A CO2 foam concrete material based on a solid waste-based multi-component gelling system and its preparation method

Abstract

The present invention belongs to the field of green, low-carbon, zero-carbon building materials and provides a CO2 foam concrete material based on a solid waste-based multi-component cementing system and its preparation method. The material is composed of the following components by mass percentage: 20%-42% solid waste-based sulphoaluminate cement, 15%-60% hemihydrate gypsum, 6%-15% Portland cement, 0%-20% mineral powder, 2%-4% sodium bicarbonate, 3%-6% potassium aluminum sulfate, 0.2%-0.4% retarder, 0.02%-0.2% water reducer, and 0.02%-0.06% calcium stearate, with the sum of the percentages of each raw material being 100%. The present invention significantly reduces the apparent density while ensuring that the foam concrete meets the strength requirements; the composite system formed by the solid waste-based sulphoaluminate cement, Portland cement, and hemihydrate gypsum of the present invention significantly improves the mechanical properties of the carbon dioxide foam concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of green low-zero carbon building materials, and specifically relates to a solid waste-based carbon dioxide foam concrete and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Currently, the preparation of CO2 foam concrete generally uses Portland cement and sulfoaluminate cement as the primary cementitious materials. Mineral admixtures such as fly ash, mineral powder, and carbide slag are added, and CO2 is introduced physically or chemically. Preparation is performed at a relatively high water-cement ratio. CO2 foam concrete primarily focuses on parameters such as density, compressive strength, thermal conductivity, porosity, and water absorption. However, under conventional preparation processes, CO2 foam concrete suffers from high density and low compressive strength. The density of foamed concrete is positively correlated with compressive strength, and reduced density inevitably leads to reduced compressive strength. Therefore, achieving high compressive strength still requires balancing the requirements of low density and lightweight. Foamed concrete is advantageous in both lightness, low density, and high compressive strength. While CO2 foam concrete at high water-cement ratios and high CO2 concentrations increases porosity and carbonation rate, it struggles to achieve both lightweight and high strength.

[0004] Therefore, the paper "Functional Ternary Cementitious Material Mix Design and Performance Research" discloses a ternary cementitious material based on sulfoaluminate cement-Portland cement-hemihydrate gypsum, but does not consider the reaction of CO2 with the cementitious system and further enhance its positive effect on the performance of foam concrete, and cannot meet the demand for lighter foam concrete materials and achieve the goal of rapid solidification and stable foaming. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a CO2 foam concrete material based on a solid waste-based multi-component gelling system and a preparation method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] For the following questions:

[0008] 1. The various admixture minerals used in existing carbon dioxide foam concrete materials emphasize increasing strength while ignoring the design goal of lightweight;

[0009] 2. The enhancement of the performance of foam concrete by the reaction of CO2 and the cementitious system is not considered.

[0010] 3. Under high water-cement ratio, the strength of carbon dioxide foam concrete material is difficult to meet industrial requirements;

[0011] 4. Under high carbon dioxide concentration, it is difficult to achieve rapid solidification of carbon dioxide foam.

[0012] The first aspect of the present invention provides a CO2 foam concrete material based on a solid waste-based multi-component cementitious system, which is composed of the following components in percentage by mass: 20%-42% of solid waste-based sulfoaluminate cement, 15%-60% of hemihydrate gypsum, 6%-15% of Portland cement, 0-20% of mineral powder, 2%-4% of sodium bicarbonate, 3%-6% of potassium aluminum sulfate, 0.2%-0.4% of retarder, 0.02%-0.2% of water reducer, and 0.02%-0.06% of calcium stearate, where the sum of the percentages of each raw material is 100%.

[0013] In some embodiments, the preparation method of the solid waste-based sulphoaluminate cement includes: drying and mixing 80-90 parts of sulphoaluminate cement clinker, 15-20 parts of desulfurized gypsum, and 5-10 parts of stone powder; adding the mixed raw materials into a kiln and calcining them at a temperature of 1250-1300°C for 30-40 minutes to prepare solid waste-based sulphoaluminate cement.

[0014] In some embodiments, the retarder is at least one of boric acid and tartaric acid.

[0015] In some embodiments, the water reducer is at least one of a polycarboxylate water reducer and a naphthalene-based water reducer.

[0016] In some embodiments, the water-cement ratio is 0.3-0.45.

[0017] The second aspect of the present invention provides a method for preparing a CO2 foam concrete material based on a solid waste-based multi-component gelling system, comprising:

[0018] Mixing solid waste-based sulphoaluminate cement, hemihydrate gypsum, Portland cement, mineral powder and sodium bicarbonate to obtain a premix;

[0019] Adding a retarder, a water reducer, and calcium stearate to the premix, and mixing them uniformly to obtain a composite material;

[0020] Prepare potassium aluminum sulfate solution;

[0021] Adding the potassium aluminum sulfate solution to the composite material and mixing them uniformly to obtain a slurry;

[0022] The slurry is poured into a mold, allowed to stand for forming, demoulded, and cured to obtain the product.

[0023] In some embodiments, a retarder, a water reducer, and calcium stearate are added to the premix and mixed for 2-5 minutes.

[0024] In some embodiments, in the potassium aluminum sulfate solution, the mass ratio of potassium aluminum sulfate to water is 3-6:30-45.

[0025] In some embodiments, the potassium aluminum sulfate solution is added to the composite material and mixed for 120-180 seconds.

[0026] More specifically, they include:

[0027] The following steps are involved:

[0028] (1) 20-42 parts of solid waste-based sulfoaluminate cement, 15-60 parts of hemihydrate gypsum, 6-15 parts of Portland cement, 0-20 parts of mineral powder, and 2-4 parts of sodium bicarbonate are fully premixed and stirred for use;

[0029] (2) The raw materials prepared in (1) are further mixed with 0.2-0.4 parts of retarder, 0.02-0.2 parts of water reducer, and 0.02-0.06 parts of calcium stearate, and the mixture is further mixed for 2 minutes to prepare a composite material for use;

[0030] (3) Take 30-45 parts of tap water, add 3-6 parts of potassium aluminum sulfate, and stir rapidly for 30-60 seconds to prepare a mixed solution for later use;

[0031] (4) Pour the mixed solution in (3) into the solution in (2) at once and stir rapidly for 120-180 seconds;

[0032] (5) The slurry mixed in (4) is poured into a mold, and allowed to stand for 1-2 days, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0033] The third aspect of the present invention provides the application of the above-mentioned CO2 foam concrete material based on the solid waste-based multi-component gelling system in the fields of construction and road construction.

[0034] It can be seen that the present invention effectively solves the following problems:

[0035] (1) Preparation of lightweight carbon dioxide foam concrete;

[0036] (2) Consider using CO2 to react with the cementitious system to enhance the performance of foamed concrete;

[0037] (3) The compound materials meet the high strength requirements of foam concrete;

[0038] (4) The pores of carbon dioxide foam concrete are optimized at low water-cement ratio.

[0039] Beneficial effects of the present invention

[0040] (1) The present invention significantly reduces the apparent density while ensuring that the foam concrete meets the strength requirements;

[0041] (2) The composite system formed by the solid waste-based sulphoaluminate cement, silicate cement and hemihydrate gypsum of the present invention significantly improves the mechanical properties of carbon dioxide foam concrete;

[0042] (3) The solid waste-based CO2 foam concrete and its preparation process of the present invention fully meet the requirements of lightweight, high strength and thermal insulation of foam concrete;

[0043] (4) The hydration synergistic effect of the sulphoaluminate cement, silicate cement and hemihydrate gypsum of the present invention greatly improves the mechanical properties and other parameters of the carbon dioxide foam concrete material, which provides a basis for lightweight and high-strength design.

[0044] (5) The carbon dioxide of the present invention has a positive effect on the system formed by sulphoaluminate cement, silicate cement and hemihydrate gypsum.

[0045] (6) The present invention can meet the construction requirements of prefabricated buildings after curing. While reducing the density, the strength can still meet the standard limit, and the curing period is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0047] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0048] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0049] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0050] In the following examples, the preparation method of the solid waste-based sulfoaluminate cement includes: drying and mixing 80 parts of sulfoaluminate cement clinker, 15 parts of desulfurized gypsum, and 5 parts of stone powder; adding the mixed raw materials into a kiln and calcining them at a temperature of 1250° C. for 30 minutes to prepare the solid waste-based sulfoaluminate cement.

[0051] The retarder is boric acid.

[0052] The water reducer is a commercially available polycarboxylate water reducer.

[0053] The materials used in the comparative experiment were as follows: 36 parts desulfurized gypsum, 16 parts red mud, 22 parts aluminum ash, and 26 parts carbide slag. Preparation method: Physical air foaming was used to prepare foamed concrete by mixing prefabricated foam with slurry. The test results are shown in the "Comparative Results" section.

[0054] Example 1

[0055] A solid waste-based CO2 foam concrete and its preparation process, the carbon dioxide foam concrete is composed of solid waste-based sulfoaluminate cement, silicate cement, hemihydrate gypsum, and mineral powder as a base cementitious mixture, a retarder, a water reducer, and a foam stabilizer as auxiliary materials, and sodium bicarbonate and potassium aluminum sulfate as foaming agents. The cementitious materials are fully mixed and the auxiliary materials and an appropriate amount of sodium bicarbonate are added. At the same time, an appropriate amount of potassium aluminum sulfate is added to a certain amount of water to dissolve and stir at high speed. The formed solution is added to the fully mixed cementitious materials at one time, and quickly stirred together. Finally, it is poured, quickly formed, and subjected to standard curing to obtain the concrete. The raw materials for preparing the solid waste-based sulfoaluminate cement are from: desulfurized gypsum, aluminum ash, steel slag, carbide slag, and limestone tailings, which are all bulk industrial solid wastes. The water reducer is a polycarboxylate water reducer, and the foam stabilizer is calcium stearate. The water meets the requirements for water used in concrete mixing.

[0056] The solid waste-based CO2 foam concrete and its preparation process proposed in the present invention include the following steps:

[0057] (1) 20 parts of solid waste-based sulfoaluminate cement, 50 parts of hemihydrate gypsum, 10 parts of Portland cement, 20 parts of mineral powder, and 2 parts of sodium bicarbonate were fully premixed and stirred for later use;

[0058] (2) The raw materials prepared in (1) are further mixed with 0.2 parts of retarder, 0.02 parts of water reducer, and 0.04 parts of calcium stearate, and the mixture is further mixed for 2 minutes to prepare a composite material for use;

[0059] (3) Take 30% tap water, add 3% potassium aluminum sulfate, and stir rapidly for 30-60 seconds to make a mixed solution for later use;

[0060] (4) Pour the mixed solution in (3) into the solution in (2) at once and stir rapidly for 120-180 seconds;

[0061] (5) The slurry mixed in (4) is poured into a mold, and allowed to stand for 1-2 days, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0062] Table 1 Performance of carbon dioxide foam concrete in Example 1

[0063]

[0064]

[0065] Example 2

[0066] A solid waste-based CO2 foam concrete and its preparation process, the carbon dioxide foam concrete is composed of solid waste-based sulfoaluminate cement, silicate cement, hemihydrate gypsum, silica fume, and mineral powder as a base cementitious mixture, a retarder, a water reducer, a gypsum retarder, and a foam stabilizer as auxiliary materials, and sodium bicarbonate and potassium aluminum sulfate as foaming agents. The cementitious materials are fully mixed and the auxiliary materials and an appropriate amount of sodium bicarbonate are added. At the same time, an appropriate amount of potassium aluminum sulfate is added to a certain amount of water to dissolve and stir at high speed. The formed solution is added to the fully mixed cementitious materials at one time, and quickly stirred together. Finally, it is poured, quickly formed, and subjected to standard curing to obtain the concrete. The raw materials for preparing the solid waste-based sulfoaluminate cement are from: desulfurized gypsum, aluminum ash, steel slag, carbide slag, and limestone tailings, which are all bulk industrial solid wastes. The water reducer is a polycarboxylate water reducer, and the foam stabilizer is calcium stearate. The water meets the requirements for water used in concrete mixing.

[0067] The solid waste-based CO2 foam concrete and its preparation process proposed in the present invention include the following steps:

[0068] (1) 20 parts of solid waste-based sulfoaluminate cement, 50 parts of hemihydrate gypsum, 10 parts of Portland cement, 20 parts of mineral powder, and 4 parts of sodium bicarbonate were fully premixed and stirred for later use;

[0069] (2) The raw materials prepared in (1) are further mixed with 0.2 parts of retarder, 0.02 parts of water reducer, and 0.06 parts of calcium stearate, and the mixture is further mixed for 2 minutes to prepare a composite material for use;

[0070] (3) Take 45% tap water, add 6% potassium aluminum sulfate, and stir rapidly for 60 seconds to make a mixed solution for later use;

[0071] (4) Pour the mixed solution in (3) into the solution in (2) at once and stir rapidly for 180 seconds;

[0072] (5) The slurry mixed in (4) is poured into a mold, allowed to stand for 2 days, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0073] Table 2 Performance of carbon dioxide foam concrete in implementation case 2

[0074]

[0075] Example 3

[0076] A solid waste-based CO2 foam concrete and its preparation process, the carbon dioxide foam concrete is composed of solid waste-based sulfoaluminate cement, silicate cement, hemihydrate gypsum, silica fume, and mineral powder as a base cementitious mixture, a retarder, a water reducer, a gypsum retarder, and a foam stabilizer as auxiliary materials, and sodium bicarbonate and potassium aluminum sulfate as foaming agents. The cementitious materials are fully mixed and the auxiliary materials and an appropriate amount of sodium bicarbonate are added. At the same time, an appropriate amount of potassium aluminum sulfate is added to a certain amount of water to dissolve and stir at high speed. The formed solution is added to the fully mixed cementitious materials at one time, and quickly stirred together. Finally, it is poured, quickly formed, and subjected to standard curing to obtain the concrete. The raw materials for preparing the solid waste-based sulfoaluminate cement are from: desulfurized gypsum, aluminum ash, steel slag, carbide slag, and limestone tailings, which are all bulk industrial solid wastes. The water reducer is a polycarboxylate water reducer, and the foam stabilizer is calcium stearate. The water meets the requirements for water used in concrete mixing.

[0077] The solid waste-based CO2 foam concrete and its preparation process proposed in the present invention include the following steps:

[0078] (1) 25 parts of solid waste-based sulfoaluminate cement, 50 parts of hemihydrate gypsum, 5 parts of Portland cement, 20 parts of mineral powder, and 2 parts of sodium bicarbonate were fully premixed and stirred for later use;

[0079] (2) The raw materials prepared in (1) are further mixed with 0.2 parts of retarder, 0.02 parts of water reducer, and 0.04 parts of calcium stearate, and the mixture is further mixed for 2 minutes to prepare a composite material for use;

[0080] (3) Take 30% tap water, add 3% potassium aluminum sulfate, and stir rapidly for 45 seconds to make a mixed solution for later use;

[0081] (4) Pour the mixed solution in (3) into the solution in (2) at once and stir rapidly for 150 seconds;

[0082] (5) The slurry mixed in (4) is poured into a mold, allowed to stand for 1.5 days, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0083] Table 3 Performance of carbon dioxide foam concrete in implementation case 3

[0084]

[0085] Comparative Example 1

[0086] The difference from Example 1 is that ordinary sulphoaluminate cement is used instead of solid waste-based sulphoaluminate cement.

[0087] Comparative Example 2

[0088] The difference from Example 1 is that no solid waste-based sulphoaluminate cement is added, and the amount of silicate cement is adjusted to 30 parts.

[0089] Comparative Example 3

[0090] The difference from Example 1 is that no silicate cement is added, and the amount of solid waste-based sulphoaluminate cement is adjusted to 30 parts.

[0091] Comparative Example 4

[0092] The difference from Example 1 is that no hemihydrate gypsum is added, and the amount of solid waste-based sulphoaluminate cement is adjusted to 70 parts.

[0093] Comparative Example 5

[0094] The difference from Example 1 is that no mineral powder is added.

[0095] Table 4 Performance of carbon dioxide foamed concrete of Example 1 and Comparative Examples 1-5

[0096]

[0097] As shown in Table 4, the effects of using solid waste-based sulfoaluminate cement in the present invention are comparable to those of ordinary sulfoaluminate cement, while being less costly and more economical. A comparison of Example 1 with Comparative Examples 2 and 3 shows that the combination of solid waste-based sulfoaluminate cement and Portland cement can better improve the dry density and compressive strength of concrete compared to the addition of only solid waste-based sulfoaluminate cement. A comparison of Example 1 with Comparative Example 4 shows that the addition of hemihydrate gypsum can better improve the performance of concrete and stabilize the foam state compared to the addition of only solid waste-based sulfoaluminate cement. A comparison of Example 1 with Comparative Example 5 shows that the addition of mineral powder effectively increases the dry density and compressive strength of concrete.

[0098] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A CO2 foam concrete material based on a solid waste-based multi-component gelling system, characterized in that: The invention is composed of the following components in percentage by mass: 20%-42% of solid waste-based sulphoaluminate cement, 15%-60% of hemihydrate gypsum, 6%-15% of Portland cement, 20% of mineral powder, 2%-4% of sodium bicarbonate, 3%-6% of potassium aluminium sulfate, 0.2%-0.4% of retarder, 0.02%-0.2% of water reducer, and 0.02%-0.06% of calcium stearate, and the sum of the percentages of each raw material is 100%; The method for preparing the CO2 foam concrete material based on the solid waste-based multi-component gelling system comprises: Mixing solid waste-based sulphoaluminate cement, hemihydrate gypsum, Portland cement, mineral powder and sodium bicarbonate to obtain a premix; Adding a retarder, a water reducer, and calcium stearate to the premix, and mixing them uniformly to obtain a composite material; Prepare potassium aluminum sulfate solution; Adding the potassium aluminum sulfate solution to the composite material and mixing them uniformly to obtain a slurry; The slurry is poured into a mold, allowed to stand for forming, demoulded, and cured to obtain the product; The preparation method of the solid waste-based sulphoaluminate cement comprises: drying and mixing 80-90 parts of sulphoaluminate cement clinker, 15-20 parts of desulfurized gypsum, and 5-10 parts of stone powder; adding the mixed raw materials into a kiln and calcining them at a temperature of 1250-1300° C. for 30-40 minutes to prepare the solid waste-based sulphoaluminate cement.

2. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: The retarder is at least one of boric acid and tartaric acid.

3. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: The water reducer is at least one of a polycarboxylic acid water reducer and a naphthalene water reducer.

4. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: Water-cement ratio 0.3-0.

45.

5. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: Add retarder, water reducer and calcium stearate to the premix and mix for 2-5 minutes.

6. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: In the potassium aluminum sulfate solution, the mass ratio of potassium aluminum sulfate to water is 3-6:30-45.

7. The CO2 foam concrete material based on a solid waste-based multi-component gelling system according to claim 1, characterized in that: The potassium aluminum sulfate solution is added to the composite material and mixed for 120-180 seconds.

8. Use of the CO2 foam concrete material based on a solid waste-based multi-component gelling system according to any one of claims 1 to 7 in the fields of construction and road construction.

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