CN110981264B - Nano bulk concrete anti-cracking agent and preparation method thereof - Google Patents
Nano bulk concrete anti-cracking agent and preparation method thereof Download PDFInfo
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- CN110981264B CN110981264B CN201911348657.6A CN201911348657A CN110981264B CN 110981264 B CN110981264 B CN 110981264B CN 201911348657 A CN201911348657 A CN 201911348657A CN 110981264 B CN110981264 B CN 110981264B
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- 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
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/198—Graphene oxide
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- 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
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
Abstract
The invention provides a nano bulk concrete crack resistance agent, and belongs to the technical field of concrete admixtures. The concrete crack resistance agent comprises: 35-55 parts of graphene oxide, 10-20 parts of nano zinc oxide, 5-15 parts of nano magnesium oxide, 10-90 parts of a dispersing agent and 500-2000 parts of deionized water; the graphene oxide is a nanosheet layer formed by oxidizing and stripping graphite powder with a strong oxidant under the action of strong acid; the average particle size of the nano zinc oxide is 20-50 nm, and the average particle size of the nano magnesium oxide is 40-80 nm. The invention also provides a preparation method of the concrete anti-cracking agent. The concrete crack resistance agent can effectively reduce the hydration heat rate of mass concrete, delay the heat release peak value, improve the strength, toughness and heat diffusion coefficient of the concrete, and reduce the shrinkage of the concrete, thereby fundamentally preventing the generation of mass concrete cracks.
Description
Technical Field
The invention belongs to the technical field of concrete admixtures, and particularly relates to a nano bulk concrete crack resistance agent and a preparation method thereof.
Background
With the rapid development of the construction industry, mass concrete is more and more frequently applied to the construction of high-rise, super high-rise and special-function structures, large equipment foundations and the like. However, the large-volume concrete has relatively large volume and small surface coefficient, and the hydration heat generated when the internal cement meets water is concentrated, so that the internal heating speed is high, large temperature difference is generated between the internal cement and the external temperature, temperature stress is caused, and further, the problem of cracks is caused. The occurrence of large volume concrete cracks can seriously affect the safe use and durability of the building structure. How to avoid the generation of concrete cracks is a problem which needs to be solved urgently by mass concrete at present.
At present, the generation of large-volume temperature cracks is prevented and controlled, and the concrete mixing proportion and temperature control measures are mainly optimized. The optimized concrete mixing proportion mainly comprises the modes of selecting cement with low hydration heat, reducing the using amount of a cementing material, increasing the proportion of a mineral admixture and the like; the temperature control measure mainly controls the mold-entering temperature, a heat dissipation device is arranged in the concrete, and the heat preservation and moisture preservation of the surface of the concrete are enhanced. Although these measures can suppress the occurrence of cracks in concrete to some extent, they increase the difficulty of construction and have high requirements for quality control, and in practical engineering applications, there are still many large-volume concrete structures with cracks.
Disclosure of Invention
The invention mainly aims to provide a nano-based bulk concrete anti-cracking agent and a preparation method thereof aiming at the defects in the prior art, the anti-cracking agent can effectively reduce the hydration heat rate, delay the heat release peak value, improve the strength and toughness of concrete, and reduce the shrinkage of concrete, thereby fundamentally preventing the generation of cracks of the bulk concrete.
The purpose of the invention is realized by the following technical scheme:
the nano bulk concrete crack resistance agent comprises, by mass, 35-55 parts of graphene oxide, 10-20 parts of nano zinc oxide, 5-15 parts of nano magnesium oxide, 10-90 parts of a dispersing agent and 500-2000 parts of deionized water;
the graphene oxide is a nanosheet layer formed by oxidizing and stripping graphite powder with a strong oxidant under the action of strong acid; the average particle size of the nano zinc oxide is 20-50 nm, and the average particle size of the nano magnesium oxide is 40-80 nm.
Further, the dispersant is one or more of Sodium Dodecyl Benzene Sulfonate (SDBS), sodium dodecyl sulfate (AEA), polyvinylpyrrolidone (PVP), polycarboxylate and sodium polyacrylate.
Further, the preparation method of the graphene oxide comprises the following steps: under ice bath condition, adding H2SO4And NaNO3Mixing, adding graphite powder under stirring, and adding KMnO4And stirring and reacting for a period of time at room temperature, and finally performing centrifugal separation, acid washing and water washing, and drying to obtain the catalyst.
Further, by mass, the graphite powder is 1-15 parts, and the concentrated sulfuric acid is50-200 parts of sodium nitrate, 1-10 parts of KMnO410 to 25 portions.
A preparation method of a nano bulk concrete crack resistance agent comprises the steps of adding a part of dispersing agent into deionized water at room temperature, adding graphene oxide, carrying out ultrasonic treatment to obtain a uniformly dispersed graphene oxide mixed solution, then adding nano zinc oxide, nano magnesium oxide and the rest of dispersing agent, and carrying out continuous ultrasonic treatment to uniformly disperse the nano zinc oxide and the nano magnesium oxide in the graphene oxide mixed solution, thus obtaining the ZnO-MgO-GO nano crack resistance agent.
The nano ZnO in the concrete crack resistance agent can react with calcium hydroxide to produce a water-insoluble hydration product in the cement hydration process, and the water-insoluble hydration product covers unhydrated cement particles to prevent further hydration of cement, and insoluble substances are destroyed as the cement hydration reaction proceeds, and the cement hydration reaction continues to proceed; therefore, the nano ZnO can play a role in retarding coagulation in concrete, can effectively reduce the hydration heat rate of mass concrete and delay the exothermic peak value, thereby achieving the role in preventing and controlling temperature cracks. The Graphene Oxide (GO) has the functions of promoting cement hydration and the like due to the nanometer filling effect and the crack blocking effect, so that the strength and toughness of the concrete can be greatly improved, and the capability of the concrete for resisting the generation of cracks can be improved; on the other hand, the graphene oxide can enhance the heat conductivity coefficient of concrete and reduce micro cracks of a concrete matrix caused by temperature stress. The nano MgO not only enhances the strength of the concrete, but also can well compensate the temperature reduction shrinkage and the drying shrinkage of the concrete due to the expansion effect of the nano MgO, and prevent the concrete from generating cracks due to the shrinkage.
Compared with the prior art, the invention has the following beneficial effects
According to the concrete anti-cracking agent disclosed by the invention, nano ZnO, nano MgO and graphene oxide are compounded and added into concrete in the form of dispersed emulsion, so that the synergistic, complementary and superimposed effects of the nano ZnO, the nano MgO and the graphene oxide are fully exerted, the anti-cracking performance of the concrete is greatly improved, and the strength of the concrete can be ensured.
The concrete crack resistance agent can effectively reduce the hydration heat rate of mass concrete, delay the heat release peak value, improve the strength, toughness and heat diffusion coefficient of the concrete, and reduce the shrinkage of the concrete, thereby fundamentally preventing the generation of mass concrete cracks.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
The concrete preparation process of the nano bulk concrete crack resistance agent of the embodiment is as follows:
1. preparing Graphene Oxide (GO): 70 parts of concentrated sulfuric acid and 2.5 parts of NaNO are mixed under ice-bath conditions3Mixing in a round-bottom flask, adding 5 parts of graphite powder, and continuously stirring for 2 hours; subsequently, 15 parts of KMnO were added to the mixture4Stirring for 1h at room temperature; and (3) centrifugally separating the reacted solution at 6000rpm for 30min, removing a bottom layer black precipitate in the mixture, taking a middle light-colored mixed solution, washing the mixed solution for several times by using 5% dilute hydrochloric acid and deionized water until no precipitate is visible, and drying the washed graphene oxide in a drying oven at 60 ℃ for 5h for later use to obtain the Graphene Oxide (GO).
2. Preparing a ZnO-MgO-GO nano anti-cracking agent: measuring 1000 parts of deionized water in a beaker at room temperature, adding 40 parts of dispersant sodium dodecyl benzene sulfonate, and then placing 45 parts of graphene oxide in the mixed solution; and (2) carrying out ultrasonic treatment for 1h at 25 ℃ to obtain a uniformly dispersed graphene oxide mixed solution, then adding 15 parts of nano ZnO, 10 parts of nano MgO and 10 parts of dispersant polyvinylpyrrolidone under the stirring condition, keeping the system temperature at 25 ℃, and continuing ultrasonic treatment for 2h to uniformly disperse the nano ZnO and the nano MgO in the graphene oxide mixed solution, thus obtaining the ZnO-MgO-GO nano anti-cracking agent.
Example 2
The concrete preparation process of the nano bulk concrete crack resistance agent of the embodiment is as follows:
1. preparing Graphene Oxide (GO): on the iceUnder bath conditions, 100 parts of concentrated sulfuric acid and 5 parts of NaNO are mixed3Mixing in a round-bottom flask, adding 10 parts of graphite powder and continuously stirring for 1.5 h; subsequently, 20 parts of KMnO were added to the mixture4And stirred at room temperature for 1 h. And (3) centrifugally separating the reacted solution at 6000rpm for 30min, removing a bottom layer black precipitate in the mixture, taking a middle light-colored mixed solution, washing the mixed solution for several times by using 5% dilute hydrochloric acid and deionized water until no precipitate is visible, and drying the washed graphene oxide in a drying oven at 60 ℃ for 5h for later use to obtain the Graphene Oxide (GO).
2. Preparing a ZnO-MgO-GO nano anti-cracking agent: at room temperature, 1500 parts of deionized water are weighed into a beaker, 60 parts of dispersant sodium dodecyl sulfate is added, and then 50 parts of graphene oxide is placed in the mixed solution. And (2) carrying out ultrasonic treatment for 2h at 25 ℃ to obtain a uniformly dispersed graphene oxide mixed solution, then adding 20 parts of nano ZnO and 10 parts of nano MgO and 10 parts of dispersant polycarboxylate while stirring, keeping the system temperature at 25 ℃, and continuing ultrasonic treatment for 2h to uniformly disperse the nano ZnO and the nano MgO in the graphene oxide mixed solution, thus obtaining the ZnO-MgO-GO nano anti-cracking agent.
Example 3
The concrete preparation process of the nano bulk concrete crack resistance agent of the embodiment is as follows:
1. preparing Graphene Oxide (GO): under ice bath conditions, 150 parts of concentrated sulfuric acid and 8 parts of NaNO are added3Mixing in a round-bottom flask, adding 15 parts of graphite powder and continuously stirring for 3 hours; subsequently, 20 parts of KMnO were added to the mixture4Stirring for 1h at room temperature; and (3) centrifugally separating the reacted solution at 6000rpm for 30min, removing a bottom layer black precipitate in the mixture, taking a middle light-colored mixed solution, washing the mixed solution for several times by using 5% dilute hydrochloric acid and deionized water until no precipitate is visible, and drying the washed graphene oxide in a drying oven at 60 ℃ for 5h for later use to obtain the Graphene Oxide (GO).
2. Preparing a ZnO-MgO-GO nano anti-cracking agent: measuring 1800 parts of deionized water in a beaker at room temperature, adding 70 parts of dispersant polyvinylpyrrolidone, and then placing 50 parts of graphene oxide in the mixed solution; and (2) carrying out ultrasonic treatment for 1h at 25 ℃ to obtain a uniformly dispersed graphene oxide mixed solution, then adding 15 parts of nano ZnO, 15 parts of nano MgO and 10 parts of dispersant polyvinylpyrrolidone under the stirring condition, keeping the system temperature at 25 ℃, and continuing ultrasonic treatment for 2h to uniformly disperse the nano ZnO and the nano MgO in the graphene oxide mixed solution, thus obtaining the ZnO-MgO-GO nano anti-cracking agent.
Comparative example 1
Based on the embodiment 1, the nano ZnO is not added, and the rest is the same as the embodiment 1.
Comparative example 2
Based on the embodiment 1, the method is the same as the embodiment 1 except that nano MgO is not added.
Comparative example 3
Based on the example 1, graphene oxide is not doped, specifically, 1000 parts of deionized water is measured in a beaker at room temperature, 40 parts of dispersant sodium dodecyl benzene sulfonate is added, the temperature is 25 ℃, then 15 parts of nano ZnO and 10 parts of nano MgO are added under the stirring condition, the temperature of the system is kept at 25 ℃, and the ZnO-MgO nano anti-cracking agent is obtained after continuous ultrasonic treatment for 2 hours.
Crack resistance test
The nano bulk concrete crack resistance agents obtained in the examples 1-3 and the comparative examples 1-3 are added into concrete according to the addition amount of 0.5 percent of the cementing material, the crack resistance agents are not added to serve as blank samples, the workability of the concrete is tested according to GB/T50080-. The concrete mixing ratio is shown in the following table 1, and the performance detection result is shown in the following table 2.
TABLE 1 concrete mix proportion
TABLE 2 concrete Property test results
It can be known from the comparison in table 2 that the nano bulk concrete crack resistance agents prepared in examples 1 to 3 can greatly improve the crack resistance of concrete and delay the setting time of concrete compared with the blank sample, and the 7d strength is reduced due to the retardation effect, but the 28d strength is increased compared with the blank sample. Compared with the comparative example 1, the setting time of the cement can be delayed, and the crack resistance of the concrete can be improved; compared with comparative example 2 and comparative example 3, the crack resistance of the concrete can be improved, and the crack area can be reduced.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (2)
1. The nano bulk concrete crack resistance agent is characterized by comprising, by mass, 35-55 parts of graphene oxide, 10-20 parts of nano zinc oxide, 5-15 parts of nano magnesium oxide, 10-90 parts of a dispersing agent and 500-2000 parts of deionized water;
the graphene oxide is a nanosheet layer formed by oxidizing and stripping graphite powder with a strong oxidant under the action of strong acid; the average particle size of the nano zinc oxide is 20-50 nm, and the average particle size of the nano magnesium oxide is 40-80 nm;
the preparation method of the nano bulk concrete anti-cracking agent comprises the steps of adding a part of dispersing agent into deionized water at room temperature, adding graphene oxide, carrying out ultrasonic treatment to obtain a uniformly dispersed graphene oxide mixed solution, then adding nano zinc oxide, nano magnesium oxide and the rest of dispersing agent, and carrying out continuous ultrasonic treatment to uniformly disperse the nano zinc oxide and the nano magnesium oxide in the graphene oxide mixed solution, thus obtaining the ZnO-MgO-GO nano anti-cracking agent.
2. The nano bulk concrete crack resistance agent according to claim 1,the preparation method of the graphene oxide comprises the following steps: under ice bath condition, adding H2SO4And NaNO3Mixing, adding graphite powder under stirring, and adding KMnO4And stirring and reacting for a period of time at room temperature, and finally performing centrifugal separation, acid washing and water washing, and drying to obtain the catalyst.
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| CN113979658A (en) * | 2020-07-27 | 2022-01-28 | 苏州万众建筑材料有限公司 | Concrete anti-cracking agent and preparation method thereof |
| CN115057649B (en) * | 2022-06-16 | 2023-04-14 | 武汉源锦建材科技有限公司 | Concrete expansion toughening anti-cracking agent and preparation method thereof |
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| JPS5437131A (en) * | 1977-08-30 | 1979-03-19 | Tadao Hanaoka | Preventives against crack etc* of reinforced concrete building structure |
| CN105819733A (en) * | 2016-03-18 | 2016-08-03 | 南通不二环境科技有限公司 | Concrete anti-cracking and anti-permeability special additive and preparation method thereof |
| CN108017345A (en) * | 2017-12-08 | 2018-05-11 | 江苏苏博特新材料股份有限公司 | A kind of ultrahigh-performance cement-based patching material and preparation method thereof |
| CN108033704A (en) * | 2017-11-10 | 2018-05-15 | 南通不二环境科技有限公司 | A kind of concrete additive |
| CN108147689A (en) * | 2017-12-31 | 2018-06-12 | 江苏申御特种建材有限公司 | A kind of magnesia antimitotic agent of graphene oxide and preparation method thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5437131A (en) * | 1977-08-30 | 1979-03-19 | Tadao Hanaoka | Preventives against crack etc* of reinforced concrete building structure |
| CN105819733A (en) * | 2016-03-18 | 2016-08-03 | 南通不二环境科技有限公司 | Concrete anti-cracking and anti-permeability special additive and preparation method thereof |
| CN108033704A (en) * | 2017-11-10 | 2018-05-15 | 南通不二环境科技有限公司 | A kind of concrete additive |
| CN108017345A (en) * | 2017-12-08 | 2018-05-11 | 江苏苏博特新材料股份有限公司 | A kind of ultrahigh-performance cement-based patching material and preparation method thereof |
| CN108147689A (en) * | 2017-12-31 | 2018-06-12 | 江苏申御特种建材有限公司 | A kind of magnesia antimitotic agent of graphene oxide and preparation method thereof |
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