CN111808243A - Low-grade concrete workability regulator and preparation method thereof - Google Patents

Low-grade concrete workability regulator and preparation method thereof Download PDF

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CN111808243A
CN111808243A CN202010736443.2A CN202010736443A CN111808243A CN 111808243 A CN111808243 A CN 111808243A CN 202010736443 A CN202010736443 A CN 202010736443A CN 111808243 A CN111808243 A CN 111808243A
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low
parts
regulator
grade concrete
mixed solution
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CN111808243B (en
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吕生华
吴磊
高党国
任洋军
刘相
赵海峰
李宁国
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Chaozhou Hongji Concrete Co.,Ltd.
Guangzhou Boyi Intellectual Property Operation Co ltd
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Shaanxi University of Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
    • C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
    • C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/16—Sulfur-containing compounds
    • C04B24/161—Macromolecular compounds comprising sulfonate or sulfate groups
    • C04B24/163—Macromolecular compounds comprising sulfonate or sulfate groups obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B24/165—Macromolecular compounds comprising sulfonate or sulfate groups obtained by reactions only involving carbon-to-carbon unsaturated bonds containing polyether side chains
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
    • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
    • C08F290/06—Polymers provided for in subclass C08G
    • C08F290/062—Polyethers

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  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention discloses a low-grade concrete workability regulator and a preparation method thereof, wherein the preparation method comprises the following specific steps: 1) putting the polyether macromonomer, the six-arm polyethylene glycol acrylate and water into a reactor, adding hydrogen peroxide and stirring uniformly to obtain a macromonomer mixed solution; 2) uniformly mixing acrylic acid, sodium methallyl sulfonate, an N-vinyl heterocycle and water to obtain a monomer mixed solution; 3) uniformly mixing mercaptopropionic acid, ascorbic acid and water to obtain a molecular weight regulator solution; 4) and heating the macromonomer mixed solution, synchronously dropwise adding the monomer mixed solution and the medium molecular weight regulator solution, preserving the temperature of the system after dropwise adding, then cooling, and adjusting the pH value of a reactant to obtain the low-grade concrete workability regulator. The preparation method is simple, the preparation cost is low, the workability of the low-grade concrete workability regulator is good, the cement paste is prevented from segregation and bleeding, the sand and stone are uniformly wrapped, and the fluidity of the concrete is improved.

Description

Low-grade concrete workability regulator and preparation method thereof
Technical Field
The invention relates to a concrete admixture technology, in particular to a low-grade concrete workability regulator and a preparation method thereof.
Background
The concrete is a composite material which is prepared by mixing, pouring and curing the cement, sand, stone, water, an additive and the like, wherein the cement and the water are mixed to form a flowable slurry body to wrap solid components such as sand and stone, cement slurry in the concrete structure before and after curing is uniformly distributed on the surfaces of sand and stone particles to form a continuous matrix, and the cement slurry plays a lubricating role in the mixing, transporting and pouring stages, so that the concrete has certain fluidity and is convenient to transport and construct; the cement slurry in the hardened concrete structure plays a role of bonding the sand and the stone into a whole. Therefore, the state of the cement paste and gravel in the concrete is very important for the working performance and mechanical property of the concrete, and the uniform phase performance of the cement paste and gravel is called the workability of the concrete and mainly refers to the state of each component in the fresh concrete. The workability of the concrete is good, so that the sand and stones are uniformly dispersed in the cement paste, the flowability of the fresh concrete is good, and the sand and stones in the hardened concrete are firmly bonded together by a continuous cement matrix to form a synergistic effect so as to present the results of high strength and long durability; when the workability of concrete is poor, gravel is unevenly dispersed in cement paste, segregation or bleeding phenomenon occurs in cement paste, that is, cement paste cannot be evenly dispersed on the surface of gravel particles, segregation and bleeding phenomenon occur, which causes poor fluidity of fresh concrete, and uneven micro and macro structures of concrete, which causes that the strength and durability of concrete cannot reach the level of prediction and design.
The concrete is formed into two stages, wherein the first stage is a stage of co-locating a cement paste body and gravels, and is a stage of mixing, transporting and pumping concrete components into a mould before solidification, the main task in the stage is to mix the gravels and cementing materials such as cement, mineral powder and fly ash with water to form a uniformly dispersed mixture, additives are often added in the modern concrete mixing construction process, the additives play an irreplaceable role, such as a water reducing agent reducing mixing water and ensuring fluidity, the stage of co-locating and mixing the cement paste body and the gravels is the most important stage of concrete engineering, and the quality of workability is the standard for judging whether the stage is qualified or not, and whether the workability is good or not is mainly determined by the compatibility and harmony among the components; the second stage is the solidification and molding of concrete, the transformation of the paste body into hardened concrete is to fix the structure state of the paste body through the cement hydration reaction process in the cement paste body, wherein the structure and the performance of the cement matrix are the most important.
The workability regulator is mainly used for regulating the compatibility and synergistic effect among all components in the concrete, ensures that a component system is not separated and does not bleed in the mixing and construction stages of the concrete, fixes a uniformly distributed structure through the curing reaction of cement, and promotes all the components to form the synergistic effect to the greatest extent so as to improve the strength and durability.
The concrete is classified into C15, C20, C25, C30, C35, C40, C45, C50, C55, C60, C65, C70, C75 and C80 according to the strength grade, and the corresponding compressive strengths are 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, 45MPa, 50MPa, 55MPa, 60MPa, 65MPa, 70MPa, 75MPa, 80MPa and the like. High strength concrete at and above C50 is also referred to as high grade concrete, and low strength concrete at and below C40 is also referred to as low grade concrete. The water-cement ratio of low-grade concrete is generally larger, the proportion of a cementing material is generally less than 11%, the viscosity is generally smaller, and the phenomena of bleeding, slurry bleeding, segregation and the like are easily generated, so that the flowability is poor, the pumping performance and the construction effect are seriously influenced, and the strength and the durability of concrete engineering are also influenced. Particularly, in concrete pumping construction of ultrahigh buildings or ultra-long distances, the phenomena of high pumping pressure and pump blockage and pipe blockage of low-grade concrete are caused due to poor workability, so that the construction progress is seriously influenced, and the construction cost is wasted.
How to improve the workability of low-grade concrete and ensure good workability and stability of the low-grade concrete becomes the key of the ultra-high-rise concrete pumping technology.
Currently, there are problems in the development and use of low-grade concrete workability modifiers: (1) the usable low-grade concrete workability regulator has few types and poor effect; (2) the compatibility with the polycarboxylic acid water reducing agent is poor, and the doping is difficult; (3) and the preparation cost is high, so that the overall economic cost of construction is high. Therefore, there is a need to develop new low-cost low-grade concrete workability modifiers with good performance.
Disclosure of Invention
The invention aims to provide a low-grade concrete workability regulator and a preparation method thereof, the low-grade concrete workability regulator can ensure that cement paste is not separated and does not bleed and gravel is uniformly wrapped and covered, and the regulator has good compatibility with a polycarboxylic acid water reducing agent, low cost, high economical and practical value, simple preparation method flow, easy operation, low price of the selected preparation raw materials and low preparation cost.
The purpose of the invention is realized by the following technical scheme:
a preparation method of a low-grade concrete workability regulator comprises the following specific steps: putting 66-73 parts of polyether macromonomer, 18-23 parts of hexa-arm polyethylene glycol acrylate and 79-89 parts of water in parts by mass into a reactor, adding 0.6-0.8 part of hydrogen peroxide, and uniformly stirring to obtain macromonomer mixed solution; step two, uniformly mixing 11-16 parts of acrylic acid, 2-3 parts of sodium methallyl sulfonate, 5-7 parts of N-vinyl heterocycle and 41-51 parts of water to obtain a monomer mixed solution; step three, uniformly mixing 0.35-0.38 part of mercaptopropionic acid, 0.21-0.25 part of ascorbic acid and 33-43 parts of water to obtain a molecular weight regulator solution; and step four, after the macromonomer mixed solution obtained in the step one is heated to 40-45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 120-150 min, the dropwise adding time of the molecular weight regulator solution is 130-160 min, after the two solutions are completely dropwise added, the system is kept for 120-150 min, then, the temperature is reduced to 25-30 ℃, and the pH value of a reactant is regulated to 6.5-7.5 by using an alkaline solution, so that the low-grade concrete workability regulator is obtained.
Further, the polyether macromonomer is one of allyl alcohol polyoxyethylene ether, methyl allyl alcohol polyoxyethylene ether and isoamyl alcohol polyoxyethylene ether, the purity is higher than 99%, the molecular weight is 2100-2600, the water content is 1%, the hydroxyl value is 21-22 mgKOH/g, the unsaturation degree is 0.3-0.35 mol/kg, and the pH value of a 1% aqueous solution is 5.0-7.0.
Further, the average molecular weight of the six-arm polyethylene glycol acrylate is 5000, and the purity is more than 95%.
Further, the hydrogen peroxide is chemically pure, wherein H is2O2The mass fraction is 29-30%.
Furthermore, the purities of the acrylic acid, the methacrylic acid, the sodium methallyl sulfonate and the ascorbic acid are all more than 99.5 percent.
Further, the N-vinyl heterocyclic ring is one or a combination of N-vinyl pyrazole, N-vinyl imidazole, N-vinyl pyridine, N-vinyl pyrrole and N-vinyl pyrimidine.
Further, the alkaline solution in the fourth step is a sodium hydroxide solution with the mass fraction of 40%.
The low-grade concrete workability regulator prepared by the preparation method of any one of the above.
Further, the low-grade concrete workability regulator has the number average molecular weight of 8.7-13.2 ten thousand, the pH value of 6.5-7.5 and the viscosity of 2400-2600 mPa & s.
Compared with the prior art, the invention has the following beneficial effects:
the preparation method has simple flow and no pollution in the preparation process, a comb-shaped structure with high viscosity, multiple active groups, multiple contact points and multiple branched chains is formed by selecting the six-arm polyethylene glycol acrylate, the acrylic acid, the sodium methallylsulfonate and the N-vinyl heterocycle during the preparation, the multiple active groups and the like contained in the comb-shaped structure have affinity, intermolecular acting force and the like with the surfaces of cement paste and sandstone, and the comb-shaped structure is dispersed among cement particles and the sandstone and has better adhesive force, so that the low-grade concrete workability regulator disclosed by the invention can ensure that the cement paste is not segregated and bleeding is not generated and the sandstone is uniformly wrapped and covered; moreover, the formed comb-shaped structure is similar to the molecular structure of the polycarboxylate water reducer, so that the compatibility of the low-grade concrete workability regulator and the polycarboxylate water reducer is good, the low-grade concrete workability regulator and the polycarboxylate water reducer are mixed into concrete through compounding with the polycarboxylate water reducer, the compound is stable and does not delaminate, the performance of the polycarboxylate water reducer is not influenced, the low-grade concrete workability regulator and the polycarboxylate water reducer have a synergistic effect when being used in a compounding way, and the low-grade concrete workability regulator and the polycarboxylate water reducer have good market application prospects; the preparation raw materials are cheap and easy to obtain, the preparation cost is low, and the economic practicability is high; the workability regulator for the low-grade concrete has obvious regulation effect and small dosage, and the mixing amount is only 0.1-0.3 percent of the polycarboxylate water reducer (the mass fraction of the polycarboxylate water reducer is 10 percent). In practical application, when the workability regulator is used for the workability regulation of concrete with the C40 grade or below, the mixing amount of the workability regulator with the purity of 20 percent is 0.55 to 0.85 percent of the mass of the cement, fresh concrete is not separated and does not bleed, the slump loss is 30 to 60mm after 2 hours, the expansion degree is 40 to 55cm, and the compressive strength and the flexural strength of the hardened concrete in 28 days are respectively improved by 15 to 20 percent and 18 to 23 percent compared with those of a reference sample.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
step one, putting 66 parts of polyether macromonomer, 18 parts of six-arm polyethylene glycol acrylate and 79 parts of water in a reactor according to parts by mass, adding 0.6 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution, wherein the structural formula of the six-arm polyethylene glycol acrylate is as follows:
Figure BDA0002605230030000061
step two, uniformly mixing 11 parts of acrylic acid, 2 parts of sodium methallyl sulfonate, 5 parts of N-vinyl heterocycle and 41 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.35 part of mercaptopropionic acid, 0.21 part of ascorbic acid and 33 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 40 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 120min, the dropwise adding time of the molecular weight regulator solution is 130min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the system is kept for 120min, then, the temperature is reduced to 25 ℃, and then, a sodium hydroxide solution with the mass fraction of 40% is used for neutralizing the pH value of a reactant to 6.5, so that the low-grade concrete workability regulator is obtained. The prepared low-grade concrete workability regulator has the number average molecular weight of 13.2 ten thousand, the pH value of 6.5 and the viscosity of 2600 mPa.
The workability regulator for the low-grade concrete prepared by the embodiment is suitable for the workability regulation of the concrete below the C40 grade, when the workability regulator with the purity of 20 percent is mixed into the C40 concrete according to 0.65 percent of the mass of the cement, the fresh concrete is not separated and does not bleed, the slump loss is 35mm after 2 hours, the expansion degree is 53cm, and the compression strength and the breaking strength of the concrete after 28 days of hardening are respectively improved by 19 percent and 21 percent compared with those of a reference sample.
Example 2
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
step one, putting 70 parts of polyether macromonomer, 19 parts of hexa-arm polyethylene glycol acrylate and 80 parts of water in parts by mass into a reactor, adding 0.6 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution;
step two, uniformly mixing 13 parts of acrylic acid, 3 parts of sodium methallyl sulfonate, 6 parts of N-vinyl heterocycle and 50 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.36 part of mercaptopropionic acid, 0.24 part of ascorbic acid and 38 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 43 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 130min, the dropwise adding time of the molecular weight regulator solution is 140min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the temperature of the system is kept for 135min, then the temperature is reduced to 27 ℃, and the pH value of a reactant is neutralized to 7.0 by using a sodium hydroxide solution with the mass fraction of 40%, so that the low-grade concrete workability regulator is obtained. The prepared low-grade concrete workability regulator has the number average molecular weight of 8.7 ten thousand, the pH value of 7.0 and the viscosity of 2400mPa & s.
The workability regulator for the low-grade concrete prepared in the embodiment is suitable for the workability regulation of the concrete below the C40 grade, when the workability regulator with the purity of 20% is mixed into the C35 concrete according to 0.65% of the mass of the cement, the fresh concrete is not separated and does not bleed, the slump loss is 50mm after 2 hours, the expansion degree is 46cm, and the compression strength and the breaking strength of the concrete after 28 days of hardening are respectively improved by 17% and 22% compared with those of a control sample.
Example 3
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
putting 73 parts of polyether macromonomer, 23 parts of hexa-arm polyethylene glycol acrylate and 89 parts of water in parts by mass into a reactor, adding 0.8 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution;
step two, uniformly mixing 16 parts of acrylic acid, 3 parts of sodium methallyl sulfonate, 7 parts of N-vinyl heterocycle and 51 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.38 part of mercaptopropionic acid, 0.25 part of ascorbic acid and 43 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 150min, the dropwise adding time of the molecular weight regulator solution is 160min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the system is kept for 150min, then, the temperature is reduced to 30 ℃, and then, a sodium hydroxide solution with the mass fraction of 40% is used for neutralizing the pH value of a reactant to 7.5, so that the low-grade concrete workability regulator is obtained. The prepared low-grade concrete workability regulator has the number average molecular weight of 13.2 ten thousand, the pH value of 7.5 and the viscosity of 2460mPa & s.
The workability regulator for the low-grade concrete prepared by the embodiment is suitable for the workability regulation of the concrete below the C40 grade, when the workability regulator with the purity of 20 percent is mixed into the C30 concrete according to 0.65 percent of the mass of the cement, the fresh concrete is not separated and does not bleed, the slump loss is 50mm after 2 hours, the expansion degree is 43cm, and the compressive strength and the breaking strength of the cherry concrete after 8 days are respectively improved by 18 percent and 21 percent compared with those of a reference sample.
Example 4
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
step one, putting 66 parts of allyl alcohol polyoxyethylene ether, 23 parts of hexa-arm polyethylene glycol acrylate and 80 parts of water in a reactor according to parts by mass, adding 0.8 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution;
step two, uniformly mixing 11 parts of acrylic acid, 3 parts of sodium methallyl sulfonate, 2 parts of N-vinyl pyrazole, 2 parts of N-vinyl imidazole, 1 part of N-vinyl pyridine, 1 part of N-vinyl pyrimidine, 1 part of N-vinyl pyrrole and 51 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.35 part of mercaptopropionic acid, 0.25 part of ascorbic acid and 43 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 120min, the dropwise adding time of the molecular weight regulator solution is 160min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the system is kept for 130min, then, the temperature is reduced to 30 ℃, and the pH value of a reactant is neutralized to 7.5 by using a potassium hydroxide solution with the mass fraction of 40%, so that the low-grade concrete workability regulator is obtained. The prepared low-grade concrete workability regulator has the number average molecular weight of 10.8 ten thousand, the pH value of 7.2 and the viscosity of 2480mPa & s.
The workability regulator for the low-grade concrete prepared by the embodiment is suitable for the workability regulation of the concrete below the C40 grade, when the workability regulator with the purity of 20 percent is mixed into the C25 concrete according to 0.65 percent of the mass of the cement, the fresh concrete is not separated and does not bleed, the slump loss is 30mm after 2 hours, the expansion degree is 54cm, and the compression strength and the breaking strength of the concrete after 28 days of hardening are respectively improved by 19 percent and 21 percent compared with those of a reference sample.
Example 5
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
putting 73 parts of methyl allyl alcohol polyoxyethylene ether, 18 parts of hexa-arm polyethylene glycol acrylate and 80 parts of water into a reactor according to the mass parts, adding 0.6 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution;
step two, uniformly mixing 16 parts of acrylic acid, 2 parts of sodium methallyl sulfonate, 3 parts of N-vinyl pyrrole, 2 parts of N-vinyl pyrimidine and 45 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.38 part of mercaptopropionic acid, 0.21 part of ascorbic acid and 40 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 150min, the dropwise adding time of the molecular weight regulator solution is 130min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the system is kept for 130min, then, the temperature is reduced to 30 ℃, and the pH value of a reactant is neutralized to 7.5 by using a potassium hydroxide solution with the mass fraction of 40%, so that the low-grade concrete workability regulator is obtained. The prepared low-grade concrete workability regulator has the number average molecular weight of 12.7 ten thousand, the pH value of 6.8 and the viscosity of 2530mPa & s.
The workability regulator for the low-grade concrete prepared by the embodiment is suitable for the workability regulation of the concrete below the C40 grade and the workability regulation of the concrete below the C40 grade, when the workability regulator with the purity of 20 percent is mixed into the C40 concrete according to 0.55 percent of the cement mass, the fresh concrete does not segregate and bleed, the slump loss is 36mm after 2 hours, the expansion degree is 52cm, and the compression strength and the breaking strength of the concrete after 28 days of hardening are respectively improved by 16 percent and 18 percent compared with those of a reference sample.
Example 6
The preparation method of the low-grade concrete workability regulator comprises the following specific steps:
putting 73 parts of isoamyl alcohol polyoxyethylene ether, 18 parts of hexa-arm polyethylene glycol acrylate and 80 parts of water into a reactor according to the mass parts, adding 0.6 part of hydrogen peroxide, and uniformly stirring to obtain a macromonomer mixed solution;
step two, uniformly mixing 16 parts of acrylic acid, 2 parts of sodium methallyl sulfonate, 3 parts of N-vinyl pyrrole, 2 parts of N-vinyl pyrimidine and 45 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.38 part of mercaptopropionic acid, 0.21 part of ascorbic acid and 40 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 150min, the dropwise adding time of the molecular weight regulator solution is 130min, after the monomer mixed solution and the molecular weight regulator solution are completely dropwise added, the system is kept for 130min, then, the temperature is reduced to 30 ℃, and the pH value of a reactant is neutralized to 7.5 by using a potassium hydroxide solution with the mass fraction of 40%, so that the low-grade concrete workability regulator is obtained.
The workability regulator for the low-grade concrete prepared in the embodiment is suitable for the workability regulation of the concrete with the grade below C40, when the workability regulator with the purity of 20% is mixed into 40 concrete according to 0.85% of the mass of the cement and the fly ash, the fresh concrete is not separated and does not bleed, the slump loss is 45mm after 2 hours, the expansion degree is 46cm, and the compression strength and the breaking strength of the concrete after 28 days of hardening are respectively improved by 20% and 23% compared with those of a reference sample.
In the present invention, the specification of the selected material is preferably: the polyether macromonomer is industrial grade, the purity is more than 99%, the molecular weight is 2100-2600, the water content is 1%, the hydroxyl value is 21-22 mgKOH/g, the unsaturation degree is 0.3-0.35 mol/kg, and the pH of 1% aqueous solution is 5.0-7.0; the average molecular weight of the six-arm polyethylene glycol acrylate is 5000, and the purity is more than 95%; the hydrogen peroxide is chemically pure, wherein H is2O2The mass fraction is 29-30%; the purities of acrylic acid, methacrylic acid, sodium methallyl sulfonate and ascorbic acid are all more than 99.5 percent.
The formula of the C40, C35, C30 and C25 low-grade concrete comprises the following components in parts by mass:
c40 formulation: the cement comprises fly ash, sand, broken stone, water, a water reducing agent, a low-grade concrete workability regulator 380, 80, 683, 1123, 165, 13.5, a water reducing agent and a low-grade concrete workability regulator.
C35 formulation: the cement comprises fly ash, sand, broken stone, water, a water reducing agent and a low-grade concrete workability regulator, wherein the weight ratio of the low-grade concrete workability regulator is 360:60:703:1143:163: 12.2.
C30 formulation: the cement comprises fly ash, sand, broken stone, water, a water reducing agent, a low-grade concrete workability regulator (330: 50:723:1163:161: 11.0).
C25 formulation: the cement comprises fly ash, sand, broken stone, water, a water reducing agent, a low-grade concrete workability regulator, 310:30:743:1183:155:9.9, and the low-grade concrete workability regulator.
Wherein the cement is ordinary Portland cement P.O.42.5, the fly ash is I-grade fly ash, the sand is yellow river sand, the broken stone is continuous graded gravel, and the water reducing agent is a Point-S type polycarboxylate water reducing agent produced by Jie New Material group of the family, the water reducing rate is 33%, and the purity is 8% water solution.
Blank control concrete samples were prepared according to the C40, C35, C30, and C25 formulations described above without incorporating the workability regulator prepared in this patent.
The concrete slump, the expansion degree, the bleeding and the like are measured according to GB/T50080-2002 Standard for testing the performance of common concrete mixtures and GB/T50081-2002 Standard for testing the mechanical properties of common concrete.

Claims (9)

1. A preparation method of a low-grade concrete workability regulator is characterized by comprising the following specific steps:
putting 66-73 parts of polyether macromonomer, 18-23 parts of hexa-arm polyethylene glycol acrylate and 79-89 parts of water in parts by mass into a reactor, adding 0.6-0.8 part of hydrogen peroxide, and uniformly stirring to obtain macromonomer mixed solution;
step two, uniformly mixing 11-16 parts of acrylic acid, 2-3 parts of sodium methallyl sulfonate, 5-7 parts of N-vinyl heterocycle and 41-51 parts of water to obtain a monomer mixed solution;
step three, uniformly mixing 0.35-0.38 part of mercaptopropionic acid, 0.21-0.25 part of ascorbic acid and 33-43 parts of water to obtain a molecular weight regulator solution;
and step four, after the macromonomer mixed solution obtained in the step one is heated to 40-45 ℃, synchronously dropwise adding the monomer mixed solution obtained in the step two and the molecular weight regulator solution obtained in the step three into the macromonomer mixed solution, wherein the dropwise adding time of the monomer mixed solution is 120-150 min, the dropwise adding time of the molecular weight regulator solution is 130-160 min, after the two solutions are completely dropwise added, the system is kept for 120-150 min, then, the temperature is reduced to 25-30 ℃, and the pH value of a reactant is regulated to 6.5-7.5 by using an alkaline solution, so that the low-grade concrete workability regulator is obtained.
2. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: the polyether macromonomer is one of allyl alcohol polyoxyethylene ether, methyl allyl alcohol polyoxyethylene ether and isoamyl alcohol polyoxyethylene ether, the purity is more than 99%, the molecular weight is 2100-2600, the water content is 1%, the hydroxyl value is 21-22 mgKOH/g, the unsaturation degree is 0.3-0.35 mol/kg, and the pH value of a 1% aqueous solution is 5.0-7.0.
3. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: the average molecular weight of the six-arm polyethylene glycol acrylate is 5000, and the purity is more than 95%.
4. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: the hydrogen peroxide is chemically pure, wherein H is2O2The mass fraction is 29-30%.
5. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: the purities of the acrylic acid, the methacrylic acid, the sodium methallyl sulfonate and the ascorbic acid are all more than 99.5 percent.
6. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: the N-vinyl heterocyclic ring is one or a combination of N-vinyl pyrazole, N-vinyl imidazole, N-vinyl pyridine, N-vinyl pyrrole and N-vinyl pyrimidine.
7. The method of preparing a low grade concrete workability modifier according to claim 1, characterized in that: and in the fourth step, the alkaline solution is a sodium hydroxide solution with the mass fraction of 40%.
8. A low grade concrete workability modifier prepared according to the method of any preceding claim.
9. The low grade concrete workability modifier of claim 8, wherein: the low-grade concrete workability regulator has the number average molecular weight of 8.7-13.2 ten thousand, the pH value of 6.5-7.5 and the viscosity of 2400-2600 mPa & s.
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Publication number Priority date Publication date Assignee Title
CN103803840A (en) * 2014-01-27 2014-05-21 济南大学 Application of hyper-branched polymer to concrete shrinkage reducing agent
CN105384928A (en) * 2015-11-30 2016-03-09 江苏苏博特新材料股份有限公司 Preparing method of star structure polymer and application
CN110078910A (en) * 2018-01-25 2019-08-02 北京砼帮汇科技有限公司 A kind of poly carboxylic acid series water reducer branch polyether monomer and its synthetic method
CN110156944A (en) * 2019-04-26 2019-08-23 中科广化（重庆）新材料研究院有限公司 Four arm starblock polycarboxylic acid super-plasticizers of one kind and its preparation method and application

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103803840A (en) * 2014-01-27 2014-05-21 济南大学 Application of hyper-branched polymer to concrete shrinkage reducing agent
CN105384928A (en) * 2015-11-30 2016-03-09 江苏苏博特新材料股份有限公司 Preparing method of star structure polymer and application
CN110078910A (en) * 2018-01-25 2019-08-02 北京砼帮汇科技有限公司 A kind of poly carboxylic acid series water reducer branch polyether monomer and its synthetic method
CN110156944A (en) * 2019-04-26 2019-08-23 中科广化（重庆）新材料研究院有限公司 Four arm starblock polycarboxylic acid super-plasticizers of one kind and its preparation method and application

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