CN116040996A

CN116040996A - Bare concrete and construction process thereof

Info

Publication number: CN116040996A
Application number: CN202210710975.8A
Authority: CN
Inventors: 孙建伟; 汤飞燕; 祁晓霞; 周成; 杨小松
Original assignee: Jiangsu Wujin Construction Engineering Group Co ltd
Current assignee: Jiangsu Wujin Construction Engineering Group Co ltd
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2023-05-02

Abstract

The application relates to the field of building materials, and particularly discloses bare concrete and a construction method thereof. The bare concrete comprises the following substances in parts by weight: 1 part of cement, 2.55-9.31 parts of coarse aggregate, 1.38-7.62 parts of fine aggregate, 0.39-1.21 parts of doping material, 0.4-1.2 parts of additive, 0-0.154 parts of expanding agent and 0.42-1.84 parts of water, wherein the fine aggregate comprises middle sand with the mud content less than or equal to 2%, the fine aggregate also comprises light sand, the additive comprises an air entraining agent, and the additive also comprises a water reducing agent, a thickening agent and a defoaming agent; the preparation method comprises the following steps: s1, mixing raw materials; s2, preparing a template; s3, preparing bare concrete. The bare concrete can be used in the fields of subway stations, airports, open sea engineering and the like, and has the advantages of neat and attractive appearance and high durability.

Description

Bare concrete and construction process thereof

Technical Field

The application relates to the field of building materials, in particular to bare concrete and a construction process thereof.

Background

The bare concrete is classified into bare concrete (simply referred to as faced bare concrete) having a decorative effect and ordinary bare concrete according to its surface texture. The former not only has the texture of the concrete, but also has the characteristics of basically consistent surface color, and the appearance is neat and beautiful and exquisite; the latter is mainly represented by the natural quality of concrete and the style of color and luster coordination.

The natural texture of the bare concrete is widely applied to the fields of subways, airports, open sea engineering and the like in recent years, people in the environments of subways, airports and the like are dense in flow, the content of carbon dioxide in the environments is high, the environments of the open sea engineering are rich in chloride salt, the environments rich in chloride salt and the environments rich in carbon dioxide can cause stronger corrosion to the bare concrete, and the service life of the bare concrete is shortened. At present, fly ash is mostly added into the bare concrete to improve the durability of the bare concrete.

Aiming at the related technology, the inventor considers that fly ash is simply added into the concrete, and the fly ash has darker color, so that the bare concrete is more prone to chromatic aberration and bubbles, the surface texture of the bare concrete is disappeared, air holes are generated, and the bare concrete is further eroded by corrosive gas in an environment filled with corrosive gas, so that the defect of poor durability of the bare concrete is caused.

Disclosure of Invention

In order to overcome the defect of poor durability of the bare concrete, the application provides the bare concrete and a construction process thereof.

In a first aspect, the present application provides a bare concrete, which adopts the following technical scheme:

the bare concrete comprises the following substances in parts by weight: 40-50 parts of cement, 100-110 parts of coarse aggregate, 70-80 parts of fine aggregate, 4-10 parts of doping material, 0.4-1.2 parts of additive and 15-25 parts of water, wherein the fine aggregate comprises middle coarse sand with the mud content less than or equal to 2%, the fine aggregate further comprises light sand, the particle size of the coarse aggregate is less than or equal to 25mm, the coarse aggregate is coarse aggregate with three-stage continuous grading, the additive comprises an air entraining agent, and the additive further comprises a water reducing agent, a thickening agent and a defoaming agent.

Through adopting above-mentioned technical scheme, at first, this application technical scheme has optimized the mud content of fine aggregate, and lower mud content not only can reduce the colour difference of bare concrete, can also reduce the content of chloride ion in the bare concrete, has reduced the corrosion effect of chloride ion to the concrete, prolongs the durability of bare concrete.

Secondly, the technical scheme adds light sand and an air entraining agent to the bare concrete for matching, the light sand is regular and round, the roundness of the fine aggregate is improved, the fine aggregate has a ball effect, and therefore the fluidity of the bare concrete is improved; the air entraining agent can introduce more tiny bubbles into the bare concrete, and the tiny bubbles can reduce friction force between gravel such as fine aggregate and coarse aggregate, so that the sliding-assisting effect similar to balls is achieved, and therefore, the workability of the bare concrete and the dispersion uniformity among all components can be synergistically improved through the matching of the light sand and the air entraining agent, the generation of macropores in the bare concrete is reduced, and the self-compaction effect and the corrosion-resistant effect of the bare concrete are improved.

And finally, the defoamer is selected to be matched with the air entraining agent, bad bubbles in the bare concrete are destroyed through the defoamer, and the content of ball bubbles in the bare concrete is regulated, so that the fluidity of the bare concrete can be improved, and the self-compaction effect of the bare concrete can be reduced. And the addition of a proper amount of thickener can adjust the plastic viscosity of the bare concrete, improve the discharge rate of bubbles in the bare concrete and effectively improve the compactness and durability of the bare concrete.

Preferably, the coarse aggregate comprises a first coarse aggregate with the particle size of 5-16mm and a second coarse aggregate with the particle size of 5-31.5mm, and the coarse aggregate is a coarse aggregate with three-stage continuous grading.

Through adopting above-mentioned technical scheme, this application technical scheme adopts first coarse aggregate and second coarse aggregate to form continuous gradation coarse aggregate, and the great pore structure that consequently second coarse aggregate formed can be filled by first coarse aggregate, effectively reduces the hole in the bare concrete, improves the compactness of bare concrete, has reduced the possibility that carbon dioxide etc. in the environment eroded the bare concrete inside along the bare concrete hole.

Preferably, the coarse aggregate is modified by a modifier, the modifier is a nanoscale modifier, and the modifier comprises any one of titanium dioxide, zinc oxide, boron oxide, ferric oxide and tin oxide.

Through adopting above-mentioned technical scheme, firstly, titanium dioxide is to coarse aggregate modification, because coarse aggregate surface has coarse surface structure, therefore titanium dioxide can fill coarse surface structure of coarse aggregate, improves coarse aggregate's surface smoothness, reduces the pore structure that produces because of coarse aggregate surface coarse structure in the concrete. In addition, the titanium dioxide has better photocatalytic activity, and under illumination, the titanium dioxide can decompose dirt, impurities and the like loaded on the surface of the concrete into water-soluble micromolecules, so that the impurities can be easily cleaned off under ordinary cleaning, the possibility that the dirt, the impurities and the like are long-time loaded on the surface of the concrete to corrode the concrete to generate a rough surface is reduced, and the corrosion resistance effect of the concrete is improved.

Meanwhile, titanium dioxide can catalyze and decompose nitrogen-containing waste gas in the environment, so that the existence of pollution gas in the environment can be reduced, and further the corrosion of the pollution gas in the environment to concrete is reduced.

Secondly, zinc oxide, boron oxide, ferric oxide and tin oxide all have better photocatalytic activity, after the coarse aggregate is modified, the modifier can be loaded on the coarse aggregate, the coarse surface of the coarse aggregate is blocked and wrapped, the pores generated among the coarse aggregates are reduced, and the photocatalytic activity of the coarse aggregate is endowed.

Preferably, the modification treatment comprises the steps of: respectively taking 3-5 parts of modifier, 30-50 parts of water and 1-2 parts of zeolite, soaking the zeolite in alkali liquor, stirring and mixing, heating, taking out and cooling to obtain zeolite subjected to alkali heat pretreatment; mixing modifier and water under stirring to obtain suspension, soaking zeolite and coarse aggregate subjected to alkali heat pretreatment in the suspension, stirring, mixing, standing, and oven drying to obtain modified coarse aggregate.

By adopting the technical scheme, alkali thermal pretreatment is preferably carried out on zeolite in the technical scheme, so that ash and organic impurities on the surface of the zeolite can be removed, and the smoothness of zeolite pore channels is improved; the specific surface area and the surface activity of the zeolite are effectively improved, and the surface pores and the surface attraction of the zeolite enable the zeolite to disperse and fix the modifier; the possibility of agglomeration of the modifier is reduced, so that the modifier can uniformly wrap zeolite and coarse aggregate, and the photocatalytic activity is fully exerted.

And zeolite can be adsorbed in the larger concave position of the coarse aggregate, so that the coarse aggregate can obtain a flat surface structure, and the pore structure in the bare concrete is further reduced. Moreover, by adding zeolite, the concrete can be induced to generate more hydrated gel, the binding property and compactness among the components in the concrete are improved, the alkali content of the bare concrete is reduced, and the durability of the concrete is further improved. In addition, the porous structure of the zeolite can absorb water in the initial stage of the concrete reaction, and the water is discharged when the concrete is hydrated, so that the internal curing effect is realized.

Preferably, the defoaming agent is of a shell-core structure, the defoaming agent comprises a core material and a shell material, the core material comprises polyether modified silicone oil, MQ silicone resin, an emulsifying agent, dimethyl silicone oil and sodium carboxymethyl cellulose in a mass ratio of 10-30:37-38:3:100:1, and the shell material comprises any one of cyclodextrin, gelatin and urea formaldehyde resin.

Through adopting above-mentioned technical scheme, first of all, the defoaming agent that adopts shell and core structure among the technical scheme of this application is preferred adds to the concrete, the kernel material slowly releases to the concrete through the shell material, consequently in the initial stage of concrete stirring, a small amount of defoaming agent material release, only destroy bad big bubble in the concrete, maintain the even tiny bubble that air entraining agent brought in the concrete, can stabilize the effect that plays the ball in the concrete, the mobility of concrete has been improved, the fine aggregate can effectively fill to coarse aggregate's hole department, improve the compactness of concrete, reduce the corruption of carbon dioxide etc. to bare concrete in the environment.

And secondly, polyether modified silicone oil, an emulsifier, dimethyl silicone oil and sodium carboxymethyl cellulose are adopted to be matched as a core material, the addition of the polyether modified silicone oil can effectively improve the defoaming performance and the foam inhibition performance of the core material, and the addition of the sodium carboxymethyl cellulose can effectively promote the combination between the polyether modified silicone oil and the dimethyl silicone oil and between the polyether modified silicone oil and the MQ silicone resin. The core material can be wrapped by cyclodextrin, gelatin or urea formaldehyde resin to form the defoaming agent with a shell-core structure.

Preferably, the preparation of the core material comprises the following steps: polyether modified silicone oil, MQ resin, an emulsifier, dimethyl silicone oil and sodium carboxymethyl cellulose are taken according to a formula, stirred and mixed, sheared and emulsified, wherein the shearing rate is 9000-12000r/min, and the emulsifying time is 10-15min.

Through adopting above-mentioned technical scheme, optimized the shear rate and the emulsification time of kernel material in this application technical scheme, suitable shear rate and emulsification time can improve the stability of kernel material, reduces the possibility of kernel material layering. The shear rate is too high, a large amount of bubbles are introduced into the core material, so that the core material forms a three-phase system, and the stability of the core material is reduced.

Preferably, the defoaming agent is coated with a reinforcing layer outside the shell-core structure, the reinforcing layer is composed of a reinforcing agent, and the reinforcing agent comprises any one of nano silicon dioxide, graphene oxide and nano nickel powder.

Through adopting above-mentioned technical scheme, adopt in this application technical scheme to have the enhancement layer at the outer cladding of defoaming agent shell nuclear structure, through the setting of enhancement layer, can improve the intensity of defoaming agent shell, reduce the possibility that defoaming agent is broken fast in concrete mixing process, extension defoaming agent slow-release time, maintain the mobility of bare concrete, improve the compactness of concrete. After the concrete is vibrated, the defoaming agent shell is broken, and the reinforcing layer loaded on the defoaming agent shell is broken and filled in the pores of the concrete, so that the compactness of the concrete is further improved.

Secondly, the particles of the nano silicon dioxide and the nano nickel powder are smaller, so that the pores of the concrete can be effectively filled. The lamellar structure of the graphene dioxide can realize lamellar penetration in the concrete, and further improves the combination property and compactness of the concrete.

Preferably, the light sand comprises any one of shale ceramic sand, perlite expanded rock and Yundan, and the light sand is subjected to pre-wetting treatment.

Through adopting above-mentioned technical scheme, the preferential light sand of carrying out the prewetting in this application technical scheme is handled, through the absorption partial moisture of light sand advance, reduce the absorption of light sand to moisture in the concrete, and when the concrete produced the hydrogel, release moisture, effectively play the effect of interior maintenance in the concrete, eliminated because of inhibiting the tensile stress that self-contraction produced, reduce the concrete and produce the possibility of shrinkage crack when drying, improved the integrality of concrete, compressive strength and chloride ion content.

Shale ceramic sand, perlite and cloud concrete stone all have more pore structures, so that after the concrete is matched, the shale ceramic sand, the perlite and the cloud concrete stone can form a continuous interface transition layer with a cementing material in the concrete and hydration gel generated by the cementing material, and therefore, the interface transition layer is not easy to crack, the number of microcracks in the concrete is reduced, the compactness of the concrete is improved, the mechanical property of the concrete is improved, and the content of chloride ions in the concrete and the permeation effect of the chloride ions are also improved.

In a second aspect, the application provides a construction process of bare concrete, which adopts the following technical scheme:

a construction process of bare concrete comprises the following construction steps: s1, mixing raw materials: respectively taking cement, coarse aggregate, fine aggregate, doping material, additive, expanding agent and water according to a formula, and stirring and mixing to obtain premix; s2, preparing a template: the method comprises the steps of construction joint roughening cleaning, positioning paying-off, terrace leveling and supplementing lines, vertical reinforcement adjustment protection layers, temporary frames, reinforcement binding, construction joint cleaning (reinforcement concealing checking and accepting), reinforcement bent frame erection, template manufacturing and assembling, clear water surface screw fastening (reinforcement protection layer treatment), template reinforcement and checking and accepting to obtain templates; s3, preparing bare concrete: pouring the premix into a template, pouring the premix according to the height of the template, vibrating the premix for multiple times, drying, removing the mould, and maintaining the premix to obtain the bare concrete.

Through adopting above-mentioned technical scheme, the mode filling concrete that adopts the mode of pouring in the preferred branch of this application, multitime vibration can effectively reduce bad bubble in the concrete to can make the shell of defoaming agent break in the multitime vibration, make defoaming agent kernel material flow out completely, further eliminate the inside bubble of concrete, improve the compactness of concrete, reduce the chloride ion content in the concrete, reduce the erosion of harmful gas to the concrete in the environment, effectively improve the durability of concrete.

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

1. according to the method, the light sand and the air entraining agent are matched, and the light sand is matched with the tiny bubbles introduced by the air entraining agent through a round structure of the light sand to be used as 'balls' in the concrete, so that the friction force between the fine aggregate, the coarse aggregate and other gravel is reduced through the ball effect, the fluidity of the concrete is improved, the components in the concrete can be uniformly dispersed and effectively filled, and the bad pores in the concrete are effectively reduced; the defoaming agent and the thickening agent are added, so that bad bubbles in the concrete can be eliminated, the content of ball bubbles in the bare concrete and the bubble discharge rate can be regulated, and the fluidity and compactness of the concrete are further improved, therefore, the concrete has excellent self-compaction effect and corrosion resistance effect.

2. The defoaming agent with the shell-core structure is preferably adopted in the application, the release speed of the defoaming component in the concrete is regulated, so that in the initial stage of concrete stirring, the defoaming agent mainly eliminates bad bubbles in the concrete, maintains the existence of tiny bubbles in the concrete, maintains the ball effect in the concrete, slowly releases the defoaming component along with stirring, and finally breaks the shell of the defoaming agent in vibrating, the defoaming component completely flows outwards and effectively destroys bubbles in the concrete, and the self-compaction effect of the concrete is effectively improved, so that the concrete has better corrosion resistance effect.

3. According to the method, the concrete is filled in a mode of pouring and vibrating for multiple times, bad bubbles in the concrete can be effectively reduced, the shell of the defoaming agent can be broken in vibrating for multiple times, bubbles in the concrete are further eliminated, the compactness of the concrete is improved, and the durability of the concrete is effectively improved.

Detailed Description

The present application is described in further detail below with reference to examples.

In the embodiment of the present application, the selected instruments and devices are shown below, but not limited to:

instrument: lu Ke TLY-1 slump tester and T H6009 digital display pressure tester.

Preparation example

Light sand preparation example

Preparation examples 1 to 4

Shale ceramic sand, perlite expanded rock and Yundan are respectively taken, and concrete mass is shown in table 1, so that light sand 1-4 is prepared.

Table 1 preparation examples 1-4 light sand composition

Preparation example 5

The difference from preparation example 4 is that: soaking the light sand 4 in water for 60min, taking out the light sand, and wiping with dry cloth to obtain the light sand subjected to pre-wetting treatment.

Preparation example 6

80kg of light sand 1 with the mud content less than or equal to 2% and 20kg of neutralization are respectively taken to prepare the fine aggregate 1.

Preparation examples 7 to 10

The difference from preparation example 6 is that: light sand 2-4, pre-wet light sand was used instead of light sand 1 in preparation example 6 to prepare fine aggregate 2-5.

Preparation of modifier

PREPARATION EXAMPLE 11

10kg of titanium dioxide was taken as modifier 1.

Preparation example 12

10kg of zinc oxide was taken as modifier 2.

Among others, it is worth noting that the modifier includes, but is not limited to, any one or more of titanium dioxide, zinc oxide, boron oxide, iron oxide, tin oxide.

Preparation example of modified coarse aggregate

Preparation examples 13 to 15

Coarse aggregate, modifier 1, water and zeolite were weighed separately, and specific mass is shown in table 2. Soaking zeolite in 10% sodium hydroxide solution, magnetically stirring for 6 hr, washing with water to neutrality, oven drying, calcining at 400 deg.c for 2 hr, taking out, and cooling to obtain alkali heat pretreated zeolite. Mixing modifier and water under stirring to obtain suspension, soaking coarse aggregate and zeolite in the suspension for 24 hr, standing, taking out, and oven drying to obtain modified coarse aggregate 1-3.

Wherein the coarse aggregate comprises a first coarse aggregate with the grain size of 5-15mm and a second coarse aggregate with the grain size of 5-31.5 mm.

TABLE 2 preparation examples 13-15 modified coarse aggregate composition

PREPARATION EXAMPLE 16

The difference from preparation example 14 is that: the modified coarse aggregate 4 was obtained by using the modifier 2 instead of the modifier 1 in preparation example 14.

Preparation of defoamer

Preparation examples 17 to 19

Polyether modified silicone oil, MQ silicone resin (the relative molecular mass is 1000), an emulsifier, dimethyl silicone oil and sodium carboxymethyl cellulose are respectively taken as the core materials, and the specific mass is shown in Table 3. Cyclodextrin is taken as a shell material. Wherein the MQ silicone resin is CY-D2 MQ silicone resin.

And (3) stirring and mixing polyether modified silicone oil, MQ silicone resin, an emulsifier, dimethyl silicone oil and sodium carboxymethylcellulose, controlling the shear rate to 9000r/min, and emulsifying for 10min to obtain the core material. Mixing cyclodextrin and water, heating to 70deg.C to obtain shell solution, adding the shell solution into core material, stirring, precipitating, filtering to obtain solid, and drying to obtain defoamer 1-3.

The preparation method of the polyether modified silicone oil comprises the following steps: taking 0.83kg of methyl hydrogen-containing silicone oil (the relative molecular weight is 254.59), 1kg of F-6 type unsaturated polyether (the relative molecular weight is 600), 0.2kg of vinyl glycol ether, heating to 120 ℃ under nitrogen atmosphere, adding 0.003kg of platinum catalyst, reacting at constant temperature for 3 hours, and cooling to below 40 ℃ to obtain polyether modified silicone oil.

TABLE 3 preparation examples 17-19 defoamer composition

Preparation example 20

The difference from preparation 18 is that: the shearing speed is controlled to be 1100r/min, the emulsifying time is controlled to be 15min, and the defoamer 4 is prepared.

Preparation example 21

The difference from preparation 18 is that: the shearing speed is controlled to be 1200r/min, the emulsifying time is controlled to be 20min, and the defoamer 5 is prepared.

PREPARATION EXAMPLE 22

The difference from preparation 18 is that: using gelatin as a shell material instead of cyclodextrin in preparation example 18, defoamer 6 was prepared.

Preparation example 23

The difference from preparation 18 is that: the defoaming agent 7 was prepared using urea resin as the shell material instead of cyclodextrin in preparation example 18.

PREPARATION EXAMPLE 24

The difference from preparation 18 is that: mixing nano silicon dioxide serving as a reinforcing agent with water to prepare reinforcing liquid with the mass fraction of 30%. And (3) immersing the solid in a silane coupling agent, taking out to obtain a coated solid, immersing the coated solid in the reinforcing liquid, stirring and mixing, taking out, retaining the solid, and drying to obtain the defoaming agent 8.

Preparation example 25

The difference from preparation example 24 is that: graphene oxide was used instead of nano silica in preparation example 24 to prepare defoamer 9.

PREPARATION EXAMPLE 26

The difference from preparation example 24 is that: the defoamer 10 was prepared using nano nickel powder instead of nano silica in preparation example 24.

Examples

Examples 1 to 10

In one aspect, the application provides bare concrete, which comprises cement, coarse aggregate, fine aggregate 1, doping materials, additives, expanding agents and water, wherein the concrete mass is shown in table 4 and table 5.

Wherein the coarse aggregate comprises a first coarse aggregate with the grain size of 5-16mm and a second coarse aggregate with the grain size of 5-31.5 mm;

the admixture comprises mineral powder and fly ash;

the additive comprises an air entraining agent, a water reducing agent, a thickening agent and a defoaming agent 1 in equal mass ratio.

On the other hand, the application provides a construction process of bare concrete, which comprises the following steps:

respectively taking cement, coarse aggregate 1, fine aggregate, doping material, additive, expanding agent and water according to the formula, stirring and mixing to obtain premix.

The method comprises the steps of construction joint roughening cleaning, positioning paying-off, terrace leveling and supplementing, vertical reinforcement adjustment protection layer, temporary frames, reinforcement binding, construction joint cleaning (reinforcement concealing checking and accepting), reinforcement bent frame erection, template manufacturing and assembling, clear water surface screw fastening setting (reinforcement protection layer treatment), template reinforcement and checking and accepting to obtain the template.

Pouring the premix into a template, pouring the premix in a fractional manner, wherein the pouring height is not more than 0.8m each time, vibrating for multiple times, tracking and vibrating, the vibration time is not more than 80 minutes, removing the mould after 48 hours without bubbles, and curing the concrete by adopting film wrapping and blanket covering to obtain the clear water concrete 1-3.

TABLE 4 examples 1-5 clear water concrete compositions

TABLE 5 examples 6-10 clear water concrete compositions

Examples 11 to 14

The difference from example 5 is that: the modified coarse aggregate 1-4 was used instead of the coarse aggregate in example 10 to prepare the fresh concrete 11-14.

Examples 15 to 23

The difference from example 5 is that: using defoamer 2-10 instead of defoamer 1 in example 10, bare concrete 15-23 was prepared.

Example 24

The difference from example 5 is that: as an alternative to the defoamer 1 of example 10, a KX-846 type defoamer was used to prepare bare concrete 24.

Examples 25 to 28

The difference from example 5 is that: fresh water concretes 25 to 28 were prepared using fine aggregates 2 to 5 instead of the fine aggregate 1 in example 10.

Comparative example

Comparative example 1

This comparative example differs from example 1 in that no air entraining agent was added in this comparative example to prepare bare concrete 29.

Comparative example 2

This comparative example differs from example 1 in that no light sand was added in this comparative example to prepare bare concrete 30.

Performance test

(1) Mechanical property test: the compression resistance and the impermeability pressure of the bare concrete are tested according to GB/T50081-2002 ordinary concrete mechanical property test method.

(2) Slump detection: detecting slump performance of the bare concrete by adopting a slump meter;

(3) And (3) detecting the content of chloride ions: and measuring the chloride ion content in the concrete by adopting a chloride ion selective electrode method.

TABLE 6 Performance test for examples 1-28, comparative examples 1-2

The comparison of performance tests in combination with Table 6 can be found:

(1) The comparison of examples 1-10 and comparative examples 1-2 shows that: the compression strength and slump of the concrete prepared in the embodiments 1-10 are improved, and the chloride ion content is reduced, which means that the air entraining agent is matched with the light sand, more 'balls' can be introduced into the concrete through the round structure of the light sand and the micro-bubble matching introduced by the air entraining agent, the friction force among all components in the concrete can be reduced through the ball effect, the fluidity and self-compaction effect of the concrete are improved, the pores of the concrete are reduced, and the durability of the concrete is improved. As can be seen from Table 6, the concrete prepared in example 5 has better mechanical properties and durability, indicating that the proportions of the components in the concrete are suitable.

(2) The comparison of examples 11-14 and example 5 can be found: the concrete prepared in examples 11-14 has improved compressive strength and slump and reduced chloride ion content, which means that the modifying agent is used for modifying the coarse aggregate, the particles of the modifying agent are smaller, the modifying agent can be loaded in the pore structure of the coarse aggregate, the surface smoothness of the coarse aggregate is improved, and the pores in the concrete are reduced. Meanwhile, by adding zeolite, the zeolite can induce a large amount of hydrogel to be generated in the concrete, so that the compactness and the binding property of the concrete are further improved. As can be seen from Table 6, the concrete prepared in example 12 has better mechanical properties and durability, indicating that the parameters of the steps in the coarse aggregate modification treatment are suitable.

(3) As can be seen from the comparison of examples 15 to 16, examples 17 to 18, examples 19 to 20, examples 21 to 23 and example 5: the concrete prepared in examples 15-23 has improved compressive strength and slump and reduced chloride ion content, which means that the defoaming agent with a shell-core structure is adopted to slowly release the defoaming component, so that a small amount of the defoaming agent is released at the initial stage of stirring the concrete, larger and bad bubbles are destroyed, the ball action of the micro bubbles is maintained, the bubbles in the concrete are gradually eliminated along with the prolonged stirring time, and finally, the bubbles in the concrete are further reduced and the compactness of the concrete is improved by vibrating and cracking the defoaming agent shell. As can be seen from Table 6, the concretes prepared in example 15 and example 18 have better mechanical properties and durability, which means that the proportions of the components in the core material in example 15 are more suitable, and the shear rate and the emulsification time in example 18 are more suitable.

(4) The comparison of examples 25-28 and example 5 can be found: the concrete prepared in examples 25-28 had improved compressive strength and slump and decreased chloride ion content, which demonstrates that the present application pre-wets the light sand and plays an internal curing role in the concrete. The shale ceramic sand, the perlite expanded rock and the cloud concrete are adopted to be matched, the surface porosity of the light sand can be tightly combined with the cementing material and the hydrogel, a continuous interface transition layer is formed, and the generation of cracks in the concrete is reduced. As can be seen from Table 6, the concrete prepared in example 12 has better mechanical properties and durability, indicating that the parameters of the steps in the coarse aggregate modification treatment are suitable.

The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims

1. The bare concrete is characterized by comprising the following substances in parts by weight: 1 part of cement, 2.55-9.31 parts of coarse aggregate, 1.38-7.62 parts of fine aggregate, 0.39-1.21 parts of doping material, 0.4-1.2 parts of additive, 0-0.154 part of expanding agent and 0.42-1.84 parts of water, wherein the fine aggregate comprises middle sand with the mud content less than or equal to 2%, the fine aggregate further comprises light sand, the additive comprises an air entraining agent, and the additive further comprises a water reducing agent, a thickening agent and a defoaming agent.

2. The bare concrete according to claim 1, wherein: the coarse aggregate comprises a first coarse aggregate with the grain diameter of 5-16mm and a second coarse aggregate with the grain diameter of 5-31.5mm, and the coarse aggregate is continuous graded coarse aggregate.

3. The bare concrete according to claim 1, wherein: the coarse aggregate is modified by a modifier, the modifier is a nanoscale modifier, and the modifier comprises any one of titanium dioxide, zinc oxide, boron oxide, ferric oxide and tin oxide.

4. A bare concrete according to claim 3, wherein: the modification treatment comprises the following steps: respectively taking 3-5 parts of modifier, 30-50 parts of water and 1-2 parts of zeolite, soaking the zeolite in alkali liquor, stirring and mixing, heating, taking out and cooling to obtain zeolite subjected to alkali heat pretreatment; mixing modifier and water under stirring to obtain suspension, soaking zeolite and coarse aggregate subjected to alkali heat pretreatment in the suspension, stirring, mixing, standing, and oven drying to obtain modified coarse aggregate.

5. The bare concrete according to claim 1, wherein: the defoaming agent is of a shell-core structure and comprises a core material and a shell material, wherein the core material comprises polyether modified silicone oil, MQ silicone resin, an emulsifier, dimethyl silicone oil and sodium carboxymethyl cellulose in a mass ratio of 10-30:37-38:3:100:1, and the shell material comprises any one of cyclodextrin, gelatin and urea-formaldehyde resin.

6. The bare concrete according to claim 5, wherein: the preparation of the core material comprises the following steps: polyether modified silicone oil, MQ resin, an emulsifier, dimethyl silicone oil and sodium carboxymethyl cellulose are taken according to a formula, stirred and mixed, sheared and emulsified, wherein the shearing rate is 9000-12000r/min, and the emulsifying time is 10-15min.

7. The bare concrete according to claim 6, wherein: the defoaming agent is characterized in that the shell-core structure of the defoaming agent is coated with a reinforcing layer, the reinforcing layer is composed of a reinforcing agent, and the reinforcing agent comprises any one of nano silicon dioxide, graphene oxide and nano nickel powder.

8. The bare concrete according to claim 1, wherein: the light sand comprises any one of shale ceramic sand, perlite and Yundan, and is subjected to prewetting treatment.

9. A construction process of bare concrete according to any one of claims 1 to 8, comprising the following construction steps:

s1, mixing raw materials: respectively taking cement, coarse aggregate, fine aggregate, doping material, additive, expanding agent and water according to a formula, and stirring and mixing to obtain premix;

s2, preparing a template: the method comprises the steps of construction joint roughening cleaning, positioning paying-off, terrace leveling and supplementing lines, vertical reinforcement adjustment protection layers, temporary frames, reinforcement binding, construction joint cleaning (reinforcement concealing checking and accepting), reinforcement bent frame erection, template manufacturing and assembling, clear water surface screw fastening (reinforcement protection layer treatment), template reinforcement and checking and accepting to obtain templates;

s3, preparing bare concrete: pouring the premix into a template, pouring the premix according to the height of the template, vibrating the premix for multiple times, drying, removing the mould, and maintaining the premix to obtain the bare concrete.