Alkali-activated cementing material and alkali-activated matrix

Abstract

The invention discloses an alkali-activated cementing material and an alkali-activated matrix, and belongs to the technical field of building materials. The alkali-activated cementing material comprises the following components in parts by weight: 35-60 parts of an alkali-activated solution and 100 parts of an alkali-activated precursor, the alkali-activated precursor contains 20 to 80 percent of basalt micro powder with high iron content; the iron content of the high-iron-content basalt micro powder is greater than 8%. According to the invention, through iron release and alkali adsorption mechanisms of the basalt powder, the formed layered strip-shaped iron-aluminum bimetal hydroxide effectively realizes nanoscale matrix bridging toughening modification. By means of a communicated pore structure of the basalt powder, a carbon curing channel is provided, conversion from environmental carbon to mineral carbon and improvement of matrix strength are achieved, the excellent carbon sequestration capacity and carbon strengthening performance of a basalt powder alkali excitation system are shown, and under the double-carbon policy, the material provides a new solution for carbon neutralization.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to an alkali-activated cementitious material and an alkali-activated matrix. Background Technology

[0002] With the development of the times, traditional civil engineering materials have shown significant disadvantages in terms of energy-saving building materials and green environmental protection, and their production is extremely dependent on fossil fuels. As the global goals of carbon reduction and carbon neutrality are being pursued, civil engineering materials urgently need to address issues such as high energy consumption, high emissions, energy waste, and low circularity through technological innovation, policy guidance, and full life cycle assessment, in order to achieve their sustainable development.

[0003] Silicate cement is the world's second-largest source of carbon emissions, and replacing it with alkali-activated materials is a potential way to achieve low-carbon building materials. However, although existing green materials have less environmental pollution, the brittle and easily cracked matrix of alkali-activated cementitious materials remains a problem. Furthermore, the alkaline activators used in alkali-activated materials are expensive. These issues limit the development potential of alkali-activated materials.

[0004] Basalt, a type of volcanic rock, is widely distributed in the Yunnan, Guizhou, and Sichuan regions of my country. It is inexpensive and has high economic value. Basalt powder is a fine particulate product produced by processing basalt through machinery. Most of it is directly discarded as industrial waste generated from basalt processing. How to effectively utilize this secondary product generated after basalt processing has become a major challenge.

[0005] The use of basalt powder and basalt fiber in cement, concrete, and other building materials is already quite mature in the market, and currently, basalt fiber and basalt powder are used to improve the impermeability and strength of cement. However, materials made from basalt used in building materials currently on the market still lack in strength and toughness compared to other materials. Therefore, optimizing its performance has become a new technical problem to be solved. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a design and reinforcement method for a low-carbon alkali-activated cementitious material based on high-iron-content basalt powder. This invention effectively achieves nanoscale matrix bridging and toughening modification by forming layered iron-aluminum bimetallic hydroxides through the iron release and alkali adsorption mechanism of basalt powder.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an alkali-activated gelling material, comprising the following components in parts by weight: 35-60 parts of alkaline activation solution and 100 parts of alkaline activation precursor; The alkali-activated precursor contains basalt micro powder with a high iron content of 20-80%. The iron content of the high-iron basalt powder is >8%.

[0008] Preferably, the basalt powder has a particle size of less than 100 μm.

[0009] Preferably, the alkaline activation solution is obtained by mixing sodium metasilicate, sodium silicate water glass solution, and water in a mass ratio of (5-15):(5-30):(10-40).

[0010] Preferably, the Na2O / SiO2 ratio of the alkaline activation solution is 1.0-1.7.

[0011] Preferably, the alkali-activated precursor also contains 20-80% slag.

[0012] The present invention also provides an alkali-activated matrix prepared from the above-mentioned alkali-activated gelling material, comprising the following preparation steps: S1. Weigh out 5-15 parts by weight of sodium metasilicate, 5-30 parts by weight of sodium silicate water glass solution, and 10-40 parts by weight of water, then mix and stir to obtain an alkaline activation solution. S2. Weigh 20-80 parts by weight of basalt micro powder with high iron content and 20-80 parts by weight of slag, mix them evenly to obtain a precursor mixture; S3. Add 100 parts of the precursor mixture to 35-60 parts of the alkaline activation solution and stir until homogeneous to obtain an alkaline activated slurry; S4. After the alkali-activated slurry has set, it is soaked, cured, and carbonized to obtain the alkali-activated matrix.

[0013] Preferably, the alkali-activated slurry has an alkali metal oxide content of 3-9%.

[0014] Preferably, the maintenance solution is an alkaline solution with a pH range of 11-14.

[0015] Preferably, the carbonization treatment method is any one of the following two: (1) 20%-90% humidity, 20 degrees Celsius ambient temperature, 20% carbon dioxide concentration, carbonization treatment time is 48h; (2) Carbonization treatment in outdoor environment for 1 year.

[0016] It contains at least the following beneficial technical effects: This invention utilizes high-iron basalt powder. In an alkaline environment, the high-iron basalt powder, through iron release and alkali adsorption mechanisms, forms layered iron-aluminum bimetallic hydroxides, effectively achieving nanoscale matrix bridging and toughening modification. Leveraging the interconnected pore structure of the basalt powder, carbon solidification channels are provided, enabling the transformation of environmental carbon into mineral carbon and enhancing matrix strength. This demonstrates the superior carbon fixation capacity and carbon strengthening performance of the basalt powder alkali-activated system. Under the "dual carbon" policy, this material offers a new solution for carbon neutrality.

[0017] This method is not only simple to operate but also low in cost and easy to scale up for production. Furthermore, this innovative technology has been extended to civil engineering fields such as green building and infrastructure construction, providing strong support for the industry's sustainable development. By applying this patented technology, the carbon footprint of engineering materials can be significantly reduced, while simultaneously improving their service life and performance, making a significant contribution to the green transformation and low-carbon development of the construction industry. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention and do not constitute an undue limitation of the invention.

[0019] Figure 1 Thermogravimetric analysis (TGA) diagrams of the alkali-activated materials prepared in Examples 1-3 and Comparative Example 1 are shown.

[0020] Figure 2 Electron microscopy and energy-dispersive X-ray spectroscopy line scans of the high-iron basalt powder particles and the transition zone at the matrix interface in the alkali-activated material prepared in Example 2. Detailed Implementation

[0021] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0022] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0023] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0024] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0025] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0026] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0027] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0028] The basalt powder with high iron content in the following examples has an average particle size of 40 μm and an iron content of 18.37%.

[0029] Example 1 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 20 parts of basalt micro powder with high iron content and 80 parts of slag, and use them as alkali-activated precursors.

[0030] Step 3 Add 100 parts of the alkali-activated precursor to 45.6 parts of the alkali-activated solution and stir for two minutes to obtain an alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two hours, it is then soaked in a solution in a 45°C water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 12. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The material was subjected to outdoor environmental exposure and carbonization treatment for one year. After carbonization treatment, a carbon-fixed, reinforced, toughened, alkali-activated material based on basalt micropowder with high iron content was obtained.

[0031] Example 2 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 50 parts of basalt micro powder with high iron content, 50 parts of slag, and 0 parts of fly ash, and use them as alkali-activated precursors. Step 3 Add 100 parts of alkali-activated precursor to 45.6 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two hours, it is then soaked in a solution in a 45°C water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 12. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The material was subjected to outdoor environmental exposure and carbonization treatment for one year. After carbonization treatment, a carbon-fixed, reinforced, toughened, alkali-activated material based on basalt micropowder with high iron content was obtained.

[0032] Example 3 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 80 parts of basalt micro powder with high iron content, 20 parts of slag, and 0 parts of fly ash, and use them as alkali-activated precursors. Step 3 Add 100 parts of alkali-activated precursor to 45.6 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two hours, it is then soaked in a solution in a 45°C water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 12. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The material was subjected to outdoor environmental exposure and carbonization treatment for one year. After carbonization treatment, a carbon-fixed, reinforced, toughened, alkali-activated material based on basalt micropowder with high iron content was obtained.

[0033] Example 4 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 15 parts of sodium metasilicate, 30 parts of sodium silicate water glass solution, and 35 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 50 parts of basalt powder with an iron oxide content of 18% and 50 parts of slag, and use them as alkali-activated precursors. Step 3 Add 100 parts of alkali-activated precursor to 80 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 9%; Step Four After the alkali-activated slurry has set for two hours, it is then soaked in a solution in a 45°C water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 13. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The alkali-activated matrix was carbonized under conditions of 55% humidity, 20 degrees Celsius ambient temperature, and 20% carbon dioxide concentration for 48 hours. After carbonization, a carbon-reinforced and toughened alkali-activated matrix based on basalt micropowder with high iron content was obtained.

[0034] Example 5 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 7 parts sodium metasilicate, 10 parts sodium silicate water glass solution, and 20 parts water, and mix and stir the sodium metasilicate, sodium silicate water glass solution, and water until they are clear to form an alkaline activated solution. Step Two Weigh out 50 parts of basalt micro powder with 18% iron oxide content and 50 parts of slag, and use them as alkali-activated precursors. Step 3 Add 100 parts of alkali-activated precursor to 37 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 3%; Step Four After the alkali-activated slurry has set for two and a half hours, it is then soaked in a solution in a 35-degree Celsius water bath curing box for 36 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 12. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The alkali-activated matrix was carbonized under the conditions of 45% humidity, 20 degrees Celsius ambient temperature, and 20% carbon dioxide concentration for 48 hours. After carbonization, a carbon-reinforced and toughened alkali-activated matrix based on basalt micro powder with high iron content was obtained.

[0035] Example 6 A method for preparing an alkali-activated matrix based on basalt micropowder with high iron content: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 50 parts of basalt micro powder with 18% iron oxide content, 20 parts of slag, and 30 parts of fly ash, and use them as alkali-activated precursors. Step 3 One hundred parts of the alkali-activated precursor were added to 45.6 parts of the alkali-activated solution and stirred for two minutes to obtain an alkali-activated slurry. Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two and a half hours, it is then soaked in a solution in a 70-degree Celsius water bath curing box for 36 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 13. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The alkali-activated matrix was carbonized under conditions of 55% humidity, 20 degrees Celsius ambient temperature, and 20% carbon dioxide concentration for 48 hours. After carbonization, a carbon-reinforced and toughened alkali-activated matrix based on basalt micropowder with high iron content was obtained.

[0036] Comparative Example 1 An alkali-activated matrix based on fly ash: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 50 parts of slag and 50 parts of fly ash, and use them as alkali-activated precursors; Step 3 Add 100 parts of alkali-activated precursor to 45.6 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two and a half hours, it is then soaked in a solution in a 35-degree Celsius water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 13. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The alkali-activated matrix was carbonized under the conditions of 70% humidity, 20 degrees Celsius ambient temperature, and 20% carbon dioxide concentration for 48 hours, resulting in an alkali-activated matrix based on fly ash.

[0037] Comparative Example 2 A low-iron-content basalt micropowder alkali-activated matrix: Step 1 Weigh out 9.5 parts of sodium metasilicate, 14.1 parts of sodium silicate water glass solution, and 22 parts of water. Mix the sodium metasilicate, sodium silicate water glass solution, and water and stir until the mixture is clear to form an alkaline activated solution. Step Two Weigh out 50 parts of slag and 50 parts of basalt powder with 3% iron oxide content, and use them as alkali-activated precursors; Step 3 Add 100 parts of alkali-activated precursor to 45.6 parts of alkali-activated solution and stir for two minutes to obtain alkali-activated slurry; Among them, the alkalinity (alkali metal oxide content) of the alkali-activated slurry is controlled at 5%; Step Four After the alkali-activated slurry has set for two hours, it is then soaked in a solution in a 45°C water bath curing box for 24 hours to obtain the alkali-activated matrix. The solution is an alkaline solution with a pH value controlled at 12. The pH value of the solution is adjusted by sodium hydroxide and sodium metasilicate. Step 5 The alkali-activated matrix was carbonized under the conditions of 70% humidity, 20 degrees Celsius ambient temperature, and 20% carbon dioxide concentration for 48 hours, resulting in a low-iron-content basalt micro-powder alkali-activated matrix.

[0038] The test results of compressive strength and tensile strength of each embodiment are shown in Table 1.

[0039] Table 1 As shown in Table 1, compared with Example 1, Example 2 of the present invention, with its significantly increased high-iron basalt powder content, significantly improves the tensile strength of the material, achieving a toughening effect. Comparing Example 2 and Comparative Example 1, it can be seen that, compared with fly ash, the alkali-activated material prepared from high-iron basalt powder exhibits a 25% increase in compressive strength and a 93% increase in tensile strength, indicating that high-iron basalt powder has a higher strengthening and toughening effect. Comparing Example 2 and Comparative Example 2, it can be seen that, compared with low-iron basalt powder, the alkali-activated material prepared from high-iron basalt powder exhibits a 30% increase in compressive strength and an 81% increase in tensile strength, indicating that high-iron basalt powder has a higher strengthening and toughening effect than low-iron basalt powder. Comparing Example 4 and Example 5 with Example 2, it can be seen that, through optimization of the alkali activation solvent ratio, the alkali activator can better achieve the strengthening and toughening effect of the alkali-activated material made from high-iron basalt powder. It should be noted that Examples 3 and 6 show that when high-iron basalt powder is partially replaced by fly ash, the performance indicators of the alkali-activated material will decrease significantly.

[0040] The raw material proportions for each embodiment and comparative example are shown in Table 2: Table 2 Figure 1 Thermogravimetric analysis (TGA) shows that the addition of high-iron basalt powder can generate layered iron-aluminum bimetallic hydroxides (LDH regions in the figure), effectively achieving nanoscale matrix bridging and toughening modification. It also confirms that the alkali-activated material, through the interconnected pore structure of the high-iron basalt powder, provides carbon solidification channels. Compared with Comparative Example 1, Examples 1, 2, and 3 form more carbon mineral phases (Carbonate Phase regions in the figure), realizing the transformation of environmental carbon into mineral carbon, confirming the beneficial effects.

[0041] Figure 2The images show electron microscopy and energy-dispersive X-ray spectroscopy analysis. The left side shows unreacted high-iron basalt powder (Unreacted BP) and the right side shows the alkaline matrix. Figure 2 The observed iron release and alkali adsorption mechanisms of high-iron basalt powder in an alkaline matrix environment corroborate the beneficial effects.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An alkali-activated cementitious material, characterized in that, Includes the following components in parts by weight: 35-60 parts of alkaline activation solution and 100 parts of alkaline activation precursor; The alkali-activated precursor contains basalt micro powder with a high iron content of 20-80%. The iron content of the high-iron basalt powder is >8%.

2. The alkali-activated cementitious material according to claim 1, characterized in that, The alkaline activation solution is obtained by mixing sodium metasilicate, sodium silicate water glass solution, and water in a mass ratio of (5-15):(5-30):(10-40).

3. The alkali-activated cementitious material according to claim 2, characterized in that, The Na2O / SiO2 ratio of the alkaline activation solution is 1.0-1.

7.

4. The alkali-activated cementitious material according to claim 1, characterized in that, The alkali-activated precursor also contains 20-80% slag.

5. The alkali-activated cementitious material according to claim 1, characterized in that, The basalt powder has a particle size of less than 100 μm.

6. An alkali-activated matrix prepared from the alkali-activated cementitious material according to any one of claims 1-4, characterized in that, The preparation steps include the following: S1. Weigh out 5-15 parts by weight of sodium metasilicate, 5-30 parts by weight of sodium silicate water glass solution, and 10-40 parts by weight of water, then mix and stir to obtain an alkaline activation solution. S2. Weigh 20-80 parts by weight of basalt micro powder with high iron content and 20-80 parts by weight of slag, mix them evenly to obtain a precursor mixture; S3. Add 100 parts of the precursor mixture to 35-60 parts of the alkaline activation solution and stir until homogeneous to obtain an alkaline activated slurry; S4. After the alkali-activated slurry has set, it is soaked, cured, and carbonized to obtain the alkali-activated matrix.

7. The alkali-activated matrix according to claim 5, characterized in that, The alkali-activated slurry has an alkali metal oxide content of 3-9%.

8. The alkali-activated matrix according to claim 5, characterized in that, The maintenance solution is an alkaline solution with a pH range of 11-14.

9. The alkali-activated matrix according to claim 5, characterized in that, The carbonization process is any one of the following two methods: (1) 20%-90% humidity, 20 degrees Celsius ambient temperature, 20% carbon dioxide concentration, carbonization treatment time is 48h; (2) Carbonization treatment in outdoor environment for 1 year.

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