CN112047683A - High-strength self-compacting concrete and preparation method thereof - Google Patents
High-strength self-compacting concrete and preparation method thereof Download PDFInfo
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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
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
- C04B2201/52—High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC]
Abstract
The application relates to the technical field of concrete, and particularly discloses high-strength self-compacting concrete and a preparation method thereof, wherein the concrete is prepared from the following raw materials in parts by weight: cement; fly ash; mineral powder; fine aggregate; coarse aggregate; a water reducing agent; a swelling agent; water, diatomaceous earth and modified sepiolite powder; the application also discloses a preparation method of the concrete, which comprises the following steps: mixing coarse aggregate and fine aggregate, then adding diatomite and modified sepiolite powder, and uniformly mixing to obtain a first mixture; mixing cement, fly ash and mineral powder to obtain a second mixture; the self-compacting concrete has the advantages that the water reducing agent, the water and the expanding agent are mixed to obtain the additive solution, and the additive solution, the first mixture and the second mixture are stirred and mixed.
Description
Technical Field
The application relates to the technical field of concrete, in particular to high-strength self-compacting concrete and a preparation method thereof.
Background
In recent years, with the rapid development of national economy and construction technology, more and more large-scale and technically difficult construction projects appear. In these projects, a large number of complex steel reinforced concrete composite structures, such as multi-cavity box-shaped structures for externally packing or internally casting concrete, multi-cavity box-shaped structures for externally packing and internally casting concrete, and steel tube composite columns with the appearance of fair-faced concrete effect, are applied, and thus the complex steel reinforced concrete composite structure columns have more strict requirements on the working performance of concrete. High strength self-compacting concrete is widely used due to its excellent workability. However, the high-strength concrete is more likely to crack than ordinary-strength concrete due to its higher self-shrinkage, thereby limiting the application of the high-strength self-compacting concrete.
Disclosure of Invention
In order to improve the self-contractibility of the high-strength self-compacting concrete, the application provides the high-strength self-compacting concrete and a preparation method thereof.
In a first aspect, the present application provides a high-strength self-compacting concrete, which adopts the following technical scheme:
the high-strength self-compacting concrete is prepared from the following raw materials in parts by weight: 200-320 parts of cement; 80-120 parts of fly ash; 30-60 parts of mineral powder; 320-450 parts of fine aggregate; 420-500 parts of coarse aggregate; 5-10 parts of a water reducing agent; 25-40 parts of an expanding agent; 100-150 parts of water, 50-100 parts of diatomite and 65-100 parts of modified sepiolite powder, wherein the modified sepiolite powder is prepared by grafting and modifying sepiolite powder and a mixed monomer of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid.
By adopting the technical scheme, the concrete obtained by proportioning the coarse and fine aggregates, the fly ash, the cement and other additives has good fluidity, segregation resistance and low shrinkage, the shrinkage of the concrete can be compensated by adding the expanding agent, the expanding agent is filled between fine cracks, and the expanding agent is matched with the cement, the fly ash, the coarse aggregates and the fine aggregates, so that the formed concrete has good fluidity and is not easy to segregate.
The large reason for the high-strength concrete contractibility is that internal moisture is consumed along with hydration of cement, and capillary pores and gel pores of mudstone in the concrete are dried more and more, so that the volume of pores is shrunk. In addition, the diatomite and the sepiolite are compounded, the diatomite has a three-dimensional pore structure and a larger pore structure, the sepiolite is a one-dimensional columnar or fibrous structure and belongs to a medium-micropore, the porous diatomite and the sepiolite with different pore structures and pore sizes are combined according to the proportion in the application, the water absorption and release performance of the obtained concrete is obviously improved, the self-contraction performance is further improved, the strength of the concrete compounded with coarse aggregates, fine aggregates and the like is higher, the workability is better, and the bleeding and the segregation are not easy to occur. Sepiolite is the sepiolite powder after vinyl monomer and acrylic acid monomer modification in this application, can show the water absorbing and releasing performance that improves sepiolite, and then improve the self-constriction of concrete to a very big extent, and the mobility of the concrete that obtains is better, difficult segregation and bleeding, finally obtain the high strength self-compaction concrete of low contractibility, this concrete has good intensity and self-compaction performance, form the high performance concrete of closely knit and even concrete structure, and show the self-constriction performance who improves the concrete, the difficult fracture that appears, the deformation problem.
Preferably, the concrete further comprises 20 to 50 parts by weight of white cement.
By adopting the technical scheme, the sepiolite, the diatomite and the white cement are compounded for use, so that the sepiolite and the diatomite have stronger moisture absorption and desorption performances due to the matching of pore structures and the increase of surface positions, and the concrete obtained by compounding has better fluidity.
Preferably, the concrete is prepared from the following raw materials in parts by weight: 250-280 parts of cement; 90-110 parts of fly ash; 40-50 parts of mineral powder; 380-420 parts of fine aggregate; 440-460 parts of coarse aggregate; 7-9 parts of a water reducing agent; 30-38 parts of an expanding agent; 110-130 parts of water, 70-85 parts of diatomite, 70-90 parts of modified sepiolite powder and 25-35 parts of white cement.
Preferably, the concrete is prepared from the following raw materials in parts by weight: 260 parts of cement; 100 parts of fly ash; 45 parts of mineral powder; 400 parts of fine aggregate; 450 parts of coarse aggregate; 8 parts of a water reducing agent; 34 parts of an expanding agent; 120 parts of water, 80 parts of diatomite, 80 parts of modified sepiolite powder and 30 parts of white cement.
Preferably, the water reducing agent is a naphthalene water reducing agent.
By adopting the technical scheme, the naphthalene water reducer has a strong dispersing effect on cement particles and prevents the dispersed particles from coagulating, so that the concrete has sufficient plastic viscosity, the fluidity of the concrete is improved, and a compact and uniform gel structure is formed.
Preferably, the expanding agent is calcium sulphoaluminate expanding agent.
By adopting the technical scheme, the compactness of the concrete obtained by compounding the naphthalene water reducing agent and the calcium sulphoaluminate expanding agent is higher, and the time loss of slump caused by the naphthalene water reducing agent can be reduced.
Preferably, the modified sepiolite powder is prepared by the following method in parts by weight:
s1, dissolving 15-20 parts of 2-acrylamide-2-methylpropanesulfonic acid in 70-80 parts of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 3-5 parts of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare acrylic acid solution with a neutralization degree of 65%;
s2, adding 8-12 parts of sepiolite powder into a 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 20-25 parts of acrylamide, stirring for dissolving, then adding 5-8 parts of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
By adopting the technical scheme, the vinyl monomer-2-acrylamide-2-methylpropanesulfonic acid, the acrylic acid amide and the acrylic acid are used as mixed monomers to carry out water-based modification on the sepiolite powder, so that the problem that the moisture absorption and release capacity of the sepiolite powder is limited is solved, the water absorption and release capacity of the obtained sepiolite powder is greatly improved, and the self-contractibility of concrete is further improved.
Preferably, the fine aggregate is natural medium sand in a region II, the fineness modulus is 2.7-2.9, and the coarse aggregate is 5-20mm continuous grade macadam.
By adopting the technical scheme, the coarse aggregate provides integral strength support, the crushed stones are 5-20mm continuous graded crushed stones, the crushed stones with different particle sizes form a densely filled overlapping framework, the porosity is reduced, the strength of the concrete is improved, the coarse aggregate and the fine aggregate are compounded, the fine aggregate is filled between the coarse aggregates, a slurry mixture formed by cement and water is filled between the fine aggregate and the coarse aggregate, the bonding property between the fine aggregate and the coarse aggregate is enhanced, and the fluidity and the workability of the concrete are improved. And the fine aggregate and the coarse aggregate are compounded with the modified sepiolite and the diatomite, so that the strength and the compactness of the concrete can be further improved.
Preferably, the cement is P.O.42.5-grade portland cement, the fly ash is F-class I-grade fly ash, and the mineral powder is S95-grade mineral powder.
By adopting the technical scheme, the strength of the concrete is improved after the cement with higher compressive strength is selected and compounded with the fly ash and the coarse aggregate and the fine aggregate.
In a second aspect, the present application provides a method for preparing a high-strength self-compacting concrete, which adopts the following technical scheme:
a preparation method of high-strength self-compacting concrete comprises the following steps:
mixing coarse aggregate and fine aggregate, then adding diatomite and modified sepiolite powder, and uniformly mixing to obtain a first mixture;
mixing cement, fly ash and mineral powder to obtain a second mixture;
and mixing the water reducing agent, water and the expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Through adopting above-mentioned technical scheme, adopt above-mentioned scheme preparation self-compaction concrete, it is simple and convenient, mix coarse aggregate and fine aggregate earlier moreover, carry out the packing between the skeleton, and more even, then add diatomaceous earth and modified sepiolite powder, further pack, then mix first mixture, second mixture and additive solution, utilize cementitious material such as cement to bond, obtain high strength self-compaction concrete, and improve the self-contraction nature of high strength concrete.
Preferably, in the step of preparing the second mixture, 20 to 50 parts by weight of white cement is further added.
In summary, the present application has the following beneficial effects:
1. the high-strength self-compacting concrete with low shrinkage is obtained, has good strength and self-compacting performance, forms high-performance concrete with a compact and uniform concrete structure, obviously improves the self-shrinking performance of the concrete, and is not easy to crack and deform;
2. the concrete obtained by proportionally matching the coarse and fine aggregates, the fly ash, the cement and other additives has good strength and fluidity, the shrinkage of the concrete can be compensated by adding the expanding agent, the shrinkage of the high-strength concrete is improved by adding the diatomite and the modified sepiolite powder, and the shrinkage performance of the high-strength concrete is improved by utilizing the porous moisture absorption and desorption function, particularly after the sepiolite powder is modified by the mixed monomer of the 2-acrylamido-2-methylpropanesulfonic acid, the acrylamide and the acrylic acid, the moisture absorption and desorption performance of the sepiolite powder is improved, and the self-shrinkage performance of the concrete is improved;
3. the preparation method provided by the application is simple and convenient, the coarse aggregate and the fine aggregate are mixed firstly, the filling between the frameworks is carried out, the frameworks are more uniform, then the diatomite and the modified sepiolite powder are added, the filling is further carried out, then the first mixture, the second mixture and the additive solution are mixed, the cementing materials such as cement are utilized for bonding, the high-strength self-compacting concrete is obtained, and the self-contractibility of the high-strength concrete is improved.
Detailed Description
The present application is further described in detail with reference to the following examples, which are specifically illustrated by the following: the following examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer, and the starting materials used in the following examples are available from ordinary commercial sources unless otherwise specified.
The high-strength self-compacting concrete has wide application space, but the high-strength concrete is remarkably characterized in that the water-cement ratio is low, the self-contractibility is large, the self-contractibility of the concrete is often in a large relation with the internal relative humidity of the concrete, as the internal moisture is consumed along with the cement hydration process, capillary pores and gel pores of cement stones in the concrete are increasingly dried, the pores are full of moisture in the early setting process of the cement hydration, the pores are dehydrated to generate a concave liquid surface in the drying process, and the concave liquid surface can generate a contractive force on the pores under the action of the surface tension of water, so that the volume of the pores is shrunk; in addition, the high-strength concrete often uses mineral admixture which is thinner than cement, the compactness of the concrete is improved, namely, the pore diameter of pores in the set cement is reduced, so that the contractility generated in the pore drying process is increased, the autogenous shrinkage is increased, and the self-shrinkage of the high-strength self-compacting concrete is larger.
Based on this, this application provides a high strength self-compaction concrete, and this concrete has good intensity and self-compaction performance, forms the high performance concrete of closely knit and even concrete structure, is showing the self-contraction performance who improves the concrete moreover, is difficult for appearing fracture, deformation problem, and this concrete is made by the raw materials that contains following parts by weight:
200-320 parts of cement; 80-120 parts of fly ash; 30-60 parts of mineral powder; 320-450 parts of fine aggregate; 420-500 parts of coarse aggregate; 5-10 parts of a water reducing agent; 25-40 parts of an expanding agent; the self-contraction performance of the concrete can be reduced by adjusting the humidity in the concrete by using the water absorption and release performance of porous structures of the diatomite and the sepiolite, but the problems of low equilibrium moisture content, especially weaker moisture release capacity and low moisture absorption and release speed exist because the water absorption and release capacity of the diatomite and the sepiolite is limited, so that the water absorption and release performance of the sepiolite is improved by selecting the modified sepiolite powder of the sepiolite modified by the mixed monomer of the 2-acrylamido-2-methylpropanesulfonic acid, the acrylic acid amide and the acrylic acid.
More preferably, the raw materials of the concrete also comprise 20-50 parts by weight of white cement, and the sepiolite, the diatomite and the white cement are compounded for use, so that the sepiolite and the diatomite have stronger moisture absorption and desorption performances due to the matching of pore structures and the increase of surface positions, and the concrete obtained by compounding has better fluidity.
Among the raw materials, the water reducing agent is a naphthalene water reducing agent which can be purchased from Shandong 37075and a Brilliant novel building material science and technology company Limited, and the solid content is more than or equal to 92 percent;
the expanding agent is calcium sulphoaluminate expanding agent which can be purchased from novel building materials of polar bear in Tangshan;
the cement is P.O.42.5-grade portland cement;
the fly ash is F class I class fly ash which can be purchased from Guangmeng mineral product processing factory in Lingshu county, the brand is Guangmeng, and the model is 200-;
the mineral powder is S95 grade mineral powder which can be purchased from Tangshan Jianlong industry Co Ltd;
the fine aggregate is natural medium sand in a region II, has a fineness modulus of 2.7-2.9, and can be purchased from Huibei Laishuixin building materials Co., Ltd;
the coarse aggregate is selected from 5-20mm continuous grade macadam, and can be purchased from West river macadam factories in Mitsun county, Beijing;
the white cement is grade 42.5 white cement purchased from Zhengzhou Bozhen source commercial and trade company Limited;
the modified sepiolite powder is prepared by the following method:
s1, dissolving 15-20 parts of 2-acrylamide-2-methylpropanesulfonic acid in 70-80 parts of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 3-5 parts of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare acrylic acid solution with a neutralization degree of 65%;
s2, adding 8-12 parts of sepiolite powder into a 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 20-25 parts of acrylamide, stirring for dissolving, then adding 5-8 parts of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
The following preparation examples 1 to 3 are preparation examples of modified sepiolite powder
Preparation example 1
A preparation method of modified sepiolite powder comprises the following steps:
s1, dissolving 18kg of 2-acrylamide-2-methylpropanesulfonic acid in 75kg of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 4kg of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare an acrylic acid solution with a neutralization degree of 65%;
s2, adding 10kg of sepiolite powder into the 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 22kg of acrylamide, stirring for dissolving, then adding 6kg of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
Preparation example 2
S1, dissolving 15kg of 2-acrylamide-2-methylpropanesulfonic acid in 70kg of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 3kg of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare an acrylic acid solution with a neutralization degree of 65%;
s2, adding 8kg of sepiolite powder into the 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 20kg of acrylamide, stirring for dissolving, then adding 5kg of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
Preparation example 3
S1, dissolving 20kg of 2-acrylamido-2-methylpropanesulfonic acid in 80kg of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamido-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 5kg of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare an acrylic acid solution with a neutralization degree of 65%;
s2, adding 12kg of sepiolite powder into the 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 25kg of acrylamide, stirring for dissolving, then adding 8kg of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
Examples
Example 1
A preparation method of high-strength self-compacting concrete comprises the following steps:
mixing 450kg of coarse aggregate and 400kg of fine aggregate, then adding 80kg of diatomite and 80kg of the modified sepiolite powder prepared in the preparation example 1, and uniformly mixing to obtain a first mixture;
mixing 260kg of cement, 100kg of fly ash, 30kg of white cement and 45kg of mineral powder to obtain a second mixture;
and mixing 8kg of water reducing agent, 120kg of water and 34kg of expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Example 2
A preparation method of high-strength self-compacting concrete comprises the following steps:
mixing 440kg of coarse aggregate and 380kg of fine aggregate, then adding 70kg of diatomite and 70kg of the modified sepiolite powder prepared in the preparation example 1, and uniformly mixing to obtain a first mixture;
mixing 250kg of cement, 90kg of fly ash, 25kg of white cement and 40kg of mineral powder to obtain a second mixture;
and mixing 7kg of water reducing agent, 110kg of water and 30kg of expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Example 3
A preparation method of high-strength self-compacting concrete comprises the following steps:
mixing 460kg of coarse aggregate and 420kg of fine aggregate, then adding 85kg of diatomite and 90kg of the modified sepiolite powder prepared in the preparation example 1, and uniformly mixing to obtain a first mixture;
mixing 280kg of cement, 110kg of fly ash, 35kg of white cement and 50kg of mineral powder to obtain a second mixture;
and mixing 9kg of water reducing agent, 130kg of water and 38kg of expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Example 4
A preparation method of high-strength self-compacting concrete comprises the following steps:
mixing 420kg of coarse aggregate and 320kg of fine aggregate, then adding 50kg of diatomite and 65kg of the modified sepiolite powder prepared in the preparation example 2, and uniformly mixing to obtain a first mixture;
mixing 200kg of cement, 80kg of fly ash, 20kg of white cement and 30kg of mineral powder to obtain a second mixture;
and mixing 5kg of water reducing agent, 100kg of water and 25kg of expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Example 5
A preparation method of high-strength self-compacting concrete comprises the following steps:
mixing 500kg of coarse aggregate and 450kg of fine aggregate, then adding 100kg of diatomite and 100kg of the modified sepiolite powder prepared in the preparation example 3, and uniformly mixing to obtain a first mixture;
mixing 320kg of cement, 120kg of fly ash, 50kg of white cement and 60kg of mineral powder to obtain a second mixture;
and mixing 10kg of water reducing agent, 150kg of water and 40kg of expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
Example 6
A method of preparing a high strength self-compacting concrete, according to the method of example 1, except that in the second mixture preparation step, white cement was not added.
Example 7
A method for preparing a high-strength self-compacting concrete according to the method of example 1, except that, in the first mixture preparation step, 50kg of diatomaceous earth was added.
Example 8
A method for preparing a high-strength self-compacting concrete according to the method of example 1, except that in the first mixture preparation step, diatomaceous earth is added in an amount of 100 kg.
Example 9
A method for preparing high-strength self-compacting concrete according to the method of example 1, except that the modified sepiolite powder was added in an amount of 65kg in the first mixture preparation step.
Example 10
A method for preparing high-strength self-compacting concrete according to the method of example 1, except that the modified sepiolite powder was added in an amount of 100kg in the first mixture preparation step.
Example 11
A method for preparing a high-strength self-compacting concrete according to the method of example 1, except that white cement was added in an amount of 20kg in the second mixture preparation step.
Example 12
A method for preparing a high-strength self-compacting concrete according to example 1, except that white cement was added in an amount of 50kg in the second mixture preparation step.
Comparative example
Comparative example 1
The preparation method of the high-strength self-compacting concrete is carried out according to the method in the example 1, except that the modified sepiolite powder is not added in the raw materials.
Comparative example 2
The preparation method of the high-strength self-compacting concrete is carried out according to the method in the example 1, and is characterized in that the modified sepiolite is not added into the raw materials, and 80kg of sepiolite powder is added.
Comparative example 3
A preparation method of high-strength self-compacting concrete is carried out according to the method in example 1, except that diatomite is not added in the raw materials.
Comparative example 4
A preparation method of high-strength self-compacting concrete is carried out according to the method in example 1, and is characterized in that diatomite and 80kg of attapulgite are not added into the raw materials.
Comparative example 5
A preparation method of high-strength self-compacting concrete is carried out according to the method in the example 1, except that the addition amount of the modified sepiolite powder is 110 kg.
Comparative example 6
A method for preparing high-strength self-compacting concrete was carried out as in example 1, except that the amount of diatomaceous earth added was 110 kg.
Comparative example 7
A method for preparing high-strength self-compacting concrete, which is carried out according to the method in the example 1, and is characterized in that the modified sepiolite powder is prepared by the following method:
s1, dissolving 18kg of 2-acrylamide-2-methylpropanesulfonic acid in 75kg of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
s2, adding 10kg of sepiolite powder into 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 22kg of acrylamide, stirring for dissolving, then adding 6kg of N, N-methylene diacrylamide and 6kg of potassium persulfate, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
Performance test
The concrete prepared in the above examples and comparative examples is prepared into a standard test block according to GB/T50081-2002 Standard of mechanical Performance test methods for ordinary concrete, the compressive strength of the standard test block after being cured for 28 days is measured, the out-of-service slump and the slump expansion of the concrete are measured by a slump flow test method, and self-shrinkage performance is also detected, wherein the self-shrinkage performance detection method comprises the following steps: a concrete sample of 100mm by 515mm was sealed with a wrap film, and the self-shrinkage rate of the concrete was measured by a CABR-NES model noncontact shrinkage deformer at (20. + -.2). The test results of the examples are shown in Table 1 below, and the test results of the comparative examples are shown in Table 2 below.
Table 1 examples concrete Properties test
| Detecting items | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 |
| Compressive strength/(MPa) | 81.5 | 78.2 | 80.4 | 75.8 | 74.5 | 81.2 |
| Slump of concrete leaving machine/(mm) | 250 | 240 | 245 | 240 | 235 | 235 |
| Concrete slump expansion/(mm) | 710 | 680 | 700 | 690 | 670 | 670 |
| Self-shrinkage ratio (10)-6m/ m) | 205 | 210 | 213 | 225 | 221 | 220 |
| Detecting items | Example 7 | Example 8 | Example 9 | Example 10 | Example 11 | Example 12 |
| Compressive strength/(MPa) | 78.4 | 82.6 | 78.2 | 81.6 | 81.2 | 81.5 |
| Slump of concrete leaving machine/(mm) | 235 | 240 | 240 | 245 | 245 | 250 |
| Concrete slump expansion/(mm) | 670 | 680 | 690 | 700 | 700 | 710 |
| Self-shrinkage ratio (10 x 10)-6m/ m) | 212 | 210 | 215 | 206 | 215 | 210 |
As can be seen from the above table 1, the high-strength self-compacting concrete prepared by the method has the machine-out slump of 255mm for 235-increased and the machine-out expansion degree of 720mm for 680-increased, and meets the technical requirements of the flow performance and the compactness of the high-strength self-compacting concrete. Further, referring to the results of the tests of examples 6 and 1, it can be seen that the fluidity of the concrete obtained by adding the white cement to the raw material is improved and the self-shrinkage rate is reduced to improve the self-shrinkage performance as compared to the case where the white cement is not added, and further, referring to the results of the tests of examples 11 and 12, it can be seen that the compressive strength does not change much as the amount of the added white cement increases, and increases slightly before changing substantially, and the fluidity increases substantially before changing, and the shrinkage reducing effect increases slightly before changing.
Referring again to the results of the tests of examples 1 and 7 to 8, it was found that the compressive strength increased with the amount of diatomaceous earth added to the raw material, but the self-shrinkage rate decreased first and then increased, the shrinkage reducing effect increased first and then decreased somewhat, and the fluidity also increased first and then decreased with the increase in diatomaceous earth, so that the optimum amount of diatomaceous earth added was 80 kg.
Referring to the results of the tests of example 1 and examples 9 to 10, it can be seen that as the amount of the modified sepiolite powder added increases, the compressive strength increases first and then does not change substantially, the fluidity increases first and then decreases, and the shrinkage reducing property increases, but when the amount is more than 80kg, the shrinkage reducing property increases with a lower degree of expansion.
TABLE 2 concrete Performance test in comparative examples
| Detecting items | Comparative example 1 | Comparative example 2 | Comparative example 3 | Comparative example 4 | Comparative example 5 | Comparative example 6 | Comparative example 7 |
| Compressive strength/(MPa) | 78.6 | 80.2 | 79.5 | 80.8 | 81.6 | 81.9 | 81.3 |
| Slump of concrete leaving machine/(mm) | 215 | 210 | 215 | 225 | 235 | 230 | 220 |
| Concrete slump expansion/(mm) | 620 | 620 | 630 | 640 | 660 | 650 | 640 |
| Self-shrinkage ratio (10)-6m/ m) | 289 | 246 | 257 | 234 | 224 | 237 | 251 |
As can be seen from table 2 above, the modified sepiolite powder is not added in the comparative example 1, the modified sepiolite powder is added in the example 1, and the self-shrinkage performance of the concrete can be greatly improved by adding the modified sepiolite powder, and referring to the detection results of the comparative examples 2 to 4, it can be seen that when the sepiolite powder is added instead of the modified sepiolite powder, the self-shrinkage rate is lower than that when the modified sepiolite powder is not added, and is higher than that when the modified sepiolite powder is added, and thus, the sepiolite powder has a certain shrinkage reducing effect, and the shrinkage reducing effect of the modified sepiolite powder is better. The self-shrinkage rate is higher when only the modified sepiolite powder is added than when the diatomite is added and the modified sepiolite powder is added, so that the shrinkage reducing effect is better when the diatomite and the modified sepiolite powder are added than when the diatomite and the modified sepiolite powder are added singly. Referring to the detection result in the comparative example 4, when the diatomite is exchanged by the attapulgite, the shrinkage reducing effect is reduced compared with the compounding of the diatomite and the modified sepiolite, and the shrinkage reducing effect is better when the diatomite and the modified sepiolite are compounded. Referring again to the test data in comparative example 7, it can be seen that when the diatomite is modified by using only 2-acrylamido-2-methylpropanesulfonic acid and acrylamide as the mixed monomer, the self-shrinkage rate is higher than that of the sepiolite powder obtained in example 1 after the sepiolite powder is modified by the mixed monomer of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid, and thus the reduction effect of the sepiolite powder after the mixed monomer of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid is better.
To sum up, the intensity and the self-compaction performance of the self-compaction concrete that excels in that the scheme that provides through this application made are excellent, can satisfy technical requirement, the shrink of concrete can be compensated in the addition of expanding agent, the interpolation of diatomaceous earth and modified sepiolite powder, utilize porous moisture absorption and desorption function, show improvement high-strength concrete shrinkage performance, make the difficult fracture that appears of high-strength concrete, the deformation problem, the interpolation of white cement, compound with modified sepiolite powder and diatomaceous earth, further improve the self-shrinkage performance of concrete, and can also improve the mobility of concrete.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (10)
1. The high-strength self-compacting concrete is characterized by being prepared from the following raw materials in parts by weight: 200-320 parts of cement; 80-120 parts of fly ash; 30-60 parts of mineral powder; 320-450 parts of fine aggregate; 420-500 parts of coarse aggregate; 5-10 parts of a water reducing agent; 25-40 parts of an expanding agent; 100-150 parts of water, 50-100 parts of diatomite and 65-100 parts of modified sepiolite powder, wherein the modified sepiolite powder is prepared by grafting and modifying sepiolite powder and a mixed monomer of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and acrylic acid.
2. The high strength self-compacting concrete according to claim 1, characterized in that: the concrete also comprises 20-50 parts by weight of white cement.
3. The high strength self-compacting concrete according to claim 2, characterized in that: the concrete is prepared from the following raw materials in parts by weight: 250-280 parts of cement; 90-110 parts of fly ash; 40-50 parts of mineral powder; 380-420 parts of fine aggregate; 440-460 parts of coarse aggregate; 7-9 parts of a water reducing agent; 30-38 parts of an expanding agent; 110-130 parts of water, 70-85 parts of diatomite, 70-90 parts of modified sepiolite powder and 25-35 parts of white cement.
4. The high strength self-compacting concrete according to claim 2, characterized in that: the concrete is prepared from the following raw materials in parts by weight: 260 parts of cement; 100 parts of fly ash; 45 parts of mineral powder; 400 parts of fine aggregate; 450 parts of coarse aggregate; 8 parts of a water reducing agent; 34 parts of an expanding agent; 120 parts of water, 80 parts of diatomite, 80 parts of modified sepiolite powder and 30 parts of white cement.
5. The high strength self-compacting concrete according to claim 1, characterized in that: the water reducing agent is a naphthalene water reducing agent.
6. The high strength self-compacting concrete according to claim 1, characterized in that: the expanding agent is calcium sulphoaluminate expanding agent.
7. The high strength self-compacting concrete according to claim 1, characterized in that: the modified sepiolite powder is prepared by the following method:
s1, dissolving 15-20 parts of 2-acrylamide-2-methylpropanesulfonic acid in 70-80 parts of water, stirring and dissolving, and adding sodium hydroxide to prepare a 2-acrylamide-2-methylpropanesulfonic acid solution with the neutralization degree of 70%;
taking 3-5 parts of 90wt% acrylic acid solution, and adding sodium hydroxide to prepare acrylic acid solution with a neutralization degree of 65%;
s2, adding 8-12 parts of sepiolite powder into a 2-acrylamide-2-methylpropanesulfonic acid solution, stirring, adding 20-25 parts of acrylamide, stirring for dissolving, then adding 5-8 parts of N, N-methylene diacrylamide and the acrylic acid solution obtained in the step S1, and reacting the mixture in a microwave reactor, wherein the microwave power is 325W, and the reaction time is 3 min;
and S3, drying and crushing the mixture obtained after the reaction to obtain the modified sepiolite powder.
8. The high strength self-compacting concrete according to claim 1, characterized in that: the cement is P.O.42.5-grade portland cement, the fly ash is F-class I-grade fly ash, and the mineral powder is S95-grade mineral powder
The fine aggregate is natural medium sand in an area II, the fineness modulus is 2.7-2.9, and the coarse aggregate is 5-20mm continuous grade macadam.
9. A method of producing a high strength self compacting concrete according to any one of claims 1-8, characterized in that it comprises the following steps:
mixing coarse aggregate and fine aggregate, then adding diatomite and modified sepiolite powder, and uniformly mixing to obtain a first mixture;
mixing cement, fly ash and mineral powder to obtain a second mixture;
and mixing the water reducing agent, water and the expanding agent to obtain an additive solution, and stirring and mixing the obtained additive solution, the first mixture and the second mixture to obtain the high-strength self-compacting concrete.
10. The high strength self-compacting concrete according to claim 9, characterized in that: in the step of preparing the second mixture, 20 to 50 parts by weight of white cement is also added.
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