Composite gel-physical foaming synergistic carbon dioxide foam concrete and preparation process thereof

Abstract

The invention discloses a composite gel-physical foaming synergetic carbon dioxide foam concrete preparation technology, and the carbon dioxide foam concrete is composed of the following components in parts by mass: 15-45 parts of sulphoaluminate cement, 10-50 parts of semi-hydrated gypsum, 5-15 parts of Portland cement, 0-30 parts of mineral powder, 0-0.3 part of a gypsum retarder, 0.2-0.4 part of a retarder, and 0.2-0.4 part of a water reducing agent. The invention relates to a cement mortar which is prepared from the following components in parts by weight: 0.2-0.6 part of calcium stearate, 0.1-0.3 part of hydroxypropyl methyl cellulose ether (HPMC), 0.2-0.45 part of water cement and 5-15 parts of prefabricated foam. When the sulphoaluminate cement, the Portland cement and the semi-hydrated gypsum are mixed according to a specific mass ratio to prepare the carbon dioxide foam concrete, the hydration synergistic effect among the sulphoaluminate cement, the Portland cement and the semi-hydrated gypsum can be exerted, so that the mechanical property of the carbon dioxide foam concrete can be greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of green low-carbon zero-carbon building materials, and specifically relates to a composite gel-physical foaming synergistic carbon dioxide foam concrete and a preparation process thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, in the preparation of carbon dioxide foam concrete materials, the cementitious materials are generally based on silicate cement and sulphoaluminate cement, and mineral admixtures such as fly ash, mineral powder, and carbide slag are added. Carbon dioxide is introduced by physical or chemical methods and prepared at a high water-cement ratio. Carbon dioxide foam concrete materials mainly focus on parameters such as density, compressive strength, thermal conductivity, porosity, and water absorption. However, under conventional preparation processes, carbon dioxide foam concrete materials have problems such as high density, low compressive strength, and strength provided by a single cement. The density of foamed concrete materials is positively correlated with the compressive strength, and a decrease in density is bound to lead to a decrease in compressive strength. Therefore, the realization of high compressive strength still needs to take into account the requirements of low density and lightweight. For foamed concrete materials, light weight, low density, and high compressive strength are all beneficial to it. Although carbon dioxide foamed concrete increases porosity and carbonization rate at high water-cement ratios and high carbon dioxide concentrations, it is difficult to take into account the requirements of light weight and high strength.

[0004] Therefore, the mechanism of action of the existing cementitious system is not comprehensive, and the interaction between the various minerals needs to be further explored. It also does not consider the reaction of CO2 with the cementitious system and further enhance its positive effect on the performance of foamed concrete. It is also unable to meet the demand for lighter foamed concrete materials and achieve the goal of rapid solidification and foam stabilization. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a composite gel-physical foaming synergistic carbon dioxide foam concrete preparation process.

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

[0007] In a first aspect, the present invention provides a composite gel-physical foaming synergistic carbon dioxide foamed concrete, which is composed of the following components in parts by mass:

[0008] Sulphoaluminate cement 15-45 parts, hemihydrate gypsum 10-50 parts, Portland cement 5-15 parts, mineral powder 1-30 parts, gypsum retarder 0-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.6 parts, hydroxypropyl methylcellulose ether (HPMC) 0.1-0.3 parts, water-cement ratio 0.2-0.45, prefabricated foam mass 5-15 parts.

[0009] The strength of existing carbon dioxide foam concrete materials mainly comes from cement, and the main purpose of adding other mineral admixtures is to assist in improving the strength of the material, which weakens the requirement of lightness to a certain extent; the enhancement of the performance of foam concrete by the reaction of CO2 and the cementitious system is not considered. A high water-cement ratio is conducive to the mineralization reaction, but at a high water-cement ratio, some strength properties will be sacrificed, making it difficult for the strength of carbon dioxide foam concrete materials to meet industrial requirements; in the prior art, there are studies that attempt to increase the carbon fixation of concrete from the material level by increasing the concentration of carbon dioxide, but high-concentration carbon dioxide foam is extremely unstable, and it is difficult to achieve rapid solidification and shaping of carbon dioxide foam at high carbon dioxide concentrations.

[0010] The composition of hemihydrate gypsum is CaSO4·0.5H2O, monoclinic system, and the crystals are microscopic needles. Hemihydrate gypsum has a fast setting speed. Relying on the characteristics of fast setting, it can achieve rapid solidification and shaping of foam in the early stage. In addition, the hydration of hemihydrate gypsum itself will also provide strength and dense system structure.

[0011] The inventors have found through experiments that when sulphoaluminate cement, silicate cement and hemihydrate gypsum are mixed in a specific mass ratio to prepare carbon dioxide foam concrete, the hydration synergistic effect between the three can be exerted, thereby greatly improving the mechanical properties of carbon dioxide foam concrete. The composite cementitious material in the present invention has the characteristics of early strength and fast hardening, and can achieve rapid solidification and shaping of foam, especially can achieve solidification and shaping of carbon dioxide foam with higher concentration.

[0012] An appropriate amount of CO2 reacts with the hydration reaction products of the cementitious system (mineralization reaction) to generate stable carbonates and silica gel, making the pore walls of the foam concrete denser, which is beneficial to improving the strength of the foam concrete and optimizing its performance.

[0013] The role of mineral powder is, on the one hand, to provide reactants; on the other hand, it is beneficial to improve the strength of foam concrete.

[0014] Calcium stearate acts as a foam stabilizer.

[0015] The role of hydroxypropyl methylcellulose ether is to act as a foam stabilizer.

[0016] In some embodiments, the mineral powder is blast furnace slag powder, mainly including S95 grade and S105 grade.

[0017] Preferably, the composite gel-physical foaming synergistic carbon dioxide foamed concrete is composed of the following components in parts by mass:

[0018] Sulphoaluminate cement 15-45 parts, hemihydrate gypsum 10-50 parts, silicate cement 5-15 parts, mineral powder 2-20 parts, gypsum retarder 0.1-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.6 parts, hydroxypropyl methylcellulose ether 0.1-0.3 parts, water-cement ratio 0.2-0.45, prefabricated foam 5-15 parts.

[0019] Further preferably, the composite gel-physical foaming synergistic carbon dioxide foamed concrete is composed of the following components in parts by mass:

[0020] Sulphoaluminate cement 15-30 parts, hemihydrate gypsum 10-40 parts, silicate cement 5-10 parts, mineral powder 2-10 parts, gypsum retarder 0.1-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.5 parts, hydroxypropyl methylcellulose ether 0.1-0.3 parts, water-cement ratio 0.2-0.4, prefabricated foam 5-15 parts.

[0021] In some embodiments, the prefabricated foam is prepared by mixing a foaming agent and water in a mass ratio of 1:20-40.

[0022] Preferably, the foaming agent is a rosin resin foaming agent, an ionic foaming agent, a protein foaming agent or a composite foaming agent.

[0023] In some embodiments, the retarder is boric acid or tartaric acid.

[0024] The amount of gypsum used in the present invention is relatively large, and the gypsum sets quickly in the early stage, so the use of a targeted gypsum retarder has a better effect; the addition of the retarder has a retarding effect on other components.

[0025] In some embodiments, the water reducer is a polycarboxylate water reducer or a naphthalene water reducer.

[0026] In a second aspect, the present invention provides a preparation process of the composite gel-physical foaming synergistic carbon dioxide foamed concrete, comprising the following steps:

[0027] Sulphoaluminate cement, hemihydrate gypsum, silicate cement, mineral powder, gypsum retarder, retarder, water reducing agent, calcium stearate and hydroxypropyl methylcellulose ether are mixed uniformly according to proportion to obtain a composite material;

[0028] Pour water into the compound material according to the set water-cement ratio and stir to form a slurry;

[0029] After mixing the slurry and prefabricated foam in proportion, pour them into the mold, form, demould and cure them.

[0030] In some embodiments, water is poured into the compound material and the rapid stirring time is 120-180 seconds.

[0031] In some embodiments, the molding time is 4-6 hours.

[0032] In some embodiments, the prefabricated foam is prepared by mixing a foaming agent and water in a mass ratio of 1:20-40.

[0033] Preferably, the foaming gas of the prefabricated foam is a mixed gas of carbon dioxide and air, and the volume percentage of carbon dioxide in the foaming gas is 20%-70%, preferably 30%-50%.

[0034] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0035] The solid waste-based CO2 foamed concrete of the present invention fully meets the requirements of lightweight, high strength and thermal insulation of foamed concrete;

[0036] The hydration synergistic effect of sulphoaluminate cement, silicate cement and hemihydrate gypsum greatly improves the mechanical properties and other parameters of carbon dioxide foam concrete materials, which provides a basis for lightweight and high-strength design.

[0037] Carbon dioxide has a positive effect on the system formed by sulphoaluminate cement, silicate cement and hemihydrate gypsum. On the basis of ensuring that the foamed concrete meets the strength requirements, the apparent density is significantly reduced.

[0038] After curing, it can meet the construction requirements of prefabricated buildings. While reducing the density, the strength can still meet the standard limit. The curing cycle is short and quick demoulding can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings in the specification, 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 descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0040] Figure 1 It is a process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0041] It should be noted that the following detailed descriptions are illustrative 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.

[0042] The present invention will be further described below in conjunction with the embodiments.

[0043] Example 1

[0044] A composite gel-physical foaming synergistic carbon dioxide foam concrete consists of the following components, measured by mass: 42 parts of sulphoaluminate cement, 14 parts of hemihydrate gypsum, 14 parts of silicate cement, 30 parts of mineral powder, 0.1 parts of gypsum retarder, 0.2 parts of retarder, 0.2 parts of water reducer, 0.6 parts of calcium stearate, 0.2 parts of hydroxypropyl methylcellulose ether, 45 parts of water, 10 parts of prefabricated foam, and a carbon dioxide concentration of 50%.

[0045] The water reducer is polycarboxylate water reducer, the foam stabilizer is calcium stearate, and the water used meets the requirements for concrete mixing water.

[0046] The preparation process of composite gel-physical foaming synergistic carbon dioxide foam concrete comprises the following steps:

[0047] (1) 42 parts of solid waste-based sulphoaluminate cement, 14 parts of hemihydrate gypsum, 14 parts of silicate cement and 30 parts of mineral powder are fully premixed and stirred for use;

[0048] (2) further adding 0.3 parts of retarder, 0.2 parts of water reducing agent, 0.6 parts of calcium stearate and 0.2 parts of hydroxypropyl methylcellulose ether to the raw material prepared in step (1), stirring and mixing for 2 minutes to prepare a composite material for use;

[0049] (3) Take 45 parts of tap water, pour it into the composite material prepared in step (2) at one time, and stir rapidly for 180 seconds to form a slurry;

[0050] (4) simultaneously preparing fresh prefabricated foam using carbon dioxide physical foaming agent at a ratio of protein foaming agent to water of 1:30, wherein the foaming gas is a mixture of carbon dioxide and air, and the volume percentage of carbon dioxide in the foaming gas is 50%;

[0051] (5) After mixing the prefabricated foam prepared in step (4) with the slurry prepared in step (3), stirring to fully mix them, then pouring the slurry into a mold, naturally forming for 6 hours, demolding, and curing under standard curing conditions, a lightweight and high-strength carbon dioxide foam concrete material is obtained.

[0052] Comparative Example 1

[0053] Material composition: 36 parts of desulfurized gypsum, 16 parts of red mud, 22 parts of aluminum ash, and 26 parts of calcium carbide slag;

[0054] Preparation method: Physical foaming of air and mixing with slurry to prepare foamed concrete.

[0055] Comparative Example 2

[0056] The difference from Example 1 is that the hemihydrate gypsum is replaced by gypsum, and the rest is the same as Example 1.

[0057] Comparative Example 3

[0058] The difference from Example 1 is that silicate cement is replaced by sulphoaluminate cement, and the rest is the same as Example 1.

[0059] Comparative Example 4

[0060] The difference from Example 1 is that sulphoaluminate cement is replaced by silicate cement, and the rest is the same as Example 1.

[0061] Comparative Example 5

[0062] The difference from Example 1 is that carbon dioxide foaming is replaced by compressed air, and the rest is the same as Example 1.

[0063] Table 1 Performance of carbon dioxide foamed concrete prepared in Example 1 and Comparative Examples 1-5

[0064] <![CDATA[Dry density (kg / m 3 )]]> Compressive strength(MPa) Example 1 769.87 7.54 Comparative Example 1 752.38 4.56 Comparative Example 2 770.56 6.62 Comparative Example 3 762.83 6.55 Comparative Example 4 745.33 5.67 Comparative Example 5 750.29 4.96

[0065] Example 2

[0066] A composite gel-physical foaming synergistic carbon dioxide foam concrete consists of the following components, measured by mass: 23 parts of sulphoaluminate cement, 40 parts of hemihydrate gypsum, 7 parts of silicate cement, 30 parts of mineral powder, 0.1 parts of gypsum retarder, 0.2 parts of retarder, 0.2 parts of water reducer, 0.6 parts of calcium stearate, 0.2 parts of hydroxypropyl methylcellulose ether, 30 parts of water, 15 parts of prefabricated foam, and a carbon dioxide concentration of 50%.

[0067] The water reducer is polycarboxylate water reducer, the foam stabilizer is calcium stearate, and the water used meets the requirements for concrete mixing water.

[0068] The preparation process of the composite gel-physical foaming synergistic carbon dioxide foamed concrete comprises the following steps:

[0069] (1) 23 parts of solid waste-based sulphoaluminate cement, 40 parts of hemihydrate gypsum, 7 parts of silicate cement and 30 parts of mineral powder are fully premixed and stirred for use;

[0070] (2) adding 0.3 parts of retarder, 0.2 parts of water reducing agent, 0.6 parts of calcium stearate and 0.2 parts of hydroxypropyl methylcellulose ether to the mixed raw material prepared in step (1), stirring and mixing for 2 minutes to prepare a composite material for use;

[0071] (3) Take 30 parts of tap water, pour it into the composite material prepared in step (2) at one time, and stir rapidly for 120-180 seconds to form a slurry;

[0072] (4) preparing fresh prefabricated foam by physical foaming with carbon dioxide in a ratio of protein foaming agent to water of 1:30, wherein the foaming gas is a mixture of carbon dioxide and air, and the volume percentage of carbon dioxide in the foaming gas is 50%;

[0073] (5) The prefabricated foam prepared in step (4) is mixed with the slurry prepared in step (3), stirred to be fully mixed, and then poured into a mold, naturally formed for 5 hours, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0074] Comparative Example 6

[0075] The difference from Example 2 is that the hemihydrate gypsum is replaced by gypsum, and the rest is the same as Example 2.

[0076] Comparative Example 7

[0077] The difference from Example 2 is that silicate cement is replaced by sulphoaluminate cement, and the rest is the same as Example 2.

[0078] Comparative Example 8

[0079] The difference from Example 2 is that sulphoaluminate cement is replaced by silicate cement, and the rest is the same as Example 2.

[0080] Comparative Example 9

[0081] The difference from Example 2 is that carbon dioxide foaming is replaced by compressed air, and the rest is the same as Example 2.

[0082] Table 2 Performance of carbon dioxide foamed concrete prepared in Example 2 and Comparative Examples 6-9

[0083] <![CDATA[Dry density (kg / m 3 )]]> Compressive strength(MPa) Example 2 711.58 7.96 Comparative Example 6 751.32 6.88 Comparative Example 7 737.15 7.01 Comparative Example 8 746.79 6.83 Comparative Example 9 706.43 4.62

[0084] Example 3

[0085] A composite gel-physical foaming synergistic carbon dioxide foam concrete consists of the following components, measured by mass: 18 parts of sulphoaluminate cement, 46 parts of hemihydrate gypsum, 6 parts of silicate cement, 30 parts of mineral powder, 0.1 parts of gypsum retarder, 0.2 parts of retarder, 0.2 parts of water reducer, 0.6 parts of calcium stearate, 0.2 parts of hydroxypropyl methylcellulose ether, 20 parts of water, 7 parts of prefabricated foam, and a carbon dioxide concentration of 50%.

[0086] The water reducer is polycarboxylate water reducer, the foam stabilizer is calcium stearate, and the water used meets the requirements for concrete mixing water.

[0087] The composite gel-physical foaming synergistic carbon dioxide foam concrete preparation process comprises the following steps:

[0088] (1) 18 parts of solid waste-based sulphoaluminate cement, 46 parts of hemihydrate gypsum, 6 parts of silicate cement and 30 parts of mineral powder are fully premixed and stirred for use;

[0089] (2) adding 0.3 parts of retarder, 0.2 parts of water reducing agent, 0.6 parts of calcium stearate and 0.2 parts of hydroxypropyl methylcellulose ether to the mixed raw material prepared in step (1), stirring and mixing for 2 minutes to prepare a composite material for use;

[0090] (3) Take 20 parts of tap water, pour it into the composite material prepared in step (2) at one time, and stir rapidly for 120 seconds to form a slurry;

[0091] (4) simultaneously, using carbon dioxide for physical foaming according to the ratio of protein foaming agent to water = 1:30 to prepare fresh prefabricated foam, wherein the foaming gas is a mixture of carbon dioxide and air, and the volume percentage of carbon dioxide in the foaming gas is 50%;

[0092] (5) The prefabricated foam prepared in step (4) is mixed with the slurry prepared in step (3), stirred to be fully mixed, and then poured into a mold, naturally formed for 4 hours, demolded, and cured under standard curing conditions to obtain a lightweight and high-strength carbon dioxide foam concrete material.

[0093] Table 3 Performance of carbon dioxide foamed concrete prepared in Example 3

[0094]

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite gel-physical foaming synergistic carbon dioxide foamed concrete, characterized in that: By mass, it is composed of the following components: Sulphoaluminate cement 15-45 parts, hemihydrate gypsum 10-50 parts, silicate cement 5-15 parts, mineral powder 1-30 parts, gypsum retarder 0-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.6 parts, hydroxypropyl methylcellulose ether 0.1-0.3 parts, water-cement ratio 0.2-0.45, prefabricated foam 5-15 parts.

2. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 1, characterized in that: The mineral powder is blast furnace slag powder.

3. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 1, characterized in that: By mass, it is composed of the following components: Sulphoaluminate cement 15-45 parts, hemihydrate gypsum 10-50 parts, silicate cement 5-15 parts, mineral powder 2-20 parts, gypsum retarder 0.1-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.6 parts, hydroxypropyl methylcellulose ether 0.1-0.3 parts, water-cement ratio 0.2-0.45, prefabricated foam 5-15 parts.

4. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 3 is characterized by: By mass, it is composed of the following components: Sulphoaluminate cement 15-30 parts, hemihydrate gypsum 10-40 parts, silicate cement 5-10 parts, mineral powder 2-10 parts, gypsum retarder 0.1-0.3 parts, retarder 0.2-0.4 parts, water reducer 0.2-0.4 parts, calcium stearate 0.2-0.5 parts, hydroxypropyl methylcellulose ether 0.1-0.3 parts, water-cement ratio 0.2-0.4, prefabricated foam 5-15 parts.

5. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to any one of claims 1 to 4, characterized in that: The prefabricated foam is prepared by mixing a foaming agent and water in a mass ratio of 1:20-40.

6. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 5, characterized in that: The foaming agent is a rosin resin foaming agent, an ionic foaming agent, a protein foaming agent or a composite foaming agent.

7. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 1, characterized in that: The retarder is boric acid or tartaric acid.

8. The composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer or a naphthalene water reducer.

9. The process for preparing the composite gel-physical foaming synergistic carbon dioxide foamed concrete according to any one of claims 1 to 8, characterized in that: The steps include: Sulphoaluminate cement, hemihydrate gypsum, silicate cement, mineral powder, gypsum retarder, retarder, water reducing agent, calcium stearate and hydroxypropyl methylcellulose ether are mixed uniformly according to proportion to obtain a composite material; Pour water into the compound material according to the set water-cement ratio and stir to form a slurry; After mixing the slurry and prefabricated foam in proportion, pour them into the mold, form, demould and cure them.

10. The process for preparing the composite gel-physical foaming synergistic carbon dioxide foamed concrete according to claim 9, characterized in that: Pour water into the compound material and stir rapidly for 120-180 seconds; Preferably, the molding time is 4-6h; Preferably, the prefabricated foam is prepared by mixing a foaming agent and water in a mass ratio of 1:20-40 for foaming; Preferably, the foaming gas of the prefabricated foam is a mixed gas of carbon dioxide and air, and the volume percentage of carbon dioxide in the foaming gas is 20%-70%, preferably 30%-50%.

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