A high-carbon-fixed recycled concrete aggregate and its preparation method and application
By introducing phenolic compounds and proteins into recycled concrete aggregates, combined with carbon sequestration technology, the problem of insufficient water absorption and strength of recycled concrete aggregates is solved, and efficient carbon sequestration performance improvement and concrete performance optimization are achieved.
Patent Information
- Application Number
- CN202411565250.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-04-01
AI Technical Summary
The large number of microcracks formed by existing recycled concrete aggregates during the production process cause their water absorption rate and water absorption rate much higher than that of natural aggregates, affecting the strength of the final concrete products, and no fundamental solution has been found for the problem of high porosity.
By introducing phenolic compounds and proteins into the regenerated concrete aggregate, combining chitosan and methyl cellulose, the performance of concrete is improved and the fixation of carbon dioxide is promoted to form high-solid carbon regenerated concrete aggregate.
The water absorption, strength and carbon sequestration performance of recycled concrete aggregates are effectively improved, the durability and carbon sequestration capabilities of concrete are improved, and the apparent density and water absorption rate of recycled concrete aggregates are further optimized.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of building materials and relates to a high-fixed carbon recycled concrete aggregate and a preparation method and application thereof. Background Art
[0002] Driven by the rapid development of the global economy and technological progress, the surge in energy demand has also led to a significant increase in greenhouse gas emissions, and the issue of carbon emissions has become a global focus. Against this background, the recycled concrete industry is showing unprecedented development opportunities.
[0003] Recycled concrete is a new type of building material made from waste concrete blocks that have been crushed, cleaned, sorted and mixed with a specific ratio of cement, water and other raw materials. It can be divided into several types according to the different combinations of ingredients: recycled concrete composed entirely of recycled aggregates, a mixed type in which the coarse aggregate is recycled and the fine aggregate is natural sand, and another mixed type in which the fine aggregate is recycled and the coarse aggregate is natural crushed stone.
[0004] Recycled concrete aggregates are made from specially treated waste concrete blocks and other similar materials, and can replace traditional natural aggregates to configure concrete with different performance requirements. According to the particle size, these aggregates can be further divided into coarse aggregates and fine aggregates. Compared with natural aggregates, recycled aggregates usually have lower bulk density and apparent density, stronger water absorption and higher shrinkage, which makes them more suitable in certain application scenarios.
[0005] However, the large number of microcracks formed in the production process of recycled aggregates cause their water absorption rate and speed to be much higher than that of natural aggregates, which in turn affects the strength of the final concrete products. Although existing physical or chemical modification methods can improve the performance of recycled concrete to a certain extent, there is no fundamental solution to the high porosity problem of the aggregate itself.
[0006] Carbon sequestration technology, also known as carbon storage technology, aims to increase the carbon content in non-atmospheric carbon pools through physical or biological means and reduce carbon dioxide in the atmosphere. Physical carbon sequestration technology involves long-term storage of carbon dioxide in underground oil and gas fields or deep sea environments; biological carbon sequestration technology uses plant photosynthesis to enhance the carbon absorption capacity of ecosystems.
[0007] Carbon capture and storage (CCS) is an important branch of carbon sequestration technology. It collects carbon dioxide emitted by large industrial facilities and uses various means to store it safely to prevent it from entering the atmosphere. The more advanced carbon capture, utilization and storage (CCUS) not only includes the traditional carbon capture and storage process, but also adds a new link to utilize carbon dioxide, making it a more comprehensive and efficient emission reduction solution. This technology has been widely recognized for its efficiency, convenience and comprehensiveness.
[0008] In summary, the combination of material modification technology and carbon sequestration technology is crucial to promoting technological innovation and development in the recycled concrete industry. This can not only promote the research and development of high-performance recycled concrete aggregates, but also conform to the trend of green transformation in the construction industry. Summary of the invention
[0009] In view of the deficiencies of recycled concrete aggregate in the prior art, the present invention provides a high-carbon-fixed recycled concrete aggregate and a preparation method and application thereof.
[0010] One object of the present invention is achieved by the following technical solutions:
[0011] A high-fixed carbon recycled concrete aggregate is processed from the following raw materials in parts by weight: 10 to 30 parts of cement, 50 to 80 parts of mortar, 0.1 to 5 parts of water reducer, 1 to 5 parts of chitosan, 0.5 to 2 parts of methyl cellulose, 0.1 to 1 part of phenolic compound, 1 to 5 parts of protein and 10 to 50 parts of water.
[0012] Preferably, the phenolic compound is a flavonoid phenolic compound, including one or more of flavonols, flavones, isoflavones, and chalcones, and more preferably flavonols.
[0013] The present invention introduces phenolic compounds into recycled concrete aggregates, which are natural substances extracted from plants and help improve the performance of concrete and promote the fixation of carbon dioxide. Since plants are rich in phenolic compounds, they have antioxidant properties and strong chemical activity, and can achieve an improvement in the carbon fixation effect.
[0014] Preferably, the protein includes one or more of soy protein, casein, keratin, fibroin, and plant protein, and more preferably soy protein.
[0015] Protein substances are macromolecules formed by amino acids connected by peptide bonds. The present invention introduces protein into recycled concrete aggregate to improve the performance of recycled concrete aggregate, which can effectively improve the toughness of concrete, reduce cracks, and participate in chemical reactions to help fix carbon.
[0016] Preferably, the water-cement ratio of the mortar is 0.5-0.7.
[0017] Preferably, the cement fineness is 50-100 μm and the density is 3-3.5 g / m 3 , the consistency is 22-27% (measured according to the relevant provisions of GB175-2007). The consistency of cement refers to the ideal state of cement paste (i.e. the paste after cement and water are mixed) under specific conditions. This state is achieved by adjusting the amount of water added, with the aim of ensuring that the cement paste has good workability and is suitable for subsequent setting time tests, stability tests, and strength tests.
[0018] Preferably, the solid content of the water reducing agent is 20-40 wt % and the density is 1.0-1.3 g / m 3 , pH value is 6.0~8.0, viscosity is 100~1000mPa·s, water reduction rate is 25~50%, slurry fluidity is 260~500mm, water seepage rate is 10~60%, and shrinkage rate is 10~90%.
[0019] Preferably, the particle size of the high carbon-fixed recycled concrete aggregate is 10 to 20 mm.
[0020] The second object of the present invention is achieved by the following technical solutions:
[0021] A method for preparing high-carbon-fixed recycled concrete aggregate, the preparation method comprising the following steps: adding water to a stirrer, then sequentially adding cement, mortar, water reducer, chitosan, methyl cellulose, phenolic compounds and protein components for stirring to form a slurry, molding and curing the mixed slurry until it is completely hardened, and finally knocking to obtain fragments, and screening to obtain the high-carbon-fixed recycled concrete aggregate.
[0022] The third object of the present invention is achieved by the following technical solutions:
[0023] A method for applying high carbon-fixing recycled concrete aggregate in carbon fixation technology, the carbon fixation technology comprising the following steps: placing high carbon-fixing recycled concrete aggregate in a carbon fixation device, introducing CO 2 And adjust the air pressure value in the carbon fixation device to carry out carbon fixation treatment.
[0024] Preferably, the ambient temperature of the carbon fixation treatment is 20-25° C. and the humidity is 45-80%.
[0025] Preferably, the carbon fixation device needs to be checked for tightness before the carbon fixation treatment, including the following steps: opening the main valve, exhaust valve and vacuum valve of the carbon fixation device, and when the internal air pressure of the carbon fixation device is ≤-0.7 bar, closing the exhaust valve and vacuum valve in sequence to ensure that the airtightness of the carbon fixation device meets the requirements.
[0026] Preferably, the CO2 Concentration>99%, the gas pressure in the carbon fixation device is 0.1~1bar.
[0027] Compared with the prior art, the present invention has the following beneficial effects:
[0028] 1. The high-carbon-fixing recycled concrete aggregate provided by the present invention adopts a variety of materials to modify the recycled concrete aggregate, produce a synergistic effect, and achieve efficient improvement of the water absorption, strength and carbon-fixing performance of the recycled concrete aggregate.
[0029] 2. The high-carbon-fixed recycled concrete aggregate provided by the present invention introduces chitosan and methyl cellulose into the raw materials. Chitosan is a natural polysaccharide with good biocompatibility and adhesion, which can improve the adhesion between materials and enhance the interface transition zone; methyl cellulose can form a colloidal solution in water, further increasing the viscosity of the material, which helps to reduce segregation, makes concrete easier to construct, and can also improve the surface quality of the final product; the two can be used together to synergistically improve the bonding state between particles and enhance the water absorption and strength of recycled concrete aggregates.
[0030] 3. The high carbon fixation recycled concrete aggregate provided by the present invention introduces phenolic compounds and proteins into the raw materials. Protein contains rich amino acid components, which will participate in the hydration reaction process of cement to promote CO 2 The absorption of phenolic compounds can also adjust the setting time of cement paste and optimize the early strength development of concrete; phenolic compounds have antioxidant properties and strong chemical activity, which can help slow down the corrosion of steel bars, extend the service life of the structure, and help fix CO 2 It not only has the function of antibacterial and mildew-proof, but also has certain antibacterial and mildew-proof effects, which is beneficial to improving the health level of the building environment; the synergistic effect of the two can further promote the durability and carbon fixation capacity of recycled concrete.
[0031] 4. The high carbon-fixing recycled concrete aggregate provided by the present invention can further improve the water absorption performance of recycled concrete aggregate and effectively improve the apparent density value of recycled concrete aggregate after modifying the recycled concrete aggregate and applying it to carbon-fixing technology, based on the improvement effect of existing carbon-fixing technology on recycled concrete aggregate. The raw materials of the present invention use a variety of natural raw materials and combine carbon-fixing technology, contributing to my country's green and low-carbon transformation. DETAILED DESCRIPTION
[0032] The technical solution of the present invention is further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.
[0033] Example 1
[0034] The high carbon fixation recycled concrete aggregate of this embodiment is made from the following raw materials in parts by weight: 20 parts of cement (fineness is 80 μm, density is 3.15 g / m 3 , standard consistency is 25.8%, in line with the relevant provisions of GB175-2007), 70 parts of mortar (in line with the relevant provisions of GB / T17671-1999, water-cement ratio 0.55), 1 part of water reducer (Ningbo Zhongshuike composite high-efficiency water reducer, solid content 30wt%, density 1.1g / m 3 , pH 7.0, viscosity 500mPa·s, water reduction rate 30%, slurry fluidity 260mm, water bleeding rate 60%, shrinkage rate 90%), 3 parts of chitosan, 1.5 parts of methyl cellulose, 0.5 parts of flavonols, 3 parts of soy protein, and 30 parts of water.
[0035] The preparation method of high-fixed carbon recycled concrete aggregate in this embodiment includes the following steps: adding water to a mixer, and then sequentially adding cement, mortar, water reducing agent, chitosan, methyl cellulose, phenolic compounds and protein components to stir to form a slurry, and molding and curing the mixed slurry until it is completely hardened; knocking to obtain fragments, and placing the fragments on a square hole sieve with a particle size of 20 mm for screening; collecting the fragments that cannot pass through the square hole sieve and knocking again until the particle size of the fragments is within the range of 10 to 20 mm, to obtain high-fixed carbon recycled concrete aggregate, and storing it in a sealed bag for future use.
[0036] Example 2
[0037] The high-fixed carbon recycled concrete aggregate of this embodiment is made from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 0.5 parts of water reducer, 2 parts of chitosan, 2 parts of methyl cellulose, 0.3 parts of flavonols, 5 parts of soy protein, and 30 parts of water.
[0038] The rest is the same as in Example 1.
[0039] Example 3
[0040] The high-fixed carbon recycled concrete aggregate of this embodiment is processed from the following raw materials in parts by weight: 30 parts of cement, 60 parts of mortar, 1.5 parts of water reducer, 4 parts of chitosan, 1 part of methyl cellulose, 1 part of flavonols, 1 part of soy protein, and 30 parts of water.
[0041] The rest is the same as in Example 1.
[0042] Example 4
[0043] The difference between the recycled concrete aggregate in this embodiment and that in Embodiment 1 is that the water-cement ratio of the mortar used is 0.5, and the rest is the same as in Embodiment 1.
[0044] Comparative Example 1
[0045] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that chitosan is not added to the raw materials, and the rest is the same as in Example 1.
[0046] The recycled concrete aggregate in this comparative example is processed from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 1 part of water reducer, 1.5 parts of methyl cellulose, 0.5 parts of flavonol, 3 parts of soy protein, and 30 parts of water.
[0047] Comparative Example 2
[0048] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that methyl cellulose is not added to the raw materials, and the rest is the same as in Example 1.
[0049] The recycled concrete aggregate in this comparative example is processed from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 1 part of water reducer, 3 parts of chitosan, 0.5 parts of flavonols, 3 parts of soy protein, and 30 parts of water.
[0050] Comparative Example 3
[0051] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that flavonol is not added to the raw materials, and the rest is the same as in Example 1.
[0052] The recycled concrete aggregate in this comparative example is processed from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 1 part of water reducing agent, 3 parts of chitosan, 1.5 parts of methyl cellulose, 3 parts of soy protein, and 30 parts of water.
[0053] Comparative Example 4
[0054] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that no soy protein is added to the raw materials, and the rest is the same as in Example 1.
[0055] The recycled concrete aggregate in this comparative example is processed from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 1 part of water reducer, 3 parts of chitosan, 1.5 parts of methyl cellulose, 0.5 parts of flavonols, and 30 parts of water.
[0056] Comparative Example 5
[0057] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that chitosan, methyl cellulose, flavonol and soy protein are not added to the raw materials, and the rest is the same as in Example 1.
[0058] The recycled concrete aggregate in this comparative example is processed from the following raw materials in parts by weight: 20 parts of cement, 70 parts of mortar, 1 part of water reducing agent, and 30 parts of water.
[0059] Comparative Example 6
[0060] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that the water-cement ratio of the mortar in the raw material is 0.45, and the rest is the same as in Example 1.
[0061] Comparative Example 7
[0062] The difference between the recycled concrete aggregate in this comparative example and that in Example 1 is that the particle size of the prepared recycled concrete aggregate is 5 to 10 mm.
[0063] The specific preparation method includes the following steps: adding water to a blender, then sequentially adding cement, mortar, water reducing agent, chitosan, methyl cellulose, phenolic compounds and protein components to stir to form a slurry, molding and curing the mixed slurry until it is completely hardened; knocking to obtain fragments, placing the fragments on a square hole sieve with a particle size of 10 mm for screening; collecting the fragments that cannot pass through the square hole sieve and knocking again until the particle size of the fragments is within the range of 5 to 10 mm, thereby obtaining high-fixed carbon recycled concrete aggregate, storing it in a sealed bag, and keeping it for later use.
[0064] The rest is the same as in Example 1.
[0065] The recycled concrete aggregates of the above-mentioned embodiment and comparative example were subjected to carbon fixation treatment, specifically comprising the following steps: performing carbon fixation treatment in an environment with a temperature of 22° C. and a humidity of 60%; opening the main valve, exhaust valve, and vacuum valve of the carbon fixation device in sequence, and when the internal air pressure of the carbon fixation device is -0.7 bar, closing the exhaust valve and vacuum valve in sequence to ensure that the airtightness of the carbon fixation device meets the requirements; then placing high carbon fixation recycled concrete aggregates; introducing CO 2 (concentration>99%) and adjust the air pressure in the carbon fixation device to 0.5 bar; after carbon fixation is completed, close the air inlet valve, open the exhaust valve and vacuum valve of the carbon fixation device in turn, and close all valves until the air pressure in the carbon fixation device is 0, and take out the recycled concrete aggregate after carbon fixation from the device.
[0066] The carbon fixation capacity of recycled concrete aggregate was tested, and the apparent density and water absorption difference of the recycled concrete aggregate after carbon fixation were tested. The specific test results are shown in Table 1.
[0067] Table 1 Test results of recycled concrete aggregate performance of examples and comparative examples
[0068]
[0069]
[0070] As shown in Table 1, it can be seen from Examples 1 to 4 and Comparative Examples 1 to 5 that the recycled concrete aggregate prepared using the raw materials within the scope of the technical solution of the present invention has a short carbon fixation time and a high carbon fixation amount, and after carbon fixation, the apparent density of the recycled concrete aggregate can be effectively improved and the water absorption rate can be reduced; in Comparative Examples 1 to 5, the recycled concrete aggregate prepared without using the raw materials within the scope of the technical solution of the present invention has a significantly longer carbon fixation time and a low overall carbon fixation amount, wherein almost no carbon fixation occurs at 20 to 50 hours, and at the same time, the improvement in water absorption performance weakens, and the apparent density cannot be improved.
[0071] In Comparative Example 6, too low a water-cement ratio of mortar is used. Although the water absorption rate is improved, the carbon fixation capacity is greatly reduced. The too low water-cement ratio leads to a longer carbon fixation time and a lower carbon fixation amount, and it cannot improve the apparent density. In Comparative Example 7, recycled concrete aggregate with a particle size of 5 to 10 mm is used. The particle size is too small, which also reduces the carbon fixation capacity and affects the water absorption performance.
[0072] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.
[0073] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.
[0074] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.
Claims
1. A high carbon-fixed recycled concrete aggregate, characterized in that: The high-fixed carbon recycled concrete aggregate is processed from the following raw materials in parts by weight: 10 to 30 parts of cement, 50 to 80 parts of mortar, 0.1 to 5 parts of water reducer, 1 to 5 parts of chitosan, 0.5 to 2 parts of methyl cellulose, 0.1 to 1 part of phenolic compounds, 1 to 5 parts of protein, and 10 to 50 parts of water.
2. The high carbon fixed recycled concrete aggregate according to claim 1, characterized in that: The phenolic compounds are flavonoid phenolic compounds, including one or more of flavonols, flavones, isoflavones and chalcones.
3. The high carbon fixed recycled concrete aggregate according to claim 1, characterized in that: The protein includes one or more of soy protein, casein, keratin, silk protein and plant protein.
4. The high carbon fixed recycled concrete aggregate according to claim 1, characterized in that: The water-cement ratio of the mortar is 0.5-0.
7.
5. The high carbon fixed recycled concrete aggregate according to claim 1, characterized in that: The cement fineness is 50-100 μm and the density is 3-3.5 g / m 3 , the consistency is 22-27%.
6. The high carbon fixed recycled concrete aggregate according to claim 1, characterized in that: The solid content of the water reducing agent is 20-40wt%, and the density is 1.0-1.3g / m 3 , pH value is 6.0~8.0, viscosity is 100~1000mPa·s, water reduction rate is 25~50%, slurry fluidity is 260~500mm, water seepage rate is 10~60%, and shrinkage rate is 10~90%.
7. The high carbon-fixing recycled concrete aggregate according to claim 1, characterized in that: The particle size of the high-fixed carbon recycled concrete aggregate is 10 to 20 mm.
8. A method for preparing a high carbon-fixed recycled concrete aggregate according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: adding water to a stirrer, then sequentially adding cement, mortar, water reducing agent, chitosan, methyl cellulose, phenolic compounds and protein components to stir to form slurry, molding and curing the mixed slurry until it is completely hardened, and finally knocking to obtain fragments, and screening to obtain high-fixed carbon recycled concrete aggregate.
9. An application of a high carbon fixation recycled concrete aggregate as claimed in any one of claims 1 to 7 in carbon fixation technology, characterized in that: The carbon fixation technology comprises the following steps: placing high carbon fixation recycled concrete aggregate in a carbon fixation device, introducing CO2 and adjusting the air pressure value in the carbon fixation device to perform carbon fixation treatment.
10. The use according to claim 1, characterized in that: The environmental temperature of the carbon fixation treatment is 20-25°C and the humidity is 45-80%; And / or, before the carbon fixation treatment, the carbon fixation device needs to be checked for tightness, including the following steps: opening the main valve, exhaust valve, and vacuum valve of the carbon fixation device, and when the internal air pressure of the carbon fixation device is ≤-0.7 bar, closing the exhaust valve and vacuum valve in sequence to ensure that the airtightness of the carbon fixation device meets the requirements; And / or, the CO2 concentration is greater than 99%, and the gas pressure in the carbon fixation device is 0.1 to 1 bar.