Preparation method of multi-component mixed gas foam concrete

Abstract

A preparation method of multi-component mixed gas foam concrete belongs to the technical field of concrete.The preparation method comprises the following steps: preparing a nanoparticle modified foaming liquid: adding a surfactant into water, uniformly stirring to obtain a surfactant solution, adding nanoparticles into the surfactant solution, and stirring with a magnetic stirrer to obtain the nanoparticle modified foaming liquid; then adding a foam stabilizer and uniformly stirring to obtain a modified foaming solution; starting a foaming machine, and introducing foaming liquid to generate stable mixed gas foam of carbon dioxide and nitrogen; stirring the cement and the water to obtain uniform cement paste; adding the prepared mixed gas foam into cement slurry, continuously stirring, filling the mixed gas foam concrete slurry into a mold, waiting for solidification, demolding, and performing standard curing to obtain the mixed gas foam concrete. The prepared carbon dioxide mixed gas foam is more stable, the strength of the foam concrete is higher, and a new scheme is provided for carbon sequestration and emission reduction while the strength of the foam concrete is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete and relates to a method for preparing multi-component mixed gas foam concrete. Background Art

[0002] In recent years, under the background of the "dual carbon" target strategy, the development of green and low-carbon concrete materials is an inevitable choice for the development of a low-carbon economy. As a thermal insulation and sound insulation material, foamed concrete is widely used in wall insulation, floor heating insulation and filling abandoned mines. It not only has a huge carbon reduction space, but also has a huge CO2 absorption capacity. Compared with air-foamed concrete, foamed concrete foamed with CO2 has better thermal insulation performance and structural strength, and has broad application prospects in the field of energy conservation and emission reduction. However, CO2 has a high solubility in water, which leads to poor foam stability, rapid foam polymerization and defoaming, and easy collapse of foamed concrete before hardening. Therefore, improving the stability of CO2 foam is of great significance to promote the development of CO2 foamed concrete.

[0003] The current related inventions use carbon dioxide to prepare foamed concrete. For example, Chinese patent CN115611589A provides a method for preparing cement-based foamed lightweight soil based on carbonation curing, using CO2 and foaming agent to mix to prepare CO2 foam, and then mixing with cement slurry in a reactor under pressure to prepare lightweight foamed concrete. Subsequently, there is a method of introducing CO2 gas into cement slurry to reduce the reaction of CO2 foam and cement slurry. For example, Chinese patent CN118125764A provides a method for preparing foamed concrete using carbon dioxide foam, using carbon dioxide gas and nanoparticle foaming agent, preparing carbon dioxide foam through a foaming machine, introducing carbon dioxide gas into cement slurry to obtain carbonized cement slurry, and then adding carbon dioxide foam and stirring to prepare lightweight concrete. For example, Chinese patent CN118373649A provides a low-density, high-strength, carbon-fixing foamed concrete and its preparation method, the composite modified foaming agent is foamed by rapid stirring in a carbon dioxide atmosphere, so that the foam wraps the carbon dioxide, and carbon dioxide gas is continuously introduced as a foam stabilizer during the preparation of the foamed concrete, so that a lightweight foamed concrete with better stability is prepared.

[0004] However, the current method of using carbon dioxide foam to prepare foamed concrete, such as the above patents, still has the following problems: 1. Since the solubility of carbon dioxide in water is higher than that in air, carbon dioxide can easily pass through the foam liquid film, resulting in poor stability of carbon dioxide foam, and its half-life (the time required for the foam volume to be reduced by half) is less than 10 minutes, which cannot meet the requirements for preparing foamed concrete. 2. Since cement paste has a high alkalinity, when carbon dioxide foam is mixed with cement paste, the carbon dioxide in the foam will quickly react with the cement paste. If you want to prepare foamed concrete that meets the density requirements, you need to add several times the calculated value of carbon dioxide foam, which will also lead to excessive water incorporation and reduce the structural strength. 3. Since the carbon dioxide in the pores of foamed concrete will continue to react with cement, the carbon dioxide in the pores will decrease in the later stage, and negative pressure will be formed in the pores. The foam pore wall will produce microcracks due to carbonization shrinkage, which will reduce the strength of the concrete. 4. At present, most of the methods for preparing foam using carbon dioxide use pure carbon dioxide cylinders as the material. The purification process of carbon dioxide increases additional energy consumption. In addition, the use of pure carbon dioxide limits the wide range of material sources. The waste gas discharged by some factories contains low concentrations of carbon dioxide. If carbon dioxide mixed gas can be used to prepare foam concrete, it can provide a reference for the use of such waste gas. Therefore, designing a preparation method of multi-component mixed gas foam concrete to enhance the stability of its foam, reduce the amount of foam used, and further reduce carbonization shrinkage and enhance the structural strength of concrete has become a problem that needs to be solved by technicians in this field. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing multi-component mixed gas foam concrete to achieve the manufacture of low-density and high-strength foam concrete.

[0006] The technical solution adopted by the present invention to solve its technical problem is: A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1, preparing a foaming liquid modified by nanoparticles, the process is as follows; S11, adding a surfactant into water and stirring evenly to obtain a surfactant solution; S12, adding nanoparticles to the surfactant solution and stirring evenly with a magnetic stirrer; S13, slowly adding a foam stabilizer to the surfactant solution, and stirring evenly with a magnetic stirrer to obtain a nanoparticle-modified foaming liquid; S2, preparing carbon dioxide mixed gas foam, the process is as follows; S21, respectively connect the gas proportioner and the carbon dioxide gas cylinder, the additional gas cylinder, and the foaming machine with gas pipes, adjust the ratio of the two mixed gases on the gas proportioner, turn on the power of the foaming machine and pass the mixed gas for a period of time; S22, placing the feed port of the foaming machine into the foaming liquid to generate a stable carbon dioxide mixed gas foam; S3, preparing carbon dioxide mixed gas foam concrete, the process is as follows: S31, adding cement and water into a cement mixing pot, and stirring for a period of time to obtain a uniform cement slurry; S32, adding the carbon dioxide mixed gas foam in step S22 to the cement slurry and continuously stirring, finally obtaining a carbon dioxide mixed gas foam concrete slurry; S33, loading the foamed concrete slurry into a mold, demoulding after molding, and performing curing to obtain carbon dioxide mixed gas foamed concrete.

[0007] Furthermore, in the step S11, the mass ratio of the surfactant to water is (1-10): 100. The surfactant, as the main foaming substance, can increase the foaming multiple and improve the stability of the foam.

[0008] Preferably, the surfactant is one or a mixture of two or more of a plant protein surfactant, an animal protein surfactant, cocamidopropyl betaine, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

[0009] Furthermore, in S12, the mass ratio of the nanoparticles to water is (0.1-10): 100. The nanoparticles can be adsorbed on the surface of the bubbles and synergistically enhance the foam stability with the foaming agent.

[0010] Preferably, the nanoparticles are one or a mixture of two or more of nano-silicon dioxide, nano-calcium carbonate, and nano-titanium dioxide, and the particle size of the nanoparticles is between 5-100 nm.

[0011] Furthermore, in S13, the mass ratio of the foam stabilizer to water is (0.1-2):100.

[0012] Preferably, the foam stabilizer is hydroxypropyl methylcellulose, sodium hydroxymethyl cellulose or a mixture of the two.

[0013] In the above S21, the gas in the additional gas cylinder is nitrogen, oxygen or air, and the gas connected to the gas proportioner is carbon dioxide and the additional gas.

[0014] Preferably, in S21, the gas cylinder is connected to a pressure reducing valve, and the gas is decompressed by the pressure reducing valve and then input into the gas proportioner. The pressure values ​​of the two gas cylinders should be adjusted to the same, and the pressure range is 0.2-0.5MPa. In this solution, when the two gas cylinders are decompressed to the same pressure and connected to the gas proportioner, the percentages of the two gases in the mixed gas can be set respectively by two knobs, and the adjustment range of the knobs is (0%-100%).

[0015] In the S22, the gas outlet rate of the gas proportioner is consistent with the gas inlet rate of the foaming machine, and the foam output rate of the foaming machine is 1-15L / min.

[0016] In the step S31, the cement is ordinary Portland cement or sulphoaluminate cement, and the mass of water is 30-50% of the mass of cement.

[0017] In the S32, the amount of carbon dioxide mixed gas foam added per kilogram of cement is 1-4L.

[0018] The technical concept of the present invention is: first, nanoparticles and foam stabilizers are added to the foaming agent. The combined effect of the nanoparticles and the cellulose foam stabilizer increases the viscosity of the foaming liquid. The increase in the viscosity of the foaming liquid can not only increase the surface strength of the liquid film and hinder the internal gas from diffusing outward, but also delay the discharge of liquid in the foam liquid film, thereby improving the ability of the bubbles to resist external interference.

[0019] Instead of using pure carbon dioxide as the foaming gas, a mixture of carbon dioxide and nitrogen or other gases is selected, which can reduce the gas percentage of carbon dioxide in the bubbles and slow down the rate of gas penetration from the bubble liquid membrane, thereby simultaneously enhancing the stability of the foam and extending its half-life.

[0020] In addition, because the foaming gas is a mixture of carbon dioxide and other things, during the mixing of the foam and cement slurry and the later service period, it can reduce the negative pressure in the foam pores caused by the reaction of internal carbon dioxide, slow down the carbonization shrinkage problem, and thus improve the strength of the foam concrete.

[0021] The beneficial effects of the present invention are mainly manifested in that the present invention can prepare more stable multi-component mixed gas foam, slow down the speed of carbon dioxide penetrating the bubble liquid membrane, increase the stability of the foam, greatly extend the half-life of the foam, and improve the strength of the foam concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a flow chart of an embodiment of the present invention.

[0023] Figure 2The schematic diagram of the structure of connecting the gas proportioner with the gas cylinder and the foaming machine to manufacture mixed gas foam, wherein 1 is the carbon dioxide gas cylinder, 2 is the additional gas cylinder, 3 is the pressure reducing gas valve, 4 is the gas pipe, 5 is the gas proportioner, 51 is the flow meter, 52 is the proportioning adjustment knob, 6 is the foaming agent, and 61 is the foaming adjustment knob. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Refer to Figure 1 and Figure 2 , a method for preparing multi-component mixed gas foam concrete, comprising the following steps: S1, preparing a foaming liquid modified by nanoparticles, the process is as follows; S11, adding a surfactant into water and stirring evenly to obtain a surfactant solution; In S11, the mass ratio of the surfactant to water is (1-10): 100. The surfactant, as the main foaming substance, can increase the foaming multiple of the foam and improve its stability. The surfactant is one or a mixture of two or more of a plant protein surfactant, an animal protein surfactant, cocamidopropyl betaine, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate;

[0026] S12, adding nanoparticles to the surfactant solution and stirring evenly with a magnetic stirrer; In S12, the mass ratio of the nanoparticles to water is (0.1-10):100. The nanoparticles can be adsorbed on the surface of bubbles and synergistically enhance the foam stability with the foaming agent. The nanoparticles are one or a mixture of two or more of nano-silicon dioxide, nano-calcium carbonate, and nano-titanium dioxide, and the particle size of the nanoparticles is between 5-100 nm;

[0027] S13, slowly adding a foam stabilizer to the surfactant solution, and stirring evenly with a magnetic stirrer to obtain a nanoparticle-modified foaming liquid; In S13, the mass ratio of the foam stabilizer to water is (0.1-2): 100. The foam stabilizer is one of hydroxypropyl methylcellulose and sodium hydroxymethyl cellulose or a mixture of the two;

[0028] S2, preparing carbon dioxide mixed gas foam, the process is as follows; S21, respectively connect the gas proportioner 5 and the carbon dioxide cylinder 1, the additional gas cylinder 2, and the foaming machine 6 with a gas pipe, adjust the ratio of the two mixed gases on the gas proportioner 5, turn on the power of the foaming machine and pass the mixed gas for a period of time; In the above S21, the gas in the additional gas cylinder is nitrogen, oxygen or air, and the gas connected to the gas proportioner is carbon dioxide and the additional gas.

[0029] Preferably, in the S21, the gas cylinders (the carbon dioxide gas cylinder 1 and the additional gas cylinder 2) are connected to the pressure reducing valve 3, and the gas is decompressed by the pressure reducing valve 3 and then input into the gas proportioner 4. The pressure values ​​of the two gas cylinders should be adjusted to be the same, and the pressure range is 0.2-0.5MPa. In this scheme, after the two gas cylinders are decompressed to the same pressure and connected to the gas proportioner, the percentages of the two gases in the mixed gas can be set respectively by two proportioning adjustment knobs 52, and the adjustment range of the proportioning adjustment knobs 52 is (0%-100%), and the flow of the two gases is displayed in real time by the flow meter 51; S22, placing the feed port of the foaming machine into the foaming liquid to generate a stable carbon dioxide mixed gas foam; In the step S22, the gas proportioner gas outlet rate is consistent with the gas intake rate of the foaming machine, and the foam output rate of the foaming machine is 1-15 L / min; the rate is adjusted by the foaming adjustment knob 61; S3, preparing carbon dioxide mixed gas foam concrete, the process is as follows: S31, adding cement and water into a cement mixing pot, and stirring for a period of time to obtain a uniform cement slurry; In the step S31, the cement is ordinary Portland cement or sulphoaluminate cement, and the mass of water is 30-50% of the mass of cement; S32, adding the carbon dioxide mixed gas foam in step S22 to the cement slurry and continuously stirring, finally obtaining a carbon dioxide mixed gas foam concrete slurry; In the S32, the amount of carbon dioxide mixed gas foam added per kilogram of cement is 1-4L; S33, loading the foamed concrete slurry into a mold, demoulding after molding, and performing curing to obtain carbon dioxide mixed gas foamed concrete.

[0030] Example 1 A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1. Weigh 50 mL of plant protein surfactant and dissolve it in 2000 mL of water, and stir evenly. Slowly add 20 g of hydrophobic nano-silica with a particle size of 40 nm to the surfactant solution stirred by a magnetic stirrer, and then treat it with an ultrasonic disperser with a frequency of 40 kHz for 20 min; slowly add 10 g of hydroxypropyl methylcellulose foam stabilizer and stir it with a magnetic stirrer for 10 min; S2. Connect the gas proportioner with the carbon dioxide cylinder and the nitrogen cylinder, adjust the outlet pressure of the two cylinders to 0.3MPa through the pressure reducing valve, adjust the two knobs on the gas proportioner to make the volume ratio of carbon dioxide and nitrogen in the mixed gas to 1:3, adjust the foaming rate of the foaming machine to 10L / min and ventilate for a period of time, and introduce the foaming liquid to generate foam with a carbon dioxide volume fraction of 25%; S3. Add 45 parts of water and 100 parts of cement into a cement mixing pot and stir evenly to obtain cement slurry, wherein the cement is ordinary Portland cement with a strength grade of 42.5; add carbon dioxide and nitrogen mixed gas foam to the cement slurry and continue stirring to obtain mixed gas foam concrete slurry, wherein the amount of carbon dioxide foam added per kilogram of cement is 1.1 L; the foamed concrete slurry is loaded into a mold, and after molding, the mold is demolded and cured under standard conditions to obtain carbon dioxide and nitrogen mixed gas foam concrete.

[0031] Example 2 A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1. Weigh 20 mL of animal protein surfactant and dissolve it in 2000 mL of water, and stir evenly. Slowly add 20 g of nano calcium carbonate with a particle size of 50 nm into the surfactant solution stirred by a magnetic stirrer, and then treat it with an ultrasonic disperser with a frequency of 40 kHz for 20 min; slowly add 10 g of sodium hydroxymethyl cellulose foam stabilizer and stir it with a magnetic stirrer for 10 min; S2. Connect the gas proportioner with the carbon dioxide cylinder and the nitrogen cylinder, adjust the outlet pressure of the two cylinders to 0.3MPa through the pressure reducing valve, adjust the two knobs on the gas proportioner to make the volume ratio of carbon dioxide and nitrogen in the mixed gas to 1:3, adjust the foaming rate of the foaming machine to 10L / min and ventilate for a period of time, and introduce the foaming liquid to generate foam with a carbon dioxide volume fraction of 25%; S3. Add 45 parts of water and 100 parts of cement into a cement mixing pot and stir evenly to obtain cement slurry, wherein the cement is ordinary Portland cement with a strength grade of 42.5; add carbon dioxide and nitrogen mixed gas foam to the cement slurry and continue stirring to obtain mixed gas foam concrete slurry, wherein the amount of carbon dioxide foam added per kilogram of cement is 1.1 L; the foamed concrete slurry is loaded into a mold, and after molding, the mold is demolded and cured under standard conditions to obtain carbon dioxide and nitrogen mixed gas foam concrete.

[0032] Example 3 A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1, weigh 50g of sodium lauryl sulfate and 50g of cocamidopropyl betaine and dissolve them in 1000mL of water, and stir evenly, slowly add 10g of hydrophobic nano-silica with a particle size of 40nm to the surfactant solution stirred with a magnetic stirrer, and then treat it with an ultrasonic disperser with a frequency of 40kHz for 20min; slowly add 10g of hydroxypropyl methylcellulose and 10g of sodium hydroxymethylcellulose foam stabilizer and stir with a magnetic stirrer for 10min; S2. Connect the gas proportioner with the carbon dioxide cylinder and the nitrogen cylinder, adjust the outlet pressure of the two cylinders to 0.3MPa through the pressure reducing valve, adjust the two knobs on the gas proportioner to make the volume ratio of carbon dioxide and nitrogen in the mixed gas to 1:3, adjust the foaming rate of the foaming machine to 10L / min and ventilate for a period of time, and introduce the foaming liquid to generate foam with a carbon dioxide volume fraction of 25%; S3. Add 50 parts of water and 100 parts of cement into a cement mixing pot and stir evenly to obtain cement slurry, wherein the cement is ordinary Portland cement with a strength grade of 42.5; add carbon dioxide and nitrogen mixed gas foam to the cement slurry and continue stirring to obtain mixed gas foam concrete slurry, wherein the amount of carbon dioxide foam added per kilogram of cement is 1.2 L; the foamed concrete slurry is loaded into a mold, and after molding, the mold is demolded and cured under standard conditions to obtain carbon dioxide and nitrogen mixed gas foam concrete.

[0033] Example 4 A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1. Weigh 25 mL of plant protein surfactant and dissolve it in 1000 mL of water, and stir evenly. Slowly add 50 g of hydrophobic nano-silicon dioxide with a particle size of 40 nm and 50 g of nano-calcium carbonate with a particle size of 100 nm to the surfactant solution stirred with a magnetic stirrer, and then treat it with an ultrasonic disperser with a frequency of 40 kHz for 20 min; 10 g of hydroxypropyl methylcellulose foam stabilizer and stir it with a magnetic stirrer for 10 min; S2. Connect the gas proportioner with the carbon dioxide cylinder and the nitrogen cylinder, adjust the outlet pressure of the two cylinders to 0.3MPa through the pressure reducing valve, adjust the two knobs on the gas proportioner to make the volume ratio of carbon dioxide and nitrogen in the mixed gas to 1:3, adjust the foaming rate of the foaming machine to 1L / min and ventilate for a period of time, and introduce the foaming liquid to generate foam with a carbon dioxide volume fraction of 25%; S3. Add 50 parts of water and 100 parts of cement into a cement mixing pot and stir evenly to obtain cement slurry, wherein the cement is ordinary Portland cement with a strength grade of 42.5; add carbon dioxide and nitrogen mixed gas foam to the cement slurry and continue stirring to obtain mixed gas foam concrete slurry, wherein the amount of carbon dioxide foam added per kilogram of cement is 1.2 L; the foamed concrete slurry is loaded into a mold, and after molding, the mold is demolded and cured under standard conditions to obtain carbon dioxide and nitrogen mixed gas foam concrete.

[0034] Example 5 A method for preparing multi-component mixed gas foam concrete comprises the following steps: S1. Weigh 50 mL of plant protein surfactant and dissolve it in 2000 mL of water, and stir evenly. Slowly add 2 g of hydrophilic nano-titanium dioxide with a particle size of 5 nm into the surfactant solution stirred by a magnetic stirrer, and then treat it with an ultrasonic disperser with a frequency of 40 kHz for 20 min; slowly add 2 g of hydroxypropyl methylcellulose foam stabilizer and stir it with a magnetic stirrer for 10 min; S2. Connect the gas proportioner with the carbon dioxide cylinder and the nitrogen cylinder, adjust the outlet pressure of the two cylinders to 0.3MPa through the pressure reducing valve, adjust the two knobs on the gas proportioner to make the volume ratio of carbon dioxide and nitrogen in the mixed gas to 1:3, adjust the foaming rate of the foaming machine to 10L / min and ventilate for a period of time, and introduce the foaming liquid to generate foam with a carbon dioxide volume fraction of 25%; S3. Add 30 parts of water and 100 parts of cement into a cement mixing pot and stir evenly to obtain cement slurry, wherein the cement is ordinary Portland cement with a strength grade of 42.5; add carbon dioxide and nitrogen mixed gas foam to the cement slurry and continue stirring to obtain mixed gas foam concrete slurry, wherein the amount of carbon dioxide foam added per kilogram of cement is 1L; the foamed concrete slurry is loaded into a mold, and after molding, demolding is performed and curing is performed under standard conditions to obtain carbon dioxide and nitrogen mixed gas foam concrete.

[0035] Example 6 A method for preparing multi-component mixed gas foam concrete, as shown in Example 1, the difference is that the gas cylinders connected to the gas proportioner in step S2 are carbon dioxide gas cylinders and air cylinders, so that the volume ratio of carbon dioxide to air in the mixed gas is 1:3; in S3, the amount of carbon dioxide foam added per kilogram of cement is 1.2L. The density of the foam concrete obtained in Example 2 is substantially the same as that in Example 1.

[0036] Example 7 A method for preparing multi-component mixed gas foam concrete, as shown in Example 1, the difference is that in step S2, the knob on the proportioner is adjusted so that the volume ratio of carbon dioxide and nitrogen in the mixed gas is 1:1, and the foaming rate of the foaming machine is adjusted to 15L / min; in S3, the amount of carbon dioxide foam added per kilogram of cement is 1.2L. The density of the foamed concrete obtained in Example 2 is substantially the same as that in Example 1.

[0037] Example 8 A method for preparing multi-component mixed gas foam concrete, as shown in Example 1, the difference is that in S2, the knob on the proportioner is adjusted so that the volume ratio of carbon dioxide and nitrogen in the mixed gas is 3:1; in S3, the amount of carbon dioxide foam added per kilogram of cement is 1.4L. The density of the foam concrete obtained in Example 3 is substantially the same as that in Example 1.

[0038] Example 9 A method for preparing multi-component mixed gas foamed concrete, as shown in Example 1, except that the knob on the proportioner is adjusted in S2 so that all the foaming gas is carbon dioxide gas; and the amount of carbon dioxide foam added per kilogram of cement in S3 is 4 L. The density of the foamed concrete obtained in Example 9 is substantially the same as that in Example 1.

[0039] Comparative Example 1 Ordinary foamed concrete was prepared as a control group. The difference between this comparative example and Example 1 is that the air inlet of the foaming machine in S2 is not connected to a gas proportioner, and the prepared foam is air foam; the amount of foam added per kilogram of cement in S3 is 1L. The density of the foamed concrete obtained in Comparative Example 1 is substantially the same as that in Example 1.

[0040] Performance test: The foam obtained by foaming in Examples 1, 7, 8, and 9 was tested for half-life and foaming multiple. The test results are shown in Table 1: Table 1

[0041] As can be seen from Table 1, the foam expansion multiples of the foam obtained by foaming with a mixture of carbon dioxide and nitrogen are similar to those obtained by foaming with carbon dioxide, but the half-life is significantly improved and the foam stability is stronger.

[0042] Referring to the determination method of JG / T266-2011 "Foamed Concrete", the dry density and 28d compressive strength of the foamed concrete of Examples 1, 7, 8, 9 and Comparative Example 1 were determined. The test results are shown in Table 2: Table 2

[0043] The dry density of the foamed concrete in the above embodiment and the comparative example is close to 1000 kg / m 3As shown in Table 2, the 28d strength of foamed concrete prepared by using a mixture of carbon dioxide and nitrogen is significantly higher than that of air and carbon dioxide foamed concrete. The 28d strength of foamed concrete foamed with 25% carbon dioxide is 55.0% higher than that of air foamed concrete. This shows that the strength of foamed concrete can be significantly improved by using a mixture of carbon dioxide and nitrogen to foam foamed concrete. In addition, compared with a high carbon dioxide volume fraction, the strength of foamed concrete foamed with a low carbon dioxide volume fraction is higher.

[0044] In summary, this embodiment proposes a new solution to improve the stability of carbon dioxide foam, while improving the stability of carbon dioxide foam in concrete, thereby enhancing the strength of carbon dioxide foam concrete.

[0045] The contents described in the embodiments of this specification are merely enumerations of implementation forms of the inventive concept and are for illustrative purposes only. The protection scope of the present invention should not be considered to be limited to the specific forms described in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be thought of by ordinary technicians in this field based on the inventive concept.

Claims

1. A method for preparing multi-component mixed gas foam concrete, characterized in that: The method comprises the following steps: S1, preparing a foaming liquid modified by nanoparticles, the process is as follows; S11, adding a surfactant into water and stirring evenly to obtain a surfactant solution; S12, adding nanoparticles to the surfactant solution and stirring evenly with a magnetic stirrer; S13, slowly adding a foam stabilizer to the surfactant solution, and stirring evenly with a magnetic stirrer to obtain a nanoparticle-modified foaming liquid; S2, preparing carbon dioxide mixed gas foam, the process is as follows; S21, respectively connect the gas proportioner and the carbon dioxide cylinder, the additional gas cylinder, and the foaming machine with gas pipes, the gas in the additional gas cylinder is nitrogen, oxygen or air, adjust the ratio of the two mixed gases on the gas proportioner, turn on the power of the foaming machine and pass the mixed gas for a period of time; S22, placing the feed port of the foaming machine into the foaming liquid to generate a stable carbon dioxide mixed gas foam; S3, preparing carbon dioxide mixed gas foam concrete, the process is as follows: S31, adding cement and water into a cement mixing pot, and stirring for a period of time to obtain a uniform cement slurry; S32, adding the carbon dioxide mixed gas foam in step S22 to the cement slurry and continuously stirring, finally obtaining a carbon dioxide mixed gas foam concrete slurry; S33, loading the foamed concrete slurry into a mold, demoulding after molding, and performing curing to obtain carbon dioxide mixed gas foamed concrete.

2. The method for preparing a multi-component mixed gas foam concrete according to claim 1, characterized in that: In the S11, the mass ratio of the surfactant to water is (1-10):

100.

3. The method for preparing a multi-component mixed gas foamed concrete according to claim 2, characterized in that: The surfactant is one or a mixture of two or more of a plant protein surfactant, an animal protein surfactant, cocamidopropyl betaine, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

4. The method for preparing a multi-component mixed gas foamed concrete according to any one of claims 1 to 3, characterized in that: In S12, the mass ratio of the nanoparticles to water is (0.1-10):

100.

5. The method for preparing a multi-component mixed gas foamed concrete according to claim 4, characterized in that: The nanoparticles are one or a mixture of two or more of nano silicon dioxide, nano calcium carbonate and nano titanium dioxide, and the particle size of the nanoparticles is between 5 and 100 nm.

6. The method for preparing a multi-component mixed gas foamed concrete according to any one of claims 1 to 3, characterized in that: In S13, the mass ratio of the foam stabilizer to water is (0.1-2):

100.

7. The method for preparing a multi-component mixed gas foamed concrete according to claim 6, characterized in that: The foam stabilizer is one of hydroxypropyl methylcellulose and sodium hydroxymethyl cellulose or a mixture of the two.

8. The method for preparing a multi-component mixed gas foamed concrete according to any one of claims 1 to 3, characterized in that: In the S21, the gas cylinder is connected to the pressure reducing valve, and the gas is input into the gas proportioner after being reduced in pressure through the pressure reducing valve. The pressure values ​​of the two gas cylinders should be adjusted to the same, and the pressure range is 0.2-0.5MPa; when the two gas cylinders are reduced in pressure to the same pressure and connected to the gas proportioner, the percentages of the two gases in the mixed gas can be set respectively through the two knobs, and the adjustment range of the knobs is (0%-100%).

9. The method for preparing a multi-component mixed gas foamed concrete according to any one of claims 1 to 3, characterized in that: In the S22, the gas outlet rate of the gas proportioner is consistent with the gas inlet rate of the foaming machine, and the foam output rate of the foaming machine is 1-15L / min.

10. The method for preparing a multi-component mixed gas foamed concrete according to any one of claims 1 to 3, characterized in that: In the S31, the cement is ordinary Portland cement or sulphoaluminate cement, and the mass of water is 30-50% of the mass of cement; in the S32, the amount of carbon dioxide mixed gas foam added per kilogram of cement is 1-4L.

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