a mixture meets a certain fluidity of construction performance and is used for easily preparing an active powder concrete prefabricated part or meets the requirement of cast in situ. The dry powder of active powder concrete and the use method of the dry powder have the advantages of stable and reliable quality, small air-entraining volume, excellent homogeneity and convenience in construction, can be widely applied to the engineering fields, such as petroleum, railway, nuclear power, municipal administration, ocean, military facilities and the like, and have excellent economic benefits.

The invention provides a method for preparing sulfate-resistant polycarboxylate water-reducing agents and application thereof. The sulfate-resistant polycarboxylate water-reducing agents comprise monomers a, monomers b and monomers c which are subjected to reversible addition-fragmentation chain transfer polymerization. The method and the application have the advantages that strong adsorption groups and phosphate groups are introduced into block polycarboxylate main chain structures definitely distributed on sequence structures, accordingly, block polycarboxylate is high in adsorption capacity, and the sulfate resistance of the block polycarboxylate can be improved; the sulfate-resistant polycarboxylate water-reducing agents are low in dosage and slump loss, high in water-reducing rate and good in cement adaptability and is sulfate-resistant, the method for synthesizing the sulfate-resistant polycarboxylate water-reducing agents is simple, is low in production cost and little in environmental pollution and has low technological requirements, and the like.

The invention discloses a modified metakaolin-based permeation-resistant and crack-resistant agent for concrete. The modified metakaolin-based permeation-resistant and crack-resistant agent for concrete comprises: by mass, 10 to 75% of modified metakaolin, 5 to 40% of fine limestone powder, 4 to 40% of superfine coal ash, 1 to 20% of calcined hydrotalcite, 2 to 40% of fine quartz sand and 0.2 to 20% of solid silane powder. A preparation method of the modified metakaolin comprises the following steps of putting dry and washed kaolin into a bowl mill, carrying out grinding to obtain kaolin powder, carrying out calcination of the kaolin powder at a temperature of 500 to 1000 DEG C for 0.5 to 6.0 hours to obtain metakaolin, putting the metakaolin into a dispersion machine, adding an organic modifier of sulfamate or triethanolamine into the metakaolin, wherein a mass ratio of the metakaolin and the organic modifier is in a range of (5000: 1) to (100: 1), and carrying out dispersion to obtain the modified metakaolin having a contact angle of 50 to 100 degrees and a specific surface area of 8000 to 15000m<2> / kg. The modified metakaolin-based permeation-resistant and crack-resistant agentfor concrete can be utilized as a concrete additive, improves strength of concrete at different ages, does not produce obvious influences on concrete work performances, obviously improves anti-chloride ion penetration capability of concrete, reduces total shrinkage of concrete and improves crack resistance of concrete.

The invention discloses a highly adaptive ultralong-slow release slump-retaining agent and a normal and low temperature preparation method thereof. Mainly, polyether macromonomer, unsaturated carboxylic acid monomer, unsaturated carboxylic ester monomer, unsaturated phosphate ester monomer, unsaturated amide monomer, oxidant, reducing agent, chain transfer agent and deionized water carry out freeradical polymerization by aqueous solution at the temperature of 5-25 DEG C, after sodium hydroxide solution is then added to regulate pH value, water is then replenished, and thereby the slump-retaining agent is prepared. The preparation method does not need a heat source, reaction is carried out under normal and low temperatures, equipment is simple, the operability is high, the production efficiency is high, the prepared slump-retaining agent has ultralong slow release capability, slump can be retained for a long time, the adaptability is high, and the performance is excellent.

The invention provides a cement concrete slowly-released water reducer. The cement concrete slow-released water reducer is characterized in that the water reducer consists of bimetal hydrate, and a cement concrete used water reducer dispersed in the stratiform bimetal hydrate; the stratiform bimetal hydrate is stratiform MgAl bimetal hydrate or stratiform CaAl bimetal hydrate; the water reducer is a water reducer of naphthalene series or a water reducer of poly carboxylic acid series; the preparation method of the slowly-released water reducer comprises the steps of preparing the stratiform bimetal hydrate, preparing a bimetal oxide and preparing the slowly-released water reducer and so on. In the invention, the roasted product of the stratiform bimetal hydrate, namely, the bimetal oxide, is added to the solution containing the water reducer which enters the layers during the reconstruction of the stratiform structure, thus preparing the powdered water reducer. When the water reducer having the slow release performance is added to and mixed in the concrete at one time, the water reducer is released slowly, thus effectively reducing the loss of the slump constant of concrete; the transportation cost of the powdered slowly-released water reducer can be significantly reduced.

The invention discloses an ether type polycarboxylic acid slump retaining agent and a preparation method thereof. The slump retaining agent is prepared by the following steps of: adding methyl allyl polyethenoxy ether, sodium p-styrene sulfonate and an oxidant into a reaction kettle; adding water, mixing and stirring to obtain uniformly mixed solution; controlling the temperature of the obtained mixed solution at 30-60 DEG C; simultaneously dropwise adding solution A and solution B, wherein the solution A is obtained by dissolving acrylic ester and acrylic acid in water, the dropping time of the solution A is controlled to be 3-4 hours, the solution B is obtained by dissolving a reducing agent and a chain transfer in water and the dropping time of the solution B is controlled to be 3.5-4.5 hours; continuously stirring the obtained solution for 1-1.5 hours; adjusting the pH value of the solution to be 7; adding a proper amount of de-ionized water; and discharging to obtain the ether type polycarboxylic acid slump retaining agent. The prepared slump retaining agent is used in cement paste; the cement paste fluidity is not lost or increased within 2 hours; and the concrete slump loss is extremely low by applying the slump retaining agent to concrete.

The invention discloses high-performance lightweight aggregate concrete. The high-performance lightweight aggregate concrete is characterized in that: high-performance porcelain granules are taken as lightweight aggregate; and the high-performance lightweight aggregate concrete is prepared by mixing the following raw materials in proportion: 400 to 430 kg / m<3> of cement, 500 to 570 kg / m<3> of high-performance porcelain granule, 40 to 55 kg / m<3> of fly ash, 40 to 55 kg / m<3> of grounded furnace slag, 540 to 565 kg / m<3> of sand, 180 to 185 kg / m<3> of water and 6 to 10 kg / m<3> of water reducing agent, wherein the performance indexes of the high-performance porcelain granule is that stacking density is less than and equal to 700 kg / m<3>, cylinder pressure strength is greater than and equal to 6.0 MPa, strength mark is greater than and equal to 35 MPa and water absorbing capacity is less than and equal to 1.0 percent. The high-performance lightweight aggregate has the advantages that the strength is high, and workability and pumpability can meet design and construction requirements.

High-performance cement, concrete and its production are disclosed. The cement consists of industrial fag end, activator, functional regulator and performance regulator, and Bosi specific surface is 300-550m2 / kg. Its advantages include excellent fluidity and endurance, less loss and hydrated heat energy, better density and strength.

The present invention is the preparation process of high efficiency sulfonated straw pulp alkali lignin water reducing agent for concrete or mortar in building engineering. The preparation process includes adding 200 weight portions of water into 100 weight portions of straw pulp alkali lignin, regulating pH value to 3-10, heating to 40-100 deg.c, adding 5-15 weight portions hydrogen peroxide and 0.1-2 weight portions of transition metal salt, catalytically oxidizing for 0.5-1 hr, adding 5-50 weight portions of condensing agent and 5-50 weight portions of sulfite for sulfomethylation of 1-5 hr, and cooling the reaction product to room temperature to obtain the liquid product. The high efficiency sulfonated straw pulp alkali lignin water reducing agent has high water reducing rate, moderate delayed setting, high slump maintaining property, and high compatibility to cement and other water reducing agent.

The invention discloses a viscosity-reduction type polycarboxylate water reducer and a preparation method thereof, and relates to the technical field of building materials. An A type water reducer and a B type water reducer are synthesized according to theoretical design, and the water reducer is formed by compounding the two water reducers, so that the water reducer is the viscosity-reduction type polycarboxylate water reducer which is small in mixing amount, obvious in viscosity-reduction effect, high in water-reducing rate and little in slump loss.

The invention provides high-fluidity pumping ceramsite concrete and a preparation method thereof. A formula of the concrete comprises cement, coal ash, water, fine aggregate, limestone flour, pumping aid, ceramsites, ceramic sand, redispersable emulsion and hydroxypropyl methyl cellulose. The method comprises the following steps: reasonably selecting respective raw materials and usage thereof according to a unit weight of concrete to be prepared, soaking the ceramsites to a saturated water absorption state in advance, then mixing with other raw materials, and stirring to prepare the ceramsite concrete. By controlling the grain size of the ceramsites and a fineness modulus of the fine aggregate, the redispersable emulsion and hydroxypropyl methyl cellulose are cooperatively added to promote the cementation of the cementing materials such as the cement, the coal ash and the limestone flour with the ceramsites, and the cohesiveness and water retaining property of the concrete are increased, and the problems of easy floating, layering and separation of the ceramsites in the ceramsite concrete are effectively solved, moreover, separation and layering of the ceramsites can be effectively avoided by using the ceramsite concrete produced according to the invention, and slump loss in a material transporting and waiting process is obviously reduced.

The invention relates to a polycarboxylic slump retaining agent and its preparation method. With a molecular weight of 15000-45000, the polycarboxylic slump retaining agent has a structural general formula shown as the following formula I, wherein a ranges from 2 to 15, b ranges from 2 to 10, c ranges from 2 to 10, and d ranges from 2 to 10. The polycarboxylic slump retaining agent provided by the invention mainly has the advantages that: 1. it can maintain the fluidity with no loss or even increase within 2h, and it can make the concrete slump loss very low after applying in concrete; 2. regulation between the dispersion property and ageing retainability of a polycarboxylic water reducing agent can be realized; and 3. the preparation process involved in the invention adopts a one-step technique and one-time feeding, the process needs no dropwise adding or heating, overcomes the defect of high temperature synthesis in traditional admixture preparation processes, the reaction period is short, the production efficiency is improved to a great extent, and the production cost is reduced, so that the application range of the polycarboxylic water reducing agent is broadened.

The invention relates to a bridge expansion joint fast reparation material which is composed of a component A and a component B. The component A is composed of, by weight, 25-30 parts of fast-hardening sulphoaluminate cement, 5-10 parts of ordinary Portland cement, 1-3 parts of anhydrite, 1-3 parts of silica fume, 55-65 parts of quartz sand, 0.5-1 part of a water reducing agent, 0.5-1 part of boric acid, and 1-3 parts of fiber. The component B is composed of, by weight, 35-45 parts of carboxylic butadiene-styrene latex, 0.5-1 part of lithium salt, 0.5-1 part of a lithium salt defoaming agent, and 55-65 parts of water. The material has the characteristics of high early strength, stably increasing late strength, low elastic modulus, high bonding strength, cracking resistance, and the like. In practical construction, the material is simple to use.

The invention provides a preparation method of a water reducing agent with a hyper-branched topological structure and an application of the water reducing agent. The preparation method has the advantages of simple process and adoption of readily-available raw materials. The obtained water-reducing agent has the advantages of low glue sand viscosity and high clay adaptability. The preparation method comprises the following steps: (1) carrying out an irregular ring-opening copolymerization reaction on glycidol serving as a monomer B and a monomer C with a specific structure in a molar ratio of 3:1-8:1 to obtain a copolymer intermediate D with a hyper-branched structure; (2) substituting a hydroxide radical of the intermediate D with a group having an adsorption function to obtain the water reducing agent with the hyper-branched topological structure, wherein a substitution proportion is 80-90 percent. The water reducing agent serving as a cement dispersant has the advantages of low glue sand viscosity, high cement adaptability, low dosage, high water reducing rate and small slump loss.

The invention provides a polycarboxylene high-performance water reducing agent, which is obtained by copolymerization of following monomer components: ester macro monomer, ether macro monomer, micro-molecule monomer and bulking agent. The invention also discloses a preparation method of the polycarboxylene high-performance water reducing agent. The polycarboxylene high-performance water reducing agent of the invention not only can show good adaptability for different concrete construction materials, but also reduces usage of a retarder, improves water-reducing rate, and has good bleeding rate and compressive strength rate. The product has more stable quality; the shortcomings that the polycarboxylene product in the prior art has single type and narrow adaptability is overcome.

The invention discloses a preparation method for high-strength self-compacting concrete with recycled fine aggregate. The preparation method comprises the following steps: mixing recycled fine aggregate with required saturated water, stirring the mixture to be uniform, adding and mixing cement, a mineral admixture, natural aggregate, 50-70 % of mixing water and a polycarboxylate superplasticizer, stirring the mixture to be uniform, and finally adding the remaining mixing water to the mixture to be mixed uniformly. According to the preparation method, the problem that the concrete slump loss is large, which is caused by the fact that recycled fine aggregate has the characteristics of higher water absorption, poor strength, irregular shape and the like, is solved, and almost no loss is caused within 2 h, so that the preparation method has wide applicability, and the problem that new mixed concrete is poor in working performance and the like in the actual construction process can be solved. The ratio and the production technology process of the high-strength self-compacting concrete with recycled fine aggregate are optimized; by changing the ratio of mineral admixture and the stirring manners as well as optimizing a recycled fine aggregate demand water saturation process and a mixing water adding process, the new mixed concrete can be excellent in working performance, the slump loss is obviously reduced, the pumpability is excellent and the construction is facilitated.

The present invention provides a preparation method of hyperbranched polycarboxylic acid type copolymer cement dispersant, including: Monomer A, B and C undergo a free radical copolymerization in an aqueous medium. The molar ratio of Monomer A, Monomer B and Monomer C conforms to B / A-A-2-10 and C / (A+B-C)-0.02-0.08. Monomer A is expressed by General Formula (1), where, R1 is H or a methyl; X1═O, CH2O, CH2CH2O; m is an integer from 5 to 200.Monomer B is expressed by General Formula (2), where, R2 is H or COOM; R3 is H or CH3 and M is H, Na, K or NH4;Monomer C is expressed by General Formula (3), where, R4 is H or methyl; X2═O, CH2O, CH2CH2O; Y═CH2, CH2CH2, CH(CH3), CH2CH2CH2, CH(CH3)CH2, C(CH3)2 and n is an integer from 5 to 200

The invention relates to a preparation method of collapse prevention type polycarboxylic acid water reducing agent. The method comprises the following specific steps: methyl allyl polyoxyethylene ether, styrene, sodium methallyl sulfonate and de-ionized water are put in a reaction kettle and evenly stirred for gradually heating to the temperature of 50-70 DEG C, then are gradually dripped with acrylic acid, hydroxyethyl acrylate, oxidizing agent, reducing agent and chain transfer agent; the whole dripping process lasts about 3-4 h; then the heat preservation and the curing are implemented for 1-2 h; finally, the temperature is decreased to 30-35 DEG C; the pH of the solution is adjusted to the neutral property; a proper amount of de-ionized water is added to obtain the colorless transparent collapse prevention type polycarboxylic acid water reducing agent. The used reaction equipment is simple; the reaction is easily controlled; the production cost is low; the water reducing rate is higher; the collapse prevention performance is excellent.

The invention provides a polycarboxylate water reducer containing modified water-soluble acrylate and a preparation method thereof. The preparation method comprises the following steps: firstly, directly carrying out esterification reaction on polyhydroxy-alcohol carbohydrates and crylic acid so as to prepare modified water-soluble acrylate micromonomers; then putting polyether macromonomers into deionized water, and fully dissolving so as to prepare a reaction base solution; dissolving the acrylate micromonomers, crylic acid, an initiator vitamin C and a chain transfer agent mercaptoacetic acid into deionized water, so as to prepare drop concentrate; putting an initiator hydrogen peroxide into the reaction base solution, dropwise adding the drop concentrate into the reaction base solution at a constant speed, reacting while stirring, then regulating the pH value of the solution to be 7-8, so as to prepare the polycarboxylate water reducer. According to the preparation method, the regulating function of the polyhydroxy-alcohol carbohydrates is directly used in the water reducer, so that the property of the water reducer is optimized; the polycarboxylate water reducer prepared by the method has high water reducing rate, and the concrete is obviously improved in fluidity retainability and has less slump loss, so that the water reducer can meet higher construction requirements.

The invention provides a modified sulfamate efficient water reducer and a preparation method thereof, particularly relates to a dinaphthol waste modified sulfamate efficient water reducer and relates to the technical field of waste treatment. The reducer comprises raw materials of, by weight, 120 parts to 130 parts of sodium sulfanilate, 400 parts of dinaphthol waste, 95 parts of phenol, 170 parts of formaldehyde, 25 parts of liquid caustic soda (30%), 30 parts to 50 parts of urea, 1 part to 10 parts of dodecyl diphenyl ether sodium disulfonate and 180 parts to 260 parts of water. By means of the water reducer and the preparation method thereof, dinaphthol waste recycling is achieved, waste water are not needed to be subjected to concentration or any other treatment of physical chemical treatment and the like, energy consumption is saved, and pollution and damage of the waste to the environment and humans are prevented.

The invention belongs to the technical field of a concrete admixture in building materials and provides a slow-release type polycarboxylic water reducing agent, a preparation method thereof and application. The slow-release type polycarboxylic water reducing agent is synthesized by adopting a free-radical polymerization method in an aqueous solution. The slow-release type polycarboxylic water reducing agent is prepared by unsaturated polyoxyethylene ether, unsaturated acid or a mixture of unsaturated acid ester and the unsaturated acid, a chain transferring agent, an oxidizing agent, a reducing agent and water. The slow-release type polycarboxylic water reducing agent has the advantages of low doping amount, good plasticity-maintaining effect, good cement adaptability and good energy-saving and environmental-friendly effects and the like; the production process is simple; the equipment investment is less and the cost is low; by the adoption of the water reducing agent, water reducing components can be gradually released, and the content of the effective water reducing components in the concrete is guaranteed, and the plasticity of the concrete is maintained, and the cement hydration can be delayed, further the maintaining capability for the slump and the fluidity is excellent for concrete with large slump and concrete with medium and small slump respectively, and the large-volume concrete cracks generated by over-high hydration temperature can be reduced, and the mixability and the mechanical property of the concrete can be improved.

The invention discloses a retarded cement grinding aid and a preparation method thereof. The retarded cement grinding aid comprises 0.01-0.02wt% of sodium carboxymethyl cellulose, 25-30wt% of molasses calcium, 5-10wt% of citric acid and the balance of water, wherein the total percent is 100%. The retarded cement grinding aid provided by the invention has the beneficial effects that the molasses calcium is used instead of the molasses and cane sugar commonly used at present, is a powdery product prepared by neutralizing the molasses with lime, has better water reducing and retarding effects than the molasses and saves the cost; and the hydration and hardening time of the cement is effectively lengthened so that the freshly mixed cement concrete can maintain the plasticity in a longer time, thus adjusting the setting time of the freshly mixed cement concrete.

The multi-functional bloater with low alkali and low mixing disclosed, use lots of material like high alumina chamotte, meta kaolin and anhydrite as components of bloater, place high alumina chamotte after burning in rotary kiln and meta kaolin and anhydrite after burning into ball mill, with a certain ratio, and add fluxing agent, and retarder after ball ring, obtaining the products after average mixing. Its alkali content is not larger than 0.18% and the the quality of mixing is 6%, the bloating rateis stable, strength of concrete can be increased by more than 20%, it has low comprehensive cost, multiple functions such as bloating, pumping, delayed coagulation and freeze proof, less loss of concrete, long period for storage and decreased engineering price.

The invention discloses slow-release collapse-preventing type polycarboxylic water reducing agent and a preparation method thereof, and belongs to the field of preparation of the water reducing agent. The slow-release collapse-preventing type polycarboxylic water reducing agent consists of methyl allyl polyoxyethylene ether, acrylic acid, methyl acrylic polyethylene glycol monoester, imide, initiator, vitamin C, chain transfer agent and deionized water. The preparation method comprises the following steps of: preparing macromonomer methyl allyl polyoxyethylene ether, acrylic acid, methyl acrylic polyethylene glycol monoester, imide and vitamin C; under the action of the polymerization initiator and the chain transfer agent, dissolving the methyl allyl polyoxyethylene ether into deionized water, rising temperature to 40 DEG C for dissolving, adding the initiator, then respectively dripping water solution A prepared by dissolving the chain transfer agent, the acrylic acid, the methyl acrylic polyethylene glycol monoester and the imide in the deionized water and V.C water solution B, and after the dripping is finished, carrying out insulation, cooling and neutralization to obtain a finished product. The slow-release collapse-preventing type polycarboxylic water reducing agent disclosed by the invention has the advantages that the loss and the evaporation of water in concrete due to long-time transportation and higher temperature are effectively prevented, and the difficulty of excessively-fast slump loss of the concrete in engineering is solved.