CN111377637A - Retarder and application thereof in preparation of modified cassava starch-polycarboxylic acid composite water reducing agent - Google Patents
Retarder and application thereof in preparation of modified cassava starch-polycarboxylic acid composite water reducing agent Download PDFInfo
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- CN111377637A CN111377637A CN201811648255.3A CN201811648255A CN111377637A CN 111377637 A CN111377637 A CN 111377637A CN 201811648255 A CN201811648255 A CN 201811648255A CN 111377637 A CN111377637 A CN 111377637A
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- starch
- retarder
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- reducing agent
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 105
- 239000003638 chemical reducing agent Substances 0.000 title claims abstract description 90
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 title claims abstract description 55
- 239000002131 composite material Substances 0.000 title claims abstract description 48
- 239000002253 acid Substances 0.000 title claims abstract description 46
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 241000658379 Manihot esculenta subsp. esculenta Species 0.000 title 1
- 229920002472 Starch Polymers 0.000 claims abstract description 71
- 239000008107 starch Substances 0.000 claims abstract description 71
- 235000019698 starch Nutrition 0.000 claims abstract description 71
- 240000003183 Manihot esculenta Species 0.000 claims abstract description 54
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims abstract description 24
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 14
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 14
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract description 14
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 14
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 13
- AEQDJSLRWYMAQI-UHFFFAOYSA-N 2,3,9,10-tetramethoxy-6,8,13,13a-tetrahydro-5H-isoquinolino[2,1-b]isoquinoline Chemical compound C1CN2CC(C(=C(OC)C=C3)OC)=C3CC2C2=C1C=C(OC)C(OC)=C2 AEQDJSLRWYMAQI-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims abstract description 12
- 235000019341 magnesium sulphate Nutrition 0.000 claims abstract description 12
- 239000001509 sodium citrate Substances 0.000 claims abstract description 12
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims abstract description 12
- FQENQNTWSFEDLI-UHFFFAOYSA-J sodium diphosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 claims abstract description 12
- 239000000176 sodium gluconate Substances 0.000 claims abstract description 12
- 235000012207 sodium gluconate Nutrition 0.000 claims abstract description 12
- 229940005574 sodium gluconate Drugs 0.000 claims abstract description 12
- 229940048086 sodium pyrophosphate Drugs 0.000 claims abstract description 12
- 235000019832 sodium triphosphate Nutrition 0.000 claims abstract description 12
- 235000019818 tetrasodium diphosphate Nutrition 0.000 claims abstract description 12
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 claims abstract description 12
- WYXIGTJNYDDFFH-UHFFFAOYSA-Q triazanium;borate Chemical compound [NH4+].[NH4+].[NH4+].[O-]B([O-])[O-] WYXIGTJNYDDFFH-UHFFFAOYSA-Q 0.000 claims abstract description 12
- 238000006266 etherification reaction Methods 0.000 claims abstract description 7
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 90
- 239000003795 chemical substances by application Substances 0.000 claims description 40
- 239000000243 solution Substances 0.000 claims description 36
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 30
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 30
- 238000003756 stirring Methods 0.000 claims description 26
- -1 alcohol fatty acid ester compound Chemical class 0.000 claims description 23
- 239000002518 antifoaming agent Substances 0.000 claims description 23
- 239000002994 raw material Substances 0.000 claims description 22
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 16
- 238000002156 mixing Methods 0.000 claims description 15
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 14
- 239000000178 monomer Substances 0.000 claims description 14
- 229920002545 silicone oil Polymers 0.000 claims description 14
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims description 14
- 235000019441 ethanol Nutrition 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 12
- 238000007334 copolymerization reaction Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 12
- 239000000725 suspension Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 9
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 7
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 7
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 7
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 7
- 239000000194 fatty acid Substances 0.000 claims description 7
- 229930195729 fatty acid Natural products 0.000 claims description 7
- RBNPOMFGQQGHHO-UHFFFAOYSA-N glyceric acid Chemical compound OCC(O)C(O)=O RBNPOMFGQQGHHO-UHFFFAOYSA-N 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 7
- 239000001257 hydrogen Substances 0.000 claims description 7
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 7
- HMMGMWAXVFQUOA-UHFFFAOYSA-N octamethylcyclotetrasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 HMMGMWAXVFQUOA-UHFFFAOYSA-N 0.000 claims description 7
- WXZMFSXDPGVJKK-UHFFFAOYSA-N pentaerythritol Chemical compound OCC(CO)(CO)CO WXZMFSXDPGVJKK-UHFFFAOYSA-N 0.000 claims description 7
- 239000003208 petroleum Substances 0.000 claims description 7
- 229920000570 polyether Polymers 0.000 claims description 7
- 229920002503 polyoxyethylene-polyoxypropylene Polymers 0.000 claims description 7
- 229920001451 polypropylene glycol Polymers 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims description 7
- 239000003784 tall oil Substances 0.000 claims description 7
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 7
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 6
- 238000004537 pulping Methods 0.000 claims description 6
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 6
- LTVDFSLWFKLJDQ-UHFFFAOYSA-N α-tocopherolquinone Chemical group CC(C)CCCC(C)CCCC(C)CCCC(C)(O)CCC1=C(C)C(=O)C(C)=C(C)C1=O LTVDFSLWFKLJDQ-UHFFFAOYSA-N 0.000 claims description 6
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 5
- 239000004567 concrete Substances 0.000 abstract description 42
- 239000004566 building material Substances 0.000 abstract description 6
- 239000002002 slurry Substances 0.000 abstract description 6
- 238000010276 construction Methods 0.000 abstract description 5
- 238000011161 development Methods 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000000034 method Methods 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000009833 condensation Methods 0.000 abstract description 2
- 230000005494 condensation Effects 0.000 abstract description 2
- 230000000694 effects Effects 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000003912 environmental pollution Methods 0.000 abstract description 2
- 238000012545 processing Methods 0.000 abstract description 2
- 230000003647 oxidation Effects 0.000 abstract 1
- 230000020477 pH reduction Effects 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 18
- 239000011259 mixed solution Substances 0.000 description 15
- 239000004568 cement Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 7
- 239000013530 defoamer Substances 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- JHUFGBSGINLPOW-UHFFFAOYSA-N 3-chloro-4-(trifluoromethoxy)benzoyl cyanide Chemical compound FC(F)(F)OC1=CC=C(C(=O)C#N)C=C1Cl JHUFGBSGINLPOW-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 238000010526 radical polymerization reaction Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 235000011083 sodium citrates Nutrition 0.000 description 3
- 229920000881 Modified starch Polymers 0.000 description 2
- 239000004368 Modified starch Substances 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 239000010881 fly ash Substances 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 235000019426 modified starch Nutrition 0.000 description 2
- 230000000979 retarding effect Effects 0.000 description 2
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 2
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 125000005395 methacrylic acid group Chemical group 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- DGVVJWXRCWCCOD-UHFFFAOYSA-N naphthalene;hydrate Chemical compound O.C1=CC=CC2=CC=CC=C21 DGVVJWXRCWCCOD-UHFFFAOYSA-N 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 239000010891 toxic waste Substances 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
Classifications
-
- 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
- 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
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
-
- 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
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/20—Retarders
- C04B2103/22—Set retarders
-
- 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
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
The invention discloses a retarder and application thereof in preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent, and belongs to the field of building materials. The retarder comprises the following components in parts by weight: 43-60 parts of sodium gluconate, 30-37 parts of sodium citrate, 22-29 parts of sodium tripolyphosphate, 13-19 parts of sodium pyrophosphate, 3-8 parts of ammonium borate, 2-4 parts of ferrous sulfate and 1-3 parts of magnesium sulfate. The cassava starch is prepared into the starch-containing composite water reducing agent through the reaction procedures of oxidation, acidification, etherification, grafting, neutralization and the like. The composite water reducing agent containing the retarder prepared by the invention can adjust the condensation time of concrete, improve the performance of the concrete, and also has the effects of specifically improving the net slurry fluidity of the concrete, reducing the construction energy consumption and the like. The development and application of the cassava starch water reducer are beneficial to improving the processing technology of the water reducer, improving the product quality of the water reducer and reducing the environmental pollution.
Description
Technical Field
The invention relates to the field of building materials, and particularly relates to a retarder and application thereof in preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent.
Background
The retarder is an additive which can delay and reduce the heat release speed of cement hydration, thereby prolonging the time of concrete full condensation, keeping the plasticity of fresh concrete for a long time, being convenient for pouring and improving the construction efficiency. The retarder can improve the construction performance of concrete. In the production of premixed concrete, a certain amount of retarder is often required to be doped, so that the plasticity of the freshly mixed concrete is kept for a long time, and the transportation and the pouring forming of the concrete are facilitated. The conventional super retarder on the market has various types and different influences on cement concrete, but most of the super retarders have the problem of reducing the later strength of the concrete, so that the construction cost is greatly increased. Therefore, it is necessary to develop a retarder which can improve the performance of concrete, save cement, reduce energy consumption and pollutant emission, and meet the market demand.
The water reducing agent is an essential important component of premixed concrete, and the dosage of the water reducing agent is gradually increased along with the acceleration of urban progress. The yield of Guangxi cement in 2014 is about 4 hundred million tons, and 80 ten thousand tons of water reducing agent is needed according to 0.2 percent of dosage. The development of the water reducing agent provides a larger space for the development of the concrete industry, but with the increasing attention of human beings on environmental protection, the requirements of people on building materials are higher and higher, and when the use performance is realized, people are concerned about whether the building materials can cause harm to the environment or not and whether the building materials threaten the personal safety or not, and the 'green' building materials are in great trend. The water reducing agents currently used in China mainly include naphthalene water reducing agents, polycarboxylic acid water reducing agents, aliphatic water reducing agents, sulfamic acid water reducing agents, lignin water reducing agents and the like, and the polycarboxylic acid water reducing agents are mainly used in Guangxi province. In the water reducing agent, more than 90% of the water reducing agent is prepared from chemical raw materials. Through analysis of the molecular structures, synthetic routes and other aspects of the water reducing agents, the water reducing agents are found to be toxic, or a large amount of toxic waste liquid is discharged in the production process, so that the water reducing agents are not biodegradable, and cannot meet the requirements of green, environmental protection and the like. Therefore, the development of environment-friendly water reducing agents is an urgent need of the market.
Starch is a natural high polymer of polysaccharides with a natural yield inferior to cellulose, and is found widely in seeds, tubers, fruits, roots and even leaves of higher plants as minute particles insoluble in cold water (1 pm to 100pm or more in diameter). The annual yield worldwide is about 3600 ten thousand tons at present. The starch has wide sources, various types and rich yield, so the price is relatively low. As can be seen from relevant data, in recent years, the research on the preparation of the cement dispersant by starch modification has been advanced to a certain extent, but the research on the preparation of the water reducing agent by starch modification is just started, so the research of the invention is very timely and has positive effects.
The cassava starch which is produced in Guangxi province is developed and utilized as a raw material, and the compound environment-friendly water reducing agent is prepared by modification, so that the method has important significance for fully playing the resource advantages of the Guangxi province, reducing the dependence on chemical raw materials, saving energy, reducing consumption and the like. The development and application of the modified starch are beneficial to improving the processing technology of the water reducing agent, improving the product quality of the water reducing agent and reducing the environmental pollution, and can also effectively solve the problem of coming out of Guangxi agricultural products and improve the added value of the products.
The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.
Disclosure of Invention
The invention aims to provide a retarder and a technical scheme of the retarder in preparation of a modified cassava starch-polycarboxylic acid composite water reducing agent, and aims to solve the problems that the existing retarder can reduce the later strength of concrete, increase the construction cost and energy consumption and the like. Can also solve the problems that the existing water reducing agent has toxicity, can not be biologically degraded and has large pollutant discharge amount in the production process.
Therefore, the invention provides a retarder which comprises the following components in parts by weight: 43-60 parts of sodium gluconate, 30-37 parts of sodium citrate, 22-29 parts of sodium tripolyphosphate, 13-19 parts of sodium pyrophosphate, 3-8 parts of ammonium borate, 2-4 parts of ferrous sulfate and 1-5 parts of magnesium sulfate.
Preferably, the retarder comprises the following components in parts by weight: 48 parts of sodium gluconate, 32 parts of sodium citrate, 25 parts of sodium tripolyphosphate, 16 parts of sodium pyrophosphate, 5.5 parts of ammonium borate, 3 parts of ferrous sulfate and 2.5 parts of magnesium sulfate.
The invention also provides a retarder and an application thereof in preparing the modified cassava starch-polycarboxylic acid composite water reducing agent, wherein the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 20-35 parts of modified cassava starch, 30-120 parts of sodium hydroxide, 2-6 parts of retarder, 0.5-4 parts of defoaming agent and 1-5.5 parts of air entraining agent.
Preferably, the modified tapioca starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 25 parts of modified cassava starch, 80 parts of sodium hydroxide, 3.5 parts of retarder, 2.5 parts of defoaming agent and 3 parts of air entraining agent.
Preferably, the defoaming agent comprises the following raw materials in parts by weight: 30-65 parts of hydrogen silicone oil, 20-40 parts of a higher alcohol fatty acid ester compound, 10-17 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 10-15 parts of octamethylcyclotetrasiloxane, 5-9 parts of polyether silicone oil and 3-6 parts of polyoxypropylene polyoxyethylene glycerol ether.
Preferably, the air entraining agent comprises the following raw materials in parts by weight: 48-60 parts of rosin powder, 38-55 parts of p-toluenesulfonic acid, 25-37 parts of sodium hydroxide, 18-22 parts of pentaerythritol, 7-14 parts of tall oil and 5-9 parts of petroleum sulfonate.
Preferably, the preparation process of the modified tapioca starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding the cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotation speed of 500-950r/min, heating to 20-40 ℃, keeping the temperature for 30-80min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent accounting for 8-20% of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 11-17h at the temperature of 35-47 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 50-110 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 3-21% of the total mass of the starch, stirring for 5-40min by ultrasonic waves, dropwise adding a monomer while stirring by ultrasonic waves, wherein the dropwise adding amount of the monomer is 10-30% of the mass of the starch, and continuously reacting for 0.5-4h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding a sodium hydroxide solution to adjust the pH value to 7-8.5, and adding water to dilute until the total mass concentration is 25%, thus obtaining the starch graft polycarboxylic acid water reducing agent.
Preferably, in the step S1, the rotation speed of the stirrer is 700r/min, the temperature is heated to 28 ℃, and the temperature is kept for 60 min.
Preferably, in the step S4, the temperature of the starch solution is controlled at 80 ℃, hydrogen peroxide accounting for 15% of the total mass of the starch is added, the mixture is stirred for 25min by ultrasonic waves, and the dropping amount of the monomer is 25% of the mass of the starch.
Preferably, the monomers are methacrylic acid, acrylonitrile and sodium propylene sulfonate according to a molar ratio of 2: 3: 1, mixing the mixture.
Compared with the prior art, the invention has the advantages that:
(1) the retarder provided by the invention can be used for conveniently adjusting the setting time of concrete, improving the performance of the concrete, and simultaneously has the effects of saving cement, reducing energy consumption, reducing pollutant emission and the like.
(2) Compared with the existing water reducing agent, the water reducing agent provided by the invention has the advantages of no toxicity, no harm, environmental protection in the production process, degradability and the like.
(3) The modified starch water reducing agent has higher dispersibility, can effectively inhibit cement hydration reaction, has strong retarding effect on cement paste, keeps the fluidity of the cement paste, and increases the retarding time along with the increase of the mixing amount of the water reducing agent.
(4) As can be seen from Table 1, under the conditions of the same concrete and the same mixing amount, the clean slurry performance of the cassava starch-polycarboxylic acid water reducing agent according to the embodiment of the invention is compared with that of a comparative example, so that the performance of the embodiment is more excellent, and the composite water reducing agent can effectively prolong the concrete setting time, ensure that the fresh concrete keeps plasticity for a longer time, improve the later strength of the concrete, and have higher water reducing rate, so that the concrete has better fluidity. The composite water reducing agent prepared by the embodiment of the invention has smaller change range of fluidity parameters, which shows that the composite water reducing agent has better adaptability to base materials. In addition, as can be seen from the data of example 2 and comparative examples 1 to 4, the retarder, the defoamer and the air entraining agent play a synergistic role in preparing the modified tapioca starch-polycarboxylic acid water reducing agent, and the water reducing rate and the net slurry fluidity are synergistically improved.
(5) As can be seen from Table 2, under the condition that the mixing amount of the modified tapioca starch-polycarboxylic acid composite water reducing agent is 0.5%, the compressive strength of the concrete is better than that of the comparative example, and the concrete product added with the complete composite water reducing agent has no air holes and air holes on the surface and has a compact structure, which shows that the composite water reducing agent containing the retarder can obviously improve the compressive strength of the concrete. It is also clear from the data of example 2 and comparative examples 1-4 that the set retarder, defoamer and air entraining agent synergistically increased the compressive strength of the concrete samples.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.
The retarder comprises the following components in parts by weight: 43-60 parts of sodium gluconate, 30-37 parts of sodium citrate, 22-29 parts of sodium tripolyphosphate, 13-19 parts of sodium pyrophosphate, 3-8 parts of ammonium borate, 2-4 parts of ferrous sulfate and 1-5 parts of magnesium sulfate.
A modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 20-35 parts of modified cassava starch, 30-120 parts of sodium hydroxide, 2-6 parts of retarder, 0.5-4 parts of defoaming agent and 1-5.5 parts of air entraining agent.
The defoaming agent comprises the following raw materials in parts by weight: 30-65 parts of hydrogen silicone oil, 20-40 parts of a higher alcohol fatty acid ester compound, 10-17 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 10-15 parts of octamethylcyclotetrasiloxane, 5-9 parts of polyether silicone oil and 3-6 parts of polyoxypropylene polyoxyethylene glycerol ether.
The air entraining agent comprises the following raw materials in parts by weight: 48-60 parts of rosin powder, 38-55 parts of p-toluenesulfonic acid, 25-37 parts of sodium hydroxide, 18-22 parts of pentaerythritol, 7-14 parts of tall oil and 5-9 parts of petroleum sulfonate.
The preparation process of the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding the cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotation speed of 500-950r/min, heating to 20-40 ℃, keeping the temperature for 30-80min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent accounting for 8-20% of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 11-17h at the temperature of 35-47 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 50-110 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 3-21% of the total mass of the starch, stirring for 5-40min by ultrasonic waves, dropwise adding a monomer while stirring by ultrasonic waves, wherein the dropwise adding amount of the monomer is 10-30% of the mass of the starch, and continuously reacting for 0.5-4h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding a sodium hydroxide solution to adjust the pH value to 7-8.5, and adding water to dilute until the total mass concentration is 25%, thus obtaining the starch graft polycarboxylic acid water reducing agent.
The monomer is methacrylic acid, acrylonitrile and sodium propylene sulfonate according to a molar ratio of 2: 3: 1, mixing the mixture.
The present invention is illustrated by the following more specific examples.
Example 1:
the retarder comprises the following components in parts by weight: 60 parts of sodium gluconate, 30 parts of sodium citrate, 29 parts of sodium tripolyphosphate, 19 parts of sodium pyrophosphate, 3 parts of ammonium borate, 2 parts of ferrous sulfate and 5 parts of magnesium sulfate.
The preparation method of the retarder comprises the following steps:
s1: uniformly mixing sodium gluconate, sodium citrate, sodium tripolyphosphate, sodium pyrophosphate, ammonium borate and water, and adjusting the pH value of the solution to 5.5 to obtain a mixed solution A;
s2: adding the mixed solution A into a reaction container, adding magnesium sulfate, introducing nitrogen, and adding ferrous sulfate at 60 ℃ for free radical polymerization; observing the reaction temperature, starting timing when the temperature is the highest, and obtaining the retarder after 2 hours.
A modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 20 parts of modified cassava starch, 30 parts of sodium hydroxide, 4 parts of retarder, 2.5 parts of defoaming agent and 5.5 parts of air entraining agent.
The defoaming agent comprises the following components in parts by weight: 30 parts of hydrogen silicone oil, 40 parts of higher alcohol fatty acid ester compound, 17 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 10 parts of octamethylcyclotetrasiloxane, 5 parts of polyether silicone oil and 3 parts of polyoxypropylene polyoxyethylene glycerol ether.
The air entraining agent comprises the following components in parts by weight: 48 parts of rosin powder, 55 parts of p-toluenesulfonic acid, 37 parts of sodium hydroxide, 18 parts of pentaerythritol, 7 parts of tall oil and 9 parts of petroleum sulfonate.
The preparation process of the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotating speed of 700r/min, heating to 20 ℃, keeping for 60min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent which is 20 percent of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 11 hours at 42 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 110 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 3% of the total mass of the starch, stirring for 25min by using ultrasonic waves, dropwise adding a monomer (a mixed mixture of methacrylic acid, acrylonitrile and sodium allylsulfonate according to a molar ratio of 2: 3: 1) while stirring for 30% of the mass of the starch, and continuously reacting for 0.5h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding an alkali solution to adjust the pH value to 8.5, and adding water to dilute the product until the total mass concentration is 25%, thus obtaining the starch graft polycarboxylic acid water reducing agent.
Example 2:
the retarder comprises the following components in parts by weight: 48 parts of sodium gluconate, 32 parts of sodium citrate, 25 parts of sodium tripolyphosphate, 16 parts of sodium pyrophosphate, 5.5 parts of ammonium borate, 3 parts of ferrous sulfate and 2.5 parts of magnesium sulfate.
The preparation method of the retarder comprises the following steps:
s1: uniformly mixing sodium gluconate, sodium citrate, sodium tripolyphosphate, sodium pyrophosphate, ammonium borate and water, and adjusting the pH value of the solution to 6.5 to obtain a mixed solution A;
s2: adding the mixed solution A into a reaction container, adding magnesium sulfate, introducing nitrogen, and adding ferrous sulfate at 60 ℃ for free radical polymerization; observing the reaction temperature, starting timing when the temperature is the highest, and obtaining the retarder after 2 hours.
A modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 25 parts of modified cassava starch, 100 parts of sodium hydroxide, 2 parts of retarder, 4 parts of defoaming agent and 3 parts of air entraining agent.
The defoaming agent comprises the following components in parts by weight: 50 parts of hydrogen silicone oil, 28 parts of higher alcohol fatty acid ester compound, 14 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 12 parts of octamethylcyclotetrasiloxane, 6.5 parts of polyether silicone oil and 4.5 parts of polyoxypropylene polyoxyethylene glycerol ether.
The air entraining agent comprises the following components in parts by weight: 52 parts of rosin powder, 44 parts of p-toluenesulfonic acid, 32 parts of sodium hydroxide, 20.5 parts of pentaerythritol, 11 parts of tall oil and 7 parts of petroleum sulfonate.
The preparation process of the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotating speed of 500r/min, heating to 30 ℃, keeping the temperature for 80min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent accounting for 8 percent of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 17 hours at 47 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 50 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 21% of the total mass of the starch, stirring for 5min by using ultrasonic waves, dropwise adding a monomer (a mixed mixture of methacrylic acid, acrylonitrile and sodium allylsulfonate according to a molar ratio of 2: 3: 1) while stirring for 10% of the mass of the starch, and continuously reacting for 4h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding an alkali solution to adjust the pH value to 7, and adding water to dilute the product until the total mass concentration is 25%, so as to obtain the starch graft polycarboxylic acid water reducing agent.
Example 3:
the retarder comprises the following components in parts by weight: 43 parts of sodium gluconate, 37 parts of sodium citrate, 22 parts of sodium tripolyphosphate, 13 parts of sodium pyrophosphate, 8 parts of ammonium borate, 4 parts of ferrous sulfate and 1 part of magnesium sulfate.
The preparation method of the retarder comprises the following steps:
s1: uniformly mixing sodium gluconate, sodium citrate, sodium tripolyphosphate, sodium pyrophosphate, ammonium borate and water, and adjusting the pH value of the solution to 5.5 to obtain a mixed solution A;
s2: adding the mixed solution A into a reaction container, adding magnesium sulfate, introducing nitrogen, and adding ferrous sulfate at 60 ℃ for free radical polymerization; observing the reaction temperature, starting timing when the temperature is the highest, and obtaining the retarder after 2 hours.
A modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 35 parts of modified cassava starch, 120 parts of sodium hydroxide, 6 parts of retarder, 0.5 part of defoaming agent and 1 part of air entraining agent.
The defoaming agent comprises the following components in parts by weight: 65 parts of hydrogen silicone oil, 20 parts of a higher alcohol fatty acid ester compound, 10 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 15 parts of octamethylcyclotetrasiloxane, 9 parts of polyether silicone oil and 6 parts of polyoxypropylene polyoxyethylene glycerol ether.
The air entraining agent comprises the following components in parts by weight: 60 parts of rosin powder, 38 parts of p-toluenesulfonic acid, 25 parts of sodium hydroxide, 22 parts of pentaerythritol, 14 parts of tall oil and 5 parts of petroleum sulfonate.
The preparation process of the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotating speed of 950r/min, heating to 40 ℃, keeping for 30min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent which is 14 percent of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 13 hours at 35 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 75 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 14% of the total mass of the starch, stirring for 40min by using ultrasonic waves, dropwise adding a monomer (a mixed mixture of methacrylic acid, acrylonitrile and sodium allylsulfonate according to a molar ratio of 2: 3: 1) while stirring for 17% of the mass of the starch, and continuously reacting for 3.5h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding an alkali solution to adjust the pH value to 7.4, and adding water to dilute the product until the total mass concentration is 25%, thus obtaining the starch graft polycarboxylic acid water reducing agent.
Comparative example 1:
the preparation process is basically the same as that of example 2, except that the raw materials for preparing the composite water reducing agent lack the retarder.
Comparative example 2:
the preparation process is basically the same as that of the example 2, except that the raw materials for preparing the composite water reducing agent are lack of the defoaming agent.
Comparative example 3:
the preparation process is basically the same as that of the example 2, except that the air entraining agent is absent in the raw materials for preparing the composite water reducing agent.
Comparative example 4:
the preparation process is basically the same as that of example 2, except that the raw materials for preparing the composite water reducing agent lack the retarder, the defoamer and the air entraining agent.
A method of preparing an antifoaming agent for use in a sample set comprising the steps of:
s1: mixing hydrogen silicone oil and polyether silicone oil in a first reaction kettle, stirring for 10min to be fully mixed, adding sulfuric acid with the mass concentration of 2% and the total mass of the mixed solution of 3%, and reacting for 4-9h at the pressure of 12Mpa and the temperature of 60 ℃ to obtain a mixed solution A;
s2: adding the mixed solution A into a second reaction kettle, heating to 85 ℃, adding polyoxyethylene polyoxypropylene pentaerythritol ether, adding octamethylcyclotetrasiloxane when the temperature rises to 130 ℃, stopping heating when the temperature rises to 155 ℃, reacting for 2-6 hours, and taking out a material B;
s3: putting the material B into a starch colloid mill with the total mass of 60% of the material B, grinding for 1.5h, and stirring for 40min to obtain a material C;
s4: and adding the high-carbon alcohol fatty acid ester compound and the polyoxypropylene polyoxyethylene glycerol ether into the material C, stirring for 20min, sealing for 1h, and homogenizing in a homogenizer for 50min to obtain the defoaming agent.
A method for preparing an air entraining agent for use in a sample set comprising the steps of:
s1: putting rosin powder, p-toluenesulfonic acid and sodium hydroxide into a reaction kettle to obtain a mixture A, adding water accounting for 50% of the total mass of the mixture A, mixing and stirring for 30min, heating to 80 ℃, keeping the temperature for 50min, heating to 80 ℃, and keeping the temperature for 45min to obtain a mixed solution A;
s2: and heating the mixed solution A to 85 ℃, slowly adding pentaerythritol and tall oil, preserving the heat for 35min, heating to 70 ℃, slowly adding petroleum sulfonate, and preserving the heat for 1h to obtain the air entraining agent.
The concrete used in the sample group comprises the following raw materials in parts by weight: 30-65 parts of general portland cement, 60-130 parts of sand, 105-227.5 parts of pebbles, 12-40 parts of fly ash, 5-9 parts of sodium carboxymethylcellulose, 0.5-1 part of modified tapioca starch-polycarboxylic acid water reducing agent and 0.1-1 part of ferrous sulfate.
The preparation method of the concrete comprises the following steps:
s1: adding general portland cement, fly ash, 75 parts of water, sodium carboxymethylcellulose, sand and pebbles into a stirrer and stirring for 15min to obtain a mixed solution A;
s2: adding the modified cassava starch-polycarboxylic acid water reducing agent into the mixed solution A, stirring for 5min, and standing for 15min to obtain a mixed solution B;
s3: adding ferrous sulfate into the mixed solution B, stirring for 4min by a stirrer, and placing into a corresponding template.
According to GB/T8077-2008 'concrete admixture homogeneity test method', the net slurry fluidity of the examples 1-3 and the comparative examples 1-4 is tested under the mixing amount of different modified tapioca starch-polycarboxylic acid composite water reducing agents in concrete, and the specific results are shown in Table 1.
TABLE 1 Water reducing agent neat paste fluidity test results
As can be seen from Table 1, under the conditions of the same concrete and the same mixing amount, the clean slurry performance of the cassava starch-polycarboxylic acid water reducing agent according to the embodiment of the invention is compared with that of a comparative example, so that the performance of the embodiment is more excellent, and the composite water reducing agent can effectively prolong the concrete setting time, ensure that the fresh concrete keeps plasticity for a longer time, improve the later strength of the concrete, and have higher water reducing rate, so that the concrete has better fluidity. The composite water reducing agent prepared by the embodiment of the invention has smaller change range of fluidity parameters, which shows that the composite water reducing agent has better adaptability to base materials. In addition, as can be seen from the data of example 2 and comparative examples 1 to 4, the retarder, the defoamer and the air entraining agent play a synergistic role in preparing the modified tapioca starch-polycarboxylic acid water reducing agent, and the water reducing rate and the net slurry fluidity are synergistically improved.
The concrete strength performance of the concrete of examples 1-3 and comparative examples 1-4 was tested when the mixing amount of the modified tapioca starch-polycarboxylic acid composite water reducing agent was 0.5%, and the specific results are shown in table 2.
TABLE 2
| Sample set | 7 day compressive strength (/ MPa) | 28 days compressive Strength (/ MPa) | Macroscopic condition of concrete sample surface |
| Example 1 | 21.5 | 29.9 | Has no air holes and air holes |
| Example 2 | 22.7 | 31.6 | Has no air holes and air holes |
| Example 3 | 22.1 | 30.5 | Has no air holes and air holes |
| Comparative example 1 | 21.3 | 29.8 | Has no air holes and air holes |
| Comparative example 2 | 20.6 | 29.5 | With air holes and sand holes |
| Comparative example 3 | 20.2 | 28.8 | With air holes and sand holes |
| Comparative example 4 | 14.9 | 21.4 | With air holes and sand holes |
As can be seen from Table 2, under the condition that the mixing amount of the modified tapioca starch-polycarboxylic acid composite water reducing agent is 0.5%, the compressive strength of the concrete is better than that of the comparative example, and the concrete product added with the complete composite water reducing agent has no air holes and air holes on the surface and has a compact structure, which shows that the composite water reducing agent containing the retarder can obviously improve the compressive strength of the concrete. It is also clear from the data of example 2 and comparative examples 1-4 that the set retarder, defoamer and air entraining agent synergistically increased the compressive strength of the concrete samples.
The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and such substitutions and modifications are to be considered as within the scope of the invention.
Claims (10)
1. The retarder is characterized by comprising the following components in parts by weight: 43-60 parts of sodium gluconate, 30-37 parts of sodium citrate, 22-29 parts of sodium tripolyphosphate, 13-19 parts of sodium pyrophosphate, 3-8 parts of ammonium borate, 2-4 parts of ferrous sulfate and 1-5 parts of magnesium sulfate.
2. The retarder according to claim 1, comprising the following components in parts by weight: 48 parts of sodium gluconate, 32 parts of sodium citrate, 25 parts of sodium tripolyphosphate, 16 parts of sodium pyrophosphate, 5.5 parts of ammonium borate, 3 parts of ferrous sulfate and 2.5 parts of magnesium sulfate.
3. The retarder according to claim 1 and the application thereof in preparing a modified tapioca starch-polycarboxylic acid composite water reducing agent, characterized in that the modified tapioca starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 20-35 parts of modified cassava starch, 30-120 parts of sodium hydroxide, 2-6 parts of retarder, 0.5-4 parts of defoaming agent and 1-5.5 parts of air entraining agent.
4. The retarder according to claim 3 and the application thereof in preparing a modified cassava starch-polycarboxylic acid composite water reducing agent, wherein the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following raw materials in parts by weight: 25 parts of modified cassava starch, 80 parts of sodium hydroxide, 3.5 parts of retarder, 2.5 parts of defoaming agent and 3 parts of air entraining agent.
5. The retarder and the application thereof in preparing the modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 3 or 4, wherein the defoaming agent comprises the following raw materials in parts by weight: 30-65 parts of hydrogen silicone oil, 20-40 parts of a higher alcohol fatty acid ester compound, 10-17 parts of polyoxyethylene polyoxypropylene pentaerythritol ether, 10-15 parts of octamethylcyclotetrasiloxane, 5-9 parts of polyether silicone oil and 3-6 parts of polyoxypropylene polyoxyethylene glycerol ether.
6. The retarder and the application thereof in preparing the modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 3 or 4, wherein the air entraining agent comprises the following raw materials in parts by weight: 48-60 parts of rosin powder, 38-55 parts of p-toluenesulfonic acid, 25-37 parts of sodium hydroxide, 18-22 parts of pentaerythritol, 7-14 parts of tall oil and 5-9 parts of petroleum sulfonate.
7. The retarder and the application thereof in preparing a modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 3 or 4, wherein the preparation process of the modified cassava starch-polycarboxylic acid composite water reducing agent comprises the following steps:
s1: performing oxidation reaction, namely simultaneously adding the cassava starch, sodium hydroxide, ethanol aqueous solution with the volume concentration of 95%, retarder, defoaming agent and air entraining agent into a stirrer, uniformly stirring at the rotation speed of 500-950r/min, heating to 20-40 ℃, keeping the temperature for 30-80min, and naturally cooling to room temperature;
s2: acidifying, namely adding a dilute hydrochloric acid solution with the mass concentration of 20% into the oxidation reaction solution, adjusting the pH to 7, filtering, pulping the solid with absolute ethyl alcohol for 4 times, and drying to obtain oxidized-acidified starch;
s3: performing etherification reaction, namely dissolving oxidized-acidified starch in absolute ethyl alcohol to prepare suspension, adjusting the pH of the suspension to 10 by using a sodium hydroxide solution, introducing nitrogen, adding an etherifying agent accounting for 8-20% of the weight of the starch, wherein the etherifying agent is 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 11-17h at the temperature of 35-47 ℃;
s4: performing a grafting reaction, controlling the temperature of a starch solution at 50-110 ℃ under the protection of nitrogen, adding hydrogen peroxide accounting for 3-21% of the total mass of the starch, stirring for 5-40min by ultrasonic waves, dropwise adding a monomer while stirring by ultrasonic waves, wherein the dropwise adding amount of the monomer is 10-30% of the mass of the starch, and continuously reacting for 0.5-4h after dropwise adding enough amount to obtain a graft copolymerization product;
s5: and (4) performing neutralization reaction, namely cooling the graft copolymerization product obtained in the step S4, adding a sodium hydroxide solution to adjust the pH value to 7-8.5, and adding water to dilute until the total mass concentration is 25%, thus obtaining the starch graft polycarboxylic acid water reducing agent.
8. The retarder and the application thereof in preparing the modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 7, wherein the rotation speed of the stirrer in step S1 is 700r/min, and the stirrer is heated to 28 ℃ for 60 min.
9. The retarder and the application thereof in preparing the modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 7 are characterized in that the temperature of the starch solution in the step S4 is controlled at 80 ℃, hydrogen peroxide accounting for 15% of the total mass of the starch is added, ultrasonic stirring is carried out for 25min, and the dropping amount of the monomers is 25% of the mass of the starch.
10. The retarder and the application thereof in preparing a modified cassava starch-polycarboxylic acid composite water reducing agent according to claim 9, wherein the monomers are methacrylic acid, acrylonitrile and sodium propylene sulfonate according to a molar ratio of 2: 3: 1, mixing the mixture.
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| CN114835430A (en) * | 2022-05-20 | 2022-08-02 | 潍坊砼筑建筑科技有限公司 | Plasticity-maintaining agent for mortar and preparation method thereof |
| CN115093157A (en) * | 2022-06-10 | 2022-09-23 | 山东冠晔新材料科技有限公司 | Concrete retarder and preparation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114835430A (en) * | 2022-05-20 | 2022-08-02 | 潍坊砼筑建筑科技有限公司 | Plasticity-maintaining agent for mortar and preparation method thereof |
| CN115093157A (en) * | 2022-06-10 | 2022-09-23 | 山东冠晔新材料科技有限公司 | Concrete retarder and preparation method thereof |
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