In-situ foamed low-carbon concrete and preparation method thereof

Abstract

The present invention discloses an in-situ foamed low-carbon concrete and a preparation method thereof. The in-situ foamed low-carbon concrete comprises the following raw materials in parts by weight: 500-2000 parts of low-carbon cement, 300-1500 parts of lightweight aggregate, 100-200 parts of zeolite, 10-40 parts of carbon curing agent, 1-10 parts of air entraining agent, 1-10 parts of foam stabilizer, 10-80 parts of sodium bicarbonate, 10-80 parts of effervescent tablets, and 400-1500 parts of water. The preparation method provided by the present invention can make full use of the waste resources of the ready-mixed concrete mixing station, and can realize the maximum absorption or solidification of carbon dioxide by each component of the concrete, thereby improving the carbon sequestration capacity of the concrete while meeting the thermal insulation and mechanical properties of the foamed concrete.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and in particular to an in-situ foamed low-carbon concrete and a preparation method thereof. Background Art

[0002] With the rapid development of the construction industry, concrete, as a major building material, has attracted increasing attention for its carbon emissions during production and use. Foamed concrete is widely used due to its lightweight, thermally insulating and other excellent properties. However, there are several significant drawbacks in the traditional foamed concrete preparation process. First, the preparation of foamed concrete usually requires the use of specialized foaming machines, which increases the complexity and energy consumption of the preparation process. Second, the carbon sequestration efficiency of traditional foamed concrete needs to be improved, and the carbon sequestration potential of the material during the preparation process is not fully utilized. In addition, the reuse of waste resources has not received sufficient attention in the production process of traditional foamed concrete, which not only increases production costs but also exacerbates environmental pressures. Therefore, the research and development of low-carbon, environmentally friendly foamed concrete is of great significance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an in-situ foamed low-carbon concrete and a preparation method thereof in response to the deficiencies of the existing technology. This method can make full use of the waste resources of ready-mixed concrete mixing stations and can achieve maximum absorption or solidification of carbon dioxide by various components of concrete, thereby improving the carbon fixation capacity of concrete while meeting the thermal insulation and mechanical properties of foamed concrete.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problems is:

[0005] An in-situ foamed low-carbon concrete comprises the following raw materials in parts by weight: 500-2000 parts of low-carbon cement, 300-1500 parts of lightweight aggregate, 100-200 parts of zeolite, 10-40 parts of carbon curing agent, 1-10 parts of air entraining agent, 1-10 parts of foam stabilizer, 10-80 parts of sodium bicarbonate, 10-80 parts of effervescent tablets, and 400-1500 parts of water;

[0006] The method for preparing the in-situ foamed low-carbon concrete comprises the following steps:

[0007] (1) placing the zeolite in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 to 10 days, and crushing the zeolite to obtain treated zeolite, wherein the average particle size of the zeolite is controlled to be less than 45 microns;

[0008] (2) placing the low-carbon cement in a grinding mill to break the shape for 1 to 3 hours, then adding the sodium bicarbonate and the effervescent tablet, and grinding for 1 to 2 hours to obtain a low-carbon cementitious material powder;

[0009] (3) uniformly mixing the low-carbon cementitious material powder, the lightweight aggregate, the carbon curing agent and the treated zeolite to obtain a premix;

[0010] (4) slowly adding the water, the foam stabilizer, and the air entraining agent into the premix and stirring uniformly to obtain concrete;

[0011] (5) Pour the concrete into a mold and wait for the concrete to solidify to obtain the in-situ foamed low-carbon concrete.

[0012] In the above solution, the low-carbon cement is a mixture of one or more of pozzolana cement, magnesia cement, aluminate cement, and high-calcium and high-iron belite sulphoaluminate cement.

[0013] In the above solution, the light aggregate is a mixture of one or more of recycled micropowder, ultrafine steel slag powder, olivine powder, and hollow glass microspheres; and the average particle size of the light aggregate is less than 45 microns.

[0014] In the above scheme, the regenerated micropowder is the micropowder obtained by crushing the broken test blocks in the mixing station laboratory or the micropowder obtained by wet grinding the waste residue from the multi-stage sedimentation tank of the mixing station.

[0015] In the above solution, the hollow glass microspheres are hollow glass microspheres containing CO2 gas and are prepared by spray granulation using waste glass powder as SiO2 raw material and CaCO3 as foaming agent.

[0016] In the above scheme, the mass ratio of the sodium bicarbonate and the effervescent tablet is 1:1.

[0017] In the above solution, the foam stabilizer is a mixture of one or more of gelatin, acrylic acid, acrylic acid ester copolymer, hydroxypropyl methylcellulose, and silicone resin polyether emulsion.

[0018] In the above solution, the carbon curing agent is at least one of melamine, triethanolamine, triisopropanolamine, and diethanolamine. Such carbon curing agent can not only react with CO2 to achieve carbon fixation, but also has an early strength effect.

[0019] In the above solution, the air entraining agent is a mixture of one or more of calcium lignin sulfonate, sodium fatty alcohol sulfate, rosin thermal polymer, rosin soap or alkylbenzene sulfonate.

[0020] In this invention, the purpose of zeolite treatment is to: zeolite has excellent adsorption properties and can absorb CO2 from cement kiln flue gas, thereby reducing carbon emissions during the production process. Furthermore, the treated zeolite can improve certain properties of concrete, such as increasing its crack resistance and durability.

[0021] In the present invention, the cement clinker particles are broken by mechanical grinding and the activity of the cement clinker is improved. Then, sodium bicarbonate and effervescent tablets are added and ground, and they can be grafted into the broken pores of the cement clinker and foam on the cement clinker when exposed to water.

[0022] In this invention, low-carbon cement, ultrafine steel slag powder, olivine powder, recycled micropowder, and hollow glass microspheres all react to a certain extent with the carbon dioxide in the pores of in-situ foamed low-carbon concrete, or directly solidify substances containing carbon dioxide within the concrete. Furthermore, the uniformity of these materials in the mix is ​​crucial to the ultimate performance of the concrete, and their combination is designed to achieve comprehensive improvements in concrete performance.

[0023] In the present invention, the addition of foam stabilizer, air entraining agent and carbon curing agent plays a key role in improving the stability, fluidity and curing speed of concrete. These additives can optimize the internal structure of concrete and improve the construction performance and long-term performance of concrete.

[0024] Compared with the existing technology, the beneficial effects of the present invention are:

[0025] (1) The present invention provides a method for preparing in-situ foamed low-carbon concrete, which improves the performance of concrete and reduces carbon emissions by optimizing material selection and the use of additives. The method has the advantages of simple operation, excellent performance, environmental protection and energy saving, and provides strong support for the sustainable development of the modern construction industry.

[0026] (2) The present invention uses a cementitious material loaded with a substance capable of generating bubbles in an alkaline environment. Upon contact with water, this substance directly generates a large number of bubbles on the surface of the cement clinker. Under the action of a foam stabilizer, the bubbles rapidly support the cement clinker and lightweight aggregate, thereby producing an in-situ foamed concrete. Compared to conventional foamed concrete, the present invention does not require a foaming machine to generate bubbles, thus shortening the foaming process.

[0027] (3) The foaming gas of the present invention is CO2. In the early stage of hydration, cement can achieve carbon adsorption and solidification through close contact with CO2. By incorporating carbonized zeolite and hollow glass microspheres and other carbon solidifying materials into concrete, they work synergistically with amine carbon curing agents to greatly improve the carbon fixation efficiency of concrete.

[0028] (4) The use of recycled micropowder in the present invention can make full use of the waste resources of traditional mixing stations, reduce the production and waste transportation costs, and has a significant effect in utilizing solid waste in large quantities, which has the effect of saving resources and reducing environmental pollution. It is not only more in line with the green building material preparation method in terms of preparation process, but also more in line with the transformation and development of traditional mixing stations into green and low-carbon factories under the background of dual carbon. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be fully and clearly described below in conjunction with specific embodiments, but the described embodiments are only some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] In a specific embodiment, the low-carbon cement used is P·P42.5 pozzolana cement that meets GB175; the lightweight aggregate used is controlled by mass ratio of ultrafine steel slag powder: olivine powder: recycled micropowder: hollow glass microspheres = 3:2:2:1; the zeolite used is commercially available Class I zeolite powder that meets JG / T566 standard; the foam stabilizer used is gelatin; the air entraining agent is calcium lignin sulfonate, and the carbon curing agent is triethanolamine; the recycled micropowder is the micropowder obtained by crushing the broken test blocks in the mixing station laboratory; the hollow glass microspheres are hollow glass microspheres containing CO2 gas, which are prepared by spray granulation using waste glass powder as SiO2 raw material and CaCO3 as a foaming agent.

[0031] Example 1

[0032] A method for preparing in-situ foamed low-carbon concrete comprises the following steps:

[0033] 1) 200 parts of zeolite were placed in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 days in advance, and then crushed to obtain treated zeolite, with an average particle size of the particles being controlled to be less than 45 μm.

[0034] 2) 800 parts of pozzolanic cement were placed in a grinder and crushed for 3 hours, and then 40 parts of sodium bicarbonate and 40 parts of effervescent tablets were added and ground for 1 hour to obtain a low-carbon cementitious material powder.

[0035] 3) Low-carbon cementitious material powder, 1500 parts of lightweight aggregate, 40 parts of carbon curing agent and treated zeolite are mixed uniformly to obtain a premix.

[0036] 4) Slowly add 500 parts of water, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix and stir evenly to obtain concrete.

[0037] 5) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce in-situ foamed low-carbon concrete.

[0038] Example 2

[0039] A method for preparing in-situ foamed low-carbon concrete comprises the following steps:

[0040] 1) 200 parts of zeolite were placed in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 days in advance, and then crushed to obtain treated zeolite, with an average particle size of the particles being controlled to be less than 45 μm.

[0041] 2) 800 parts of pozzolanic cement were placed in a grinder and crushed for 3 hours, and then 50 parts of sodium bicarbonate and 50 parts of effervescent tablets were added and ground for 1 hour to obtain a low-carbon cementitious material powder.

[0042] 3) Low-carbon cementitious material powder, 1500 parts of lightweight aggregate, 40 parts of carbon curing agent and treated zeolite are mixed uniformly to obtain a premix.

[0043] 4) Slowly add 500 parts of water, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix and stir evenly to obtain concrete.

[0044] 5) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce in-situ foamed low-carbon concrete.

[0045] Example 3

[0046] A method for preparing in-situ foamed low-carbon concrete comprises the following steps:

[0047] 1) 200 parts of zeolite were placed in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 days in advance, and then crushed to obtain treated zeolite, with an average particle size of the particles being controlled to be less than 45 μm.

[0048] 2) 800 parts of pozzolanic cement were placed in a grinder and crushed for 2 hours, and then 40 parts of sodium bicarbonate and 40 parts of effervescent tablets were added and ground for 1 hour to obtain a low-carbon cementitious material powder.

[0049] 3) Low-carbon cementitious material powder, 1500 parts of lightweight aggregate, 40 parts of carbon curing agent and treated zeolite are mixed uniformly to obtain a premix.

[0050] 4) Slowly add 450 parts of water, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix and stir evenly to obtain concrete.

[0051] 5) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce in-situ foamed low-carbon concrete.

[0052] Comparative Example 1

[0053] A method for preparing ordinary lightweight aggregate foam concrete comprises the following steps:

[0054] 1) 200 parts of zeolite were placed in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 days in advance, and then crushed to obtain treated zeolite, with an average particle size of the particles being controlled to be less than 45 μm.

[0055] 2) 800 parts of pozzolana cement, 1500 parts of lightweight aggregate, 40 parts of carbon curing agent and treated zeolite are mixed uniformly to obtain a premix.

[0056] 3) Slowly add 500 parts of water, 25 parts of protein foaming agent, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix, and stir evenly to obtain concrete.

[0057] 4) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce ordinary lightweight aggregate foam concrete.

[0058] Comparative Example 2

[0059] A method for preparing in-situ foamed ordinary concrete comprises the following steps:

[0060] 1) 1000 parts of pozzolanic cement were placed in a grinder and crushed for 3 hours, and then 40 parts of sodium bicarbonate and 40 parts of effervescent tablets were added and ground for 1 hour to obtain a low-carbon cementitious material powder.

[0061] 2) low-carbon cementitious material powder, 1500 parts of machine-made sand, and 40 parts of carbon curing agent were mixed uniformly to obtain a premix.

[0062] 3) Slowly add 500 parts of water, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix and stir evenly to obtain concrete.

[0063] 4) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce in-situ foamed ordinary concrete.

[0064] Comparative Example 3

[0065] A method for preparing ordinary foam concrete comprises the following steps:

[0066] 1) 1000 parts of pozzolanic cement, 1500 parts of machine-made sand, and 40 parts of carbon curing agent were mixed uniformly to obtain a premix.

[0067] 2) Slowly add 500 parts of water, 25 parts of protein foaming agent, 10 parts of foam stabilizer and 10 parts of air entraining agent to the premix, and stir evenly to obtain concrete.

[0068] 3) Pour the concrete into the mold, ensure that the bubbles are evenly distributed, and wait for the concrete to solidify to produce ordinary foam concrete.

[0069] The concrete samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to relevant performance tests, and the relevant test results are shown in Table 1.

[0070] Table 1 Test results of each sample

[0071]

[0072] As can be seen from Table 1, the in-situ foamed low-carbon concrete prepared by the present invention adopts an in-situ foaming process, and carbonized zeolite and hollow glass microspheres and other carbon curing materials are added to the concrete, which works synergistically with the amine carbon curing agent. The concrete has a lower dry density, higher 28d strength, lower thermal conductivity, and higher carbon fixation rate compared to the sample of the comparative example.

[0073] In summary, the in-situ foamed low-carbon concrete provided by the present invention can improve the carbon sequestration capacity of concrete while meeting the requirements of thermal insulation and mechanical properties of foamed concrete.

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art who, within the technical scope disclosed by the present invention, makes equivalent substitutions or changes based on the technical solutions and improved concepts of the present invention shall be covered by the scope of protection of the present invention.

Claims

1. An in-situ foamed low-carbon concrete, characterized in that: The invention comprises the following raw materials in parts by weight: 500-2000 parts of low carbon cement, 300-1500 parts of lightweight aggregate, 100-200 parts of zeolite, 10-40 parts of carbon curing agent, 1-10 parts of air entraining agent, 1-10 parts of foam stabilizer, 10-80 parts of sodium bicarbonate, 10-80 parts of effervescent tablets, and 400-1500 parts of water; The method for preparing the in-situ foamed low-carbon concrete comprises the following steps: (1) placing the zeolite in a flue gas passage of a cement production kiln to adsorb carbon dioxide for 7 to 10 days, and crushing the zeolite to obtain treated zeolite, wherein the average particle size of the zeolite is controlled to be less than 45 microns; (2) placing the low-carbon cement in a grinding mill to break the mold for 1 to 3 hours, then adding the sodium bicarbonate and the effervescent tablet, and grinding for 1 to 2 hours to obtain a low-carbon cementitious material powder; (3) uniformly mixing the low-carbon cementitious material powder, the lightweight aggregate, the carbon curing agent and the treated zeolite to obtain a premix; (4) slowly adding the water, the foam stabilizer, and the air entraining agent to the premix, and stirring evenly to obtain concrete; (5) Pour the concrete into a mold and wait for the concrete to solidify to obtain the in-situ foamed low-carbon concrete.

2. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The low-carbon cement is a mixture of one or more of pozzolana cement, magnesia cement, aluminate cement, and high-calcium and high-iron belite sulphoaluminate cement.

3. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The light aggregate is a mixture of one or more of recycled micropowder, ultrafine steel slag powder, olivine powder, and hollow glass microspheres; and the average particle size of the light aggregate is less than 45 microns.

4. The in-situ foamed low-carbon concrete according to claim 3, characterized in that: The regenerated micropowder is the micropowder obtained by crushing the broken test blocks in the mixing station laboratory or the micropowder obtained by wet grinding the waste residue from the multi-stage sedimentation tank of the mixing station.

5. The in-situ foamed low-carbon concrete according to claim 3, characterized in that: The hollow glass microspheres are hollow glass microspheres containing CO2 gas and are prepared by spray granulation using waste glass powder as SiO2 raw material and CaCO3 as foaming agent.

6. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The mass ratio of the sodium bicarbonate to the effervescent tablet is 1:

1.

7. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The foam stabilizer is a mixture of one or more of gelatin, acrylic acid ester copolymer, hydroxypropyl methylcellulose and silicone resin polyether emulsion.

8. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The carbon curing agent is at least one of melamine, triethanolamine, triisopropanolamine and diethanolamine.

9. The in-situ foamed low-carbon concrete according to claim 1, characterized in that: The air entraining agent is a mixture of one or more of calcium lignin sulfonate, sodium fatty alcohol sulfate, rosin thermal polymer, rosin soap or alkylbenzene sulfonate.

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