CN112939562B

CN112939562B - Crack-resistant concrete and preparation method thereof

Info

Publication number: CN112939562B
Application number: CN202110363062.9A
Authority: CN
Inventors: 杨建利; 党朋朋; 鲁超明; 屈晨
Original assignee: Shaanxi Shifeng Concrete Co ltd
Current assignee: Xi'an Xinyida Building Products Co ltd
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2022-03-15
Anticipated expiration: 2041-04-02
Also published as: CN112939562A

Abstract

The application relates to the field of concrete, and particularly discloses crack-resistant concrete and a preparation method thereof. The concrete comprises the following components in parts by weight: the concrete comprises cement, coarse aggregate, fine aggregate, water, a water reducing agent, a defoaming agent, fly ash, diatomite, super absorbent resin, carbon fiber, styrene-acrylic emulsion and silica gel, and has high compressive strength and excellent crack resistance; the preparation method of the concrete comprises the following steps: s1, crushing the silica gel, mixing the crushed silica gel with the diatomite at a high temperature, and naturally cooling to room temperature to obtain a mixture; s2, stirring cement, coarse aggregate, fine aggregate and a defoaming agent, adding the mixture into the step S1 to obtain a mixture, and adding water, fly ash, styrene-acrylic emulsion and a water reducing agent to obtain a mixture; s3, mixing the super absorbent resin and the carbon fibers at a medium temperature, cooling to room temperature, and adding the mixture into the mixture obtained in the step S2 to obtain the crack-resistant concrete. The preparation method provided by the application is simple and easy to operate.

Description

Crack-resistant concrete and preparation method thereof

Technical Field

The application relates to the field of concrete, in particular to crack-resistant concrete and a preparation method thereof.

Background

The common concrete is artificial stone which is prepared by taking cement as a main cementing material, mixing water, sand, stones and chemical additives and mineral admixtures as necessary according to a proper proportion, uniformly stirring, densely forming, curing and hardening. Because the common concrete has good plasticity, the concrete can be poured into various complex shapes, is widely applied to pouring of road surfaces, bridges, wharfs and the like, is also widely applied to urban road engineering, and becomes the most main building material in the world at present.

Hydration is an important characteristic of cement, the hydration process of the cement is accompanied with the generation of hydration heat, the change of a micro-pore structure and the change of mechanical strength among cement, stone and sand, and the concrete consumes a large amount of water in the hydration process, so that delayed concrete is easy to crack, the crack of the concrete can cause leakage, the durability of the concrete is reduced, the service life of the concrete is shortened, and the strength and the durability of a building structure can be adversely affected. At present, in order to improve the crack resistance of concrete, the amount of water is increased in the manufacturing process of the concrete so as to reduce the elastic modulus of the concrete.

The related technology has the disadvantages that in the concrete preparation process, when more water is added, the water-cement ratio is increased, so that the ultimate tensile value of the concrete is reduced, the compressive strength of the concrete is reduced, and the compression resistance of the concrete is not facilitated.

Disclosure of Invention

In order to reduce the generation of cracks of concrete due to drying shrinkage on the basis of ensuring the strength of the concrete, the application provides crack-resistant concrete and a preparation method thereof.

In a first aspect, the present application provides a crack-resistant concrete, which adopts the following technical scheme: the crack-resistant concrete comprises the following raw material components:

340-420 parts of cement, 840-850 parts of coarse aggregate, 460-490 parts of fine aggregate, 150-190 parts of water, 6-8 parts of water reducing agent, 2-3.5 parts of defoaming agent, 200-230 parts of fly ash, 26-32 parts of diatomite, 18-22 parts of super absorbent resin, 40-45 parts of carbon fiber, 45-55 parts of styrene-acrylic emulsion and 0.8-1.2 parts of silica gel; the styrene-acrylic emulsion is nonionic styrene-acrylic emulsion, and the water reducing agent is a polycarboxylic acid water reducing agent or a naphthalene water reducing agent.

By adopting the technical scheme, the cement is a cementing material of the crack-resistant concrete, the coarse aggregate is a rigid framework in the crack-resistant concrete, the fly ash is in a spherical structure and has continuous particle size distribution, the fly ash and the cement particles form a grading system on a microcosmic scale and are matched with the fine aggregate for use, and the gap between the coarse aggregate in the concrete can be filled, so that the whole structure of the concrete after being cured is compact, the crack resistance of the concrete is improved, and the crack resistance of the concrete caused by shrinkage is facilitated in the hydration process.

In addition, after the fly ash is doped into the concrete, the consumption of cement can be reduced, the raw material cost of the concrete can be reduced, the hydration heat of the concrete can be reduced, and the loss of a large amount of water in the concrete due to hydration in the concrete can be slowed down, so that the possibility of generating shrinkage cracks due to lower internal humidity of the concrete can be reduced; the coal ash is matched with the styrene-acrylic emulsion, so that the water consumption can be further reduced, the ultimate tensile value of the concrete is improved, and the compressive strength of the concrete is correspondingly increased; the non-ionic styrene-acrylic emulsion can disperse all components in the concrete, so that the whole concrete system tends to be in a stable state.

The super absorbent resin is a high molecular polymer with a plurality of hydrophilic groups and a three-dimensional network structure, is a water-retaining agent capable of repeatedly absorbing and releasing water, can greatly improve the internal relative humidity of concrete in the same age, and can greatly slow down the occurrence of dry shrinkage cracks in the concrete by adding the super absorbent resin compared with the simple increase of the mixing water amount; the silica gel has more micropores inside, stable chemical properties and higher mechanical strength, and the addition of a proper amount of silica gel into the concrete is beneficial to improving the mechanical hardness of the concrete, enhancing the water absorption performance of the concrete and improving the water retention performance inside the concrete, so that the concrete is not easy to generate shrinkage cracks due to excessive water loss; the diatomite is a porous material, and the holes on the surface of the diatomite enable the diatomite to be more tightly combined with cement, so that the concrete needs larger load when being broken, and the breaking strength is higher; the silica gel, the super absorbent resin and the diatomite can store water in the concrete, and when the cement needs water under the hydration action, the water is slowly released from the microporous structures in the silica gel, the super absorbent resin and the diatomite, so that the normal hydration process of the concrete is met, the speed of the hydration action is reduced, the water loss in the hydration process of the concrete is reduced, the balance of the relative humidity in the concrete is maintained, and the occurrence of shrinkage cracks in the concrete is reduced.

The styrene-acrylic emulsion, the diatomite and the carbon fibers act together, so that the bonding force among internal structures of the concrete can be improved, the mechanical property of the crack-resistant concrete is effectively improved, the concrete is not easy to crack or separate from each other, the compression resistance of the concrete is improved, and the service performance of the concrete is improved.

The defoaming agent is adopted in the preparation process of the concrete, the defoaming agent can reduce the surface tension, and the concrete is uniform in texture after being cured by eliminating foam generated in the concrete, so that the phenomena of pores such as honeycombs, pitted surfaces and the like are not easy to occur, and the compressive strength of the concrete is further increased.

In conclusion, the silica gel, the super absorbent resin and the diatomite are mixed with the cement, the coarse aggregate, the fine aggregate, the fly ash, the water reducing agent and the styrene-acrylic emulsion, so that the water consumption and the cement content of the concrete are effectively reduced, the hydration heat of the concrete is reduced, the concrete still has better compressive strength while the crack resistance of the concrete is improved, the tensile strength of the concrete is greatly improved by increasing the bonding force in the concrete after the carbon fiber is mixed with the raw materials, the concrete is further difficult to crack, the crack resistance of the concrete is improved, and the crack resistance of the concrete can be widely applied to various occasions; the polycarboxylic acid water reducing agent or the naphthalene water reducing agent can fully disperse cement particles, reduce the water consumption and reduce the porosity of the anti-crack concrete, thereby improving the strength of the anti-crack concrete.

Optionally, the raw materials comprise the following raw material components in parts by weight:

380-400 parts of cement, 840-850 parts of coarse aggregate, 470-480 parts of fine aggregate, 160-180 parts of water, 7-8 parts of water reducing agent, 3.2-3.5 parts of defoaming agent, 220-225 parts of fly ash, 29-31 parts of diatomite, 20-21 parts of super absorbent resin, 42-44 parts of carbon fiber, 50-53 parts of styrene-acrylic emulsion and 1-1.2 parts of silica gel.

Through the technical scheme, experiments show that in the manufacturing process of the concrete, when the components in the concrete are in the best proportion, the raw materials in the concrete can exert better performance, and are matched with each other, so that the compressive strength and the crack resistance of the concrete can be improved to some extent, and the practicability and the durability of the concrete can be improved.

Optionally, the particle size of the diatomite is 600-800 meshes.

By adopting the technical scheme, the 600-800-mesh diatomite is beneficial to filling gaps among fine aggregates and further forms gradation with the coarse aggregates and the fine aggregates, so that the compactness of the concrete is improved, and the crack resistance and the compressive strength of the concrete are improved.

Optionally, the length of the carbon fiber is 200-400 μm.

By adopting the technical scheme, the carbon fibers are high-strength and high-modulus fibers with the carbon content of more than 90%, the longer the carbon fibers are in a certain range, the larger the bonding degree between concrete is, the tighter the internal connection of the concrete is, and the more difficult the concrete is to crack, but when the carbon fibers are too long, the load of the concrete is not facilitated, so that the carbon fibers need to keep proper length when in use.

Optionally, the raw materials further comprise 22-26 parts by weight of sodium carboxymethylcellulose or sodium alginate and 150-180 parts by weight of mineral powder.

By adopting the technical scheme, the sodium carboxymethyl cellulose or the sodium alginate has extremely strong bonding and film forming capabilities, the sodium carboxymethyl cellulose or the sodium alginate can enable mineral powder to be tightly filled in coarse aggregate and fine aggregate, so that concrete is not easy to crack, in the concrete preparation process, the addition of the mineral powder can improve the pore structure and strength of the hardened concrete, and part of the mineral powder can be adsorbed on the surface of cement particles, so that a cement flocculation structure which is possibly formed originally cannot be formed, the effect similar to a water reducing agent is achieved, and the durability of the concrete is favorably improved; in addition, the addition of the sodium carboxymethylcellulose or the sodium alginate is beneficial to stabilizing the styrene-acrylic emulsion and enabling the styrene-acrylic emulsion to better play a role.

Optionally, the defoaming agent is at least one of GP-type glyceryl polyether, GPE-type polyoxyethylene ether and PPG-type polypropylene glycol.

Through the technical scheme, the polyether defoamer is non-toxic, odorless and non-irritant, is beneficial to environmental protection of concrete in later use, can be rapidly dispersed when being added into water, has good compatibility with styrene-acrylic emulsion, and is beneficial to quickly and efficiently playing roles in defoaming and foam inhibition in the concrete manufacturing process.

Optionally, the super absorbent resin is prepared by the following method,

1) uniformly mixing methacrylic acid and inorganic base, adding acrylamide, and dispersing for 25-30 min to obtain a mixed solution;

2) adding an initiator and a polymerization agent into the mixed solution obtained in the step 1), uniformly mixing at the temperature of 30-35 ℃, then carrying out microwave radiation at the power of 200-250W, and reacting for 1-2 h to obtain the super absorbent resin;

the weight ratio of the methacrylic acid, the inorganic base, the acrylamide, the initiator and the polymerization agent is 1 (0.9-1.2): (1.5-1.8): 0.07-0.09): 0.5-0.9.

By adopting the technical scheme, the super absorbent resin prepared under specific conditions has a moderately cross-linked three-dimensional network structure, so that the super absorbent resin has enough capacity to store water, and absorbed water cannot be easily lost, therefore, the super absorbent resin prepared by the method has the characteristics of large water absorption capacity and strong water retention.

Optionally, the initiator in the step 2) adopts ammonium persulfate or potassium persulfate, and the polymerizer adopts trimethylolpropane tri (3-aziridinyl propionate).

By adopting the technical scheme, a microwave radiation method is adopted, peroxide with a specific using amount is used as an initiator, the reaction process is activated, and methacrylic acid and acrylamide form a high-molecular three-dimensional cross-linked polymer under the cross-linking action of specific amount of hydroxymethyl propane tri (3-aziridinyl propionate), so that the super absorbent resin has high water absorption performance.

In a second aspect, the present application provides a method for preparing a strong concrete, which adopts the following technical scheme:

the preparation method of the crack-resistant concrete comprises the following steps:

s1, mixing the crushed silica gel with diatomite, heating for 1.5-2 hours at the temperature of 600-800 ℃, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring cement, coarse aggregate, fine aggregate and a defoaming agent for 5-10 min, adding the mixture obtained in the step S1, adding water, fly ash, styrene-acrylic emulsion and a water reducing agent, and mixing and stirring at the temperature of 30-40 ℃ for 15-20 min to obtain a mixture;

s3, stirring the super absorbent resin and the carbon fibers at the temperature of 200-230 ℃ for 6-8 min, cooling to room temperature, adding the mixture into the mixture obtained in the step S2, and mixing and stirring at the rotating speed of 450-500 r/min for 30-35 min to obtain the crack-resistant concrete.

Optionally, the mineral powder is added in step S1, and sodium alginate or sodium carboxymethyl cellulose is added in step S2.

By adopting the technical scheme, the components in the crack-resistant concrete are mixed in batches under a specific condition, so that the components in the crack-resistant concrete can be fully and uniformly mixed, the adhesion of the components in the crack-resistant concrete is improved, the compression strength of the concrete is ensured, the possibility of occurrence of shrinkage cracks in the crack-resistant concrete is reduced, and the durability of the concrete is improved; it is worth mentioning that although the required temperature is higher than the room temperature during the mixing and stirring process in the step S2, the hydration between the cement and the water gives off heat during the concrete preparation process, so that the required heat is provided to the step S2, and the heating operation is not required.

In summary, the present application has the following beneficial effects:

1. the high water-absorbing resin, the diatomite, the styrene-acrylic emulsion, the carbon fibers and the silica gel are added into the crack-resistant concrete, so that the crack-resistant concrete has high water absorption and compressive strength, and can be widely applied to various occasions;

2. the fly ash, the mineral powder and the water reducing agent are added into the crack-resistant concrete, so that the use amount of cement is reduced, the hydration effect is reduced, the compressive strength of the concrete is further enhanced, and the concrete is not suitable for generating shrinkage cracks;

3. the sodium carboxymethylcellulose or the sodium alginate is added into the crack-resistant concrete, so that the maximum advantages of various raw materials in the concrete can be exerted, and the compressive strength and the crack resistance of the concrete can be improved;

4. the preparation method of the crack-resistant concrete is simple in steps, easy to operate, low in cost of used raw materials and suitable for large-scale production.

Detailed Description

The present application will be described in further detail with reference to examples.

In the process of construction and later use of concrete, cracks are often generated due to drying shrinkage, so that normal use of the concrete is influenced, the drying shrinkage is caused by that the internal relative humidity of the concrete is reduced due to the fact that free water is consumed by hydration reaction in the concrete, capillary holes in the concrete are formed, and when the water migration rate in the concrete is lower than the rate of formation of the capillary holes, the capillary holes tend to be in an unsaturated state, so that the concrete is shrunk by self-drying.

In view of the above problems, the inventors propose the following:

the crack-resistant concrete comprises the following raw material components in parts by weight: 340-420 parts of cement, 840-850 parts of coarse aggregate, 460-490 parts of fine aggregate, 150-190 parts of water, 6-8 parts of water reducing agent, 2-3.5 parts of defoaming agent, 200-230 parts of fly ash, 26-32 parts of diatomite, 18-22 parts of super absorbent resin, 40-45 parts of carbon fiber, 45-55 parts of styrene-acrylic emulsion and 0.8-1.2 parts of silica gel.

In order to improve the dry shrinkage crack resistance of the concrete on the basis of ensuring the compressive strength of the concrete, 20-21 parts of super absorbent resin, 1-1.2 parts of silica gel and 42-44 parts of carbon fiber are adopted, and preferably, 42 parts, 42.8 parts or 43 parts of carbon fiber are adopted; 50-53 parts of styrene-acrylic emulsion can be adopted, and preferably, 50 parts, 51 parts or 53 parts of styrene-acrylic emulsion can be adopted.

Sources of raw materials used in the following embodiments:

cement: grade P.042.5 available from Tianjin Zhenxing Cement Co., Ltd, and the physical properties are shown in Table 1;

table 1:

coarse aggregate: selecting pebbles purchased from a yellow stone Qinglong stone crushing plant, wherein the particle size is 5-10 mm, and the apparent density is 2700kg/m³Bulk density 1450kg/m³；

Fine aggregate: selecting coke as river sand with bulk density of 1450kg/m³Fineness modulus 3.2, continuous gradation; fly ash: selecting Hebei Zhengli mineral products, Inc.;

mineral powder: s105-grade blast furnace slag powder of Jinan green jade new material limited, the specific surface area is 525cm2/g, the fluidity ratio is 106%, the specific activity index 7d is 95%, and 28d is 115%;

silica gel: 955 silica gel from clarien chemical ltd;

polycarboxylic acid water reducing agent, naphthalene water reducing agent: the water reducer is purchased from Shanghai-phobia-metallurgy industry Co., Ltd, wherein the model of the polycarboxylic acid water reducer is HPEG-2400; the model of the naphthalene water reducing agent is SDN-C;

GP type glyceryl polyether, GPE type polyoxyethylene ether, and PPG type polypropylene glycol: available from Shandong Haosen New materials, Inc.;

diatomite: purchased from collected mineral products ltd, lingshou county;

carbon fiber: purchased from clariant chemical ltd;

trimethylolpropane tris (3-aziridinyl propionate): purchased from Hubei Xinkang pharmaceutical chemical Co., Ltd;

sodium carboxymethylcellulose, sodium alginate: purchased from xuzhou fengrui biotechnology limited;

styrene-acrylic emulsion, potassium hydroxide, sodium hydroxide: purchased from Shanghai Linfeng Chemicals, Inc.;

methacrylic acid, acrylamide, ammonium persulfate, potassium persulfate: purchased from federal fine chemicals limited, guangdong.

The particle size of the diatomite is 600-800 meshes in the following examples; the length of the cellulose is 200 to 400 μm.

Preparation examples the following preparation examples 1 to 5 are preparation examples of a super absorbent resin, and all the microwave irradiation processes were carried out by placing the materials in an MP3000A microwave radiator.

Preparation example 1

1) Mixing 29kg of methacrylic acid and 26.1kg of sodium hydroxide uniformly, adding 43.5kg of acrylamide, and dispersing for 30min to obtain a mixed solution;

2) adding 2.03kg of ammonium persulfate and 26.1kg of trimethylolpropane tris (3-aziridinyl propionate) into the mixed solution in the step 1), uniformly mixing at the temperature of 30 ℃ and the stirring speed of 350r/min, then performing microwave radiation at the power of 200W, and reacting for 2h to obtain the super absorbent resin.

Preparation example 2

1) Uniformly mixing 31kg of methacrylic acid and 37.2kg of potassium hydroxide, adding 46.5kg of acrylamide, and dispersing for 25min to obtain a mixed solution;

2) adding 2.79kg of ammonium persulfate and 15.5kg of trimethylolpropane tris (3-aziridinyl propionate) into the mixed solution in the step 1), uniformly mixing at the temperature of 35 ℃ and the stirring speed of 300r/min, and then carrying out microwave radiation under the power of 250W for reaction for 1h to obtain the super absorbent resin.

Preparation example 3

1) Uniformly mixing 34kg of methacrylic acid and 30.6kg of ammonia water, adding 61.2kg of acrylamide, and dispersing for 25min to obtain a mixed solution;

2) adding 3.06kg of potassium persulfate and 17kg of trimethylolpropane tris (3-aziridinyl propionate) into the mixed solution in the step 1), uniformly mixing at the temperature of 33 ℃ and the stirring speed of 340r/min, then performing microwave radiation at the power of 230W, and reacting for 1.5h to obtain the super absorbent resin.

Preparation example 4

1) Uniformly mixing 36kg of methacrylic acid and 40.8kg of ammonia water, adding 55.6kg of acrylamide, and dispersing for 28min to obtain a mixed solution;

2) adding 3.2kg of ammonium persulfate and 30.5kg of trimethylolpropane tris (3-aziridinyl propionate) into the mixed solution in the step 1), uniformly mixing at the temperature of 35 ℃ and the stirring speed of 340r/min, then performing microwave radiation at the power of 200W, and reacting for 1h to obtain the super absorbent resin.

Preparation example 5

1) Uniformly mixing 40kg of methacrylic acid and 42.3kg of potassium hydroxide, adding 71.6kg of acrylamide, and dispersing for 26min to obtain a mixed solution;

2) adding 2.8kg of ammonium persulfate and 20kg of trimethylolpropane tris (3-aziridinyl propionate) into the mixed solution in the step 1), uniformly mixing at the temperature of 34 ℃ and the stirring speed of 320r/min, then performing microwave radiation under the power of 240W, and reacting for 2h to obtain the super absorbent resin.

Examples

Example 1

A preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 0.8kg of 955 silica gel, mixing with 32kg of diatomite and 150kg of S105-grade blast furnace slag powder, heating at 800 ℃ for 1.5h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing 380kg of cement, 850kg of stones, 460kg of river sand and 3.5kg of GP type glyceryl polyether at the rotating speed of 400r/min and stirring for 10min, adding the mixture obtained in the step S1, adding 150kg of water, 230kg of fly ash, 45kg of nonionic styrene-acrylic emulsion, 26kg of sodium carboxymethylcellulose and 6kg of polycarboxylic acid water reducer, and mixing and stirring for 15min at the temperature of 40 ℃ to obtain a mixture;

s3, taking 22kg of the super absorbent resin and 40kg of the carbon fiber in the preparation example 1, stirring for 6min at the temperature of 230 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 30min at the rotation speed of 500r/min at room temperature to obtain the crack-resistant concrete.

Example 2

A preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 1.2kg of 955 silica gel, mixing with 26kg of diatomite and 180kg of S105-grade blast furnace slag powder, heating at 600 ℃ for 1.5h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring 420kg of cement, 840kg of stones, 490kg of river sand and 2kg of GPE type polyoxyethylene ether at the rotating speed of 400r/min for 10min, adding the mixture obtained in the step S1, adding 190kg of water, 200kg of fly ash, 55kg of nonionic styrene-acrylic emulsion, 22kg of sodium alginate and 8kg of polynaphthalene water reducer, and mixing and stirring at the temperature of 40 ℃ for 15min to obtain a mixture;

s3, taking 18kg of the super absorbent resin and 45kg of the carbon fiber in the preparation example 2, stirring for 6min at the temperature of 230 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 30min at the rotation speed of 500r/min at room temperature to obtain the crack-resistant concrete.

Example 3

S1, crushing 1.2kg of 955 silica gel, mixing with 26kg of diatomite and 180kg of S105-grade blast furnace slag powder, heating at 800 ℃ for 2h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring 420kg of cement, 840kg of stones, 490kg of river sand and 2kg of PPG type polypropylene glycol at the rotating speed of 600r/min for 10min, adding the mixture obtained in the step S1, adding 190kg of water, 200kg of fly ash, 55kg of nonionic styrene-acrylic emulsion, 22kg of sodium alginate and 8kg of polycarboxylic acid water reducer, mixing and stirring at the temperature of 30 ℃ for 15min to obtain a mixture;

s3, taking 18kg of the super absorbent resin and 45kg of the carbon fiber in the preparation example 3, stirring for 6min at the temperature of 230 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 35min at the rotation speed of 450r/min at room temperature to obtain the crack-resistant concrete.

Example 4

A preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 1kg955 silica gel, mixing with 31kg diatomite and 150kg S105-grade blast furnace slag powder, heating at 700 ℃ for 1.8h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring 400kg of cement, 840kg of stones, 480kg of river sand, 2.1kg of GP-type glycerol polyether and 1.1kg of GPE-type polyoxyethylene ether at the rotating speed of 500r/min for 8min, adding the mixture obtained in the step S1, adding 160kg of water, 225kg of fly ash, 50kg of nonionic styrene-acrylic emulsion, 26kg of sodium carboxymethylcellulose and 7kg of naphthalene water reducer, and mixing and stirring at the temperature of 35 ℃ for 18min to obtain a mixture;

s3, taking 20kg of the super absorbent resin and 44kg of the carbon fiber in the preparation example 4, stirring for 7min at the temperature of 220 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 35min at the room temperature and the rotating speed of 480r/min to obtain the crack-resistant concrete.

Example 5

A preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 1.2kg of 955 silica gel, mixing with 29kg of diatomite and 180kg of S105-grade blast furnace slag powder, heating at 700 ℃ for 1.8h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing 380kg of cement, 845kg of stones, 470kg of river sand, 1.8kg of GP type glyceryl polyether and 1.7kg of PPG type polypropylene glycol at the rotating speed of 430r/min, stirring for 7min, adding the mixture obtained in the step S1, adding 180kg of water, 220kg of fly ash, 51kg of nonionic styrene-acrylic emulsion, 24kg of sodium carboxymethylcellulose and 8kg of polycarboxylic acid water reducer, and mixing and stirring for 16min at the temperature of 35 ℃ to obtain a mixture;

s3, taking 21kg of the super absorbent resin and 42kg of the carbon fiber in the preparation example 5, stirring at 210 ℃ for 6.5min, cooling to room temperature, adding into the mixture obtained in the step S2, and mixing and stirring at room temperature and at the rotating speed of 480r/min for 33min to obtain the crack-resistant concrete.

Example 6

A preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 1.1kg955 silica gel, mixing with 30kg diatomite and 156kg S105-grade blast furnace slag powder, heating at 700 ℃ for 1.8h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring 390kg of cement, 845kg of pebble, 476kg of river sand, 2.1kg of GP-type glycerol polyether and 1.3kg of GPE-type polyoxyethylene ether at the rotating speed of 500r/min for 8min, adding the mixture obtained in the step S1, adding 172kg of water, 220kg of fly ash, 52kg of nonionic styrene-acrylic emulsion, 24kg of sodium carboxymethylcellulose and 7.5kg of naphthalene-based water reducer, and mixing and stirring at the temperature of 35 ℃ for 18min to obtain a mixture;

s3, taking 20.3kg of the super absorbent resin and 43kg of the carbon fiber in the preparation example 4, stirring for 7min at the temperature of 220 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 35min at the rotation speed of 480r/min at room temperature to obtain the crack-resistant concrete.

Example 7

The difference from example 6 is that: in step S3, 40kg of carbon fibers were added.

Example 8

The difference from example 6 is that: in step S3, 45kg of carbon fibers were added.

Example 9

The difference from example 6 is that: in step S1, 0.8kg of silica gel was added.

Example 10

The difference from example 6 is that: in step S1, 1.0kg of silica gel was added.

Example 11

The difference from example 6 is that: in step S1, 1.2kg of silica gel was added.

Example 12

A preparation method of crack-resistant concrete comprises the following steps:

example 6 differs in that 45kg of a nonionic styrene-acrylic emulsion was added in step S2.

Example 13

A preparation method of crack-resistant concrete comprises the following steps:

example 6 is different in that 50kg of a nonionic styrene-acrylic emulsion was added in step S2.

Example 14

A preparation method of crack-resistant concrete comprises the following steps:

example 6 differs in that 55kg of a nonionic styrene-acrylic emulsion was added in step S2.

Example 15

The difference from example 6 is that: no S105-grade blast furnace slag powder was added in step S1, and no sodium carboxymethylcellulose was added in step S2.

Example 16

The difference from example 6 is that: sodium carboxymethylcellulose was not added in step S2.

Comparative example

Comparative example 1

The crack-resistant concrete was prepared using the following preparation method:

s1, crushing 0.7kg of 955 silica gel, mixing with 35kg of diatomite and 190kg of S105-grade blast furnace slag powder, heating at 800 ℃ for 1.5h, and naturally cooling to room temperature to obtain a mixture, wherein the granularity of the diatomite is 600-800 meshes;

s2, mixing and stirring 440kg of cement, 900kg of stones, 430kg of river sand and 3.6kg of GP type glyceryl polyether for 10min at the rotating speed of 400r/min, adding the mixture obtained in the step S1, adding 200kg of water, 400kg of fly ash, 30kg of nonionic styrene-acrylic emulsion, 21kg of sodium carboxymethylcellulose and 6kg of polycarboxylic acid water reducer, and mixing and stirring for 15min at the temperature of 40 ℃ to obtain a mixture;

s3, stirring 30kg of the super absorbent resin and 60kg of the carbon fiber in preparation example 1 at 230 ℃ for 6min, cooling to room temperature, adding into the mixture obtained in the step S2, and mixing and stirring at room temperature and a rotation speed of 500r/min for 30min to obtain the crack-resistant concrete, wherein the length of the cellulose is 200-400 microns.

Comparative example 2

The crack-resistant concrete was prepared using the following preparation method: a preparation method of crack-resistant concrete comprises the following steps:

s1, crushing 0.8kg of 955 silica gel, mixing with 32kg of diatomite and 150kg of S105-grade blast furnace slag powder, heating at 900 ℃ for 1h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing 380kg of cement, 850kg of stones, 460kg of river sand and 3.5kg of GP type glyceryl polyether at the rotating speed of 600r/min and stirring for 20min, adding the mixture obtained in the step S1, adding 150kg of water, 230kg of fly ash, 45kg of nonionic styrene-acrylic emulsion, 26kg of sodium carboxymethylcellulose and 6kg of polycarboxylic acid water reducer, and mixing and stirring at the temperature of 80 ℃ for 10min to obtain a mixture;

s3, taking 22kg of the super absorbent resin and 40kg of the carbon fiber in preparation example 1, stirring for 10min at the temperature of 300 ℃, cooling to room temperature, then adding into the mixture obtained in the step S2, and mixing and stirring for 30min at the temperature of 70 ℃ and the temperature of room temperature and at the rotating speed of 600r/min to obtain the crack-resistant concrete, wherein the length of the cellulose is 200-400 microns.

Comparative example 3

the difference from example 6 is that: in step S1, diatomaceous earth and 955 silica gel were not added, styrene-acrylic emulsion was not added in step S2, and super absorbent resin and carbon fiber were not added in step S3.

Comparative example 4

the difference from example 6 is that: in step S1, diatomaceous earth and 955 silica gel were not added, in step 2, styrene-acrylic emulsion was not added, and in step S3, carbon fiber was not added.

Comparative example 5

the difference from example 6 is that: in step S1, diatomaceous earth and 955 silica gel were not added, and in step 2, styrene-acrylic emulsion was not added.

Comparative example 6

the difference from example 6 is that: in step S1, no diatomaceous earth was added, and in step 2, no styrene-acrylic emulsion was added.

Comparative example 7

the difference from example 6 is that: in step S2, no nonionic styrene-acrylic emulsion is added.

Comparative example 8

the difference from example 6 is that: no 955 silica gel was added in step S1, 32kg of diatomaceous earth was added, and no nonionic styrene-acrylic emulsion was added in step S2.

Comparative example 9

the difference from example 6 is that: all the substances in example 8 were mixed at once and stirred at 480r/min for 33min at room temperature.

Comparative example 10

the difference from example 6 is that: GP type glyceryl polyether and PPG type polypropylene glycol are not added in the step S2.

Comparative example 11

the difference from example 6 is that: the diatomite has a particle size of 400-500 meshes and the carbon fiber has a length of 600-800 μm.

Performance test

The concrete prepared in examples 1 to 12 and comparative examples 1 to 11 was examined for compressive strength and crack resistance. According to GB/T50081-2002 standard of mechanical property test method of common concrete, 28d compressive strength (MPa) and 28d flexural strength (MPa) of concrete are detected, and the test results are shown in Table 2; and the crack resistance of the concrete is tested according to the circular ring method in the national standard, and the experimental data are shown in the table 2.

Table 2:

table continuation:

table continuation:

table continuation:

as can be seen from table 2:

the 28d compressive strength and the 28d flexural strength of the anti-crack concrete prepared in the embodiments 1-16 are respectively 49.4-55.1 MPa and 5.1-6.7 MPa; the cracking time is more than 166 hours, the cracking degree is not more than 1cm, and the comparison of the data in the examples 1-16 and the comparative examples 1-11 shows that the anti-cracking concrete prepared by the preparation method in the range has higher compressive strength and anti-cracking performance, particularly, the substances in the example 6 are used in combination to achieve better anti-cracking performance and compressive strength, and the anti-cracking concrete prepared by the preparation method in the range can be widely applied to various occasions.

Comparing example 1 with comparative example 1, it can be found that the mixture ratio of the materials has a great influence on the cracking resistance and compressive strength of the concrete, and when the mixture ratio of the materials outside the range defined in the application is used, the cracking resistance and compressive strength of the concrete are greatly reduced.

As can be seen from comparative examples 3 to 6, when diatomaceous earth, 955 silica gel, styrene-acrylic emulsion, carbon fiber, and super absorbent resin were not added to the concrete, the concrete had a certain compressive strength, but the crack resistance was poor; when only the super absorbent resin is added into the concrete (comparative example 4), although the crack resistance of the concrete is enhanced, the compressive strength is reduced, so that the application adds the carbon fiber into the crack-resistant concrete (comparative example 5), and the data shows that the compressive strength of the comparative example 5 is improved and the crack resistance is slightly improved; and comparing examples 6-8, it can be known that when the amount of the carbon fiber is 43kg, the anti-cracking concrete prepared by the method has better compressive strength and anti-cracking performance, and further, the raw material ratio is one of the important factors influencing the compressive strength and the anti-cracking performance of the concrete.

According to the application, the silica gel is continuously added on the basis to continuously improve the anti-cracking performance of the anti-cracking concrete, the data of the comparative example 6 shows that the anti-cracking performance of the concrete after the silica gel is added is really and remarkably improved, and the compressive strength of the concrete is basically kept unchanged, but according to the data of the example 6 and the examples 9-11, when the amount of the silica gel is gradually increased, the anti-cracking strength of the concrete is gradually increased and then tends to be stable.

In order to further enhance the crack resistance of the crack-resistant concrete, the diatomite is added on the basis of the comparative example 6 to obtain the data of the comparative example 7, and the data obviously shows that the crack resistance and the compression resistance of the concrete added with the diatomite are greatly improved, so that an unexpected effect is achieved.

It can be seen from comparative example 8 that when only diatomite is added, but not 955 silica gel, during the concrete preparation process, the crack resistance and compressive resistance of the obtained concrete are both improved, but the crack resistance and compressive resistance of the concrete are inferior to those of the concrete prepared in comparative example 7. Therefore, the diatomite and the 955 silica gel have a synergistic effect and are not necessary, and probably because the diatomite and the 955 silica gel are both in a porous structure, gradation can be formed in concrete, the compressive strength of the concrete is enhanced, and water can be stored and released in the diatomite and the 955 silica gel, so that the water loss rate in the concrete can be reduced, and the anti-cracking performance of the concrete is enhanced.

It can be known from the data of comparative example 7 and example 6 that the anti-cracking performance and the compressive performance of the concrete are greatly affected and increased due to the interaction between the styrene-acrylic emulsion and other substances in the concrete, so that the interior of the concrete is not easy to crack or separate from each other, and the compressive resistance and the crack resistance of the concrete are improved.

Comparing example 6 with examples 12-14, it can be seen that when the amount of the non-ionic styrene-acrylic emulsion is 51kg, the anti-crack concrete prepared by the method of the present application has better compressive strength, the cracking time is prolonged, and the crack width is smaller;

it can be known from the comparison between the example 6 and the examples 15 to 16 that, when the S105-grade slag powder and the sodium carboxymethylcellulose (sodium carboxymethylcellulose can be replaced by sodium alginate) should be added into the concrete in the preparation process, the performance is significantly improved compared with the case of adding either one of them in combination, and the reason for this is probably that the S105-grade slag powder can interact with the sodium carboxymethylcellulose or the sodium alginate, so that the compactness of the internal structure of the anti-crack concrete is improved, the anti-crack concrete is not easy to deform and crack, and can bear higher pressure, and thus the compressive strength and the anti-crack performance of the anti-crack concrete are improved.

In addition, as can be seen from comparison of example 1 and comparative example 2, the crack-resistant concrete with superior properties in various aspects could not be obtained by any preparation method, and the crack resistance and compressive strength of the crack-resistant concrete prepared in comparison 2 were both reduced, which indicates that the preparation method of the crack-resistant concrete provided by the present application can sufficiently combine the raw materials to exert superior properties, and that the data in comparative example 9 can also demonstrate that the properties of the crack-resistant concrete prepared by mixing all the ingredients provided by the present application at one time are not very good in various aspects.

Comparing example 6 with comparative example 10, it can be seen that the defoaming agent (GP type glyceryl polyether, GPE type polyoxyethylene ether or PPG type polypropylene glycol) has the greatest effect on the compressive strength of the anti-crack concrete, probably because the use of the defoaming agent can make the interior of the concrete compact by defoaming and foam inhibition, and the situation of loose texture is not easy to occur, thus being beneficial to the compressive resistance of the concrete.

It can be seen from comparison between example 6 and comparative example 11 that the length of the carbon fiber and the particle size of the alginic soil also have a great influence on the compressive strength and crack resistance of the crack-resistant concrete because the carbon fiber and the alginic soil have a synergistic effect with other raw materials.

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

1. The crack-resistant concrete is characterized by comprising the following raw material components in parts by weight:

340-420 parts of cement, 840-850 parts of coarse aggregate, 460-490 parts of fine aggregate, 150-190 parts of water, 6-8 parts of water reducing agent, 2-3.5 parts of defoaming agent, 200-230 parts of fly ash, 26-32 parts of diatomite, 18-22 parts of super absorbent resin, 40-45 parts of carbon fiber, 45-55 parts of styrene-acrylic emulsion and 0.8-1.2 parts of silica gel, wherein the raw material further comprises 22-26 parts of sodium carboxymethylcellulose or sodium alginate and further comprises 150-180 parts of mineral powder;

the 28d compressive strength of the anti-cracking concrete is 49.4-55.1 MPa, and the 28d flexural strength is 5.1-6.7 MPa.

2. A crack resistant concrete according to claim 1, characterized in that: the raw materials comprise the following raw material components in parts by weight:

3. A crack resistant concrete according to claim 1, characterized in that: the particle size of the diatomite is 600-800 meshes.

4. A crack resistant concrete according to claim 1, characterized in that: the length of the carbon fiber is 200-400 mu m.

5. A crack resistant concrete according to claim 1, characterized in that: the defoaming agent adopts at least one of GP type glyceryl polyether, GPE type polyoxyethylene ether and PPG type polypropylene glycol.

6. A crack resistant concrete according to claim 1, characterized in that: the super absorbent resin is prepared by adopting the following method,

7. A crack resistant concrete according to claim 6, characterized in that: in the step 2), ammonium persulfate or potassium persulfate is adopted as the initiator, and trimethylolpropane tri (3-aziridinyl propionate) is adopted as the polymerizer.

8. A method for the preparation of a crack-resistant concrete according to any one of claims 1 to 4, characterized in that: comprises the following steps of (a) carrying out,

s1, mixing the crushed silica gel with diatomite, heating at 600-800 ℃ for 1.5-2 h, and naturally cooling to room temperature to obtain a mixture;

s2, mixing and stirring cement, coarse aggregate, fine aggregate and a defoaming agent for 5-10 min, adding the mixture obtained in the step S1, adding water, fly ash, a styrene-acrylic emulsion and a water reducing agent, and mixing and stirring at the temperature of 30-40 ℃ for 15-20 min to obtain a mixture;

9. A method of producing a crack resistant concrete according to claim 8, characterised in that: the mineral powder is added in the step S1, and sodium alginate or sodium carboxymethyl cellulose is added in the step S2.