CN116119974B - Polycarboxylate superplasticizer applicable to plateau areas and preparation method thereof - Google Patents
Polycarboxylate superplasticizer applicable to plateau areas and preparation method thereof Download PDFInfo
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- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
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- 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
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
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- 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
- C04B24/24—Macromolecular compounds
- C04B24/28—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/32—Polyethers, e.g. alkylphenol polyglycolether
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- 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
- C04B24/24—Macromolecular compounds
- C04B24/38—Polysaccharides or derivatives thereof
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- 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
- C08F251/00—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof
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- 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
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- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
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- 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
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
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- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/60—Agents for protection against chemical, physical or biological attack
- C04B2103/601—Agents for increasing frost resistance
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
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Abstract
The invention provides a polycarboxylate water reducer applicable to a plateau region and a preparation method thereof, wherein the preparation raw materials of the polycarboxylate water reducer comprise the following components in parts by weight: 250-320 parts of isopentenyl alcohol polyoxyethylene ether, 25-40 parts of unsaturated carboxylic acid, 30-70 parts of etherified high amylose starch, 1-2 parts of styrene, 4-8 parts of ethylene glycol acrylic ester hydrophobic monomer and 1-2 parts of ultraviolet absorber. The polycarboxylate water reducer is prepared from the raw materials, and can effectively resist carbonization of concrete caused by ultraviolet radiation, so that the concrete has good freeze-thawing cycle resistance and crack resistance.
Description
Technical Field
The invention relates to the field of concrete building materials, in particular to a polycarboxylate superplasticizer applicable to a plateau region, and also relates to a preparation method of the polycarboxylate superplasticizer applicable to the plateau region.
Background
The concrete in the plateau area generally has the following characteristics that the air entraining is difficult due to low air pressure, and the stability of the introduced air bubbles is poor, so that the coarse aggregate of the concrete slurry has poor wrapping property and poor freezing and thawing resistance in winter; the temperature difference between the shade surface and the sun surface is larger under the irradiation of the sun, so that the same concrete prefabricated member or pavement has different hydration speeds of different surfaces under the day and night and the sunlight, and the shrinkage stress is uneven, thereby causing temperature cracks; in addition, the strong ultraviolet radiation can cause the accelerated carbonization of the concrete, so that the carbonization shrinkage has less influence on the cracking of the concrete, but has adverse influence on the corrosion of the steel bars; in addition, the plateau areas are mostly dry in wind, and the lack of curing of concrete can lead to shrinkage cracks.
Disclosure of Invention
In view of the above, the invention provides a polycarboxylate water reducer suitable for a plateau area to resist carbonization of concrete caused by ultraviolet radiation, so that the concrete has better freeze-thawing cycle resistance and crack resistance.
In order to achieve the above purpose, the technical scheme of the invention is realized as follows:
the polycarboxylate water reducer suitable for the plateau area comprises the following raw materials in parts by weight: 250-320 parts of isopentenyl alcohol polyoxyethylene ether, 25-40 parts of unsaturated carboxylic acid, 30-70 parts of etherified high amylose starch, 1-2 parts of styrene, 4-8 parts of ethylene glycol acrylic ester hydrophobic monomer and 1-2 parts of ultraviolet absorber.
Further, the isopentenyl alcohol polyoxyethylene ether comprises at least one of TPEG-1200, TPEG-2400 and TPEG-4000.
Further, the etherified high amylose starch has a degree of polymerization of 1000 to 5000 and a degree of substitution of 0.5 to 0.8.
Further, the ethylene glycol acrylic ester hydrophobic monomer comprises at least one of polyethylene glycol dimethacrylate, polyethylene glycol acrylic ester, diethylene glycol monoacrylate and ethylene glycol dimethacrylate.
Further, the ultraviolet absorber comprises dimethylallyl p-benzoyl benzyl ammonium bromide.
The invention also provides a preparation method of the polycarboxylate superplasticizer applicable to the plateau region, which comprises the following steps:
adding isopentenol polyoxyethylene ether, etherified high amylose starch, unsaturated carboxylic acid, styrene and deionized water into a reaction kettle, mixing, heating to 50-70 ℃, stirring for dissolution, adding an oxidant, then dropwise adding a mixed aqueous solution of unsaturated carboxylic acid and glycol acrylic ester hydrophobic monomers and a mixed aqueous solution of a reducing agent and a chain transfer agent, preserving heat, adding alkali for neutralization to neutrality, adding dimethyl allyl p-benzoyl benzyl ammonium bromide, stirring uniformly, and adding water for dilution to obtain the polycarboxylic acid water reducer suitable for the plateau region.
Further, the oxidant comprises at least one of hydrogen peroxide and ferrous sulfate.
Further, the reducing agent includes ascorbic acid.
Further, the chain transfer agent includes at least one of mercaptopropionic acid and sodium hypophosphite.
The polycarboxylate water reducer suitable for the plateau area is prepared by taking isopentenol polyoxyethylene ether, acrylic acid, etherified high amylose starch, styrene and glycol acrylic ester hydrophobic monomers as raw materials, initiating a free radical copolymerization reaction by a redox system, and then compounding a water-based ultraviolet absorbent.
Detailed Description
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
The experimental methods in the following examples are conventional methods unless otherwise specified. The test materials used in the examples described below, unless otherwise specified, were purchased from conventional biochemical reagent stores. In addition, unless specifically described otherwise, each term and process referred to in this embodiment is understood by those skilled in the art in light of the commonly recognized and conventional approaches in the art.
The polycarboxylate water reducer suitable for the plateau area comprises the following raw materials in parts by weight: 250-320 parts of isopentenyl alcohol polyoxyethylene ether, 25-40 parts of unsaturated carboxylic acid, 30-70 parts of etherified high amylose starch, 1-2 parts of styrene, 4-8 parts of ethylene glycol acrylic ester hydrophobic monomer and 1-2 parts of ultraviolet absorber.
The polycarboxylic acid water reducer suitable for the plateau area is prepared by taking isopentenol polyoxyethylene ether, unsaturated carboxylic acid, etherified high amylose starch, styrene and glycol acrylic ester hydrophobic monomers as raw materials, initiating a free radical copolymerization reaction by a redox system to form a polymer water reducer macromolecule, and then compounding with a water-based ultraviolet absorbent.
The polymer water reducer macromolecules in the polycarboxylate water reducer suitable for the plateau areas are comb-shaped, the polymer water reducer macromolecules are formed by polymerizing unsaturated carboxylic acid, etherified starch and polyether, styrene and glycol acrylic ester hydrophobic monomers, carboxylic acid groups on the macromolecules can be directionally adsorbed on the surfaces of cement particles to form ion distribution of a diffusion double electric layer (Zeta potential), the ion distribution of the diffusion double electric layer is formed on the surfaces, cement particles are dispersed under the action of electrostatic repulsive force to form electrostatic repulsive force, the cement particles are mutually dispersed, a flocculation structure is disintegrated, and part of water to be wrapped is released to participate in flowing, so that the fluidity of the concrete mixture is effectively increased. The unsaturated carboxylic acid may be at least one of acrylic acid, methacrylic acid, and maleic anhydride.
The groups provided by the isopentenyl alcohol polyoxyethylene ether, the etherified high amylose starch, the styrene and the ethylene glycol acrylic ester hydrophobic monomer generate steric hindrance among cement particles to prevent the cement particles from agglomerating. The isopentenyl alcohol polyoxyethylene ether preferably adopts at least one of TPEG-1200, TPEG-2400 and TPEG-4000, and unsaturated double bonds of the isopentenyl alcohol polyoxyethylene ether in water reducer molecules are grafted on a polycarboxylic acid main chain through polymerization, carboxyl groups on the main chain and the like form a 'multi-point anchoring', and the unsaturated double bonds are adsorbed on the surfaces of cement particles; and polyethylene glycol branched chains of the isopentenyl alcohol polyoxyethylene ether form a solvated polymer chain layer on the surface of cement particles through hydrogen bonding with water molecules, and the cement particles are dispersed by utilizing the steric hindrance effect, so that the water reducing effect is realized.
The etherified high amylose starch has the properties of ion exchange, chelation and polyanion flocculation, and can also form a complex with a high molecular substance. The salt and shearing resistance of the starch is low, so that the starch is excited to generate free radicals under the condition of heating and acidic stirring, thereby participating in free radical polymerization reaction, and the size and the time of the energy receiving can influence the generation of the free radicals. The etherified high amylose starch can be preferably selected to be in accordance with the products of GB 29937-2013 and GB 29930-2013, the preferable polymerization degree is 1000-5000, the substitution degree is 0.5-0.8, the etherified high amylose starch can play a role of balls in cement paste due to the special glucose unit structure, the dispersing uniformity among cement particles is improved, meanwhile, certain water retaining capacity is provided in the molecular weight distribution interval, and the etherified high amylose starch can provide excellent performance and simultaneously avoid free molecular entanglement as far as possible due to fewer branched chains or even no branched chains in the structure, and has good solubility in normal temperature acidic aqueous medium when the substitution degree is more than 0.5 due to etherification modification, so that common starch precipitation phenomenon can not occur.
Styrene is a hydrophobic substance, and when the polycarboxylate water reducer is introduced, the surface activity of the water reducer can be improved, so that the water reducer is suitable for high-altitude areas. The elevation increases to reduce the atmospheric pressure, the molecular spacing in the air increases, the attractive force is weakened, the liquid density is slightly influenced by the atmospheric pressure, at the moment, the attractive force of the molecules on the liquid-gas interface is obviously higher than that of the liquid molecules under the standard atmospheric pressure, namely, the surface tension value of the liquid is larger at the high elevation and the low atmospheric pressure, so that the air entraining capability of the air entraining agent is equivalently weakened. Compared with the traditional water reducing agent, the polycarboxylic acid water reducing agent with styrene can more effectively reduce the surface tension of slurry and free water in concrete so as to generate fine bubbles, and the phenyl has certain rigidity due to the phenyl, so that the liquid film of the bubbles is thicker, the bubbles are more stable, the strength is higher, the cracking resistance of the concrete can be improved.
The surface tension is an important driving force for shrinkage of concrete, and the ethylene glycol acrylic ester hydrophobic monomer is introduced into the polycarboxylate water reducer, so that the shrinkage reducing group provided by the hydrophobic monomer can effectively reduce the surface tension of a void solution and delay hydration of cement. The ethylene glycol acrylic acid ester hydrophobic monomer preferably comprises at least one of polyethylene glycol dimethacrylate, polyethylene glycol acrylate, diethylene glycol monoacrylate and ethylene glycol dimethacrylate.
The ultraviolet absorbent is a water-soluble ultraviolet absorbent, and specifically is dimethyl allyl p-benzoyl benzyl ammonium bromide, the ultraviolet absorption spectrum is 200-325 nm, the maximum absorption peak is positioned at a lambda max=255 nm position, the strong ultraviolet radiation environment can cause carbonization shrinkage of concrete, the carbonization shrinkage has small influence on cracking of the concrete, but has adverse influence on steel bar corrosion, so after the ultraviolet absorbent is introduced to absorb ultraviolet light energy, thermal vibration of molecules occurs, internal hydrogen bonds are broken, chelate rings are opened, the energy of ultraviolet light is released, and the reinforced concrete diseases caused by ultraviolet radiation and the failure of polycarboxylic acid water reducing agent and air entraining agent caused by ultraviolet are resisted to a certain extent. The quaternary ammonium salt group is contained in the molecule, so that the water solubility of the water-reducing agent is enhanced, the water-reducing agent is dispersed more uniformly when the water-reducing agent is mixed with concrete, and the water-reducing agent has good compatibility with macromolecules of the polymer water-reducing agent.
The invention also provides a preparation method of the polycarboxylate superplasticizer suitable for the plateau region, which specifically comprises the following steps:
250-320 parts of isopentenol polyoxyethylene ether, 30-70 parts of etherified high-amylose starch, 5-10 parts of acrylic acid, 1-2 parts of styrene and 400-500 parts of deionized water are added into a reaction kettle, the temperature is raised to 50-70 ℃, stirring is started in the process of waiting for the temperature to be raised so that components in the kettle are fully dissolved, and then 2-4 parts of oxidant is added. Then, dropwise adding A, B feed liquid, wherein the feed liquid A is 20-30 parts of unsaturated carboxylic acid, 4-8 parts of ethylene glycol acrylic ester hydrophobic monomer and 25-35 parts of deionized water, and the dropwise adding time is 180 minutes; the material liquid B is 0.4-0.6 part of reducing agent, 55-65 parts of deionized water, 0.8-2 parts of chain transfer agent, dropwise adding for 195 minutes, keeping the temperature for 90 minutes after the reaction is finished, adding liquid caustic soda to neutralize to be neutral, adding 1-2 parts of dimethylallyl p-benzoyl benzyl ammonium bromide, stirring for 30 minutes, and adding dilution water to dilute the solid content to 35-45%, thereby obtaining the polycarboxylate water reducer suitable for the plateau area. Wherein the oxidant comprises at least one of hydrogen peroxide and ferrous sulfate. The reducing agent comprises ascorbic acid. The chain transfer agent includes at least one of mercaptopropionic acid and sodium hypophosphite.
The present invention employs an oxidant/reductant system to initiate polymerization. The single electron transfer between the oxidant and the reducing agent causes the oxidation-reduction reaction to generate free radicals, so that the decomposition activation energy of the oxidant can be reduced, the polymerization of the monomer can be initiated under the condition of lower temperature, and the decomposition rate of the oxidant can be increased, thereby increasing the polymerization rate. Therefore, redox polymerization has two advantages of low polymerization temperature and fast polymerization rate.
Specific embodiments of the present invention are described in detail below.
Example 1
The preparation method of the polycarboxylate superplasticizer suitable for the plateau area comprises the following process steps:
320 parts of isopentenol polyoxyethylene ether, 30 parts of etherified high amylose starch, 5 parts of acrylic acid, 1.2 parts of styrene and 465 parts of deionized water are added into a reaction kettle, the temperature is raised to 60 ℃, stirring is started in the heating process to fully dissolve components in the kettle, then 2 parts of hydrogen peroxide and 0.5 part of 1% concentration ferrous sulfate aqueous solution are added, dropwise adding of A, B feed liquid is started, the feed liquid A is 30 parts of acrylic acid, 4 parts of ethylene glycol acrylic ester hydrophobic monomers and 30 parts of deionized water, and the dropwise adding time is 180 minutes; the B feed liquid is 0.4 part of ascorbic acid, 60 parts of deionized water, 0.8 part of mercaptopropionic acid, 0.8 part of sodium hypophosphite, dropwise adding time of 195 minutes, keeping the temperature for 90 minutes after the reaction is finished, adding liquid alkali to neutralize to be neutral, adding 1.5 parts of dimethylallyl p-benzoyl benzyl ammonium bromide, stirring for 30 minutes, and adding dilution water to dilute the solid content of 40% to obtain the polycarboxylate water reducer mother liquid suitable for the plateau region.
Example 2
The preparation method of the polycarboxylate superplasticizer suitable for the plateau area comprises the following process steps:
280 parts of isopentenyl alcohol polyoxyethylene ether, 70 parts of etherified high amylose starch, 5 parts of acrylic acid, 1.2 parts of styrene and 465 parts of deionized water are added into a reaction kettle, the temperature is raised to 80 ℃, stirring is started in the heating process to fully dissolve components in the kettle, then 2.5 parts of hydrogen peroxide and 0.5 part of 1% concentration ferrous sulfate aqueous solution are added, dropwise adding of A, B feed liquid is started, the feed liquid A is 30 parts of acrylic acid, 4 parts of ethylene glycol acrylic ester hydrophobic monomers and 30 parts of deionized water, and the dropwise adding time is 180 minutes; the B feed liquid is 0.4 part of ascorbic acid, 60 parts of deionized water, 0.8 part of mercaptopropionic acid, 0.8 part of sodium hypophosphite, dropwise adding time of 195 minutes, keeping the temperature for 90 minutes after the reaction is finished, adding liquid alkali to neutralize to be neutral, adding 1.5 parts of dimethylallyl p-benzoyl benzyl ammonium bromide, stirring for 30 minutes, and adding dilution water to dilute the solid content of 40% to obtain the polycarboxylate water reducer mother liquid suitable for the plateau region.
Example 3
The preparation method of the polycarboxylate superplasticizer suitable for the plateau area comprises the following process steps:
320 parts of isopentenyl alcohol polyoxyethylene ether, 30 parts of etherified high amylose starch, 5 parts of acrylic acid, 1.5 parts of styrene and 465 parts of deionized water are added into a reaction kettle, the temperature is raised to 80 ℃, stirring is started in the heating process to fully dissolve components in the kettle, then 2.2 parts of hydrogen peroxide and 0.5 part of 1% concentration ferrous sulfate aqueous solution are added, dropwise adding of A, B feed liquid is started, the feed liquid A is 30 parts of acrylic acid, 6 parts of ethylene glycol acrylic ester hydrophobic monomers and 30 parts of deionized water, and the dropwise adding time is 180 minutes; the B feed liquid is 0.4 part of ascorbic acid, 60 parts of deionized water, 0.9 part of mercaptopropionic acid, 0.9 part of sodium hypophosphite, dropwise adding time of 195 minutes, keeping the temperature for 90 minutes after the reaction is finished, adding liquid alkali to neutralize to be neutral, adding 1.5 parts of dimethylallyl p-benzoyl benzyl ammonium bromide, stirring for 30 minutes, and adding dilution water to dilute the solid content of 40% to obtain the polycarboxylate water reducer mother liquid suitable for the plateau region.
Example 4
The preparation method of the polycarboxylate superplasticizer suitable for the plateau area comprises the following process steps:
320 parts of isopentenyl alcohol polyoxyethylene ether, 30 parts of etherified high amylose starch, 5 parts of acrylic acid, 1.5 parts of styrene and 465 parts of deionized water are added into a reaction kettle, the temperature is raised to 80 ℃, stirring is started in the heating process to fully dissolve components in the kettle, then 2.2 parts of hydrogen peroxide and 0.5 part of 1% concentration ferrous sulfate aqueous solution are added, dropwise adding of A, B feed liquid is started, the feed liquid A is 30 parts of acrylic acid, 8 parts of ethylene glycol acrylic ester hydrophobic monomers and 30 parts of deionized water, and the dropwise adding time is 180 minutes; the B feed liquid is 0.4 part of ascorbic acid, 60 parts of deionized water, 0.9 part of mercaptopropionic acid, 0.9 part of sodium hypophosphite, dropwise adding time of 195 minutes, keeping the temperature for 90 minutes after the reaction is finished, adding liquid alkali to neutralize to be neutral, adding 2 parts of dimethylallyl p-benzoyl benzyl ammonium bromide, stirring for 30 minutes, and adding dilution water to dilute the solid content to 40% to obtain the polycarboxylate superplasticizer mother liquid suitable for the plateau area.
Comparative example 1
The water reducer is prepared by adopting the preparation method of the low-cost polycarboxylate water reducer disclosed in publication No. CN 108456287A.
Comparative example 2
The comparative example uses a shrinkage reducing agent prepared by a preparation method of a shrinkage reducing agent having water reducing property of publication No. CN 106084147A.
The following are performance tests of the present invention:
the cement is Emeing P.O.42.5 cement; sand is manually machined, and the fineness modulus of the sand is 2.9; the stones are 5-10mm and 10-20mm gravels, and concrete performance test is carried out according to the standard of the common concrete mechanical performance test method (GB/T50080-2002). The test is carried out by adopting the C30 mixing ratio, the additive is only the water-reducing mother solution of the example and the comparative example, and the slump-retaining mother solution GK-BT (no water reduction in the initial stage) is compounded, and the proportion is 7:3, the effective solid content is 0.28% of the cementing material mass, and other components are not compounded, and the mixing ratio is shown in table 1.
TABLE 1 concrete mix ratio
Basic performance test of concrete
The experimental results of various indexes of concrete slump, expansion, air content and compressive strength are shown in Table 2:
table 2 concrete test results
From table 2, it can be observed that the slump and the expansion degree of examples 1 to 4 are slightly higher than those of the comparative examples at the same blending amount, the cement particles have higher water reducing rate, better dispersing effect is achieved, the air content is obviously higher than that of the comparative examples, and the strength difference between the examples and the comparative example 28d is not great, so that the air bubbles can be effectively introduced in the examples but the strength of the concrete is not greatly reduced, because the air bubbles introduced in the invention are uniform micro-air bubbles, the state of the fresh concrete can be effectively improved without affecting the strength of the hardened concrete. Compared with the raw materials such as equal sand, stone, cement and the like, the concrete tests in the areas with different altitudes and atmospheric pressure find that the embodiment has better air entraining and bubble stabilizing capabilities.
Concrete shrinkage test
The influence of the embodiment of the polycarboxylate water reducer on the shrinkage performance of the concrete is examined by referring to a non-contact method in a shrinkage test of GB/T50082-2009 Experimental method for the long-term performance and the durability of common concrete. The test results are shown in Table 3:
TABLE 3 results of shrinkage test of concrete at different ages
From the data in Table 3, it can be seen that the present invention can effectively reduce the drying shrinkage of concrete, and as the ethylene glycol acrylic ester type hydrophobic monomer increases in the polymerization component, the tendency of the shrinkage reducing ability is shown as increasing first and then decreasing, and the amount of the ethylene glycol acrylic ester type hydrophobic monomer is optimized in the formulation in example 3.
Freeze thawing cycle test
Tests were performed using 10X 40 (cm) specimens, according to the standard, using the examples of this patent, and the test results are shown in Table 4:
TABLE 4 weight change after freeze-thaw cycle
As can be seen from Table 4, the invention reduces the shrinkage of the test body after freeze thawing and increases the freeze thawing resistance of the test body.
Carbonization depth test
In order to evaluate the ultraviolet resistance of the invention, the carbonization depth of the test block is tested by adopting the maintenance of the test block under different ultraviolet condition environments, and the two ultraviolet environments are as follows:
environment 1: curing 21 d under standard curing conditions, curing 7 d under the conditions of temperature (20+/-3) DEG C and relative humidity (70+/-5)%, and finally curing 7 d under the conditions of temperature (20+/-3) DEG C, relative humidity (70+/-5)%, and CO2 concentration (20+/-3)% (no ultraviolet radiation in the whole curing stage);
environment 2: 21D under standard curing conditions, 7D under ultraviolet irradiation conditions at a temperature of 20+ -3 deg.C and a relative humidity of 70+ -5%, and 7D under a temperature of 20+ -3 deg.C and a relative humidity of 70+ -5% and a CO2 concentration of 20+ -3% (ultraviolet lamp: ZW80D19W 80W);
the carbonization depth test method is as follows:
the concrete carbonization depth is detected by cutting edges under a dry condition and cleaning the edges by alcohol, wherein the color change reaction is characterized by adopting 1% phenolphthalein alcohol solution, the non-color change (the area is neutral) is measured as a carbonized part, and the test data is accurate to 0.5 mm.
TABLE 5 influence of different environments on the depth of carbonization of concrete
As shown in Table 5, the product of the invention can resist the negative influence of ultraviolet radiation on the carbonization depth of concrete to a certain extent, and has a certain improvement effect on carbonization resistance along with the increase of the ultraviolet absorber component.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Claims (8)
1. The polycarboxylate water reducer suitable for the plateau area is characterized in that: the preparation raw materials of the polycarboxylate superplasticizer suitable for the plateau area comprise the following components in parts by weight: 250-320 parts of isopentenyl alcohol polyoxyethylene ether, 25-40 parts of unsaturated carboxylic acid, 30-70 parts of etherified high amylose starch, 1-2 parts of styrene, 4-8 parts of ethylene glycol acrylic ester hydrophobic monomer and 1-2 parts of ultraviolet absorbent; the etherified high amylose starch has a degree of polymerization of 1000-5000 and a degree of substitution of 0.5-0.8.
2. The polycarboxylate superplasticizer applicable to a plateau region according to claim 1, wherein: the isopentenol polyoxyethylene ether comprises at least one of TPEG-1200, TPEG-2400 and TPEG-4000.
3. The polycarboxylate superplasticizer applicable to a plateau region according to claim 1, wherein: the ethylene glycol acrylic ester hydrophobic monomer comprises at least one of polyethylene glycol dimethacrylate, polyethylene glycol acrylic ester, diethylene glycol monoacrylate and ethylene glycol dimethacrylate.
4. A polycarboxylate superplasticizer suitable for use in plateau areas according to any one of claims 1-3, wherein: the ultraviolet absorber comprises dimethylallyl p-benzoyl benzyl ammonium bromide.
5. A method for preparing a polycarboxylate water reducer suitable for use in plateau areas according to any one of claims 1 to 4, characterized in that it comprises the following steps:
adding isopentenol polyoxyethylene ether, etherified high amylose starch, unsaturated carboxylic acid, styrene and deionized water into a reaction kettle, mixing, heating to 50-70 ℃, stirring for dissolution, adding an oxidant, then dropwise adding a mixed aqueous solution of unsaturated carboxylic acid and glycol acrylic ester hydrophobic monomers and a mixed aqueous solution of a reducing agent and a chain transfer agent, preserving heat, adding alkali for neutralization to neutrality, adding dimethyl allyl p-benzoyl benzyl ammonium bromide, stirring uniformly, and adding water for dilution to obtain the polycarboxylic acid water reducer suitable for the plateau region.
6. The method for preparing the polycarboxylate superplasticizer applicable to the plateau region as recited in claim 5, wherein: the oxidant comprises at least one of hydrogen peroxide and ferrous sulfate.
7. The method for preparing the polycarboxylate superplasticizer applicable to the plateau region as recited in claim 5, wherein: the reducing agent comprises ascorbic acid.
8. The method for preparing the polycarboxylate superplasticizer applicable to the plateau region according to any one of claims 5 to 7, wherein: the chain transfer agent includes at least one of mercaptopropionic acid and sodium hypophosphite.
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| CN103497285A (en) * | 2013-10-23 | 2014-01-08 | 中国矿业大学(北京) | Method for preparing efficient polycarboxylate graft copolymer super plasticizer through microwave-assisting method |
| CN111592269A (en) * | 2019-02-21 | 2020-08-28 | 天水师范学院 | Method and device for synthesizing polycarboxylate superplasticizer through multi-copolymerization |
| CN112126022A (en) * | 2020-09-11 | 2020-12-25 | 浙江玖龙新材料有限公司 | Formula and preparation method of polycarboxylate superplasticizer |
| CN115745468A (en) * | 2023-01-06 | 2023-03-07 | 石家庄市长安育才建材有限公司 | Starch-based slump retaining water reducer and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103497285A (en) * | 2013-10-23 | 2014-01-08 | 中国矿业大学(北京) | Method for preparing efficient polycarboxylate graft copolymer super plasticizer through microwave-assisting method |
| CN111592269A (en) * | 2019-02-21 | 2020-08-28 | 天水师范学院 | Method and device for synthesizing polycarboxylate superplasticizer through multi-copolymerization |
| CN112126022A (en) * | 2020-09-11 | 2020-12-25 | 浙江玖龙新材料有限公司 | Formula and preparation method of polycarboxylate superplasticizer |
| CN115745468A (en) * | 2023-01-06 | 2023-03-07 | 石家庄市长安育才建材有限公司 | Starch-based slump retaining water reducer and preparation method thereof |
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