Preparation method of negative carbon cement-based baking-free brick material based on slag interface strengthening effect

Abstract

The application relates to the field of building materials, and particularly discloses a preparation method of a negative-carbon cement-based non-burning brick material based on a slag interface strengthening effect, which comprises the following steps: (1) uniformly mixing slag powder, silica ash, a strengthening agent powder, wollastonite powder, carbide slag powder, multi-walled carbon nanotubes, sodium silicate powder and water, and then curing; after the completion, crushing and grinding a hardened body to obtain modified slag powder; (2) uniformly mixing the modified slag powder and water to form wet materials, and then performing carbonization treatment in a carbon dioxide atmosphere; after the completion, drying, performing microwave irradiation treatment on the obtained powder, and finally performing grinding to obtain interface-strengthened slag powder; and (3) taking the interface-strengthened slag powder, Portland cement, fly ash, fine aggregate and a water reducing agent as raw materials, uniformly mixing the raw materials with mixing water to obtain the non-burning brick material. The application not only improves the strength of the non-burning brick, but also can solidify carbon dioxide, further reduces carbon emission in the preparation of the non-burning brick, and promotes the green and low-carbon application of the slag.

Description

Technical Field

[0001] This invention relates to the field of building materials, specifically to a method for preparing negative carbon cement-based non-fired bricks based on the interfacial strengthening effect of slag and soil. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Statistics show that the global construction industry consumes hundreds of billions of wall bricks annually. Traditional clay brick production requires excavating farmland and high-temperature firing, with each standard brick emitting approximately 0.3-0.5 kg of carbon dioxide. The emergence of non-fired bricks precisely addresses this need. Non-fired bricks are a building material made primarily from cementitious materials, aggregates, and industrial solid waste (such as fly ash, slag, steel slag, tailings, and construction waste), produced through pressing and curing without the need for high-temperature sintering. Compared to traditional sintered clay bricks, non-fired bricks offer advantages such as high waste utilization rates, low energy consumption, and low carbon emissions. In particular, their low-carbon emissions and resource utilization throughout their entire life cycle have made them an important direction for promoting green, low-carbon, and sustainable development in building materials production. Currently, non-fired bricks are widely used in building walls, municipal road slope protection, retaining walls, and other engineering projects.

[0004] Construction waste refers to the excavated soil generated during the construction, renovation, expansion, and foundation pit excavation of various engineering projects. With the continuous advancement of urbanization and infrastructure construction, construction waste is characterized by large volume, wide distribution, rapid growth, and significant disposal pressure. Scientific disposal and resource utilization of construction waste have become a crucial link in supporting sustainable urban development. Utilizing construction waste to produce non-fired bricks is an important way to achieve its resource utilization and high-value use. However, because construction waste contains a large amount of inert components that cannot participate in the hydration reaction, these components only play a physical filling role. This leads to insufficient bonding between the construction waste particles and the brick body, and also causes a decrease in the content of cementitious components in the brick body. Consequently, the deterioration of the strength of the non-fired bricks has become one of the main problems limiting their application. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing negative carbon cement-based non-fired brick materials based on the interfacial strengthening effect of slag and soil. This method not only improves the strength of the non-fired bricks but also solidifies carbon dioxide, further reducing carbon emissions from the preparation of non-fired bricks and promoting the green and low-carbon application of slag and soil. Specifically, the technical solution of this invention is as follows.

[0006] A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) The calcined kaolinite powder was first calcined and cooled. The calcined product was then added to a choline solution and stirred. After the process was completed, the solid product was separated, dried, and ground to obtain the reinforcing agent powder.

[0007] (2) Mix the slag powder, silica fume, the aforementioned reinforcing agent powder, wollastonite powder, calcium carbide slag powder, multi-walled carbon nanotubes, sodium silicate powder, and water, and then cure the mixture. After completion, crush and grind the hardened body to obtain modified slag powder.

[0008] (3) The modified slag powder is mixed with water to form a wet material and then carbonized in a carbon dioxide atmosphere. After completion, it is dried, and then the obtained powder is subjected to microwave irradiation treatment. Finally, it is ground to obtain interface-reinforced slag powder.

[0009] (4) Using the interface-strengthened slag powder, silicate cement, fly ash, fine aggregate and water-reducing agent as raw materials, mix them with mixing water to obtain the negative carbon cement-based non-fired brick material.

[0010] Furthermore, in step (1), the calcination temperature is 540~580℃ and the time is 60~90min.

[0011] Further, in step (1), the ratio of the calcined product to the choline solution is 1g:10~20mL. Optionally, the concentration of the choline solution is 1.5~3mol / L.

[0012] Furthermore, in step (1), the stirring treatment time is 3 to 5 hours and the temperature is 55 to 70°C.

[0013] Furthermore, in step (2), the fineness of the slag powder, reinforcing agent powder, wollastonite powder, and carbide slag powder is 200~350 mesh.

[0014] Further, in step (2), the proportions of each component are as follows: 100 parts by weight of slag powder, 20-25 parts by weight of silica fume, 11-18 parts by weight of reinforcing agent powder, 6-9 parts by weight of wollastonite powder, 20-30 parts by weight of calcium carbide slag powder, 2.6-4 parts by weight of multi-walled carbon nanotubes, and 1.5-2 parts by weight of sodium silicate powder.

[0015] Furthermore, in step (2), the mass ratio of the clean water to the total of the slag powder, silica fume, reinforcing agent powder, wollastonite powder, and carbide slag powder is 0.42~0.47:1.

[0016] Furthermore, in step (2), the curing time is 48 to 72 hours and the relative humidity is 90 to 95%.

[0017] Furthermore, in step (2), the fineness of the modified slag powder is 400~500 mesh.

[0018] Furthermore, in step (3), the moisture content of the wet material is 35~45 wt.%.

[0019] Furthermore, in step (3), the carbonization process takes 3 to 5 hours and the temperature is 65 to 80°C.

[0020] Further, in step (3), the microwave irradiation treatment time is 45~60 min, and the microwave power is 1000~1200W. Optionally, the fineness of the powder is 150~250 mesh.

[0021] Further, in step (4), the proportions of each component are: 100 parts by weight of interface-strengthened slag powder, 29-33 parts by weight of silicate cement, 10-16 parts by weight of fly ash, 125-140 parts by weight of fine aggregate, and 1.5-2.2 parts by weight of water-reducing agent.

[0022] Furthermore, in step (4), the mass ratio of the mixing water to the total mass of the interface-strengthened slag powder, silicate cement, and fly ash is 0.45~0.5:1.

[0023] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention first calcines hydrous kaolinite powder and then treats it with choline solution to remove alumina. Simultaneously, the silica-oxygen bonds in the silica-oxygen mineral phase depolymerize under the alkaline conditions provided by the choline solution, forming active silicates. This transforms the nanotube structure in the hydrous kaolinite into porous nanotubes composed of active silicates. Then, using slag powder, silica fume, reinforcing agent powder, wollastonite powder, carbide slag powder, multi-walled carbon nanotubes, and sodium silicate powder as raw materials, this invention prepares a slurry and cures it. The reinforcing agent powder carries a positive charge due to choline, thus precisely adsorbing onto the electronegative surface of the slag powder particles, facilitating the later construction of the interface reinforcement zone. During the curing process, the reinforcing agent powder and silica fume react with calcium hydroxide released from the carbide slag under the activation effect of sodium silicate to form hydrated calcium silicate cementitious products. Simultaneously, during this process, the cementitious products formed between the slag particles grow inward through the pores on the tube wall of the tubular hydrated calcium silicate cementitious products formed by the reinforcing agent powder, and the two are bonded and locked together. This physical and chemical interlocking structure constructed at the interface between slag powder particles significantly improves the interfacial bonding ability between slag powder particles, so that the modified slag powder not only has a tight bond between slag powder particles, but also has a large amount of cementitious products on the surface of the modified slag powder particles themselves, effectively improving the compatibility and bonding ability with the cement-based non-fired brick matrix.

[0024] Furthermore, in this invention, the modified slag powder obtained after the above treatment is first carbonized with carbon dioxide, and then treated with microwave irradiation. This process not only converts the wollastonite in the modified slag powder into calcium carbonate and active nano-silica, but also converts the sodium silicate into silicic acid, which decomposes into nano-silica under the heating effect of the multi-walled carbon nanotubes during microwave irradiation. Excess calcium carbide slag powder is also converted into calcium carbonate by carbon dioxide. This not only solidifies a large amount of carbon dioxide, reducing carbon emissions from non-fired brick production, but also effectively increases the particle density and strength of the resulting interface-reinforced slag powder. When using the above-mentioned interface-reinforced slag powder to prepare cement-based non-fired brick materials, the hydration product of silicate cement, calcium hydroxide, reacts with the nano-silica in the interface-reinforced slag powder particles to form hydrated calcium silicate cementitious products. Moreover, under the enrichment effect of calcium ions by the multi-walled carbon nanotubes, a higher content of cementitious products can be formed at the interface between the two, which significantly enhances the interfacial bonding between the slag powder particles and the non-fired brick matrix, effectively overcoming the adverse effects of slag on the strength of non-fired bricks. Attached Figure Description

[0025] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein: Figure 1 The image shows a sample of interface-reinforced slag powder prepared in Example 1 below.

[0026] Figure 2 The image shows a sample of the interface-reinforced slag powder prepared in Example 2 below.

[0027] Figure 3 The image shows a sample of the interface-reinforced slag powder prepared in Example 3 below.

[0028] Figure 4 The image shows a sample of the interface-reinforced slag powder prepared in Example 5 below.

[0029] Figure 5 The image shows a sample of the interface-reinforced slag powder prepared in Example 6 below.

[0030] Figure 6 The image shows a sample of the interface-reinforced slag powder prepared in Example 7 below.

[0031] Figure 7 The image shows a sample of the interface-reinforced slag powder prepared in Example 8 below. Detailed Implementation

[0032] The present invention is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention.

[0034] Example 1 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) Calcined kaolinite powder was heated to 560℃ and held at that temperature for 80 min. After calcination, it was cooled to room temperature. The calcined product was then mixed with 2 mol / L choline aqueous solution at a ratio of 1 g: 15 mL and heated to 65℃ with continuous stirring for 4 hours. After calcination, the solid product was filtered out, dried, and ground to obtain the reinforcing agent powder for later use.

[0035] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 23 parts by weight of silica fume, 14 parts by weight of the reinforcing agent powder described in this embodiment, 7.5 parts by weight of wollastonite powder, 25 parts by weight of calcium carbide slag powder, 3.5 parts by weight of multi-walled carbon nanotubes, and 2 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 300 mesh. Mix the above components evenly, then add 76 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 92% for 60 hours. After completion, crush and grind the hardened body, and then pass it through a 500-mesh sieve to obtain modified slag powder for later use.

[0036] (3) The modified slag powder was mixed with water and stirred evenly to obtain a wet material with a moisture content of 41 wt.%. This wet material was then placed in a sealed carbonization box, carbon dioxide was introduced, and the mixture was heated to 70°C. The mixture was kept at this temperature for 4.5 hours for carbonization. After carbonization, the material was dried to remove moisture. The resulting powder was then subjected to microwave irradiation for 50 minutes at a microwave power of 1000 W. Afterward, the powder was ground and passed through a 200-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 1 (As shown), for later use.

[0037] (4) Take the following proportions of raw materials: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 32 parts by weight of 42.5 ordinary Portland cement, 13 parts by weight of fly ash, 135 parts by weight of fine aggregate, and 2 parts by weight of polycarboxylate superplasticizer. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 69 parts by weight of clean water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0038] Performance Testing: The cement-based non-fired brick material described in this embodiment was poured into a mold and pressed (pressure 10 MPa, time 60 s), then naturally cured for 7 days to obtain non-fired bricks. The compressive strength and softening coefficient (K) of the non-fired bricks were tested according to "Test Methods for Masonry Bricks" GB / T2542-2012. f The results are: compressive strength = 23.61 MPa, softening coefficient = 0.952.

[0039] Example 2 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) The hydrous kaolinite powder was heated to 540℃ and kept at that temperature for 90 min for calcination. After the calcination was completed, it was cooled to room temperature. The calcined product was then mixed with 1.5 mol / L choline aqueous solution at a ratio of 1 g: 20 mL and heated to 70℃ with continuous stirring for 3 hours. After the calcination was completed, the solid product was filtered out, dried, and ground to obtain the reinforcing agent powder for later use.

[0040] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 25 parts by weight of silica fume, 11 parts by weight of the reinforcing agent powder described in this embodiment, 6 parts by weight of wollastonite powder, 20 parts by weight of calcium carbide slag powder, 2.6 parts by weight of multi-walled carbon nanotubes, and 1.5 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 200 mesh. Mix the above components evenly, then add 68 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 95% for 48 hours. After completion, crush and grind the hardened body, and then pass it through a 400-mesh sieve to obtain modified slag powder for later use.

[0041] (3) The modified slag powder is mixed with water and stirred evenly to obtain a wet material with a moisture content of 35 wt.%. This wet material is then placed in a carbonization box, sealed, and heated to 80°C with carbon dioxide. The mixture is kept at this temperature for 3 hours for carbonization. After carbonization, the material is dried to remove moisture. The resulting powder is then subjected to microwave irradiation for 60 minutes at a microwave power of 1000 W. Afterward, it is ground and passed through a 150-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 2 (As shown), for later use.

[0042] (4) Take the following raw materials in the following proportions: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 33 parts by weight of 42.5 ordinary Portland cement, 16 parts by weight of fly ash, 140 parts by weight of fine aggregate, and 2.2 parts by weight of polycarboxylate superplasticizer. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 67 parts by weight of water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0043] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 25.39 MPa, softening coefficient = 0.968.

[0044] Example 3 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) Calcined kaolinite powder was heated to 580℃ and held at that temperature for 60 min. After calcination, it was cooled to room temperature. The calcined product was then mixed with 3 mol / L choline aqueous solution at a ratio of 1 g: 10 mL and heated to 55℃ with continuous stirring for 5 hours. After calcination, the solid product was filtered out, dried, and ground to obtain the reinforcing agent powder for later use.

[0045] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 20 parts by weight of silica fume, 18 parts by weight of the reinforcing agent powder described in this embodiment, 9 parts by weight of wollastonite powder, 30 parts by weight of calcium carbide slag powder, 4 parts by weight of multi-walled carbon nanotubes, and 2 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 350 mesh. Mix the above components evenly, then add 83.2 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 90% for 72 hours. After completion, crush and grind the hardened body, and then pass it through a 400-mesh sieve to obtain modified slag powder for later use.

[0046] (3) The modified slag powder is mixed with water and stirred evenly to obtain a wet material with a moisture content of 45 wt.%. This wet material is then placed in a carbonization box, sealed, and heated to 65°C with carbon dioxide. The mixture is kept at this temperature for 5 hours for carbonization. After carbonization, the material is dried to remove moisture, and then subjected to microwave irradiation treatment for 45 minutes at a microwave power of 1200 W. Afterward, the powder is ground and passed through a 250-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 3 (As shown), for later use.

[0047] (4) Take the following raw materials in the following proportions: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 29 parts by weight of 42.5 ordinary Portland cement, 10 parts by weight of fly ash, 125 parts by weight of fine aggregate, and 1.5 parts by weight of naphthalene-based water-reducing agent. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 69.5 parts by weight of clean water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0048] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 22.74 MPa, softening coefficient = 0.937.

[0049] Example 4 A method for preparing a cement-based non-fired brick material made from slag and soil includes the following steps: Take the following raw materials in the following proportions: 100 parts by weight of slag powder with a fineness of 200 mesh (unmodified), 32 parts by weight of 42.5 ordinary Portland cement, 13 parts by weight of fly ash, 135 parts by weight of fine aggregate, and 2 parts by weight of polycarboxylate superplasticizer; the fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials thoroughly, then add 69 parts by weight of water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0050] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 16.27 MPa, softening coefficient = 0.821.

[0051] Example 5 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) The water-rich kaolinite powder was heated to 560℃ and kept at that temperature for 80 minutes for calcination. After the calcination was completed, it was cooled to room temperature. The calcined product was then ground to obtain the reinforcing agent powder for later use.

[0052] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 23 parts by weight of silica fume, 14 parts by weight of the reinforcing agent powder described in this embodiment, 7.5 parts by weight of wollastonite powder, 25 parts by weight of calcium carbide slag powder, 3.5 parts by weight of multi-walled carbon nanotubes, and 2 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 300 mesh. Mix the above components evenly, then add 76 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 92% for 60 hours. After completion, crush and grind the hardened body, and then pass it through a 500-mesh sieve to obtain modified slag powder for later use.

[0053] (3) The modified slag powder was mixed with water and stirred evenly to obtain a wet material with a moisture content of 41 wt.%. This wet material was then placed in a sealed carbonization box, carbon dioxide was introduced, and the mixture was heated to 70°C. The mixture was kept at this temperature for 4.5 hours for carbonization. After carbonization, the material was dried to remove moisture. The resulting powder was then subjected to microwave irradiation for 50 minutes at a microwave power of 1000 W. Afterward, the powder was ground and passed through a 200-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 4 (As shown), for later use.

[0054] (4) Take the following proportions of raw materials: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 32 parts by weight of 42.5 ordinary Portland cement, 13 parts by weight of fly ash, 135 parts by weight of fine aggregate, and 2 parts by weight of polycarboxylate superplasticizer. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 69 parts by weight of clean water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0055] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 19.92 MPa, softening coefficient = 0.882.

[0056] Example 6 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) The hydrous kaolinite powder was heated to 540℃ and kept at that temperature for 90 min for calcination. After the calcination was completed, it was cooled to room temperature. The calcined product was then mixed with 1.5 mol / L choline aqueous solution at a ratio of 1 g: 20 mL and heated to 70℃ with continuous stirring for 3 hours. After the calcination was completed, the solid product was filtered out, dried, and ground to obtain the reinforcing agent powder for later use.

[0057] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 25 parts by weight of silica fume, 11 parts by weight of the reinforcing agent powder described in this embodiment, 6 parts by weight of wollastonite powder, 20 parts by weight of calcium carbide slag powder, 2.6 parts by weight of multi-walled carbon nanotubes, and 1.5 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 200 mesh. Mix the above components evenly, then add 68 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 95% for 48 hours. After completion, crush and grind the hardened body, and then pass it through a 400-mesh sieve to obtain modified slag powder for later use.

[0058] (3) The modified slag powder was microwave-irradiated for 60 minutes at a microwave power of 1000W. After completion, it was ground and passed through a 150-mesh sieve to obtain interface-reinforced slag powder (e.g. Figure 5 (As shown), for later use.

[0059] (4) Take the following raw materials in the following proportions: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 33 parts by weight of 42.5 ordinary Portland cement, 16 parts by weight of fly ash, 140 parts by weight of fine aggregate, and 2.2 parts by weight of polycarboxylate superplasticizer. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 67 parts by weight of water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0060] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 20.46 MPa, softening coefficient = 0.905.

[0061] Example 7 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) The hydrous kaolinite powder was heated to 540℃ and kept at that temperature for 90 min for calcination. After the calcination was completed, it was cooled to room temperature. The calcined product was then mixed with 1.5 mol / L choline aqueous solution at a ratio of 1 g: 20 mL and heated to 70℃ with continuous stirring for 3 hours. After the calcination was completed, the solid product was filtered out, dried, and ground to obtain the reinforcing agent powder for later use.

[0062] (2) Take the following components in the following proportions: 100 parts by weight of slag powder, 25 parts by weight of silica fume, 11 parts by weight of the reinforcing agent powder described in this embodiment, 6 parts by weight of wollastonite powder, 20 parts by weight of calcium carbide slag powder, 2.6 parts by weight of multi-walled carbon nanotubes, and 1.5 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 200 mesh. Mix the above components evenly, then add 68 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 95% for 48 hours. After completion, crush and grind the hardened body, and then pass it through a 400-mesh sieve to obtain modified slag powder for later use.

[0063] (3) The modified slag powder is mixed with water and stirred evenly to obtain a wet material with a moisture content of 35 wt.%. This wet material is then placed in a carbonization box, sealed, and carbon dioxide is introduced and heated to 80°C. The material is then kept at this temperature for 3 hours for carbonization. After carbonization, the material is dried to remove moisture, ground, and passed through a 150-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 6 (As shown), for later use.

[0064] (4) Take the following raw materials in the following proportions: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 33 parts by weight of 42.5 ordinary Portland cement, 16 parts by weight of fly ash, 140 parts by weight of fine aggregate, and 2.2 parts by weight of polycarboxylate superplasticizer. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 67 parts by weight of water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0065] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 21.58 MPa, softening coefficient = 0.911.

[0066] Example 8 A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil includes the following steps: (1) Take the following components in the following proportions: 100 parts by weight of slag powder, 20 parts by weight of silica fume, 9 parts by weight of wollastonite powder, 30 parts by weight of calcium carbide slag powder, 4 parts by weight of multi-walled carbon nanotubes, and 2 parts by weight of sodium silicate powder. The fineness of the slag powder, reinforcing agent powder, wollastonite powder, and calcium carbide slag powder is 350 mesh. Mix the above components and stir evenly, then add 74.73 parts by weight of water and stir for 3 minutes. Pour the resulting slurry into a mold, demold after hardening, and then cure in a curing box with a relative humidity of 90% for 72 hours. After completion, crush and grind the hardened body, and then pass it through a 400-mesh sieve to obtain modified slag powder for later use.

[0067] (2) The modified slag powder was mixed with water and stirred evenly to obtain a wet material with a moisture content of 45 wt.%. This wet material was then placed in a carbonization box, sealed, and heated to 65°C with carbon dioxide. The mixture was kept at this temperature for 5 hours for carbonization. After carbonization, the material was dried to remove moisture, and then subjected to microwave irradiation treatment for 45 minutes at a microwave power of 1200 W. Afterward, the powder was ground and passed through a 250-mesh sieve to obtain interface-reinforced slag powder (e.g., ...). Figure 7 (As shown), for later use.

[0068] (3) Take the following proportions of raw materials: 100 parts by weight of the interface-reinforced slag powder described in this embodiment, 29 parts by weight of 42.5 ordinary Portland cement, 10 parts by weight of fly ash, 125 parts by weight of fine aggregate, and 1.5 parts by weight of naphthalene-based water-reducing agent. The fine aggregate is river sand with a particle size distribution between 1 and 2 mm. Mix the above raw materials and stir evenly. Then add 69.5 parts by weight of clean water and stir for 3 minutes to obtain cement-based non-fired brick material.

[0069] Performance testing: The 7-day compressive strength and softening coefficient (K) of the unfired bricks prepared from the cement-based unfired brick material of this embodiment were tested using the same method as in Example 1 above. f The results are: compressive strength = 17.51 ​​MPa, softening coefficient = 0.856.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil, characterized in that, Includes the following steps: (1) The calcined kaolinite powder was first calcined and cooled. The calcined product was then added to a choline solution and stirred. After the process was completed, the solid product was separated, dried, and ground to obtain the reinforcing agent powder. (2) Mix the slag powder, silica fume, the reinforcing agent powder, wollastonite powder, calcium carbide slag powder, multi-walled carbon nanotubes, sodium silicate powder and water and then cure them; after completion, crush and grind the hardened body to obtain modified slag powder. (3) The modified slag powder is mixed with water to form a wet material and then carbonized in a carbon dioxide atmosphere. After completion, it is dried, and then the obtained powder is subjected to microwave irradiation treatment and finally ground to obtain interface-strengthened slag powder. (4) Using the interface-strengthened slag powder, silicate cement, fly ash, fine aggregate and water-reducing agent as raw materials, mix them with mixing water to obtain the negative carbon cement-based non-fired brick material. In step (1), the calcination temperature is 540~580℃; the ratio of the calcined product to the choline solution is 1g:10~20mL; In step (2), the proportions of each component are as follows: 100 parts by weight of slag powder, 20-25 parts by weight of silica fume, 11-18 parts by weight of reinforcing agent powder, 6-9 parts by weight of wollastonite powder, 20-30 parts by weight of calcium carbide slag powder, 2.6-4 parts by weight of multi-walled carbon nanotubes, and 1.5-2 parts by weight of sodium silicate powder. In step (4), the proportions of each component are as follows: 100 parts by weight of interface-strengthened slag powder, 29-33 parts by weight of silicate cement, 10-16 parts by weight of fly ash, 125-140 parts by weight of fine aggregate, and 1.5-2.2 parts by weight of water-reducing agent.

2. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (1), the calcination time is 60~90min.

3. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (1), the concentration of the choline solution is 1.5~3 mol / L; or, in step (1), the stirring time is 3~5 hours and the temperature is 55~70℃.

4. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (2), the fineness of the slag powder, reinforcing agent powder, wollastonite powder, and carbide slag powder is 200~350 mesh.

5. The method for preparing negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (2), the mass ratio of the clean water to the total of the slag powder, silica fume, reinforcing agent powder, wollastonite powder, and carbide slag powder is 0.42~0.47:

1.

6. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (2), the curing time is 48 to 72 hours and the relative humidity is 90 to 95%; or, in step (2), the fineness of the modified slag powder is 400 to 500 mesh.

7. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (3), the moisture content of the wet material is 35~45 wt.%.

8. The preparation method of negative carbon cement-based non-fired brick material based on the interface strengthening effect of slag and soil according to claim 1, characterized in that, In step (3), the carbonization process takes 3 to 5 hours and the temperature is 65 to 80°C; or, in step (3), the fineness of the powder is 150 to 250 mesh.

9. The method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil according to claim 1, characterized in that, In step (3), the microwave irradiation treatment time is 45~60min and the microwave power is 1000~1200W.

10. The method for preparing negative carbon cement-based non-fired brick material based on the interfacial strengthening effect of slag and soil according to any one of claims 1-9, characterized in that, In step (4), the mass ratio of the mixing water to the total mass of the interface-strengthened slag powder, silicate cement, and fly ash is 0.45~0.5:1.

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