CN117945687A

CN117945687A - Modified micro-nano bubble water and preparation method thereof, low-volume-weight concrete doped with modified micro-nano bubble water and preparation method thereof

Info

Publication number: CN117945687A
Application number: CN202311833346.5A
Authority: CN
Inventors: 叶俊辉; 尹键丽; 肖伟; 薛博宇
Original assignee: Xiamen Tianrun Jinlong Building Material Co ltd
Current assignee: Xiamen Tianrun Jinlong Building Material Co ltd
Priority date: 2023-12-28
Filing date: 2023-12-28
Publication date: 2024-04-30

Abstract

The invention relates to the technical field of building materials, in particular to modified micro-nano bubble water and a preparation method thereof, low-volume-weight concrete doped with the modified micro-nano bubble water and a preparation method thereof. The components of the modified micro-nano bubble water comprise micro-nano bubble water, a modifier dispersed in the micro-nano bubble water and graphene dispersion liquid; the modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder. The invention provides the modified micro-nano bubble water, and concrete is prepared by adopting the mode of doping the modified micro-nano bubble water, and the modified micro-nano bubble water is introduced to replace the traditional lightweight aggregate, so that the volume weight of the concrete can be effectively reduced under lower manufacturing cost, the performances of the low-volume-weight concrete are ensured to be equivalent to those of common high-performance concrete, the concrete has good pumping performance, mechanical performance and durability, and the concrete has better appearance and no obvious bubbles.

Description

Modified micro-nano bubble water and preparation method thereof, low-volume-weight concrete doped with modified micro-nano bubble water and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to modified micro-nano bubble water and a preparation method thereof, low-volume-weight concrete doped with the modified micro-nano bubble water and a preparation method thereof.

Background

The low-volume-weight concrete is a special concrete material, and compared with the common ready-mixed concrete, the volume weight (namely the apparent density) of the low-volume-weight concrete is reduced by about 200kg/m ³, but the low-volume-weight concrete cannot reach the category of light concrete.

Since the concrete material itself has a serious disadvantage that it cannot be avoided, further development thereof is limited, and it is required to reduce the volume weight thereof.

Conventionally, lightening of concrete can be achieved by means of a high-strength lightweight aggregate instead of a conventional aggregate to obtain low-volume-weight concrete, but the low-volume-weight concrete obtained by means of the method has the following defects:

The high-strength lightweight aggregate has high cost, so that the preparation cost is high; even if the volume weight of the concrete can be reduced by replacing the high-strength lightweight aggregate, the compressive strength and other properties of the concrete can be correspondingly and negatively affected, for example, the compressive strength is reduced by about 10 percent or even higher when the volume weight of the concrete prepared by replacing the high-strength lightweight aggregate is reduced by 7-9 percent compared with that of standard concrete (the aggregate adopts conventional aggregate). Thus, this solution for preparing low-weight concrete is still less applicable.

The method aims to solve the problems, and aims to solve the technical problems of how to develop low-cost preparation of low-volume-weight concrete, ensure that the concrete has good compression strength, fluidity and other performances while the whole structure of the concrete is light.

Disclosure of Invention

In order to solve the problems in the background art, the invention provides modified micro-nano bubble water and a preparation method thereof, and adopts the modified micro-nano bubble water to prepare low-volume-weight concrete doped with the modified micro-nano bubble water, and the technical scheme is as follows:

The components of the modified micro-nano bubble water comprise micro-nano bubble water, a modifier dispersed in the micro-nano bubble water and graphene dispersion liquid; micro-nano bubbles are dispersed in the micro-nano bubble water; the modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder; the mass ratio of the micro-nano bubble water to the modifier to the graphene dispersion liquid is (18-21) (0.05-0.1) (3-4).

In some embodiments, the micro-nano bubble water is prepared from water by a micro-nano bubble water generating device, so that micro-nano bubbles are dispersed in the micro-nano bubble water.

The micro-nano bubble water is prepared by a micro-nano bubble water generation device, macroscopic large bubbles are gradually dissipated along with time, and only micro-nano bubbles are reserved.

In some embodiments, the modifying agent consists of an anionic air entraining agent, a foam stabilizer, and a retarder.

In some embodiments, the mass ratio of the anionic air entraining agent, the foam stabilizer and the retarder is (3-10): 0.02-0.08): 1-4; the anionic air entraining agent is one or a combination of a plurality of alpha-alkenyl sodium alkyl sulfonate and alkyl polyoxyethylene ether sodium sulfonate, and the carbon number of alkyl in the alkyl polyoxyethylene ether sodium sulfonate is 8-12; the foam stabilizer is one or a combination of more of dodecyl dimethyl amine oxide, alkyl polyoxyethylene ether and polyvinyl alcohol; the retarder is one or a combination of more of white sugar, sodium gluconate and sodium citrate; the graphene dispersion liquid is formed by dispersing graphene in solvent water, and the solid content of the graphene dispersion liquid is 0.05% -0.2%; the graphene comprises one or more of graphene oxide and reduced graphene oxide, and the whole graphene is black. Among them, graphene sheets contain a large amount of oxygen-containing functional groups such as hydroxyl groups, carboxyl groups, epoxy groups, and the like, and are easily dispersed in water due to the presence of these polar hydrophilic groups.

The invention also provides a preparation method of the modified micro-nano bubble water, which comprises the following preparation steps:

Adding the modifier and the graphene dispersion liquid into the first part of water, and uniformly dispersing to obtain a solution C;

Introducing a second part of water into the solution C through a micro-nano bubble water generating device, and standing to obtain the modified micro-nano bubble water;

Wherein the modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder; the second part of water is introduced into the solution C through a micro-nano bubble water generating device so that the second part of water is mixed with the first part of water and micro-nano bubbles are dispersed in the second part of water to form the micro-nano bubble water; the mass ratio of the micro-nano bubble water to the modifier to the graphene dispersion liquid is (18-21) (0.05-0.1) (3-4), wherein the mass ratio balance mode is as follows: in the mass ratio balance process of the micro-nano bubble water, the modifier and the graphene dispersion liquid, the mass of the micro-nano bubble water is the sum of the first part of water and the second part of water.

In some embodiments, the mass ratio of the anionic air entraining agent, the foam stabilizer and the retarder is (3-10): 0.02-0.08): 1-4; the mass ratio of the first part of water to the second part of water is (0.5-1): (1-1.5).

In some embodiments, the anionic air entraining agent is one or more of alpha-alkenyl alkyl sodium sulfonate and alkyl polyoxyethylene ether sodium sulfonate, and the alkyl in the alkyl polyoxyethylene ether sodium sulfonate has 8-12 carbon atoms; the foam stabilizer is one or a combination of more of dodecyl dimethyl amine oxide, alkyl polyoxyethylene ether and polyvinyl alcohol; the retarder is one or a combination of more of white sugar, sodium gluconate and sodium citrate; the graphene dispersion liquid is formed by dispersing graphene in solvent water, and the solid content of the graphene dispersion liquid is 0.05% -0.2%; the graphene comprises one or more of graphene oxide and reduced graphene oxide.

The invention also provides low-volume-weight concrete doped with the modified micro-nano bubble water, which comprises the following raw materials in parts by weight: cement, modified micro-nano bubble water, fly ash, mineral powder, silica fume, coarse aggregate, fine aggregate and high-performance water reducer; wherein the modified micro-nano bubble water adopts the modified micro-nano bubble water; or the modified micro-nano bubble water prepared by the preparation method is adopted.

In some embodiments, the raw material components include, in parts by weight: 221 to 294 parts of cement, 147 to 167 parts of modified micro-nano bubble water, 73 to 147 parts of fly ash, 73 to 147 parts of mineral powder, 15 to 39 parts of silica fume, 1050 to 1100 parts of coarse aggregate, 680 to 740 parts of fine aggregate and 3.9 to 5.9 parts of high-performance water reducer.

In some embodiments, the cement is one or more of p.o42.5 cement, p.ii 42.5 cement, p.i 42.5 cement; the fly ash is one or a combination of more of class I fly ash and class II fly ash; the mineral powder is mineral powder with the specific surface area of 650m ²/kg～750m²/kg obtained by grinding S95-grade mineral powder, and the activity index of 28d is 115% -122%; the silica fume is one or a combination of more of SF 94-grade silica fume and SF 96-grade silica fume; the coarse aggregate is one or a combination of a plurality of crushed stones with the particle size of 5 mm-10 mm, crushed stones with the particle size of 10 mm-20mm and crushed stones with the particle size of 5 mm-20mm, the apparent density is 2620kg/m ³～2650kg/m³, the void ratio is 38% -41%, and the crushing value is 2% -4%; the fine aggregate is machine-made sand, the fineness modulus is 2.6-2.8, the apparent density is 2600kg/m ³～2640kg/m³, the void ratio is 40-44%, and the mud content is 0.1-0.5%;

the high-performance water reducer is formed by compounding polycarboxylic acid water-reducing mother liquor, a slump retaining agent, a defoaming agent, a water-retaining agent, a regulator and water.

The high-performance water reducer compounded by the formula has strong dispersion effect on the cementing material, shortens the concrete stirring time, rapidly mixes various concrete raw materials, optimizes various performances of the concrete, has a water reducing rate of 28-33%, and has a 28d compressive strength ratio of 170-183%.

The invention also provides a preparation method of the low-volume-weight concrete doped with the modified micro-nano bubble water, which comprises the following preparation steps:

weighing the following raw material components: weighing cement, modified micro-nano bubble water, fly ash, mineral powder, silica fume, coarse aggregate, fine aggregate and high-performance water reducer according to a certain weight part;

Uniformly mixing coarse aggregate and fine aggregate to obtain a mixture A;

uniformly mixing cement modified micro-nano bubble water, fly ash, mineral powder and silica fume to obtain a mixture B;

Uniformly mixing a high-performance water reducing agent and modified micro-nano bubble water to obtain a mixed solution C;

Uniformly mixing the mixture A and the mixture B, and then adding the mixed solution C to uniformly mix to obtain a mixture;

pouring the obtained mixture into a fixed die for hardening and forming to obtain the low-volume-weight concrete doped with the modified micro-nano bubble water.

Compared with the prior art, the invention has the following beneficial effects:

Compared with the scheme that the high-strength lightweight aggregate replaces the traditional lightweight aggregate, the invention provides the modified micro-nano bubble water, the concrete prepared by doping the modified micro-nano bubble water is used for replacing the traditional lightweight aggregate in a mode of introducing the modified micro-nano bubble water, so that the volume weight of the concrete can be effectively reduced at lower manufacturing cost, on the basis of reducing the volume weight, the properties of the low-volume weight concrete are ensured to be equivalent to those of common high-performance concrete, the concrete has good pumping performance, mechanical property and durability, and the appearance of the concrete is better and has no obvious bubbles; the low-volume-weight concrete is convenient for carrying and installing components, and has the performance meeting the application requirements, and has economy and practicability.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the following description will be made in connection with the technical solutions in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention provides an implementation example of a preparation method of low-volume-weight concrete doped with modified micro-nano bubble water, which comprises the following preparation steps:

1. And (3) brushing template paint on the surface layer of the steel mould with the size of 150mm and 150mm, standing for 24-36 h, and assembling and splicing to form the mould, wherein no pore at the joint is required to be ensured.

2. Weighing the raw material components of the concrete: weighing cement, modified micro-nano bubble water, fly ash, mineral powder, silica fume, coarse aggregate, fine aggregate and high-performance water reducer according to a certain weight portion.

Wherein, the raw materials comprise the following components in parts by weight: 221 to 294 parts of cement, 147 to 167 parts of modified micro-nano bubble water, 73 to 147 parts of fly ash, 73 to 147 parts of mineral powder, 15 to 39 parts of silica fume, 1050 to 1100 parts of coarse aggregate, 680 to 740 parts of fine aggregate and 3.9 to 5.9 parts of high-performance water reducer.

3. Uniformly mixing coarse aggregate and fine aggregate to obtain a mixture A; uniformly mixing cement modified micro-nano bubble water, fly ash, mineral powder and silica fume to obtain a mixture B; and uniformly mixing the high-performance water reducer and the modified micro-nano bubble water to obtain a mixed solution C.

4. And pouring the mixture A and the mixture B into a stirrer to stir for 10-30 s, adding the mixed solution C, and stirring for 210-300 s to obtain the mixture.

5. Uniformly pouring the mixture into a steel mould, vibrating for 4-7 s by using a vibrating table, inserting and tamping the upper side wall around for a plurality of times by using a spatula, wiping off superfluous concrete on the upper layer, and covering a film.

6. And after 48-72 hours, dismantling the steel template, placing the low-volume-weight concrete test piece into a standard curing room, and performing relevant performance test after reaching the age.

The invention also provides a preferred embodiment of the preparation method of the modified micro-nano bubble water, which comprises the following specific steps:

1. dividing water (e.g., tap water) into two portions, respectively obtaining a first portion of water A and a second portion of water B; the mass ratio of the first part of water to the second part of water is (0.5-1): (1-1.5).

2. Adding a modifier and graphene dispersion liquid into the first part of water A according to a proportion, and electrically stirring uniformly at a stirring speed of 400-600 r/min for 15-30 min to obtain a solution C;

3. And then introducing the second part of water B into the solution C by using a micro-nano bubble water generating device, wherein a bubble discharge port is required to be placed at a position 1/3 of the height from the bottom of the solution until all the second part of water B is used up, and standing for 5-8 min to obtain the modified micro-nano bubble water.

Wherein the mass ratio of the anionic air entraining agent, the foam stabilizer and the retarder in the modifier is (3-10) (0.02-0.08) (1-4).

The mass ratio of the micro-nano bubble water to the modifier to the graphene dispersion liquid is (18-21) (0.05-0.1) (3-4); in the preparation process, introducing a second part of water into the solution C through a micro-nano bubble water generating device, so that the second part of water is mixed with the first part of water and micro-nano bubbles are dispersed in the second part of water to form micro-nano bubble water; therefore, the mass ratio balance is as follows: in the mass ratio balance process of the micro-nano bubble water, the modifier and the graphene dispersion liquid, the weight of the micro-nano bubble water is the sum of the first part of water and the second part of water.

The invention also provides the formulations (unit: parts by weight) of the examples and comparative examples shown in table 1:

TABLE 1

Specifically, the preparation processes of the examples, the comparative examples and the comparative examples provided by the invention are as follows:

Example 1

In this embodiment, the concrete comprises the following raw materials in parts by weight: 221 parts of cement, 147 parts of modified micro-nano bubble water, 122 parts of fly ash, 147 parts of mineral powder, 24 parts of silica fume, 1100 parts of coarse aggregate, 680 parts of fine aggregate and 5.9 parts of high-performance water reducer.

The preparation method of the modified micro-nano bubble water comprises the following steps:

(1) Equally dividing tap water into two parts to respectively obtain tap water A and tap water B;

(2) Adding a modifier and graphene dispersion liquid into tap water A according to a proportion, and electrically stirring uniformly at a stirring speed of 400r/min for 30min to obtain a solution C;

(3) And then introducing tap water B into the solution C by using the micro-nano bubble water generating device, wherein a bubble discharge port is required to be placed at a position 1/3 of the height from the bottom of the solution until all tap water B is used up, and standing for 5min to obtain the modified micro-nano bubble water.

Wherein, in the components in the modified micro-nano bubble water, the mass ratio of the micro-nano bubble water, the anionic air entraining agent, the foam stabilizer, the retarder and the graphene dispersion liquid is 1840:5:0.05:1.8:360. The anionic air entraining agent is alpha-alkenyl alkyl sodium sulfonate, the foam stabilizer is alkyl polyoxyethylene ether, and the retarder is white sugar. Graphene oxide is dispersed in solvent water to form graphene dispersion liquid, and the solid content of the graphene dispersion liquid is 0.06%.

The cement is P.II 42.5 cement; the fly ash is I-grade fly ash; the mineral powder is S95-grade mineral powder, and the specific surface area of the mineral powder reaches 654m ²/kg, and the 28d activity index of the mineral powder reaches 115%; the silica fume is SF 96-grade silica fume; the coarse aggregate is 5-20 mm continuous graded broken stone, the apparent density is 2640kg/m ³, the void ratio is 38%, and the crushing value is 2%; the fine aggregate is machine-made sand, the fineness modulus is 2.6, the apparent density is 2600kg/m ³, the void ratio is 43%, and the mud content is 0.5%; the high-performance water reducer is a special polycarboxylic acid water reducer Point-60HGS for the high-performance concrete, the water reduction rate is up to 32%, and the high-performance water reducer is prepared by compounding special polycarboxylic acid water reduction mother liquor, slump retaining agent, defoaming agent, water retaining agent, regulator and water.

In this embodiment, a low-volume-weight concrete doped with modified micro-nano bubble water includes the following preparation steps:

(1) And (3) brushing template paint on the surface layer of the steel mould with the size of 150mm and 150mm, standing for 36h, and assembling and splicing to form the mould, wherein no pore at the joint is required to be ensured.

(2) Weighing the following raw material components: weighing cement, modified micro-nano bubble water, fly ash, mineral powder, silica fume, coarse aggregate, fine aggregate and high-performance water reducer according to a certain weight portion.

(3) Uniformly mixing coarse aggregate and fine aggregate to obtain a mixture A; uniformly mixing cement modified micro-nano bubble water, fly ash, mineral powder and silica fume to obtain a mixture B; and uniformly mixing the high-performance water reducer and the modified micro-nano bubble water to obtain a mixed solution C.

(4) And pouring the mixture A and the mixture B into a stirrer to stir for 20s, adding the mixed solution C, and stirring for 240s to obtain the low-volume-weight concrete mixture doped with the modified micro-nano bubble water.

(5) Uniformly pouring the concrete mixture into a steel mould, vibrating for 6s by using a vibrating table, inserting and tamping the peripheral upper side walls for a plurality of times by using a spatula, wiping off the excessive concrete on the upper layer, and covering the film.

(6) And after 72 hours, the steel template is removed, the low-volume-weight concrete test piece is placed into a standard curing room, and after the age is reached, the relevant performance test is carried out.

Example 2

In this embodiment, each raw material composition includes, in parts by weight: 294 parts of cement, 157 parts of modified micro-nano bubble water, 73 parts of fly ash, 123 parts of mineral powder, 24 parts of silica fume, 1050 parts of coarse aggregate, 740 parts of fine aggregate and 4.8 parts of high-performance water reducer.

The cement is P.II 42.5 cement; the fly ash is I-grade fly ash; the mineral powder is S95-grade mineral powder, and the specific surface area of the mineral powder reaches 654m ²/kg, and the 28d activity index of the mineral powder reaches 115%; the silica fume is SF 96-grade silica fume; the coarse aggregate is 5-20 mm continuous graded broken stone, the apparent density is 2640kg/m ³, the void ratio is 38%, and the crushing value is 2%; the fine aggregate is machine-made sand, the fineness modulus is 2.6, the apparent density is 2600kg/m ³, the void ratio is 43%, and the mud content is 0.5%; the high-performance water reducer is a special polycarboxylic acid water reducer Point-60HGS for the Jie high-performance concrete, the water reduction rate is up to 32%, and the high-performance water reducer is prepared by compounding special polycarboxylic acid water reduction mother liquor, slump retaining agent, defoaming agent, water retaining agent, regulator and water.

Example 3

In this embodiment, each raw material composition includes, in parts by weight: 221 parts of cement, 167 parts of modified micro-nano bubble water, 147 parts of fly ash, 122 parts of mineral powder, 24 parts of silica fume, 1100 parts of coarse aggregate, 680 parts of fine aggregate and 3.9 parts of high-performance water reducer.

Comparative example 1

The difference between this comparative example 1 and example 3 is only that: comparative example 1 the modified micro-nano bubble water of example 3 was replaced with tap water in equal amount. Other conditions remain unchanged.

Comparative example 2

This comparative example 2 differs from example 3 only in that: comparative example 2 the micro-nano bubble water of example 3 was not modified (without adding modifier and graphene dispersion), and other conditions were kept unchanged.

Comparative example 3

This comparative example 3 differs from example 3 only in that: comparative example 3 the micro-nano bubble water of example 3 was modified with the addition of modifier only, without the addition of graphene dispersion, and the other conditions remained unchanged.

Comparative example 4

This comparative example 4 differs from example 3 only in that: comparative example 4 the silica fume of example 3 was replaced equally with cement, the other conditions being kept unchanged, wherein the cement was p.ii 42.5 cement.

Comparative example 5

This comparative example 5 differs from example 3 only in that: comparative example 5 the micro-nano bubble water of example 3 was modified with modifier only, graphene dispersion, retarder was not added, and other conditions were kept unchanged.

Wherein, in the examples and comparative examples, the prepared bubble water was first placed for 1 day and then mixed with the concrete raw material to prepare a mixture.

Performance test of the products prepared in examples and comparative examples:

The concrete prepared in the above examples and comparative examples were subjected to performance test according to the standard GB/T50080-2016 "Standard for common concrete mixture Performance test method", GB/T50081-2019 "Standard for concrete physical and mechanical Property test method", GB/T50082-2009 "Standard for common concrete Long-term Performance and durability test method", and the results are shown in Table 2:

TABLE 2

In Table 2, the slump, expansion, and plastic viscosity are fresh concrete mix properties; the dry apparent density refers to the mass per unit volume after the concrete is molded, hardened and demolded; the compressive strength of 56d represents the compressive strength of the concrete after 56 days, and the chloride ion diffusion coefficient of 56d represents the chloride ion diffusion resistance coefficient of the concrete after 56 days.

Wherein the volume weight of the concrete is represented by a dry apparent density characterization result; concrete pumping performance is represented by slump, expansion, viscosity and other characterization results; the mechanical property of the concrete is represented by the compression strength characterization result; the durability of the concrete is represented by the characteristic result of chloride ion diffusion coefficient.

From the test results in table 2, it can be seen that:

(1) Examples 1 to 3

From the test results of examples 1-3, it can be seen that: the modified micro-nano bubble water is added, so that the dry apparent density of the concrete can be effectively reduced by 7-9%, and the pumping performance, the mechanical performance and the durability can be improved on the basis of achieving the effect of light weight. Compared with the conventional concrete added in the comparative example 1 and being pure tap water, the dry apparent density of the concrete is effectively reduced by 7-9%, the compressive strength is kept between 95.72-99.23%, and the compressive strength is reduced by about 10% under the condition that the dry apparent density of the concrete prepared by replacing the conventional aggregate with the high-strength lightweight aggregate is reduced by 7-9% by adopting the conventional mode of replacing the conventional aggregate with the high-strength lightweight aggregate. The performances of the concrete prepared by the embodiment of the invention can meet the standard requirements of C50 high-performance concrete, and the standard requirements are that the compressive strength is more than or equal to 59.87MPa and the chloride ion diffusion coefficient is < ">

3.0 X 10 ^-12m²/s, and obvious bubbles are not generated on the surface of the concrete due to the introduction of a large amount of gas, thus the concrete has better appearance. It can be seen that the solution of the invention can also maintain good pumping performance, compressive strength and durability on the basis of reducing the dry apparent density of the concrete.

Comparing the test results of examples 1-3, it can be seen that: according to the scheme, the dosage of the modified micro-nano bubble water is increased, so that the dry apparent density of concrete can be effectively reduced, the strength of the concrete can be slightly reduced due to the fact that a large number of micro-nano bubbles are introduced, and the viscosity of the concrete can be greatly reduced.

(2) Examples 1-3 and comparative example 1 comparison

Tap water was used in comparative example 1; comparative example 1 has a larger slump and expansion degree of concrete, a greatly increased dry apparent density and plastic viscosity, and a slightly increased chloride ion diffusion coefficient as compared with example 3.

According to the embodiment of the invention, the modified micro-nano bubble water is doped, so that a closed micro-nano size space can be formed in the concrete, the apparent density of the concrete is reduced, the ball effect of bubbles in the slurry can be reduced, the plastic viscosity of the concrete is greatly reduced, the bubbles are uniformly distributed, the bubble space forms a barrier to the penetration of chloride ions, the migration distance of the chloride ions is increased, the chloride ion diffusion coefficient of the concrete is reduced (the chloride ion diffusion coefficient of the concrete is reduced, the protection of the steel bars in the concrete is facilitated, the corrosion of free chloride ions on the surfaces of the steel bars is prevented, the material performance is deteriorated), and the influence on the strength of the concrete is small.

(3) Examples 1-3 and comparative example 2 comparison

Comparative example 2 the micro-nano bubble water of example 3 was not modified (no modifier and graphene dispersion were added); compared with comparative example 1, the slump of the micro-nano bubble water in comparative example 2 is similar to that of comparative example 1, but the non-modified micro-nano bubble water is doped, so that the apparent density of the concrete is slightly reduced, the concrete strength is enhanced, the chloride ion resistance is slightly improved, and the non-modified micro-nano bubble water also has the effects of reducing the volume weight and improving the mechanics and durability.

However, compared with the modified micro-nano bubble water, the dry apparent density of the comparative example 2 is reduced slightly, and the apparent effect cannot meet the volume weight requirement.

(4) Comparison of examples 1-3 with comparative example 3

In the modification process of the bubble water of comparative example 3, only the modifier is added for modification, and the graphene dispersion liquid is not added. Compared with the embodiment 3, the modified micro-nano bubble water of the embodiment 3 is not added with graphene dispersion liquid, so that the dry apparent density is reduced, the strength is obviously reduced, and the graphene dispersion liquid has a certain defoaming effect, and the compressive strength of the concrete can be obviously improved.

Compared with comparative example 2, the dry apparent density and compressive strength of comparative example 3 are both greatly reduced, which means that the addition of the modifier can effectively lower the dry apparent density and plastic viscosity thereof, improve the chloride ion resistance thereof, but has a larger influence on the strength thereof. It is known that only the modifier is used for modifying the micro-nano bubble water, although micro-nano bubbles in the micro-nano bubble water can exist stably, the risk of crushing is avoided, and the concrete volume weight can be effectively reduced when the concrete is applied to the concrete; however, the concrete with a reduced volume weight could not be maintained with good compressive strength, and the compressive strength of the concrete of comparative example 3 was greatly reduced.

(5) Comparison of examples 1-3 with comparative example 4

Comparative example 4 compared with example 3, comparative example 4 replaces the same amount of silica fume with cement, the dry apparent density and plastic viscosity of the concrete are slightly increased, the compressive strength and the penetration resistance to chloride ions are reduced, which shows that the silica fume can slightly reduce the apparent density and plastic viscosity of the concrete, and the compressive strength and the penetration resistance to chloride ions of the concrete can be effectively improved.

The silica fume is used as a light mineral admixture, has large specific surface area and small particles, can effectively fill the pores among cement particles, and improves various properties of concrete.

(6) Examples 1-3 and comparative example 5 comparison

Comparative example 5 compared with example 3, the modified micro-nano bubble water in comparative example 5 was free of retarder, the fluidity of concrete was increased, the dry apparent density was increased, and the strength was enhanced.

The retarder has the effect of prolonging the retention time of bubbles, and as the introduced micro-nano bubbles are reduced, the bubbles are lost in the forming and hardening process of the concrete, and the dry apparent density is increased, and although the retarder has a certain increasing effect on the strength, the requirement of low-volume-weight concrete cannot be met due to chain reaction caused by the increase of the dry apparent density.

In summary, the present invention provides a solution comprising the following novel originality, mechanism of action and principle and beneficial effects:

First one

Compared with the conventional scheme of replacing the traditional aggregate by the high-strength lightweight aggregate to obtain the low-volume-weight concrete, the invention not only can effectively reduce the preparation cost, but also can ensure that the concrete keeps good pumping performance, compressive strength and durability on the basis of reducing the volume weight, and each performance of the concrete can meet the standard requirement of C50 high-performance concrete, and the chloride ion diffusion coefficient of the concrete is reduced.

The invention achieves the action mechanism and principle of the required effect that: 1. the micro-nano bubble water is prepared by the micro-nano bubble water generation device, macroscopic large bubbles are gradually dissipated along with time, and only micro-nano bubbles are reserved.

2. The micro-nano bubble water produced by the micro-nano bubble water generating device is treated through the modifier and the graphene dispersion liquid, and the modified micro-nano bubble water is doped to form a closed micro-nano size space inside the concrete, so that the apparent density of the concrete is reduced, the ball effect can be formed by bubbles in the slurry, the plastic viscosity of the concrete is greatly reduced, the bubbles are uniformly distributed, the bubble space forms a barrier to the permeation of chloride ions, the migration distance of the chloride ions is increased, the chloride ion diffusion coefficient of the concrete is reduced, and the influence on the strength of the concrete is small. (1) modifier:

the modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder; one of the functions of the modifier is to reduce the surface tension of the liquid of the generated micro-nano bubble water, so that micro-nano bubbles are easier to keep in aqueous solution, and a large number of micro-nano bubbles which are tiny and stable exist in the micro-nano bubble water;

The anionic air entraining agent has the effects that air entraining molecules are orderly arranged at a gas-liquid interface to form a stable gas-liquid interface, introduced bubbles are more stable in the process of stirring a solution, the bubbles are not generated, surface charges can be generated on micro-nano bubbles on the other hand, static stabilization is promoted, micro-nano bubbles are inhibited from being fused, and the risk of enlarging and cracking of the volume of the bubbles is reduced;

the foam stabilizer can generate a protective layer on the surface of the micro-nano bubbles to enhance the stability of the bubbles;

The retarder can improve the surface viscosity of bubbles, reduce the risk of cracking and prolong the retention time of bubbles in the bubble water.

1) If one of the components in the modifier is missing, this will result in poor results in the production of concrete:

For example: in the prepared micro-nano bubble water, the micro-nano bubbles are not easy to keep in the water for a long time, and when the concrete is mixed for use after standing for a certain time, the bubbles are more lost, so that the prepared concrete cannot meet the requirement of low-volume-weight concrete.

Similarly, no foam stabilizer or anionic air entraining agent is added in the modifier, and the stability of the micro-nano bubbles in the prepared micro-nano bubble water is poor.

2) If the period of modifier addition varies, this will result in poor results in the concrete being made:

If the retarder in the modifier is not added into micro-nano bubble water in advance to modify the micro-nano bubble water, but is added when the retarder is mixed with other raw materials of concrete, the retarder cannot stabilize bubbles in the micro-nano bubble water and prolong the bubble retention time, so that the volume weight of the concrete cannot reach the required effect.

Similarly, if a modifier containing a foam stabilizer, an anionic air entraining agent and a retarder is not added into micro-nano bubble water in advance to modify the micro-nano bubble water, but is added when being mixed with other raw materials of concrete, the modifier cannot stabilize bubbles in the micro-nano bubble water and prolong the bubble retention time.

3) In addition, if the proportion of the modifier exceeds the limit of the application, the prepared concrete has poor effect:

According to the scheme, the modifier is controlled within a reasonable mass range, so that the content and the existence stability of bubbles in the bubble water are controlled, and if the addition amount of the modifier is lower than the limit range of the application, the amount of tiny bubbles in the bubble water is unstable and the content is lower, so that the prepared concrete cannot achieve the effects of light weight and low volume weight. And if the amount of the modifier is more than the range defined in the present application, the amount of air bubbles is excessive, which drastically reduces the compressive strength of the concrete.

(2) The addition modification of graphene dispersion mainly has two roles:

the graphene dispersion liquid is added into micro-nano bubble water in advance, so that more supporting sites are provided for micro-nano bubbles in the bubble water, and the micro-nano bubbles can be uniformly distributed in the whole interface;

In addition, the graphene can exert the advantages of a special two-dimensional structure, super-strong mechanical property, super-high specific surface area and the like, and can not only effectively absorb the stress of the concrete, but also prevent the permeation of moisture and gas, so that the strength and durability of the concrete are enhanced.

1) If the graphene dispersion is absent, the prepared concrete has poor effect:

In the scheme of the invention, the compressive strength of the concrete is obviously reduced without adding graphene dispersion liquid, and the required application requirement cannot be met.

2) If the addition period of the graphene dispersion liquid is changed, the prepared concrete has poor effect:

The graphene dispersion liquid needs to be added into micro-nano bubble water in advance, so that the effect of providing a bubble supporting effect can be achieved, and micro-nano bubbles can be uniformly distributed; if the additive is added when mixing with other raw materials of concrete, the required effect cannot be achieved.

3) In addition, if the ratio of the graphene dispersion liquid exceeds the limit range of the application, the prepared concrete has poor effect:

According to the scheme, the graphene dispersion liquid is controlled within a reasonable mass range so as to achieve a required effect; if the added amount of the graphene dispersion is less than the limit range of the application, the stability and uniform dispersion of micro-bubbles in the bubble water are poor, and the compressive strength and durability of the concrete do not reach the required performance.

Whereas if the amount of graphene dispersion added is above the limit defined by the present application, the following drawbacks occur: (1) cost increases; (2) the volume weight reduction amplitude of the concrete is reduced; (3) even the pumping performance is deteriorated.

Second one

Compared with the scheme (for example, application number 202210304373.2) that only the stabilizer and the surfactant are added in the preparation of the micro-nano bubble water, the innovative design and the action effect of the invention are obviously different from those of the invention:

The scheme of the application number 202210304373.2 is essentially different from the method for producing and modifying micro-nano bubble water, and the application and the purpose are different; according to the scheme, modified micro-nano bubble water is generated through a bubble initiator, and then the modified micro-nano bubble water is stabilized by using a stabilizer, so that the micro-nano bubble water with stable bubbles is prepared; the modified micro-nano bubble water is produced by using the modified micro-nano bubble water generating device, and is obtained by carrying out composite modification on the air entraining agent, the foam stabilizer and the graphene dispersion liquid, so that the invention has the effect of keeping good pumping, compression resistance and other performances of concrete on the basis of reducing the volume weight of the concrete.

Although, the micro-nano bubbles are dispersed and bubble water exists in the micro-nano bubbles, the bubbles can form a ball effect in the slurry, the plastic viscosity of the concrete is greatly reduced, the workability is improved, and the compressive strength of the concrete can be theoretically improved. However, if a large amount of bubble water containing stable bubbles is introduced so that the volume weight of concrete can be reduced to a certain extent based on the purpose of introducing bubble-containing water to reduce the volume weight of concrete to a certain extent, it is inevitable to cause a great reduction in compressive strength, for example, micro-nano bubble water in which bubbles stably exist is modified with a modifier used in comparative example 3, the specific gravity thereof is reduced, but the compressive strength is obviously reduced to a great extent.

In application number 202210304373.2, although the use of stabilizers and surfactants to stabilize micro-nano bubbles in bubble water is described, the application of the ball effect to increase compressive strength is clearly not applied in the case of greatly reducing the volume weight of concrete. The scheme discloses a simple bubble water with a large amount of bubbles stably existing, and the simple bubble water is directly applied to concrete, and when the volume weight of the concrete is reduced to a certain extent, the concrete cannot be guaranteed to have good compressive strength and durability.

Compared with the scheme disclosed in the application number 202210304373.2, the invention is based on the aim of greatly reducing the volume weight of concrete, and on the basis of modifying by a modifier to stabilize micro-nano bubbles, a graphene dispersing agent is also added, so that the concrete has foam stabilizing and homogenizing effects, and can maintain good compressive strength and durability on the basis of reducing the volume weight.

Third, the novelty and utility of the present invention:

According to the scheme, the modified micro-nano bubble water is doped into the concrete, so that the apparent density of the concrete can be effectively reduced, more obviously, each performance of the low-volume-weight concrete is guaranteed to be equivalent to that of common high-performance concrete, the apparent appearance of the concrete is good, and no obvious bubbles exist. The low-volume-weight concrete has less rising of manufacturing cost and economy; the modified micro-nano bubble water is used for achieving the light weight effect, replaces the traditional high-strength lightweight aggregate mode of reducing the volume weight, and has novel creativity. The method increases the workability of the concrete, reduces manpower, has simple whole-process preparation method and easily obtained materials, and has practicability.

In summary, the invention has the following effects

Compared with the scheme that the high-strength lightweight aggregate replaces the traditional lightweight aggregate, the invention provides the modified micro-nano bubble water, the concrete prepared by doping the modified micro-nano bubble water is used for replacing the traditional lightweight aggregate in a mode of introducing the modified micro-nano bubble water, so that the volume weight of the concrete can be effectively reduced under lower manufacturing cost, on the basis of reducing the volume weight, the properties of the low-volume weight concrete are ensured to be equivalent to those of common high-performance concrete, the concrete has good pumping performance, mechanical property and durability, and the concrete has better appearance and no obvious bubbles; the low-volume-weight concrete is convenient for carrying and installing components, and has the performance meeting the application requirements, and has economy and practicability.

In summary, the invention provides the modified micro-nano bubble water and the low-volume-weight concrete doped with the modified micro-nano bubble water, and the low-volume-weight concrete is doped with the modified micro-nano bubble water and the high-performance additive, so that the problem of high apparent density of the concrete can be effectively solved, and more obviously, the strength of the concrete can be ensured to meet the preparation requirement on the premise of having cost performance, and the compactness of the concrete is improved by optimizing the mixing ratio of the concrete, so that the effect of improving the durability of the concrete is achieved.

It should be noted that:

Herein, "to" is used to denote a numerical range, and the expression range of the expression includes two endpoint values;

The specific parameters of the embodiments described above, or some common reagents or raw materials, are specific embodiments or preferred embodiments under the inventive concept, and are not limiting thereof; and can be adaptively adjusted by those skilled in the art within the concept and the protection scope of the invention.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. A modified micro-nano bubble water is characterized in that: the components of the graphene foam comprise micro-nano bubble water, a modifier dispersed in the micro-nano bubble water and graphene dispersion liquid;

Micro-nano bubbles are dispersed in the micro-nano bubble water; the modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder;

The mass ratio of the micro-nano bubble water to the modifier to the graphene dispersion liquid is (18-21) (0.05-0.1) (3-4).

2. The modified micro-nano bubble water according to claim 1, wherein: the micro-nano bubble water is prepared from water through a micro-nano bubble water generation device, so that micro-nano bubbles are dispersed in the micro-nano bubble water.

3. The modified micro-nano bubble water according to claim 1, wherein:

The mass ratio of the anionic air entraining agent to the foam stabilizer to the retarder is (3-10) (0.02-0.08) (1-4);

the anionic air entraining agent is one or a combination of more of alpha-alkenyl alkyl sodium sulfonate and alkyl polyoxyethylene ether sodium sulfonate; the carbon number of alkyl in the alkyl polyoxyethylene ether sodium sulfonate is 8-12;

the foam stabilizer is one or a combination of more of dodecyl dimethyl amine oxide, alkyl polyoxyethylene ether and polyvinyl alcohol;

The retarder is one or a combination of more of white sugar, sodium gluconate and sodium citrate;

the graphene dispersion liquid is formed by dispersing graphene in solvent water, and the solid content of the graphene dispersion liquid is 0.05% -0.2%; the graphene comprises one or more of graphene oxide and reduced graphene oxide.

4. The preparation method of the modified micro-nano bubble water is characterized by comprising the following preparation steps:

the second part of water is introduced into the solution C through a micro-nano bubble water generating device, so that the second part of water is mixed with the first part of water and micro-nano bubbles are dispersed in the second part of water to form the micro-nano bubble water; the mass ratio of the micro-nano bubble water to the modifier to the graphene dispersion liquid is (18-21) (0.05-0.1) (3-4);

The modifier comprises an anionic air entraining agent, a foam stabilizer and a retarder.

5. The method for preparing the modified micro-nano bubble water according to claim 4, which is characterized in that: the mass ratio of the anionic air entraining agent to the foam stabilizer to the retarder is (3-10) (0.02-0.08) (1-4);

The mass ratio of the first part of water to the second part of water is (0.5-1): (1-1.5).

6. The method for preparing the modified micro-nano bubble water according to claim 4, which is characterized in that:

The anionic air entraining agent is one or a combination of a plurality of alpha-alkenyl sodium alkyl sulfonate and alkyl polyoxyethylene ether sodium sulfonate, and the carbon number of alkyl in the alkyl polyoxyethylene ether sodium sulfonate is 8-12;

7. The low-volume-weight concrete doped with the modified micro-nano bubble water is characterized in that: the raw material comprises the following components in parts by weight: cement, modified micro-nano bubble water, fly ash, mineral powder, silica fume, coarse aggregate, fine aggregate and high-performance water reducer;

Wherein the modified micro-nano bubble water is the modified micro-nano bubble water according to any one of claims 1-3; or the modified micro-nano bubble water prepared by the preparation method according to any one of claims 4-6.

8. The modified micro-nano aerated water doped low-volume-weight concrete according to claim 7, wherein the concrete is characterized in that: the raw material comprises the following components in parts by weight:

221 to 294 parts of cement, 147 to 167 parts of modified micro-nano bubble water, 73 to 147 parts of fly ash, 73 to 147 parts of mineral powder, 15 to 39 parts of silica fume, 1050 to 1100 parts of coarse aggregate, 680 to 740 parts of fine aggregate and 3.9 to 5.9 parts of high-performance water reducer.

9. The modified micro-nano aerated water doped low-volume-weight concrete according to claim 7, wherein the concrete is characterized in that:

The cement is one or a combination of more of P.O42.5 cement, P. I I42.5 cement and P.I42.5 cement;

The fly ash is one or a combination of more of class I fly ash and I I fly ash;

The mineral powder is mineral powder with the specific surface area of 650m ²/kg～750m²/kg obtained by grinding S95-grade mineral powder, and the activity index of 28d is 115% -122%;

the silica fume is one or a combination of more of SF 94-grade silica fume and SF 96-grade silica fume;

The coarse aggregate is one or a combination of a plurality of crushed stones with the particle size of 5 mm-10 mm, crushed stones with the particle size of 10 mm-20 mm and crushed stones with the particle size of 5 mm-20 mm, the apparent density is 2620kg/m ³～2650kg/m³, the void ratio is 38% -41%, and the crushing value is 2% -4%;

The fine aggregate is machine-made sand, the fineness modulus is 2.6-2.8, the apparent density is 2600kg/m ³～2640kg/m³, the void ratio is 40-44%, and the mud content is 0.1-0.5%;

10. A method for preparing the modified micro-nano bubble water doped low-volume-weight concrete according to any one of claims 7 to 9, comprising the following preparation steps:

Uniformly mixing coarse aggregate and fine aggregate to obtain a mixture A;