CN115073085A

CN115073085A - Fair-faced concrete and production process thereof

Info

Publication number: CN115073085A
Application number: CN202210650932.5A
Authority: CN
Inventors: 郑智富; 陈建坤; 邱武结
Original assignee: Xiamen Haitou Building Materials Co ltd
Current assignee: Xiamen Haitou Building Materials Co ltd
Priority date: 2022-06-10
Filing date: 2022-06-10
Publication date: 2022-09-20

Abstract

The application relates to fair-faced concrete and a production process thereof, wherein the raw material of the fair-faced concrete comprises the following components in parts by weight: cement 416 and 436; 37-57 parts of mineral powder; 746 parts of mechanism sand 726 and 746 parts of mechanism sand; 966 and 986 parts of gravels; water 165 and 185 portions; 9.88-11.88 parts of a water reducing agent; 10-15 parts of polyvinylidene chloride fiber; 20-30 parts of dense filler; 5-10 parts of organic silicon resin emulsion; 3-5 parts of hydroxypropyl cyclodextrin; 1-3 parts of methyl cellulose. The production process comprises the following steps: s1, uniformly mixing the organic silicon resin emulsion, hydroxypropyl cyclodextrin, methyl cellulose and the dense filler to obtain a dense mixture; s2, uniformly mixing cement, mineral powder, a water reducing agent and water to obtain cement slurry; s3, uniformly mixing the machine-made sand, the crushed stone, the dense mixture, the polyvinylidene chloride fiber and the cement slurry to obtain the concrete mixture. This application has the effect that promotes clear water concrete impermeability.

Description

Fair-faced concrete and production process thereof

Technical Field

The application relates to the field of concrete, in particular to fair-faced concrete and a production process thereof.

Background

The fair-faced concrete is concrete which directly utilizes natural texture of the formed concrete as a facing effect and can be divided into common fair-faced concrete, facing fair-faced concrete and decorative fair-faced concrete. The fair-faced concrete is poured once without any external decoration, has the advantages of saving the total construction cost of a project, reducing the construction cost, greatly reducing construction waste and the like, and is increasingly applied to industrial and civil construction engineering in recent years.

The main difference between the fair-faced concrete and the common concrete is that the fair-faced concrete is exposed in the external environment for a long time without a decorative material protective layer on the surface of the common concrete, and water, carbon dioxide, sulfur dioxide and the like in the environment can enter the interior of the fair-faced concrete to cause corrosion damage, so that the service life of the fair-faced concrete is seriously influenced.

In order to solve the problems, the inventor thinks that the existing fair-faced concrete has the defects of poor impermeability and low durability.

Disclosure of Invention

In order to improve the impermeability of fair-faced concrete, the application provides fair-faced concrete and a production process thereof.

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

the fair-faced concrete is prepared from a concrete mixture, wherein the concrete mixture comprises the following components in parts by weight:

cement 416 and 436;

37-57 parts of mineral powder;

746 parts of mechanism sand 726 and 746 parts of mechanism sand;

966 and 986 parts of gravels;

water 165 and 185 portions;

9.88-11.88 parts of a water reducing agent;

10-15 parts of polyvinylidene chloride fiber;

20-30 parts of dense filler;

5-10 parts of organic silicon resin emulsion;

3-5 parts of hydroxypropyl cyclodextrin;

1-3 parts of methyl cellulose;

the dense filler is selected from three or more of barite powder, hydroxyapatite powder, wollastonite powder, nano talcum powder and nano mica powder.

By adopting the technical scheme, the filling of the polyvinylidene chloride fiber can enhance the crack resistance of the clear water concrete; inorganic mineral material that has certain intensity and barrier property is chooseed for use to closely knit filler, be equipped with the silicone resin emulsion, hydroxypropyl cyclodextrin and methylcellulose, four synergism, the generation has the closely knit mix of prevention of seepage barrier property, closely knit mix mixes in the concrete, can fill to the space of concrete, make the inside closely knit nature of fair-faced concrete reinforcing, and then promote the impermeability and compressive strength of fair-faced concrete, closely knit mix can carry out the adhesion bonding with polyvinylidene chloride fibre when condensing along with the concrete, and then make the muscle and bone effect of polyvinylidene chloride fibre in the concrete strengthen, and then promote the fracture resistance of concrete, the inside closely knit of concrete, intensity and impermeability promotion, make fair-faced concrete durable more.

Preferably, the mass ratio of the dense filler to the silicone resin emulsion to the hydroxypropyl cyclodextrin to the methyl cellulose is (28-30): 7-9): 4-5): 2-3.

Through adopting above-mentioned technical scheme, confirm the quality ratio between closely knit filler, silicone resin emulsion, hydroxypropyl cyclodextrin, the methylcellulose for can exert better synergism between the four, each component homodisperse in the closely knit mixture system that helps to form, the system is stable, and the filling effect is better, and then further promotes fair-faced concrete's impervious performance and compressive strength.

Preferably, the mass ratio of the dense filler to the silicone resin emulsion to the hydroxypropyl cyclodextrin to the methyl cellulose is 28:8:5: 3.

Through adopting above-mentioned technical scheme, when closely knit filler, silicone resin emulsion, hydroxypropyl cyclodextrin, methyl cellulose adopt specific proportion combination to compound, can exert best synergistic effect between the four, closely knit mixture's permeability and cohesiveness are suitable, and then strengthen closely knit mixture and to the gain effect of concrete.

Preferably, the dense filler is prepared by mixing barite powder, hydroxyapatite powder and nano mica powder according to the mass ratio of 1:1: 0.4.

By adopting the technical scheme, the barite powder has high chemical stability, larger density, good acid-base resistance, light resistance and heat resistance, good filling property, leveling property and anti-permeability, and can increase the stability and impermeability of concrete when being filled into the concrete gap; the hydroxyapatite powder has strong hardness and surface activity, and can contribute to improving the compressive strength of concrete; the nano mica powder has excellent barrier property and can prevent external moisture from permeating into gaps of concrete; the dense filler is better in compatibility and dispersibility with organic silicon resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose colloid matrix, the formed dense mixture is stable in anti-seepage and blocking performance, and the dense mixture is filled into gaps of concrete to play a certain blocking role in external moisture and the like, so that the corrosion resistance of the concrete is promoted, and the durability of the fair-faced concrete is promoted.

Preferably, the emulsion also comprises 1-3 parts by mass of a water repellent agent, wherein the water repellent agent is prepared by mixing lotus leaf powder and polytetrafluoroethylene emulsion according to the mass ratio of (1-1.2) to (0.3-0.5).

By adopting the technical scheme, the addition of the hydrophobic agent is beneficial to improving the waterproofness of the mixture, so that the impermeability of the concrete gap is improved, and the corrosion resistance and the durability of the concrete are further improved; the water repellent agent prepared from the lotus leaf powder and the polytetrafluoroethylene emulsion according to a specific proportion is added into the dense mixture, so that the dense mixture can easily permeate into the gap inside the concrete, the filling and compacting effects of the dense mixture on the concrete are promoted, and the impermeability of the concrete is improved.

Preferably, the water reducing agent is a retarding polycarboxylic acid high-efficiency water reducing agent.

Through adopting above-mentioned technical scheme, adopt the polycarboxylic acids high efficiency water reducing agent of slow setting type for the clear water concrete setting time is postponed, has fine construction workability, each component can abundant mix in the concrete, makes fashioned concrete surface properties excellent, and inside is closely knit.

In a second aspect, the production process of the fair-faced concrete provided by the application adopts the following technical scheme:

a production process of fair-faced concrete comprises the following steps:

s1, uniformly mixing the organic silicon resin emulsion, hydroxypropyl cyclodextrin, methyl cellulose and the dense filler to obtain a dense mixture;

s2, mixing cement, mineral powder, a water reducing agent and water, and uniformly stirring to obtain cement slurry;

s3, adding the machine-made sand, the broken stone, the dense mixture and the polyvinylidene chloride fiber into the cement slurry, mixing and stirring uniformly to obtain a concrete mixture;

and S4, pouring the concrete mixture into a mold, and curing to obtain the bare concrete.

By adopting the technical scheme, the organic silicon resin emulsion, hydroxypropyl cyclodextrin, methyl cellulose and the dense filler are uniformly mixed, so that the components in the dense mixture can be fully dispersed and compatible; then, mineral powder and a water reducing agent are mixed by cement and water, the uniformity of internal components of cement slurry is increased, finally, machine-made sand, broken stone, a dense mixture and polyvinylidene chloride fiber are added into the cement slurry to be stirred, organic silicon resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose in the dense mixture are dissolved in water to form a colloid, the dense filler is doped in the colloid to form a mixture with impermeability together with the colloid, the mixture is filled in gaps inside concrete in the concrete setting process and can be bonded with the polyvinylidene chloride fiber, the compactness of the concrete is further improved, the impermeability, corrosion resistance, compression resistance and cracking resistance of the fair-faced concrete are greatly improved, and the prepared concrete has good durability.

Preferably, a hydrophobic agent is further added in step S1.

Through adopting above-mentioned technical scheme, in the hydrophobe added closely knit mixture, can realize abundant mixture with the component in the closely knit mixture, and then help realizing the infiltration auxiliary efficiency to closely knit mixture in the preparation process of follow-up concrete mixture, promote the waterproof performance of closely knit mixture, and then promote the impermeability of concrete.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the filling of the polyvinylidene chloride fiber can enhance the crack resistance of the clear water concrete; the compact filler is prepared from an inorganic mineral material with certain strength and barrier property, and is matched with organic silicon resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose, and the four materials have synergistic effects to generate a compact mixture with the barrier property, and the compact mixture is doped in concrete and can be filled into gaps of the concrete, so that the internal compactness of the fair-faced concrete is enhanced, the barrier property and the compressive strength of the fair-faced concrete are further improved, and the durability of the fair-faced concrete is improved;

2. the dense mixture can be adhered with polyvinylidene chloride fiber when being condensed with concrete, so that the rib and bone function of the polyvinylidene chloride fiber in the concrete is enhanced, and the fracture resistance and crack resistance of the concrete are improved;

3. the mass ratio of the compact filler, the organic silicon resin emulsion, the hydroxypropyl cyclodextrin and the methyl cellulose is limited, so that the four components can play a good synergistic effect, the components in a formed compact mixing material system can be uniformly dispersed, the system is stable, the filling effect is better, and the impermeability and the compressive strength of the fair-faced concrete are further improved;

4. the hydrophobic agent prepared by lotus leaf powder and polytetrafluoroethylene emulsion according to a specific proportion is added into the compact mixture, so that the compact mixture is easier to permeate into the gap inside the concrete, the compact filling effect of the compact mixture on the concrete is promoted, and the performance of the concrete is further improved.

Detailed Description

Preparation example

Preparation example 1

The preparation example discloses a preparation method of a hydrophobing agent, which comprises the following specific steps: mixing and adding 7.69kg of lotus leaf powder and 2.31kg of polytetrafluoroethylene emulsion into a stirring pot, namely, the mass ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion is 1:0.3, and stirring at the normal temperature for 5min under the condition of the rotating speed of 1500r/min to obtain the hydrophobing agent.

Preparation example 2

The preparation example discloses a preparation method of a hydrophobing agent, which comprises the following specific steps: mixing and adding 7.06kg of lotus leaf powder and 2.94kg of polytetrafluoroethylene emulsion into a stirring pot, namely, the mass ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion is 1.2:0.5, and stirring at the normal temperature for 5min under the condition of the rotating speed of 1500r/min to obtain the hydrophobing agent.

Preparation example 3

The preparation example discloses a preparation method of a hydrophobing agent, which comprises the following specific steps: 5kg of lotus leaf powder and 5kg of polytetrafluoroethylene emulsion are mixed and added into a stirring pot, namely the mass ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion is 1:1, and the mixture is stirred for 5min at normal temperature under the condition of the rotating speed of 1500r/min to obtain the hydrophobing agent.

Preparation example 4

The preparation example discloses a preparation method of a hydrophobing agent, which comprises the following specific steps: 3.33kg of lotus leaf powder and 6.67kg of polytetrafluoroethylene emulsion are mixed and added into a stirring pot, namely the mass ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion is 0.5:1, and the mixture is stirred for 5min at normal temperature under the condition of the rotating speed of 1500r/min to obtain the hydrophobing agent.

Examples

Examples 1 to 6

Examples 1-6 disclose a fair-faced concrete prepared from a concrete mix comprising: 436kg of P.O 42.5 ordinary portland cement 416-57 kg, 37-57kg of mineral powder, 746kg of machine-made sand 726-4, 966-986kg of macadam, 9.88-11.88kg of retarding polycarboxylic acid high-efficiency water reducing agent, 20-30kg of dense filler, 5-10kg of organic silicon resin emulsion, 3-5kg of hydroxypropyl cyclodextrin and 1-3kg of methyl cellulose.

Embodiments 1-6 also disclose the production process of the fair-faced concrete, comprising the following steps:

s1, preparing a compact mixture:

s1-1, adding barite powder, hydroxyapatite powder and nano mica powder into a stirrer according to the mass ratio of 1:1:0.4, and stirring for 15min at normal temperature and the rotating speed of 40r/min to obtain a dense filler;

s1-2, adding the organic silicon resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose into a dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixed material;

s2, mixing cement, mineral powder, a water reducing agent and water, adding into a stirrer, and stirring for 5 minutes at room temperature and at the rotating speed of 50r/min to obtain cement slurry;

s3, adding the machine-made sand, the crushed stone, the dense mixture and the polyvinylidene chloride fiber into the cement slurry for mixing, and stirring for 15 minutes at room temperature and at the rotating speed of 60r/min to obtain a concrete mixture;

and S4, pouring the concrete mixture into a mold, and placing the mold into a standard curing room with the temperature of 20 ℃ and the relative humidity of 95% for curing for 28 days to obtain the fair-faced concrete.

The amounts (unit: kg) of the respective raw material components of examples 1 to 6 are specified in Table 1.

TABLE 1

Examples 7 to 11

Examples 7 to 11 disclose a production process of fair-faced concrete, which is different from example 3 in that: in step S1-1, the components in the dense filler are in different proportions, and the specific components and the component input amount (kg) are detailed in Table 2.

TABLE 2

Example 12

A production process of fair-faced concrete, which is different from the embodiment 3 in that: in S1-2, adding 7.5kg of organic silicon resin emulsion, 4kg of hydroxypropyl cyclodextrin, 2kg of methylcellulose and 1kg of hydrophobic agent into 25kg of dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixture; wherein, the hydrophobizing agent prepared in the preparation example 1 is selected as the hydrophobizing agent.

Example 13

A production process of fair-faced concrete, which is different from the embodiment 3 in that: in S1-2, adding 7.5kg of organic silicon resin emulsion, 4kg of hydroxypropyl cyclodextrin, 2kg of methylcellulose and 3kg of hydrophobic agent into 25kg of dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixture; wherein, the hydrophobizing agent prepared in the preparation example 2 is selected as the hydrophobizing agent.

Example 14

A production process of fair-faced concrete, which is different from the embodiment 3 in that: in S1-2, adding 7.5kg of organic silicon resin emulsion, 4kg of hydroxypropyl cyclodextrin, 2kg of methylcellulose and 3kg of hydrophobic agent into 25kg of dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixture; wherein, the hydrophobizing agent prepared in the preparation example 3 is selected as the hydrophobizing agent.

Example 15

A production process of fair-faced concrete, which is different from the embodiment 3 in that: in S1-2, adding 7.5kg of organic silicon resin emulsion, 4kg of hydroxypropyl cyclodextrin, 2kg of methylcellulose and 3kg of hydrophobic agent into 25kg of dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixture; wherein, the hydrophobizing agent prepared in the preparation example 4 is selected as the hydrophobizing agent.

Example 16

A production process of fair-faced concrete, which is different from that in embodiment 6 in that: in S1-2, adding 8kg of organic silicon resin emulsion, 5kg of hydroxypropyl cyclodextrin, 3kg of methylcellulose and 3kg of hydrophobic agent into 28kg of dense filler, and stirring for 10min under the condition that the rotating speed is 60r/min to obtain a dense mixture; wherein, the hydrophobizing agent prepared in the preparation example 2 is selected as the hydrophobizing agent.

Comparative example

Comparative example 1

A production process of fair-faced concrete, which is different from the embodiment 3 in that: hydroxypropyl cyclodextrin was replaced with an equal amount of silicone resin emulsion.

Comparative example 2

A production process of fair-faced concrete, which is different from the embodiment 3 in that: the methylcellulose was replaced with an equal amount of silicone resin emulsion.

Comparative example 3

A production process of fair-faced concrete, which is different from the embodiment 3 in that: replacing hydroxypropyl cyclodextrin and methylcellulose with equal amount of silicone resin emulsion.

Comparative example 4

A production process of fair-faced concrete, which is different from the embodiment 3 in that: the organic silicon resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose are replaced by the same amount of compact filler.

Comparative example 5

A production process of fair-faced concrete, which is different from the embodiment 3 in that: in the concrete mixture, the dense filler, the organic silicon resin emulsion, the hydroxypropyl cyclodextrin and the methyl cellulose are replaced by the same amount of broken stones.

Comparative example 6

A commercially available bare concrete was selected for this comparative example.

Performance test

The bare concrete of examples 1 to 16 and comparative examples 1 to 6 were sampled with reference to GB/T50081-2002 Standard test methods for mechanical Properties of ordinary concrete and GB/T50082-2009 Standard test methods for Long-term Performance and durability of ordinary concrete, respectively, and the compressive strength (28d), flexural strength (28d), water penetration height and chloride penetration depth were measured, with the test results shown in Table 3 below; the higher the numerical value of the compressive strength and the flexural strength in the table, the better the compressive resistance and the crack resistance of the fair-faced concrete and the excellent mechanical property are shown; the larger the water penetration resistance height and the chloride ion penetration depth value are, the poorer the impermeability and corrosion resistance of the concrete are.

TABLE 3

According to the detection data of examples 1-3 and comparative example 6 in table 3, the clear water concrete prepared in examples 1-3 has higher test values of compressive strength and flexural strength than the common clear water concrete sold in comparative example 6, which indicates that the concrete prepared in examples 1-3 has better mechanical properties than the concrete sold in market; the water penetration resistance and the chloride ion penetration depth are small, which shows that the concrete prepared in the examples 1 to 3 has better anti-permeability and corrosion resistance and is durable compared with the commercial concrete.

In the embodiments 1 to 3, polyvinylidene chloride fiber is added to the concrete formulation to improve the flexural strength and crack resistance of the concrete, and a certain amount of dense filler mixed with inorganic mineral powder is added, the dense filler is matched with silicone resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose to form a dense mixture with anti-seepage and barrier properties, the dense mixture is doped in the concrete mixture and can be filled into a gap formed by concrete coagulation, so that the compactness and barrier properties of the concrete are improved, the anti-seepage and compressive properties of the concrete are improved, a colloid with a certain viscosity can be formed when the silicone resin emulsion, hydroxypropyl cyclodextrin and methyl cellulose in the dense mixture are added in the concrete mixture, the mixture can be mixed with the dense filler, and the stability of the dense mixture is stabilized, and the polyvinylidene chloride fiber can be adhered to the polyvinylidene chloride fiber, so that the 'rib and bone' supporting function of the polyvinylidene chloride fiber in the concrete after the concrete is solidified is enhanced, the breaking strength and the crack resistance of the concrete are further improved, and the fair-faced concrete prepared in the embodiments 1-3 has better durability.

Embodiments 4 to 6 further limit the combination ratio of the compact filler, the silicone resin emulsion, the hydroxypropyl cyclodextrin, and the methylcellulose in the concrete mixture, and when the compact filler, the silicone resin emulsion, the hydroxypropyl cyclodextrin, and the methylcellulose are combined and compounded in a specific ratio, the compact mixture system is stable, each component in the system is uniformly dispersed, and a better synergistic effect can be exerted among the components, so that the filling effect on the concrete gap is better than that of the polyvinylidene chloride fiber, and the clear water concrete prepared in embodiments 4 to 6 has improved mechanical properties, impermeability, and corrosion resistance compared with the clear water concrete prepared in embodiments 1 to 3.

In comparative examples 1-5, the dense filler, the organic silicon resin emulsion, the hydroxypropyl cyclodextrin and the methyl cellulose in the dense mixture are respectively replaced, in comparative example 5, the components of the dense mixture are completely replaced by the same amount of broken stones, in comparative example 5, the dense mixture is equivalent to no dense mixture, and the strength and the impermeability of the fair-faced concrete prepared in comparative example 5 are obviously lower than those of the concrete prepared in examples 1-3; in comparative examples 1-3, hydroxypropyl cyclodextrin and methyl cellulose are respectively replaced by organic silicon resin emulsion, and components forming a colloid matrix in the dense mixture are absent, so that the system stability of the dense mixture is greatly influenced, the filling and blocking effects of the dense mixture on gaps in concrete are reduced, and the dense mixture cannot have a good bonding effect with polyvinylidene chloride fibers, so that the mechanical properties and the impermeability and corrosion resistance of the clear water concrete prepared in comparative examples 1-3 are reduced compared with those of the concrete prepared in examples 1-3; the compact mixture only comprises this single component of compact filler in comparative example 4, and the space of concrete can be filled to a certain extent to the compact mixture, but can't play the shutoff separation effect to the space, and each component is loose in the compact filler, and the wholeness can be relatively poor, and then makes the performance of the fair-faced concrete that comparative example 4 made relatively poor.

In comparative examples 1-5, after replacing the components in the dense mixture, the strength performance and the impermeability and corrosion resistance of the prepared concrete do not reach the performance of the concrete prepared in examples 1-3, which also indicates that in the technical scheme of the application, the dense mixture is an important factor for improving the performance of the concrete, and the components in the dense mixture are matched with each other and act synergistically with each other to play a role in enhancing the concrete, but the lack is not the right.

In examples 7 to 11, inorganic mineral components of the dense filler in the dense mixture are respectively tested, in examples 7 to 11, barite powder, hydroxyapatite powder, wollastonite powder, nano talc powder and nano mica powder are respectively combined and compounded, performance test data of the concrete prepared in examples 7 to 11 show obvious differences, and the differences also show that different combination ratios among the components have different effects, some combinations can obviously enhance the mechanical property of the concrete, but the effect of enhancing the impermeability of the concrete is not obvious; some combinations can improve the impermeability of concrete, but the strength improvement is not satisfactory; the dense filler is formed by mixing barite powder, hydroxyapatite powder and nano mica powder according to the mass ratio of 1:1:0.4, so that the balance between the strength performance and the impermeability of the concrete is achieved, and the overall performance of the concrete is balanced and stable.

In examples 12 to 15, a certain amount of a hydrophobing agent is added into the dense mixture, the hydrophobing agent is prepared by mixing lotus leaf powder and polytetrafluoroethylene emulsion according to a mass ratio of (1-1.2) to (0.3-0.5), and the addition of the hydrophobing agent enhances the barrier property of the dense mixture, so that the impermeability of concrete to moisture and chloride ions in the external environment is improved; the addition of the hydrophobing agent is also beneficial to improving the permeability of the dense mixture, so that the filling effect of the permeable mixture on concrete gaps is better, and the fair-faced concrete prepared in the examples 12-15 has better strength performance, impermeability and corrosion resistance. In examples 13 and 14, the mass ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion is changed, and after the ratio of the lotus leaf powder to the polytetrafluoroethylene emulsion breaks through the limitation of the application, good synergistic effect cannot be formed between the components in the hydrophobing agent and between the hydrophobing agent component and other components in the dense mixture, so that the performance improvement effect of the concrete prepared in examples 13 and 14 is poor.

In example 16, a dense mixture with a suitable component ratio is used, and a hydrophobizing agent is further added to the dense mixture, so that the performance of the fair-faced concrete prepared in example 16 is further improved.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: equivalent changes in structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The bare concrete is characterized in that: the concrete mixture is prepared from the following components in parts by weight:

cement 416 and 436;

37-57 parts of mineral powder;

746 parts of mechanism sand 726 and sand;

966 and 986 parts of gravels;

water 165 and 185 portions;

9.88-11.88 parts of a water reducing agent;

10-15 parts of polyvinylidene chloride fiber;

20-30 parts of dense filler;

5-10 parts of organic silicon resin emulsion;

3-5 parts of hydroxypropyl cyclodextrin;

1-3 parts of methyl cellulose;

2. A bare concrete according to claim 1 wherein: the mass ratio of the dense filler to the silicone resin emulsion to the hydroxypropyl cyclodextrin to the methyl cellulose is (28-30): 7-9): 4-5): 2-3.

3. A bare concrete according to claim 2 wherein: the mass ratio of the dense filler to the organic silicon resin emulsion to the hydroxypropyl cyclodextrin to the methyl cellulose is 28:8:5: 3.

4. A bare concrete according to claim 1 wherein: the dense filler is prepared by mixing barite powder, hydroxyapatite powder and nano mica powder according to the mass ratio of 1:1: 0.4.

5. A bare concrete according to claim 1 wherein: the water repellent agent is prepared by mixing lotus leaf powder and polytetrafluoroethylene emulsion according to the mass ratio of (1-1.2) to (0.3-0.5).

6. A bare concrete according to claim 1 wherein: the water reducing agent is a retarding polycarboxylate superplasticizer.

7. A process for the production of bare concrete according to any one of claims 1 to 6, characterised in that: the method comprises the following steps:

8. A process for the production of bare concrete according to claim 7 wherein: a hydrophobizing agent is also added in step S1.