CN116573882A - Concrete accelerating early strength agent and preparation method and application thereof - Google Patents
Concrete accelerating early strength agent and preparation method and application thereof Download PDFInfo
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- CN116573882A CN116573882A CN202310346291.9A CN202310346291A CN116573882A CN 116573882 A CN116573882 A CN 116573882A CN 202310346291 A CN202310346291 A CN 202310346291A CN 116573882 A CN116573882 A CN 116573882A
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- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- 239000000843 powder Substances 0.000 claims abstract description 79
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 71
- 239000011707 mineral Substances 0.000 claims abstract description 71
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 53
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical class O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000006229 carbon black Substances 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000004372 Polyvinyl alcohol Substances 0.000 claims abstract description 21
- 229920002451 polyvinyl alcohol Polymers 0.000 claims abstract description 21
- 239000003607 modifier Substances 0.000 claims abstract description 13
- 238000001035 drying Methods 0.000 claims abstract description 11
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 7
- 238000001914 filtration Methods 0.000 claims abstract description 6
- 238000000227 grinding Methods 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims abstract description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 230000000694 effects Effects 0.000 claims description 16
- 239000000243 solution Substances 0.000 claims description 15
- 238000002156 mixing Methods 0.000 claims description 10
- 229920005646 polycarboxylate Polymers 0.000 claims description 7
- 241000872198 Serjania polyphylla Species 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- -1 polymethylsiloxane Polymers 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- 238000013329 compounding Methods 0.000 claims description 3
- 238000005728 strengthening Methods 0.000 claims description 3
- 239000008030 superplasticizer Substances 0.000 claims description 3
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 3
- 238000005303 weighing Methods 0.000 claims description 3
- 239000000654 additive Substances 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 22
- 230000036571 hydration Effects 0.000 description 16
- 238000006703 hydration reaction Methods 0.000 description 16
- 239000004568 cement Substances 0.000 description 14
- 239000003638 chemical reducing agent Substances 0.000 description 7
- 239000013078 crystal Substances 0.000 description 6
- 238000010276 construction Methods 0.000 description 4
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 239000010881 fly ash Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000004575 stone Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 2
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 2
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- 239000000378 calcium silicate Substances 0.000 description 2
- 229910052918 calcium silicate Inorganic materials 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000002159 nanocrystal Substances 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- QBUKAFSEUHGMMX-MTJSOVHGSA-N (5z)-5-[[3-(1-hydroxyethyl)thiophen-2-yl]methylidene]-10-methoxy-2,2,4-trimethyl-1h-chromeno[3,4-f]quinolin-9-ol Chemical group C1=CC=2NC(C)(C)C=C(C)C=2C2=C1C=1C(OC)=C(O)C=CC=1O\C2=C/C=1SC=CC=1C(C)O QBUKAFSEUHGMMX-MTJSOVHGSA-N 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- SLINHMUFWFWBMU-UHFFFAOYSA-N Triisopropanolamine Chemical compound CC(O)CN(CC(C)O)CC(C)O SLINHMUFWFWBMU-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229940103272 aluminum potassium sulfate Drugs 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- GRLPQNLYRHEGIJ-UHFFFAOYSA-J potassium aluminium sulfate Chemical compound [Al+3].[K+].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRLPQNLYRHEGIJ-UHFFFAOYSA-J 0.000 description 1
- 238000005036 potential barrier Methods 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007306 turnover 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
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/0006—Waste inorganic materials
-
- 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
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/06—Oxides, Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2623—Polyvinylalcohols; Polyvinylacetates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/40—Compounds containing silicon, titanium or zirconium or other organo-metallic compounds; Organo-clays; Organo-inorganic complexes
- C04B24/42—Organo-silicon compounds
- C04B24/425—Organo-modified inorganic compounds, e.g. organo-clays
-
- 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
- C04B2103/10—Accelerators; Activators
- C04B2103/12—Set accelerators
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Environmental & Geological Engineering (AREA)
- Dispersion Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses a concrete accelerating early strength agent, a preparation method and application thereof, and belongs to the technical field of concrete additives. The concrete accelerating early strength agent comprises the following components in parts by weight: 5 to 10 parts of superfine mineral powder A, 0.5 to 5 parts of polyvinyl alcohol, 10 to 20 parts of modified superfine mineral powder B, 5 to 12 parts of modified white carbon black and 40 to 80 parts of water; the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier in water to prepare a modified liquid, adding a calcium hydroxide solution to adjust the pH value to be more than 12, adding superfine mineral powder B, heating to 50-80 ℃, reacting for 1-3 h, filtering, drying and grinding to obtain the modified superfine mineral powder B. The accelerating early strength agent is added with the modified superfine mineral powder B, the polyvinyl alcohol and the modified white carbon black on the basis of the superfine mineral powder A, and the components are mutually cooperated, so that the early strength of the concrete can be obviously improved, the later strength can be obviously enhanced, and the demoulding time of the concrete can be obviously shortened.
Description
Technical Field
The invention belongs to the technical field of concrete additives, and particularly relates to a concrete accelerating early strength agent, a preparation method and application thereof.
Background
In construction buildings of large-volume concrete such as large bridges and high-rise buildings, winter construction and special rush-repair projects, the concrete is required to have high strength and high performance, and meanwhile, the early strength of the concrete is required to develop faster, so that the form removal time is shortened, the turnover rate of a template is improved, the construction of the next procedure is facilitated, the construction period is shortened, and the project progress is improved.
The addition of early strength agents to concrete is the most common means of improving the early strength of concrete. The concrete early strength agent which is commonly used at present mainly comprises: (1) chloride early strength agent: the chloride early strength agent has good early strength effect, wherein the calcium chloride early strength effect is good, the cost is low, and the application is the most widely. (2) sulfate early strength agent: mainly comprises sodium sulfate, sodium thiosulfate, calcium sulfate, aluminum potassium sulfate and the like, wherein sodium sulfate is applied more. (3) organic early strength agent: the organic amine early strength agent mainly comprises triethanolamine, triisopropanolamine, diethanolamine and the like, wherein the early strength effect is better than that of the triethanolamine. The early strength agents of the above classes in engineering can be singly mixed or compounded. However, the above early strength agents have some defects, such as obvious corrosion effect of chloride salt early strength agents on reinforcing steel bars, and sulfate early strength agents also cause 'frosting' of concrete and risk of alkali aggregate reaction hazard, so that alcohol amine early strength agents are extremely sensitive to doping amount, overstock is easy to cause, and the application of the alcohol amine early strength agents is greatly limited.
In recent years, the early strength of concrete is improved by utilizing artificially synthesized calcium silicate hydrate nanocrystal cores, so that the calcium silicate hydrate nanocrystal cores can be used as seed crystals to accelerate the hydration of cement, and further the early strength is improved. As disclosed in chinese patent CN107555829a, a crystal nucleus type accelerating early strength agent for concrete and a preparation method thereof are disclosed, the early strength agent is a C-S-H crystal nucleus, and is made of 1.55 parts of calcium nitrate, 1.24 parts of sodium silicate and 1 part of 18# early strength type polycarboxylate water reducer, which can effectively reduce the nucleation barrier in the cement hydration process, thereby achieving the effects of accelerating and improving the strength, and the early strength enhancement is superior to the traditional type early strength agent; however, the crystal nucleus has large particle size and poor dispersion stability, and the effect of improving early strength of cement-based materials is not remarkable when the crystal nucleus is used as a crystal nucleus material.
On the other hand, the mineral powder is doped in the concrete, and as the mineral powder replaces a part of cement clinker, the relative content of the cement clinker participating in hydration in early stage is reduced, so that the early strength of the concrete is greatly reduced; in addition, as the activity of the mineral powder is too low, a long period of time is required from the excitation of the activity of the mineral powder to the participation of the mineral powder in hydration to generate a hydration product with strength, so that the hydration speed of cement is greatly reduced after the mineral powder is doped, the early strength requirements are not met, the strength of 1d and 3d is lower, and the demolding time of the prefabricated part is longer, so that the use of the prefabricated part is limited.
Therefore, the early strength agent for concrete prepared from mineral powder can obviously improve the early strength of concrete, and has important significance without reducing the later strength of concrete.
Disclosure of Invention
Aiming at the defects of the prior art, one of the purposes of the invention is to provide a concrete accelerating early strength agent, which can accelerate the cement hydration process, shorten the demoulding time of prefabricated parts, remarkably improve the early strength of concrete and not reduce the later strength of concrete.
In order to achieve the above purpose, the specific technical scheme of the invention is as follows:
the concrete accelerating early strength agent comprises the following components in parts by weight: 5 to 10 parts of superfine mineral powder A, 0.5 to 5 parts of polyvinyl alcohol, 10 to 20 parts of modified superfine mineral powder B, 5 to 12 parts of modified white carbon black and 40 to 80 parts of water;
the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier in water to prepare a modified liquid, adding a calcium hydroxide solution to adjust the pH value to be more than 12, adding superfine mineral powder B, heating to 50-80 ℃, reacting for 1-3 hours, filtering, drying and grinding to obtain the modified superfine mineral powder B;
the modifier is formed by compounding a powder polycarboxylate superplasticizer and polymethylsiloxane according to the mass ratio of 1 (1-1.5).
Preferably, the preparation method of the modified white carbon black comprises the following steps: mixing white carbon black with sodium hydroxide solution, reacting for 1-3 hours at 60-100 ℃, cooling to room temperature, washing and drying to obtain the modified white carbon black. The early strength effect of the early strength agent can be obviously improved by modifying the white carbon black with sodium hydroxide.
Preferably, the specific surface area of the superfine mineral powder A is more than or equal to 850m 2 The activity index per kg is more than or equal to 130 percent.
Further preferably, the content of the superfine mineral powder A with the particle size smaller than 13 μm is more than 97%.
Preferably, the specific surface area of the superfine mineral powder B is more than or equal to 850m 2 The activity index per kg is more than or equal to 130 percent.
The invention also aims to provide a preparation method of the concrete accelerating early strength agent, which comprises the following steps:
s1, weighing the components according to parts by weight, firstly adding water into polyvinyl alcohol to prepare a polyvinyl alcohol solution, then adding superfine ore powder A, and performing ultrasonic dispersion to obtain a mixed solution;
s2, adding modified superfine mineral powder B into the mixed solution obtained in the step S1, uniformly stirring, adding modified white carbon black, and continuously stirring for 2-3 hours to obtain the concrete accelerating and early strength agent.
It is a further object of the present invention to provide the use of said accelerating and early strength agent for concrete, said accelerating and early strength agent being incorporated in the concrete in an amount of 3 to 10% of the cementitious material
Compared with the prior art, the invention has the following advantages:
(1) The superfine mineral powder A has remarkable reinforcing effect, not only is the reinforcing effect of the superfine mineral powder A in tiny gaps, but also depends on the ultra-high volcanic ash activity, and free calcium oxide in the superfine mineral powder and cement and early hydration product Ca (OH) of the cement in early hydration 2 The reaction produces more hydration productsThe early strength is improved.
(2) The modified superfine mineral powder B can effectively reduce potential barrier generated by C-S-H gel, and induce hydration, so that a large amount of C-S-H gel is generated in the early stage of hydration, thereby remarkably improving the early hydration process of cement and remarkably improving the early strength of concrete.
(3) Under the action of polyvinyl alcohol, the superfine mineral powder A, the modified superfine mineral powder B and the modified white carbon black can react with free calcium oxide in cement and calcium hydroxide which is a cement early hydration product in early hydration stage to generate more hydration products, so that the early strength of the concrete is further improved.
(4) Compared with mineral powder and white carbon black in the prior art, the accelerating early strength agent provided by the invention innovatively uses the superfine mineral powder A, the modified superfine mineral powder B, the polyvinyl alcohol and the modified white carbon black, and the components are in synergistic effect, so that the early strength of concrete is obviously improved, the later strength is also obviously enhanced, and the demoulding time of the concrete can be obviously shortened.
Detailed Description
The following description of the present invention will be made clearly and fully, and it is apparent that the embodiments described are only some, but not all, of the embodiments of the present invention. All other embodiments, which can be made by one of ordinary skill in the art without undue burden on the person of ordinary skill in the art based on embodiments of the present invention, are within the scope of the present invention.
In the following examples and comparative examples, the specific surface area of the ultrafine ore powder A was not less than 850m 2 The activity index of the composition is more than or equal to 130 percent; the average grain diameter of the superfine mineral powder is less than 513 mu m, and the content of the grain diameter less than 13 mu m is more than 97 percent; the specific surface area of the superfine mineral powder B is more than or equal to 850m 2 The activity index of the composition is more than or equal to 130 percent; the average grain diameter of the superfine mineral powder is less than 513 mu m, and the content of the grain diameter less than 13 mu m is more than 97 percent.
Example 1
The embodiment provides a concrete accelerating early strength agent, which comprises the following components in parts by weight: 8 parts of superfine mineral powder A, 3 parts of polyvinyl alcohol, 15 parts of modified superfine mineral powder B, 9 parts of modified white carbon black and 68 parts of water;
the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier into water to prepare a modified solution with the mass concentration of 10%, then taking 200g of the modified solution, adding a calcium hydroxide solution to adjust the pH value to 12, adding 12g of superfine mineral powder B, heating to 65 ℃, reacting for 1.5h, filtering, drying, and grinding to the particle size of 20-50 nm to obtain modified superfine mineral powder B;
the modifier is formed by mixing a polycarboxylate water reducer and polymethyl siloxane according to a mass ratio of 1:1;
the preparation method of the modified white carbon black comprises the following steps: mixing the white carbon black with a sodium hydroxide solution, reacting for 1.5 hours at 80 ℃, cooling to room temperature, and then washing and drying to obtain the modified white carbon black.
The preparation method of the concrete accelerating early strength agent comprises the following steps:
s1, weighing the components according to parts by weight, firstly adding water into polyvinyl alcohol to prepare a polyvinyl alcohol solution with the mass concentration of 20%, and then adding superfine ore powder A into the solution to obtain a mixed solution through ultrasonic dispersion;
s2, adding modified superfine mineral powder B into the mixed solution obtained in the step S1, uniformly stirring, adding modified white carbon black and the rest of water, and continuously stirring for 2-3 hours to obtain the concrete accelerating and early strength agent.
Example 2
Example 2 is substantially the same as example 1 except that the concrete accelerating early strength agent of this example comprises the following components in parts by weight: 1 part of superfine mineral powder A, 5 parts of polyvinyl alcohol, 10 parts of modified superfine mineral powder B, 5 parts of modified white carbon black and 75 parts of water;
the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier into water to prepare a modified solution with the mass concentration of 10%, then taking 200g of the modified solution, adding a calcium hydroxide solution to adjust the pH value to 13, adding 12g of superfine mineral powder B, heating to 80 ℃, reacting for 1h, filtering, drying, and grinding to the particle size of 20-50 nm to obtain modified superfine mineral powder B;
the modifier is formed by mixing a polycarboxylate water reducer and polymethyl siloxane according to the mass ratio of 1:1.5;
the preparation method of the modified white carbon black comprises the following steps: mixing the white carbon black with a sodium hydroxide solution, reacting for 3 hours at 60 ℃, cooling to room temperature, and then washing and drying to obtain the modified white carbon black.
Example 3
Example 3 is substantially the same as example 1 except that the concrete accelerating early strength agent of this example comprises the following components in parts by weight: 5 parts of superfine mineral powder A, 1 part of polyvinyl alcohol, 20 parts of modified superfine mineral powder B, 12 parts of modified white carbon black and 60 parts of water;
the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier into water to prepare a modified solution with the mass concentration of 10%, then taking 200g of the modified solution, adding a calcium hydroxide solution to adjust the pH value to 12, adding 12g of superfine mineral powder B, heating to 50 ℃, reacting for 3 hours, filtering, drying, and grinding to the particle size of 20-50 nm to obtain modified superfine mineral powder B;
the modifier is formed by mixing a polycarboxylate water reducer and polymethyl siloxane according to a mass ratio of 1:1;
the preparation method of the modified white carbon black comprises the following steps: mixing white carbon black with sodium hydroxide solution, reacting for 1h at 100 ℃, cooling to room temperature, washing and drying to obtain the modified white carbon black.
Comparative example 1
Comparative example 1 is substantially the same as example 1 except that the modifier is a powder polycarboxylate superplasticizer, and no polymethylsiloxane is contained.
Comparative example 2
Comparative example 2 is substantially the same as example 1 except that the accelerating early strength agent of this comparative example comprises the following components in parts by weight: 23 parts of superfine mineral powder A, 3 parts of polyvinyl alcohol, 9 parts of modified white carbon black and 68 parts of water;
that is, compared with example 1, the accelerating early strength agent of the comparative example does not contain modified superfine mineral powder B, and the dosage of the superfine mineral powder A is correspondingly increased.
Comparative example 3
Comparative example 3 is substantially the same as example 1 except that the accelerating early strength agent of this comparative example comprises the following components in parts by weight: 8 parts of superfine mineral powder A, 15 parts of modified superfine mineral powder B, 9 parts of modified white carbon black and 71 parts of water;
that is, the accelerating early strength agent of this comparative example does not contain polyvinyl alcohol as compared with example 1.
Comparative example 4
Comparative example 4 is substantially the same as example 1 except that the accelerating early strength agent of this comparative example comprises the following components in parts by weight: 8 parts of superfine mineral powder A, 3 parts of polyvinyl alcohol, 15 parts of modified superfine mineral powder B, 9 parts of white carbon black and 68 parts of water;
that is, compared with example 1, unmodified white carbon black was used instead of modified white carbon black.
Test examples
The accelerating and early-strengthening agents of examples 1 to 3 and comparative examples 1 to 4 were used in concrete, the mixing amount of the accelerating and early-strengthening agent was 6% of the total mass of the cementing material, and the compounding ratios of the concrete are shown in Table 1.
Table 1 shows the concrete mix ratio (kg/m) 3 )
Cement and its preparation method | Fly ash | Sand and sand | Broken stone | Water and its preparation method | Water reducing agent |
370 | 80 | 726 | 1025 | 175 | 6.75 |
Wherein, the cement is conch P.I 52.5; the fly ash is class II fly ash; the sand is machine-made sand, and the fineness modulus is 2.6; the crushed stone is 5-20 mm continuous graded crushed stone; the water reducer is a high-performance polycarboxylic acid powder water reducer, and the water reducing rate is 28%.
According to the specification of GB/T50081-2019 'ordinary concrete mechanical property test method Standard', the compressive strength of concrete 1d and 28d is measured; the setting time of the concrete was tested as specified in GB/T50080-2019 Standard for Performance test method for general concrete mixtures, and the test results are shown in Table 2.
Table 2 results of concrete performance test
As can be seen from the results in Table 2, the early-stage mechanical properties (1 d strength) of the concrete can be remarkably improved by incorporating the accelerating early-stage hardening accelerator of the present invention, the post-stage strength of the concrete can be remarkably enhanced, and the demoulding time can be shortened, as compared with the blank.
Compared with example 1, the modifier of comparative example 1 does not contain polymethyl siloxane, the unmodified white carbon black is adopted in comparative example 4, the early strength of concrete is obviously reduced, the later strength is also obviously reduced, and the demoulding time of a concrete prefabricated part is prolonged. As can be seen from the comparison of example 1 and comparative example 2, comparative example 2 replaces the modified ultrafine mineral powder B with the ultrafine mineral powder A, the early strength of the concrete is significantly reduced, and the demolding time of the concrete preform is also significantly prolonged. Therefore, the modified superfine mineral powder B not only can improve the early-stage and later-stage strength of the concrete, but also can cooperate with other components to shorten the demoulding time of the concrete prefabricated member; as can be seen from the comparison of example 1 and comparative example 3, comparative example 3 does not contain polyvinyl alcohol, not only does the demolding time of the concrete precast element significantly extend, but also the early and late strength of the concrete also significantly decrease, indicating that polyvinyl alcohol can not only shorten the demolding time of the concrete precast element, but also can improve the early and late strength of the concrete in cooperation with other components. In conclusion, changing or replacing any component in the early strength agent greatly reduces the compressive strength of concrete and prolongs the demoulding time; from the embodiment 1 and the comparative examples 1-3, the accelerating early strength agent of the invention can obviously improve the early strength and the later strength of concrete and can also obviously shorten the demoulding time of a concrete prefabricated member due to the synergistic effect of the modified superfine mineral powder B, the polyvinyl alcohol and the modified white carbon black.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. The concrete accelerating early strength agent is characterized by comprising the following components in parts by weight: 5 to 10 parts of superfine mineral powder A, 0.5 to 5 parts of polyvinyl alcohol, 10 to 20 parts of modified superfine mineral powder B, 5 to 12 parts of modified white carbon black and 40 to 80 parts of water;
the preparation method of the modified superfine mineral powder B comprises the following steps: dissolving a modifier in water to prepare a modified liquid, adding a calcium hydroxide solution to adjust the pH value to be more than 12, adding superfine mineral powder B, heating to 50-80 ℃, reacting for 1-3 hours, filtering, drying and grinding to obtain the modified superfine mineral powder B;
the modifier is formed by compounding a powder polycarboxylate superplasticizer and polymethylsiloxane according to the mass ratio of 1 (1-1.5).
2. The concrete accelerating early strength agent according to claim 1, wherein the preparation method of the modified white carbon black is as follows: mixing white carbon black with sodium hydroxide solution, reacting for 1-3 hours at 60-100 ℃, cooling to room temperature, washing and drying to obtain the modified white carbon black.
3. The concrete accelerating and early strength agent according to claim 1, wherein the specific surface area of the superfine mineral powder A is more than or equal to 850m 2 The activity index per kg is more than or equal to 130 percent.
4. The concrete set accelerating and early strengthening agent according to claim 1, wherein the content of the superfine mineral powder A with the particle size smaller than 13 μm is more than 97%.
5. The concrete accelerating and early strength agent according to claim 1, wherein the specific surface area of the superfine mineral powder B is more than or equal to 850m 2 The activity index per kg is more than or equal to 130 percent.
6. The method for preparing the concrete accelerating early strength agent according to any one of claims 1 to 5, comprising the following steps:
s1, weighing the components according to parts by weight, firstly adding water into the polyvinyl alcohol to prepare a polyvinyl alcohol solution, then adding the superfine ore powder A, and performing ultrasonic dispersion to obtain a mixed solution;
s2, adding the modified superfine mineral powder B into the mixed solution obtained in the step S1, uniformly stirring, adding the modified white carbon black, and continuously stirring for 2-3 hours to obtain the concrete accelerating and early strength agent.
7. The use of the accelerating and early strength agent for concrete according to any one of claims 1 to 5, wherein the mixing amount of the accelerating and early strength agent in the concrete is 3 to 10 percent of the cementing material.
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