Enhanced recycled aggregate cement concrete based on long-term carbon sequestration and preparation method

Abstract

The application discloses a kind of based on long-acting carbon sequestration enhanced recycled aggregate cement concrete and preparation method, the proportion of each substance in the cement concrete is, recycled aggregate component 45-50wt%, active carbon capture agent 2-5wt%, microencapsulated material 1-2wt%, river sand 24-28wt%, water reducing agent 0.8-1.2wt%, cement 15-18wt%, auxiliary admixture 1.2-4.8wt%, water 6-9wt%.The preparation method includes the following steps: preparation recycled aggregate component, active carbon capture agent, microencapsulated material, microcapsule particle;Each substance is put into mixing kettle and is mixed uniformly, to obtain based on carbon sequestration enhanced recycled aggregate cement concrete slurry;Slurry is filled into test piece forming mold, and microcapsule particle is spread on the upper surface of slurry, vibration forming, standing, demolding, curing after obtaining test piece;Microcapsule particle suspension is coated on the outer surface of test piece, to obtain based on long-acting carbon sequestration enhanced recycled aggregate cement concrete test piece.The application can not only continuously adsorb and sequestrate carbon dioxide, but also improve the strength and durability of recycled aggregate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of road engineering materials and environmental protection, and particularly relates to an enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and a preparation method thereof. BACKGROUND

[0002] With the rapid advancement of industrialization and urbanization, the construction industry is developing rapidly, and new construction projects such as infrastructure construction can be seen everywhere. A large number of original buildings reach the service life or cannot meet the use requirements and are demolished. This phenomenon not only causes a huge waste of construction resources, but also leads to the increasingly serious problem of building garbage surrounding cities. If a large amount of construction waste cannot be effectively utilized or reasonably disposed of, it will cause serious waste of resources and also exacerbate serious damage to the natural environment. Therefore, effective recycling and recycling of construction waste is an important research direction in the field of environmental protection.

[0003] As an important part of infrastructure construction in China, road engineering has a large engineering volume and can consume a large amount of natural sand and stone materials every year. In addition, roads can be divided into multiple levels according to functional differences and multiple layers according to structural layer differences, and have the possibility of absorbing a large amount of recycled aggregates with different physical properties. However, the strength and durability of recycled aggregates are poor, which limits their use in actual road engineering.

[0004] Recycled aggregates can be used to produce cement concrete, but a large amount of carbon dioxide will be emitted during the recycling crushing or processing of recycled aggregates and the production and preparation of recycled aggregate cement concrete, which will cause serious pollution to the environment. In order to reduce carbon emissions and improve the sustainable development of building materials, green and environmentally friendly recycled aggregate cement concrete technology has become a research hotspot in the industry.

[0005] In the production and preparation process of recycled aggregate cement concrete, the existing technology mainly injects high-concentration carbon dioxide prepared by industry into cement test blocks to sequester carbon dioxide in the form of carbonate to improve the strength of recycled aggregates. However, the amount of carbon dioxide absorbed by recycled aggregates is limited, which leads to the emission of a large amount of carbon dioxide again, and the cost is high. In addition, high-concentration carbon dioxide cannot be continuously absorbed into cement test blocks, and the effect of long-acting carbon sequestration cannot be achieved. Therefore, it is urgent to develop an enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and a preparation method thereof to achieve the effect of continuously adsorbing and sequestering carbon dioxide and significantly improving the strength and durability of recycled aggregates.

[0006] The invention patent with the application publication number CN117536045A discloses a carbon sequestration full-solid waste assembled permeable pavement system, which comprises, from bottom to top, a carbon sequestration solidified slurry muck base layer, an assembled interlocking permeable carbon sequestration recycled concrete base layer, a carbon sequestration recycled fine aggregate leveling layer, and an assembled interlocking permeable carbon sequestration recycled brick pavement. The system further comprises a drainage pipeline arranged in the assembled interlocking permeable carbon sequestration recycled concrete base layer and a soil nail vertically penetrating from the assembled interlocking permeable carbon sequestration recycled concrete base layer to the carbon sequestration solidified slurry muck base layer. When preparing the carbon sequestration solidified slurry muck base layer, carbon dioxide with a concentration of 15-40% is injected for carbonization curing. When preparing the permeable frame, carbon dioxide with a concentration of 15-40% is injected three times to achieve three times of carbon sequestration. When preparing the carbon sequestration recycled fine aggregate leveling layer, carbon dioxide with a concentration of 15-40% is injected for carbonization curing. When preparing the interlocking gap brick, carbon dioxide with a concentration of 15-40% is injected for carbonization curing. The technical solution adopts the method of directly injecting high-concentration carbon dioxide into the material to achieve carbon sequestration. However, since high-concentration carbon dioxide cannot be continuously absorbed into the material, long-term carbon sequestration cannot be achieved. In addition, since the amount of carbon dioxide absorbed by solid waste materials is limited, a large amount of carbon dioxide may be emitted during the injection of carbon dioxide. SUMMARY

[0007] To solve the problems in the prior art, the present application provides an enhanced recycled aggregate cement concrete based on long-term carbon sequestration. The mixing amount of each substance in the enhanced recycled aggregate cement concrete accounts for 45-50wt% of the mass percentage of the enhanced recycled aggregate cement concrete, 2-5wt% of the active carbon capture agent, 1-2wt% of the microencapsulated material, 24-28wt% of the river sand, 0.8-1.2wt% of the water reducing agent, 15-18wt% of the cement, 1.2-4.8wt% of the auxiliary admixture, and 6-9wt% of the water.

[0008] Preferably, the mixing amount of each substance in the recycled aggregate component accounts for 40-60wt% of the mass percentage of the recycled aggregate component, 40-60wt% of the aggregate, and 40-60wt% of the recycled aggregate. The aggregate includes any one or several of limestone, basalt, granite, and diabase. The recycled aggregate is low-brick mixed construction waste recycled aggregate, i.e., construction waste generated by the demolition of concrete buildings, with a brick-mixed content of 5-10wt%.

[0009] Preferably in any of the above solutions, the aggregate includes four grades of particle size, each grade of particle size accounts for 8-11wt% of the aggregate, the particle size of 16-19mm accounts for 34-50wt% of the aggregate, the particle size of 9.5-16mm accounts for 35-51wt% of the aggregate, the particle size of 4.75-9.5mm accounts for 4-6wt% of the aggregate; the recycled aggregate includes four grades of particle size, each grade of particle size accounts for 8-11wt% of the recycled aggregate, the particle size of 16-19mm accounts for 34-50wt% of the recycled aggregate, the particle size of 9.5-16mm accounts for 35-51wt% of the recycled aggregate, the particle size of 4.75-9.5mm accounts for 4-6wt% of the recycled aggregate.

[0010] Preferably in any of the above solutions, the active carbon capture agent includes the following substances, and the mixing amount of each substance accounts for 40-50wt% of the active carbon capture agent, modified magnesium oxide 20-30wt%, calcium hydroxide component 10-20wt%, silicate 5-10wt%, catalyst 5-10wt%, industrial solid waste 1-3wt%, trace enhancer.

[0011] Preferably in any of the above solutions, the calcium hydroxide component includes the following substances, and the mixing amount of each substance accounts for 95-98.5wt% of the calcium hydroxide component, calcium hydroxide 1-3wt%, metal oxide 0.5-2wt%, the metal oxide is Al2O3 and / or Fe2O3, the rare earth element is Ce and / or La, the particle size of the calcium hydroxide, the metal oxide, and the rare earth element is 0.1-1μm.

[0012] Preferably in any of the above solutions, the silicate includes any one or several of anhydrous sodium silicate, potassium silicate, sodium-potassium silicate, and sodium-potassium composite silicate; the catalyst includes any one or several of titanium oxide, zirconium dioxide, magnesium-aluminum layered double hydroxide, and hydrated magnesium carbonate-aluminum; the industrial solid waste includes any one or several of steel slag, carbide slag, fly ash, desulfurization gypsum, red mud, and glass slag; the trace enhancer is a lithium-based compound and / or a manganese-based compound, the lithium-based compound includes any one or several of lithium carbonate, lithium hydroxide, and lithium chloride, and the manganese-based compound includes any one or several of manganese dioxide, manganese chloride, and potassium manganate.

[0013] Preferably in any of the above solutions, the microencapsulated material includes the following substances, and the mixing amount of each substance accounts for 20-30wt% of the microencapsulated material, chitosan 50-60wt%, polylactic acid 20-30wt%, and the mass ratio of the chitosan to the polylactic acid is 1:2.2-3, and the particle size of the silica microspheres is 0.01-10μm.

[0014] Preferably in any of the above aspects, the river sand comprises eight grades of particle size, each grade of particle size accounts for the mass percentage of the river sand, the particle size of 4.75-9.5mm accounts for 7-9wt%, the particle size of 2.36-4.75mm accounts for 3-5wt%, the particle size of 1.18-2.36mm accounts for 10-16wt%, the particle size of 0.6-1.18mm accounts for 15-25wt%, the particle size of 0.3-0.6mm accounts for 25-35wt%, the particle size of 0.15-0.3mm accounts for 20-30wt%, the particle size of 0.075-0.15mm accounts for 4-6wt%, and the particle size of 0-0.075mm accounts for 4-6wt%.

[0015] Preferably in any of the above aspects, the water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture comprises any one or more of fly ash, slag powder, and silica fume.

[0016] The application also provides a preparation method of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration, for preparing the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration, and comprising the following steps in sequence:

[0017] Step one: preparing the recycled aggregate component, the active carbon capture agent, and the microencapsulated material according to the designed material ratio and process parameters;

[0018] Step two: weighing the recycled aggregate component, the active carbon capture agent, the microencapsulated material, the river sand of each grade of particle size, the water reducing agent, the cement, the auxiliary admixture, and the water for standby according to the designed material ratio;

[0019] Step three: adding part of the active carbon capture agent to the microencapsulated material and stirring uniformly to make the active carbon capture agent wrapped in the inside of the microencapsulated material, forming a microcapsule raw material liquid; adopting a spray drying method to disperse the microcapsule raw material liquid into fine droplets, and rapidly evaporating the solvent in the high-temperature hot air flow to make the solid substances in the microcapsule raw material liquid polymerize and solidify, forming microcapsule particles;

[0020] Step four: putting the recycled aggregate component and the remaining part of the active carbon capture agent into a mechanical stirrer for stirring, and taking out the mixture of the recycled aggregate component and the active carbon capture agent from the mechanical stirrer for standby after uniform stirring;

[0021] Step five: putting the river sand of each grade of particle size, the cement, the mixture of the recycled aggregate component and the active carbon capture agent, and the auxiliary admixture into a mixing pot for mixing in sequence, and taking out for standby after uniform mixing;

[0022] Step six: Put water and water reducing agent into a container and mix them evenly to form a mixed solution of water and water reducing agent; put the mixed solution of water and water reducing agent into the mixing pot and mix it with the materials in the mixing pot, and after mixing evenly, the enhanced recycled aggregate cement concrete slurry based on carbon sequestration is obtained;

[0023] Step seven: Take the obtained enhanced recycled aggregate cement concrete slurry based on carbon sequestration from the mixing pot and put it into a storage container, and at the same time, manually mix it; after the manual mixing is completed, fill the enhanced recycled aggregate cement concrete slurry based on carbon sequestration into the test specimen forming mold, use a scraper to flatten the upper surface of the slurry in the test specimen forming mold, then evenly sprinkle part of the microcapsule particles on the upper surface of the slurry, and use a scraper to flatten the upper surface of the microcapsule particles;

[0024] Step eight: Place the test specimen forming mold on the electric vibrating table, start the electric vibrating table, and start the vibration forming. If there is a depression during the vibration forming, supplement the enhanced recycled aggregate cement concrete slurry based on carbon sequestration at the depression site. After the vibration forming is completed, the test specimen forming mold and the slurry formed inside are left to stand for a certain period of time before demolding, then placed in a standard curing chamber for curing, and the enhanced recycled aggregate cement concrete test specimen based on carbon sequestration is obtained.

[0025] Step nine: Put the remaining microcapsule particles into anhydrous ethanol to form a suspension; stir the suspension evenly and coat the outer surface of the enhanced recycled aggregate cement concrete test specimen based on carbon sequestration with the suspension evenly, and the enhanced recycled aggregate cement concrete test specimen based on long-acting carbon sequestration is obtained.

[0026] Preferably, in step one, the preparation process of the recycled aggregate component is as follows: first, the construction waste generated by the demolition of concrete buildings is crushed and washed, and is sieved according to the designed particle size grade to obtain recycled aggregates of each particle size grade; then, the recycled aggregates of each particle size grade are weighed according to the designed material ratio, and are subjected to carbonization pretreatment, that is, the recycled aggregates of each particle size grade are soaked in a 5% sodium carbonate solution, and the sodium carbonate solution can just cover the recycled aggregates of each particle size grade, the soaking temperature is room temperature, and the soaking time is 1-2h; after the soaking is completed, melamine is added to the sodium carbonate solution and the recycled aggregates of each particle size grade and is stirred, the addition amount of melamine is 0.5-1wt% of the total mass of the recycled aggregates, the stirring temperature is room temperature, and the stirring time is 0.5-1h; after the stirring is completed, the carbonization pretreatment of the recycled aggregates is completed; finally, the aggregates of each particle size grade are weighed according to the designed material ratio, and the aggregates of each particle size grade and the recycled aggregates of each particle size grade after carbonization pretreatment are mixed evenly, and the recycled aggregate component is obtained.

[0027] Preferably in any of the above solutions, in step one, the preparation process of the active carbon capture agent is as follows: first, modified magnesium oxide is prepared by placing magnesium oxide into a calcining furnace for low-temperature calcination at a temperature of 700-900°C for 3-5h, and then the calcined magnesium oxide is washed and purified, and then placed into an oven for drying treatment at a temperature of 80-100°C for 2-3h, and then the dried magnesium oxide is mixed with an alkali carbonate to obtain modified magnesium oxide, the alkali carbonate being added in an amount of 1-3wt% of the mass of the modified magnesium oxide, the alkali carbonate including any one or several of lithium carbonate, potassium carbonate and cesium carbonate; second, a calcium hydroxide component is prepared by mixing calcium hydroxide, metal oxide and rare earth elements uniformly at room temperature according to the designed material ratio; then the modified magnesium oxide, the calcium hydroxide component, silicate, catalyst, industrial solid waste and trace enhancer are mixed uniformly at room temperature according to the designed material ratio, and the mixed materials are subjected to ball milling to obtain a solid powder with a particle size of less than 5μm; finally, the solid powder is placed into an oven for drying treatment at a temperature of 80-100°C for 2-3h, and the active carbon capture agent is obtained after the drying treatment is completed.

[0028] Preferably in any of the above solutions, in step one, the preparation process of the microencapsulated material is as follows: first, chitosan, polylactic acid and silica microspheres are weighed according to the designed material ratio for standby; then the chitosan and polylactic acid are mixed uniformly and then dissolved in anhydrous ethanol to form a solution, the mass of the anhydrous ethanol being 20-30 times the total mass of the chitosan and polylactic acid; finally, the silica microspheres are added into the solution and stirred uniformly to obtain the microencapsulated material.

[0029] Preferably in any of the above solutions, in step three, the mass of the part of the active carbon capture agent is 40-50wt% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 150-200°C, and the particle size of the microcapsule particles is 100-120μm.

[0030] Preferably in any of the above solutions, in step four, the mass of the remaining part of the active carbon capture agent is 50-60wt% of the total mass of the active carbon capture agent, the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 120-180rpm, and the stirring time is 4-6min.

[0031] Preferably in any of the above solutions, in step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40-60rpm, and the mixing time is 60-90s.

[0032] Preferably in any of the above solutions, in step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40-60rpm, and the mixing time is 3-4min.

[0033] In any of the above schemes, preferably, in step seven, the mixing temperature is room temperature, and the mixing time is 1-2 min; the length, width and height of the inner cavity of the test piece forming mold are 100 mm, 100 mm and 100 mm, respectively; and the mass of the part of the microcapsule particles is 20-30 wt% of the total mass of the microcapsule particles.

[0034] In any of the above schemes, preferably, in step eight, the standing temperature is room temperature, and the standing time is 24 h; and the curing time is 28 days.

[0035] In any of the above schemes, preferably, in step nine, the mass of the remaining part of the microcapsule particles is 70-80 wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 20-30 times the mass of the remaining part of the microcapsule particles.

[0036] In the present application, the mechanical stirrer, mixing pot, electric vibration table, calcining furnace, oven and the like used are conventional devices in the field, and there are no special requirements for the model, structure and the like of the devices; and the spray drying method used is also a conventional method in the field, and there are no special requirements for the process flow and process parameters, wherein only the temperature of the high-temperature hot air flow needs to be ensured to be in the range of 150-200 ℃.

[0037] The aggregate and the recycled aggregate both include four particle size grades, i.e., particle size ≥19 mm, 16 mm≤particle size<19 mm, 9.5 mm≤particle size<16 mm and 4.75 mm≤particle size<9.5 mm. The river sand includes eight particle size grades, i.e., 4.75 mm≤particle size<9.5 mm, 2.36 mm≤particle size<4.75 mm, 1.18 mm≤particle size<2.36 mm, 0.6 mm≤particle size<1.18 mm, 0.3 mm≤particle size<0.6 mm, 0.15 mm≤particle size<0.3 mm, 0.075 mm≤particle size<0.15 mm and 0 mm≤particle size<0.075 mm. For each particle size grade, the material obtained after the material sequentially passes through the upper and lower two screen holes has a particle size between the upper and lower two screen holes, for example, the particle size is 1.18-2.36 mm (1.18 mm≤particle size<2.36 mm), i.e., the material obtained after the material sequentially passes through 2.36 mm and 1.18 mm screen holes has a particle size between 1.18 mm and 2.36 mm.

[0038] In the process of preparing the modified magnesium oxide, the magnesium oxide is excited by low-temperature calcination; in the process of preparing the calcium hydroxide component, the calcium hydroxide is excited by adding metal oxides and rare earth elements, the metal oxides can enable the calcium hydroxide to absorb more carbon dioxide, and the rare earth elements can enable the absorbed carbon dioxide to generate calcium carbonate crystals and make the calcium carbonate crystals grow uniformly; the carbonization pretreatment of the recycled aggregate of each size range can increase the contact area between the recycled aggregate and the carbon dioxide.

[0039] In the preparation process of the recycled aggregate component, the active carbon capture agent and the microencapsulated material, the selection of each substance, the addition amount of each substance, the addition sequence of each substance and the process parameters of each step are very crucial, and in the whole preparation process of the enhanced recycled aggregate cement concrete, the selection of each substance, the addition amount of each substance, the addition sequence of each substance and the process parameters of each step are also very crucial, only the synergistic effect of each formula parameter and process parameter can achieve the expected technical effect of the present application.

[0040] The enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and the preparation method have the following beneficial effects:

[0041] (1) The recycled aggregate cement concrete obtained by using the material ratio and the preparation process of the present application can not only continuously adsorb and sequester carbon dioxide, but also significantly improve the overall performance of the recycled aggregate cement concrete, such as strength and durability.

[0042] (2) The present application improves the ability of the recycled aggregate cement concrete to continuously inhale carbon dioxide and long-acting carbon sequestration during a long service period by introducing a microencapsulated carbon capture agent.

[0043] (3) The present application enables the recycled aggregate of each size range to have enhanced interfacial bonding performance and high-efficiency carbon dioxide capture ability by carbonization pretreatment, and realizes the dynamic carbon capture and long-acting carbon sequestration ability of the recycled aggregate cement concrete during the service period by combining the carbon capture active agent with the microencapsulated carbon sequestration material.

[0044] (4) The present application solves the problems of low strength and poor interfacial bonding performance of traditional recycled aggregate, and has wide application prospects in the field of green building and low-carbon infrastructure construction. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a flow chart of a preferred embodiment of the preparation method of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration according to the present application;

[0046] Figure 2 is a flow chart of a preferred embodiment of the preparation method of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration according to the present application; Figure 1 is a real photo of the active carbon capture agent prepared in the embodiment shown.

[0047] Figure 3 For Figure 1 Actual photos of microencapsulated materials prepared in the embodiments shown;

[0048] Figure 4 For Figure 1 Actual photos of long-term carbon sequestration enhanced recycled aggregate cement concrete test pieces prepared in the embodiments shown;

[0049] Figure 5 SEM photos of the long-term carbon sequestration enhanced recycled aggregate cement concrete test pieces of Example One after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months;

[0050] Figure 6 SEM photos of the ordinary recycled aggregate cement concrete test pieces of Comparative Example Two after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months;

[0051] Figure 7 XRD photos of the long-term carbon sequestration enhanced recycled aggregate cement concrete test pieces of Example One after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months;

[0052] Figure 8 XRD photos of the ordinary recycled aggregate cement concrete test pieces of Comparative Example Two after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months. DETAILED DESCRIPTION

[0053] In order to further understand the inventive content of the present application, the present application will be described in detail below with specific embodiments.

[0054] Example One:

[0055] According to a preferred embodiment of the enhanced recycled aggregate cement concrete based on long-term carbon sequestration of the present application, the mixing amount of each substance in the enhanced recycled aggregate cement concrete accounts for the mass percentage of the enhanced recycled aggregate cement concrete, which is 47wt% of recycled aggregate component, 3wt% of active carbon capture agent, 1wt% of microencapsulated material, 24wt% of river sand, 1wt% of water reducing agent, 15wt% of cement, 3wt% of auxiliary admixture, and 6wt% of water.

[0056] The mixing amount of each substance in the recycled aggregate component accounts for 50wt% of the mass percentage of the recycled aggregate component, and the aggregate is limestone, and the recycled aggregate is low-brick mixed construction waste recycled aggregate, that is, the construction waste generated by the demolition of concrete buildings, and the brick-mixed content is 5-10wt%.

[0057] The aggregate includes four grades of particle sizes, and each grade of particle size accounts for 10wt% of the mass percentage of the aggregate, 42wt% of the particle size of 16-19mm, 43wt% of the particle size of 9.5-16mm, and 5wt% of the particle size of 4.75-9.5mm; the recycled aggregate includes four grades of particle sizes, and each grade of particle size accounts for 10wt% of the mass percentage of the recycled aggregate, 42wt% of the particle size of 16-19mm, 43wt% of the particle size of 9.5-16mm, and 5wt% of the particle size of 4.75-9.5mm.

[0058] The mixing amount of each substance in the active carbon capture agent accounts for 45wt% of the mass percentage of the active carbon capture agent, 25wt% of the calcium hydroxide component, 15wt% of the silicate, 7wt% of the catalyst, 7wt% of the industrial solid waste, and 1wt% of the trace enhancer.

[0059] The mixing amount of each substance in the calcium hydroxide component accounts for 97wt% of the mass percentage of the calcium hydroxide component, 2wt% of the metal oxide, and 1wt% of the rare earth element, the metal oxide is Al2O3, the rare earth element is Ce, the particle size of the calcium hydroxide, the metal oxide, and the rare earth element is 0.5μm. The silicate is anhydrous sodium silicate, the catalyst is magnesium-aluminum layered double hydroxide, the industrial solid waste is steel slag, and the trace enhancer is a lithium-based compound, and the lithium-based compound is lithium carbonate.

[0060] The mixing amount of each substance in the microencapsulated material accounts for 20wt% of the mass percentage of the microencapsulated material, 60wt% of the polylactic acid, and 20wt% of the silica microspheres, and the mass ratio of the chitosan to the polylactic acid is 1:3, ensuring that the particle size of the silica microspheres is 5μm in the range of 1:2.2-3.

[0061] The river sand includes eight grades of particle sizes, and the mass percentage of each grade of particle size in the river sand is as follows: 7wt% of particle size 4.75-9.5mm, 3wt% of particle size 2.36-4.75mm, 10wt% of particle size 1.18-2.36mm, 20wt% of particle size 0.6-1.18mm, 25wt% of particle size 0.3-0.6mm, 25wt% of particle size 0.15-0.3mm, 5wt% of particle size 0.075-0.15mm, and 5wt% of particle size 0-0.075mm. The water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture is fly ash.

[0062] As shown in Figure 1 The embodiment also provides a preparation method of enhanced recycled aggregate cement concrete based on long-acting carbon sequestration, for preparing the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration, and the preparation method comprises the following steps in sequence:

[0063] Step one: preparing a recycled aggregate component, an active carbon capture agent, and a microencapsulated material according to designed material proportions and process parameters;

[0064] Step two: weighing the recycled aggregate component, the active carbon capture agent, the microencapsulated material, river sand of each grade of particle size, a water reducing agent, cement, an auxiliary admixture, and water for standby according to designed material proportions;

[0065] Step three: adding part of the active carbon capture agent to the microencapsulated material and stirring until the active carbon capture agent is wrapped in the interior of the microencapsulated material to form a microcapsule raw material liquid; using a spray drying method to disperse the microcapsule raw material liquid into fine droplets, and rapidly evaporating a solvent in a high-temperature hot air flow to make solid substances in the microcapsule raw material liquid polymerize and solidify to form microcapsule particles;

[0066] Step four: putting the recycled aggregate component and the remaining part of the active carbon capture agent into a mechanical stirrer to stir, and taking the mixture of the recycled aggregate component and the active carbon capture agent from the mechanical stirrer for standby after uniform stirring;

[0067] Step five: putting the river sand of each grade of particle size, the cement, the mixture of the recycled aggregate component and the active carbon capture agent, and the auxiliary admixture into a mixing pot in sequence to mix, and taking the mixture for standby after uniform mixing;

[0068] Step six: mixing water and the water reducing agent in a container to form a mixed solution of water and the water reducing agent; putting the mixed solution of water and the water reducing agent into the mixing pot to mix with the materials in the mixing pot, and obtaining an enhanced recycled aggregate cement concrete slurry based on carbon sequestration after uniform mixing;

[0069] Step seven: the obtained carbon sequestration-based enhanced recycled aggregate cement concrete slurry is taken out of the mixing pot and placed in a storage container while being manually mixed; after manual mixing is completed, the carbon sequestration-based enhanced recycled aggregate cement concrete slurry is filled into a test specimen forming mold, and the upper surface of the slurry in the test specimen forming mold is leveled using a scraper, then a portion of the microcapsule particles is evenly spread on the upper surface of the slurry, and the upper surface of the microcapsule particles is leveled using a scraper;

[0070] Step eight: the test specimen forming mold is placed on an electric vibrating table, and the electric vibrating table is started to begin vibration forming; during vibration forming, if recesses appear, the carbon sequestration-based enhanced recycled aggregate cement concrete slurry is supplemented at the recessed positions; after vibration forming is completed, the test specimen forming mold and the slurry that has been formed inside are left to stand for a certain period of time before being demolded, then placed in a standard curing chamber for curing, and a carbon sequestration-based enhanced recycled aggregate cement concrete test specimen is obtained;

[0071] Step nine: the remaining microcapsule particles are dissolved in anhydrous ethanol to form a suspension; the suspension is stirred uniformly and coated uniformly on the outer surface of the carbon sequestration-based enhanced recycled aggregate cement concrete test specimen, and a long-acting carbon sequestration-based enhanced recycled aggregate cement concrete test specimen is obtained.

[0072] In step one, the preparation process of the recycled aggregate component is as follows: first, the construction waste generated by the demolition of concrete buildings is crushed and washed, and is sieved according to the designed particle size grades to obtain recycled aggregates of various particle sizes; then, the recycled aggregates of various particle sizes are weighed according to the designed material ratio, and are subjected to carbonization pretreatment, that is, the recycled aggregates of various particle sizes are soaked in a 5% sodium carbonate solution, the sodium carbonate solution can just cover the recycled aggregates of various particle sizes, the soaking temperature is room temperature, and the soaking time is 1.5 h; after soaking is completed, melamine is added to the sodium carbonate solution and the recycled aggregates of various particle sizes and is stirred, the addition amount of melamine is 0.8 wt% of the total mass of the recycled aggregates, the stirring temperature is room temperature, and the stirring time is 0.8 h; after stirring is completed, the carbonization pretreatment of the recycled aggregates is completed; finally, the aggregates of various particle sizes are weighed according to the designed material ratio, and the aggregates of various particle sizes and the recycled aggregates of various particle sizes subjected to carbonization pretreatment are mixed uniformly, and the recycled aggregate component is obtained.

[0073] In step one, the preparation process of the active carbon capture agent is as follows: first, modified magnesium oxide is prepared by placing magnesium oxide into a calcining furnace for low-temperature calcination at a temperature of 800 DEG C for 4 hours, washing and purifying the calcined magnesium oxide, and drying the washed and purified magnesium oxide in an oven at a temperature of 90 DEG C for 2.5 hours; then, an alkali carbonate is added to the dried magnesium oxide and mixed uniformly to obtain modified magnesium oxide, the alkali carbonate being lithium carbonate and the amount of the alkali carbonate being 2wt% of the mass of the modified magnesium oxide; second, a calcium hydroxide component is prepared by mixing calcium hydroxide, metal oxides, and rare earth elements uniformly at room temperature according to the designed material ratio; third, the modified magnesium oxide, the calcium hydroxide component, silicates, a catalyst, industrial solid waste, and a trace enhancer are mixed uniformly at room temperature according to the designed material ratio, and the mixed materials are subjected to ball milling to obtain a solid powder with a particle size of less than 5 μm; and finally, the solid powder is dried in an oven at a temperature of 90 DEG C for 2.5 hours to obtain the active carbon capture agent.

[0074] In step one, the preparation process of the microencapsulated material is as follows: first, chitosan, polylactic acid, and silica microspheres are weighed according to the designed material ratio and reserved; then, the chitosan and the polylactic acid are mixed uniformly and dissolved in anhydrous ethanol to form a solution, the mass of the anhydrous ethanol being 25 times the total mass of the chitosan and the polylactic acid; and finally, the silica microspheres are added to the solution and stirred uniformly to obtain the microencapsulated material.

[0075] In step three, the mass of the part of the active carbon capture agent is 45wt% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 180 DEG C, and the particle size of the microcapsule particles is 110 μm.

[0076] In step four, the mass of the remaining part of the active carbon capture agent is 55wt% of the total mass of the active carbon capture agent, the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 150 rpm, and the stirring time is 5 minutes.

[0077] In step five, the stirring temperature of the stirring pot is room temperature, the stirring speed is 50 rpm, and the stirring time is 75 seconds.

[0078] In step six, the stirring temperature of the stirring pot is room temperature, the stirring speed is 50 rpm, and the stirring time is 3.5 minutes.

[0079] In step seven, the stirring temperature of the manual stirring is room temperature, the stirring time is 1.5 minutes, the length of the inner cavity of the test piece forming mold is 100 mm, the width is 100 mm, the height is 100 mm, and the mass of the part of the microcapsule particles is 25wt% of the total mass of the microcapsule particles.

[0080] In step eight, the standing temperature is room temperature, and the standing time is 24 h; the curing time is 28 days.

[0081] In step nine, the mass of the remaining portion of the microcapsule particles is 75 wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 25 times the mass of the remaining portion of the microcapsule particles.

[0082] In this embodiment, the actual photos of the prepared activated carbon capture agent are as shown in Figure 2 The actual photos of the prepared microencapsulated material are as shown in Figure 3 The actual photos of the prepared long-acting carbon sequestration enhanced recycled aggregate cement concrete test piece are as shown in Figure 4

[0083] In this embodiment, the mechanical stirrer, mixing pot, electric vibration table, calcining furnace, oven and the like used are conventional devices in the art, and there are no special requirements for the model, structure and the like of the devices; the spray drying method used is also a conventional method in the art, and there are no special requirements for the process flow and process parameters, as long as the temperature of the high-temperature hot air flow is in the range of 150-200 ℃.

[0084] The aggregate and the recycled aggregate both include four particle size grades, i.e., particle size ≥ 19 mm, 16 mm ≤ particle size < 19 mm, 9.5 mm ≤ particle size < 16 mm, and 4.75 mm ≤ particle size < 9.5 mm. The river sand includes eight particle size grades, i.e., 4.75 mm ≤ particle size < 9.5 mm, 2.36 mm ≤ particle size < 4.75 mm, 1.18 mm ≤ particle size < 2.36 mm, 0.6 mm ≤ particle size < 1.18 mm, 0.3 mm ≤ particle size < 0.6 mm, 0.15 mm ≤ particle size < 0.3 mm, 0.075 mm ≤ particle size < 0.15 mm, and 0 mm ≤ particle size < 0.075 mm. For each particle size grade, the material obtained after the material passes through the upper and lower two screen holes in turn has a particle size between the upper and lower two screen holes, for example, the particle size is 1.18-2.36 mm (1.18 mm ≤ particle size < 2.36 mm), i.e., the material obtained after the material passes through the 2.36 mm screen hole and the 1.18 mm screen hole in turn has a particle size between 1.18 mm and 2.36 mm.

[0085] ​In the process of preparing the modified magnesium oxide, the magnesium oxide is excited by low-temperature calcination; in the process of preparing the calcium hydroxide component, the calcium hydroxide is excited by adding metal oxides and rare earth elements, the metal oxides can enable the calcium hydroxide to absorb more carbon dioxide, and the rare earth elements can enable the absorbed carbon dioxide to generate calcium carbonate crystals and make the calcium carbonate crystals grow uniformly; the carbonization pretreatment of the recycled aggregate of each size range can increase the contact area between the recycled aggregate and the carbon dioxide.

[0086] In the preparation process of the recycled aggregate component, the active carbon capture agent, and the microencapsulated material, the selection of each substance, the addition amount of each substance, the addition sequence of each substance, and the process parameters of each step are very critical. Meanwhile, in the entire preparation process of the enhanced recycled aggregate cement concrete, the selection of each substance, the addition amount of each substance, the addition sequence of each substance, and the process parameters of each step are also very critical. Only the synergistic effect of each formula parameter and process parameter can achieve the technical effect expected by the embodiment.

[0087] The enhanced recycled aggregate cement concrete based on long-term carbon sequestration and the preparation method have the following beneficial effects:

[0088] (1) The prepared recycled aggregate cement concrete not only can continuously adsorb and sequester carbon dioxide, but also can significantly improve the overall performance of the recycled aggregate cement concrete, such as strength and durability.(2) By introducing the microencapsulated carbon capture agent, the ability of the recycled aggregate cement concrete to continuously inhale carbon dioxide and long-term carbon sequestration during a long service period is improved.(3) By carbonization pretreatment of the recycled aggregate of each size range, the recycled aggregate has the ability to enhance the interfacial bonding performance and efficiently capture carbon dioxide; meanwhile, the combination of the carbon capture active agent and the microencapsulated carbon sequestration material realizes the dynamic carbon capture and long-term carbon sequestration ability of the recycled aggregate cement concrete during the service period.

[0089] Embodiment Two:

[0090] According to another preferred embodiment of the enhanced recycled aggregate cement concrete based on long-term carbon sequestration and the preparation method, the material ratio, the preparation process, the technical principle, the used equipment, and the beneficial effects are basically the same as those of Embodiment One, except that:

[0091] The addition amount of each substance in the enhanced recycled aggregate cement concrete accounts for 45wt% of the mass percentage of the enhanced recycled aggregate cement concrete, 2wt% of the active carbon capture agent, 1wt% of the microencapsulated material, 24wt% of the river sand, 0.8wt% of the water reducing agent, 18wt% of the cement, 1.2wt% of the auxiliary admixture, and 8wt% of the water.

[0092] The mixing amount of each substance in the recycled aggregate component accounts for 40wt% of the aggregate, 60wt% of the recycled aggregate; the aggregate is limestone, and the recycled aggregate is low-brick mixed construction waste recycled aggregate, that is, construction waste generated by the demolition of concrete buildings, with a brick-mixed content of 5-10wt%. The aggregate includes four grades of particle size, each accounting for 11wt% of the aggregate, 50wt% of the aggregate, 35wt% of the aggregate, and 4wt% of the aggregate, respectively. The recycled aggregate includes four grades of particle size, each accounting for 11wt% of the recycled aggregate, 50wt% of the recycled aggregate, 35wt% of the recycled aggregate, and 4wt% of the recycled aggregate, respectively.

[0093] The mixing amount of each substance in the active carbon capture agent accounts for 40wt% of the modified magnesium oxide, 20wt% of the calcium hydroxide component, 20wt% of the silicate, 10wt% of the catalyst, 8wt% of the industrial solid waste, and 2wt% of the trace enhancer. The mixing amount of each substance in the calcium hydroxide component accounts for 95wt% of the calcium hydroxide, 3wt% of the metal oxide, and 2wt% of the rare earth element. The metal oxide is Al2O3, and the rare earth element is Ce. The particle size of the calcium hydroxide, the metal oxide, and the rare earth element is 1μm. The silicate is anhydrous sodium silicate, the catalyst is magnesium-aluminum layered double hydroxide, the industrial solid waste is steel slag, and the trace enhancer is a lithium-based compound, which is lithium carbonate.

[0094] The mixing amount of each substance in the microencapsulated material accounts for 25wt% of the chitosan, 55wt% of the polylactic acid, and 20wt% of the silica microspheres. The ratio of the mass of the chitosan to the mass of the polylactic acid is 1:2.2, ensuring that the particle size of the silica microspheres is 10μm within the range of 1:2.2-3.

[0095] The river sand includes eight grades of particle sizes, and the mass percentage of each grade of particle size in the river sand is as follows: 8wt% for a particle size of 4.75-9.5 mm, 4wt% for a particle size of 2.36-4.75 mm, 13wt% for a particle size of 1.18-2.36 mm, 15wt% for a particle size of 0.6-1.18 mm, 32wt% for a particle size of 0.3-0.6 mm, 20wt% for a particle size of 0.15-0.3 mm, 4wt% for a particle size of 0.075-0.15 mm, and 4wt% for a particle size of 0-0.075 mm. The water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture is fly ash.

[0096] In step one, in the preparation process of the recycled aggregate component: the recycled aggregate of each grade of particle size is soaked in a sodium carbonate solution with a concentration of 5%, the sodium carbonate solution can just cover the recycled aggregate of each grade of particle size, the soaking temperature is room temperature, and the soaking time is 2 hours. After the soaking is completed, melamine is added to the sodium carbonate solution and the recycled aggregate of each grade of particle size and stirring is performed, the addition amount of melamine is 1wt% of the total mass of the recycled aggregate, the stirring temperature is room temperature, and the stirring time is 1 hour. After the stirring is completed, the carbonization pretreatment of the recycled aggregate is completed.

[0097] In the preparation process of the active carbon capture agent: first, modified magnesium oxide is prepared, that is, the magnesium oxide is placed in a calcining furnace for low-temperature calcination, the calcination temperature is 900°C, and the calcination time is 3 hours. The calcined magnesium oxide is washed and purified, and then placed in an oven for drying treatment, the drying temperature is 100°C, and the drying time is 2 hours. Alkaline carbonate is added to the dried magnesium oxide and uniformly mixed to obtain the modified magnesium oxide. The addition amount of the alkaline carbonate is 3wt% of the mass of the modified magnesium oxide, and the alkaline carbonate is lithium carbonate. Finally, the solid powder is placed in an oven for drying treatment, the drying temperature is 100°C, and the drying time is 2 hours. After the drying treatment is completed, the active carbon capture agent is obtained.

[0098] In the preparation process of the microencapsulated material: the chitosan and polylactic acid are uniformly mixed and then dissolved in anhydrous ethanol to form a solution. The mass of the anhydrous ethanol is 30 times the total mass of the chitosan and polylactic acid.

[0099] In step three, the mass of the part of the active carbon capture agent is 50wt% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 200°C, and the particle size of the microcapsule particles is 120μm.

[0100] In step four, the mass of the remaining part of the active carbon capture agent is 50wt% of the total mass of the active carbon capture agent, the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 180rpm, and the stirring time is 4 minutes.

[0101] In step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 60 rpm, and the mixing time is 60 s.

[0102] In step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 60 rpm, and the mixing time is 3 min.

[0103] In step seven, the mixing temperature is room temperature, and the mixing time is 2 min; the length, width, and height of the inner cavity of the test piece forming mold are 100 mm, 100 mm, and 100 mm, respectively; and the mass of the part of the microcapsule particles is 30 wt% of the total mass of the microcapsule particles.

[0104] In step eight, the standing temperature is room temperature, and the standing time is 24 h; the curing time is 28 days.

[0105] In step nine, the mass of the remaining part of the microcapsule particles is 70 wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 30 times the mass of the remaining part of the microcapsule particles.

[0106] Example Three:

[0107] According to another preferred embodiment of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and the preparation method, the material ratio, the preparation process, the technical principle, the used equipment, and the beneficial effects are basically the same as those of example one, except that:

[0108] The mixing amount of each substance in the enhanced recycled aggregate cement concrete accounts for 48 wt% of the mass percentage of the enhanced recycled aggregate cement concrete, 3.5 wt% of the active carbon capture agent, 1.5 wt% of the microencapsulated material, 24 wt% of the river sand, 0.8 wt% of the water reducing agent, 15 wt% of the cement, 1.2 wt% of the auxiliary admixture, and 6 wt% of the water.

[0109] The mixing amount of each substance in the recycled aggregate component accounts for 60 wt% of the mass percentage of the recycled aggregate component, and 40 wt% of the recycled aggregate; the aggregate is basalt, and the recycled aggregate is low-brick mixed construction waste recycled aggregate, that is, the construction waste generated by the demolition of concrete buildings, and the brick-mixed content is 5-10 wt%. The aggregate includes four particle sizes, and each particle size accounts for 8 wt% of the mass percentage of the aggregate, 35 wt% of the particle size of 16-19 mm, 51 wt% of the particle size of 9.5-16 mm, and 6 wt% of the particle size of 4.75-9.5 mm; the recycled aggregate includes four particle sizes, and each particle size accounts for 8 wt% of the mass percentage of the recycled aggregate, 35 wt% of the particle size of 16-19 mm, 51 wt% of the particle size of 9.5-16 mm, and 6 wt% of the particle size of 4.75-9.5 mm.

[0110] The adding amount of each substance in the active carbon capture agent accounts for 50wt% of the mass percentage of the active carbon capture agent, modified magnesium oxide 50wt%, calcium hydroxide component 27wt%, silicate 10wt%, catalyst 5wt%, industrial solid waste 5wt%, trace enhancer 3wt%. The adding amount of each substance in the calcium hydroxide component accounts for 98.5wt% of the mass percentage of the calcium hydroxide component, calcium hydroxide 98.5wt%, metal oxide 1wt%, rare earth element 1.5wt%, the metal oxide is Fe2O3, the rare earth element is La, the particle size of the calcium hydroxide, the metal oxide and the rare earth element is 0.1μm. The silicate is potassium silicate, the catalyst is hydrated magnesium carbonate aluminate, the industrial solid waste is desulfurization gypsum, and the trace enhancer is a lithium-based compound, which is lithium hydroxide.

[0111] The adding amount of each substance in the microencapsulated material accounts for 22wt% of the mass percentage of the microencapsulated material, chitosan 22wt%, polylactic acid 57wt%, and silica microspheres 21wt%, and the mass ratio of the chitosan to the polylactic acid is 1:2.59, ensuring that the particle size of the silica microspheres is 1μm within the range of 1:2.2-3.

[0112] The river sand includes eight grades of particle size, each accounting for 9wt% of the mass percentage of the river sand, particle size 4.75-9.5mm 9wt%, particle size 2.36-4.75mm 5wt%, particle size 1.18-2.36mm 10wt%, particle size 0.6-1.18mm 20wt%, particle size 0.3-0.6mm 28wt%, particle size 0.15-0.3mm 20wt%, particle size 0.075-0.15mm 4wt%, and particle size 0-0.075mm 4wt%. The water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture is slag powder.

[0113] In step one, during the preparation of the recycled aggregate component: each grade of recycled aggregate is soaked in a 5% sodium carbonate solution, the sodium carbonate solution can cover each grade of recycled aggregate, the soaking temperature is room temperature, and the soaking time is 1h. After soaking, melamine is added to the sodium carbonate solution and each grade of recycled aggregate and stirred, the amount of melamine added is 0.5wt% of the total mass of the recycled aggregate, the stirring temperature is room temperature, and the stirring time is 0.5h. After stirring, the carbonization pretreatment of the recycled aggregate is completed.

[0114] In the preparation process of the active carbon capture agent: first, modified magnesium oxide is prepared, i.e. the magnesium oxide is put into a calcining furnace for low-temperature calcination, the calcination temperature is 700℃, the calcination time is 5h, the calcined magnesium oxide is washed and purified, the washed and purified magnesium oxide is put into an oven for drying treatment, the drying temperature is 80℃, the drying time is 3h, the alkali carbonate is added to the dried magnesium oxide and mixed uniformly to obtain the modified magnesium oxide, the addition amount of the alkali carbonate is 1wt% of the mass of the modified magnesium oxide, and the alkali carbonate is potassium carbonate; finally, the solid powder is put into an oven for drying treatment, the drying temperature is 80℃, the drying time is 3h, and after the drying treatment is completed, the active carbon capture agent can be obtained.

[0115] In the preparation process of the microcapsulated material: the chitosan and polylactic acid are mixed uniformly and then dissolved in anhydrous ethanol to form a solution, and the mass of the anhydrous ethanol is 20 times the total mass of the chitosan and polylactic acid.

[0116] In step three, the mass of the part of the active carbon capture agent is 40wt% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 150℃, and the particle size of the microcapsule particles is 100μm.

[0117] In step four, the mass of the remaining part of the active carbon capture agent is 60wt% of the total mass of the active carbon capture agent, the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 120rpm, and the stirring time is 6min.

[0118] In step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40rpm, and the mixing time is 90s.

[0119] In step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40rpm, and the mixing time is 4min.

[0120] In step seven, the mixing temperature of the manual mixing is room temperature, the mixing time is 1min, the length of the inner cavity of the test piece forming mold is 100mm, the width is 100mm, the height is 100mm, and the mass of the part of the microcapsule particles is 20wt% of the total mass of the microcapsule particles.

[0121] In step eight, the standing temperature is room temperature, and the standing time is 24h; the curing time is 28 days.

[0122] In step nine, the mass of the remaining part of the microcapsule particles is 80wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 20 times the mass of the remaining part of the microcapsule particles.

[0123] Example four:

[0124] Another preferred embodiment of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration according to the present application is basically the same as the first embodiment in material ratio, preparation process, technical principle, equipment used, and beneficial effects, except that:

[0125] The mixing amount of each substance in the enhanced recycled aggregate cement concrete accounts for 46wt% of the recycled aggregate component, 5wt% of the active carbon capture agent, 2wt% of the microencapsulated material, 24wt% of the river sand, 0.8wt% of the water reducing agent, 15wt% of the cement, 1.2wt% of the auxiliary admixture, and 6wt% of the water.

[0126] The mixing amount of each substance in the recycled aggregate component accounts for 45wt% of the aggregate and 55wt% of the recycled aggregate. The aggregate is diabase, and the recycled aggregate is low-brick mixed construction waste recycled aggregate, i.e., construction waste generated by the demolition of concrete buildings, with a brick-mixed content of 5-10wt%. The aggregate includes four particle sizes, each accounting for 9wt% of the aggregate with a particle size of 19mm or more, 46wt% of the aggregate with a particle size of 16-19mm, 39wt% of the aggregate with a particle size of 9.5-16mm, and 6wt% of the aggregate with a particle size of 4.75-9.5mm. The recycled aggregate includes four particle sizes, each accounting for 9wt% of the recycled aggregate with a particle size of 19mm or more, 46wt% of the recycled aggregate with a particle size of 16-19mm, 39wt% of the recycled aggregate with a particle size of 9.5-16mm, and 6wt% of the recycled aggregate with a particle size of 4.75-9.5mm.

[0127] The mixing amount of each substance in the active carbon capture agent accounts for 47wt% of the modified magnesium oxide, 22wt% of the calcium hydroxide component, 17wt% of the silicate, 8wt% of the catalyst, 5wt% of the industrial solid waste, and 1wt% of the trace enhancer. The mixing amount of each substance in the calcium hydroxide component accounts for 98wt% of calcium hydroxide, 1.5wt% of metal oxide, and 0.5wt% of rare earth elements. The metal oxide is Al2O3, and the rare earth elements are Ce. The particle sizes of the calcium hydroxide, the metal oxide, and the rare earth elements are all 0.8μm. The silicate is sodium-potassium silicate, the catalyst is titanium oxide, the industrial solid waste is steel slag, and the trace enhancer is a manganese-based compound, which is manganese dioxide.

[0128] The mixing amount of each substance in the microencapsulated material accounts for 20wt% of the mass percentage of the microencapsulated material, 50wt% of polylactic acid, 30wt% of silica microspheres, and the mass ratio of the chitosan to the polylactic acid is 1:2.5, ensuring that the particle size of the silica microspheres is 8μm in the range of 1:2.2-3.

[0129] The river sand includes eight grades of particle sizes, and each grade accounts for 7wt% of the mass percentage of the river sand, 3wt% of the particle size of 2.36-4.75mm, 10wt% of the particle size of 1.18-2.36mm, 15wt% of the particle size of 0.6-1.18mm, 33wt% of the particle size of 0.3-0.6mm, 20wt% of the particle size of 0.15-0.3mm, 6wt% of the particle size of 0.075-0.15mm, and 6wt% of the particle size of 0-0.075mm. The water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture is silica fume.

[0130] In step one, during the preparation of the recycled aggregate component: the recycled aggregate of each grade of particle size is soaked in a 5% sodium carbonate solution, the sodium carbonate solution can just cover the recycled aggregate of each grade of particle size, the soaking temperature is room temperature, the soaking time is 1.8h, after the soaking is completed, melamine is added to the sodium carbonate solution and the recycled aggregate of each grade of particle size and stirring is performed, the addition amount of melamine is 0.9wt% of the total mass of the recycled aggregate, the stirring temperature is room temperature, and the stirring time is 0.9h, after the stirring is completed, the carbonization pretreatment of the recycled aggregate is completed.

[0131] In the preparation process of the active carbon capture agent: first, modified magnesium oxide is prepared, that is, the magnesium oxide is placed in a calcining furnace for low-temperature calcination, the calcination temperature is 850℃, the calcination time is 3.5h, the calcined magnesium oxide is washed and purified, the washed and purified magnesium oxide is placed in an oven for drying treatment, the drying temperature is 95℃, the drying time is 2.8h, the alkali carbonate is added to the dried magnesium oxide and mixed uniformly to obtain the modified magnesium oxide, the addition amount of the alkali carbonate is 2.5wt% of the mass of the modified magnesium oxide, and the alkali carbonate is lithium carbonate; finally, the solid powder is placed in an oven for drying treatment, the drying temperature is 95℃, the drying time is 2.8h, and after the drying treatment is completed, the active carbon capture agent can be obtained.

[0132] In the preparation process of the microencapsulated material: the chitosan and the polylactic acid are mixed uniformly and then dissolved in anhydrous ethanol to form a solution, and the mass of the anhydrous ethanol is 28 times the total mass of the chitosan and the polylactic acid.

[0133] In step three, the mass of the partial active carbon capture agent is 48% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 190 DEG C, and the particle size of the microcapsule particles is 115 microns.

[0134] In step four, the mass of the remaining partial active carbon capture agent is 52% of the total mass of the active carbon capture agent, the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 165 rpm, and the stirring time is 4.5 minutes.

[0135] In step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 55 rpm, and the mixing time is 70 seconds.

[0136] In step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 55 rpm, and the mixing time is 3.2 minutes.

[0137] In step seven, the mixing temperature of the manual mixing is room temperature, the mixing time is 1.8 minutes, the length of the inner cavity of the test piece forming mold is 100 mm, the width is 100 mm, the height is 100 mm, and the mass of the partial microcapsule particles is 28% of the total mass of the microcapsule particles.

[0138] In step eight, the standing temperature is room temperature, the standing time is 24 hours, and the curing time is 28 days.

[0139] In step nine, the mass of the remaining partial microcapsule particles is 72% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 28 times the mass of the remaining partial microcapsule particles.

[0140] Example five:

[0141] According to another preferred embodiment of the application, the material ratio, preparation process, technical principle, equipment used, and beneficial effects of the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and the preparation method are basically the same as those of example one, except that:

[0142] The mixing amount of each substance in the enhanced recycled aggregate cement concrete is 48% of the mass percentage of the enhanced recycled aggregate cement concrete, the recycled aggregate component is 48%, the active carbon capture agent is 2.5%, the microencapsulated material is 1.5%, the river sand is 24%, the water reducing agent is 1.2%, the cement is 15%, the auxiliary admixture is 1.8%, and the water is 6%.

[0143] The mixing amount of each substance in the recycled aggregate component accounts for 40wt% of the aggregate, 60wt% of the recycled aggregate; the aggregate is limestone, and the recycled aggregate is low-brick mixed construction waste recycled aggregate, that is, the construction waste generated by the demolition of concrete buildings, with a brick-mixed content of 5-10wt%. The aggregate includes four grades of particle size, each accounting for 11wt% of the aggregate, 40wt% of the aggregate, 45wt% of the aggregate, and 4wt% of the aggregate, respectively. The recycled aggregate includes four grades of particle size, each accounting for 11wt% of the recycled aggregate, 40wt% of the recycled aggregate, 45wt% of the recycled aggregate, and 4wt% of the recycled aggregate, respectively.

[0144] The mixing amount of each substance in the active carbon capture agent accounts for 43wt% of the modified magnesium oxide, 30wt% of the calcium hydroxide component, 12wt% of the silicate, 6wt% of the catalyst, 6wt% of the industrial solid waste, and 3wt% of the trace enhancer. The mixing amount of each substance in the calcium hydroxide component accounts for 96wt% of calcium hydroxide, 2.5wt% of metal oxide, and 1.5wt% of rare earth elements. The metal oxide is Al2O3, and the rare earth element is Ce. The particle size of the calcium hydroxide, the metal oxide, and the rare earth element is 0.4μm. The silicate is anhydrous sodium silicate, the catalyst is magnesium-aluminum layered double hydroxide, the industrial solid waste is steel slag, and the trace enhancer is a manganese-based compound, which is potassium manganate.

[0145] The mixing amount of each substance in the microencapsulated material accounts for 20wt% of chitosan, 56wt% of polylactic acid, and 24wt% of silica microspheres, and the ratio of the mass of the chitosan to the mass of the polylactic acid is 1:2.8, ensuring that the particle size of the silica microspheres is 4μm within the range of 1:2.2-3.

[0146] The river sand includes eight grades of particle sizes, and the mass percentage of each grade of particle size in the river sand is as follows: 8wt% for a particle size of 4.75-9.5mm, 4wt% for a particle size of 2.36-4.75mm, 15wt% for a particle size of 1.18-2.36mm, 18wt% for a particle size of 0.6-1.18mm, 25wt% for a particle size of 0.3-0.6mm, 22wt% for a particle size of 0.15-0.3mm, 4wt% for a particle size of 0.075-0.15mm, and 4wt% for a particle size of 0-0.075mm. The water reducing agent is a high-performance polycarboxylic acid water reducing agent, the cement is P.O 42.5 ordinary portland cement, and the auxiliary admixture is fly ash.

[0147] In step one, in the preparation process of the recycled aggregate component: the recycled aggregate of each grade of particle size is soaked in a sodium carbonate solution with a concentration of 5%, the sodium carbonate solution can just cover the recycled aggregate of each grade of particle size, the soaking temperature is room temperature, and the soaking time is 1.2h; after the soaking is completed, melamine is added to the sodium carbonate solution and the recycled aggregate of each grade of particle size and stirring is performed, the addition amount of melamine is 0.6wt% of the total mass of the recycled aggregate, the stirring temperature is room temperature, and the stirring time is 0.6h; after the stirring is completed, the carbonization pretreatment of the recycled aggregate is completed.

[0148] In the preparation process of the active carbon capture agent: first, modified magnesium oxide is prepared, that is, the magnesium oxide is placed into a calcining furnace for low-temperature calcination, the calcination temperature is 750℃, and the calcination time is 4.5h; the calcined magnesium oxide is washed and purified, and the washed and purified magnesium oxide is placed into an oven for drying treatment, the drying temperature is 85℃, and the drying time is 2.2h; the alkali carbonate is added to the dried magnesium oxide and uniformly mixed to obtain the modified magnesium oxide, the addition amount of the alkali carbonate is 1.5wt% of the mass of the modified magnesium oxide, and the alkali carbonate is lithium carbonate; finally, the solid powder is placed into an oven for drying treatment, the drying temperature is 85℃, and the drying time is 2.2h; after the drying treatment is completed, the active carbon capture agent can be obtained.

[0149] In the preparation process of the microencapsulated material: the chitosan and polylactic acid are uniformly mixed and then dissolved in anhydrous ethanol to form a solution, and the mass of the anhydrous ethanol is 22 times the total mass of the chitosan and polylactic acid.

[0150] In step three, the mass of the part of the active carbon capture agent is 42wt% of the total mass of the active carbon capture agent, the temperature of the high-temperature hot air flow is 170℃, and the particle size of the microcapsule particles is 105μm.

[0151] In step four, the mass of the remaining part of the active carbon capture agent is 58wt% of the total mass of the active carbon capture agent; the stirring temperature of the mechanical stirrer is room temperature, the stirring speed is 135rpm, and the stirring time is 5.5min.

[0152] In step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 45 rpm, and the mixing time is 80 s.

[0153] In step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 45 rpm, and the mixing time is 3.8 min.

[0154] In step seven, the mixing temperature of manual mixing is room temperature, and the mixing time is 1.2 min; the length of the inner cavity of the test piece forming mold is 100 mm, the width is 100 mm, and the height is 100 mm; the mass of the part of the microcapsule particles is 22 wt% of the total mass of the microcapsule particles.

[0155] In step eight, the standing temperature is room temperature, and the standing time is 24 h; the curing time is 28 days.

[0156] In step nine, the mass of the remaining part of the microcapsule particles is 78 wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 22 times the mass of the remaining part of the microcapsule particles.

[0157] Comparative Example One:

[0158] This comparative example is a natural aggregate cement concrete, which is composed of aggregate, river sand, water reducing agent, cement, auxiliary admixture and water, without adding recycled aggregate, activated carbon capture agent and microencapsulated material. The mass percentage of each substance in the natural aggregate cement concrete is as follows: aggregate 45-50 wt%, river sand 24-28 wt%, water reducing agent 0.8-1.2 wt%, cement 15-18 wt%, auxiliary admixture 1.2-4.8 wt%, and water 6-9 wt%. The specific substances selected, the gradation of the aggregate, the gradation of the river sand, etc. are all the same as in Example One; the preparation process and process parameters of the natural aggregate cement concrete are also basically the same as in Example One, except that the preparation steps of the recycled aggregate component, the activated carbon capture agent, and the microencapsulated material are deleted.

[0159] Comparative Example Two:

[0160] The comparative example is a common recycled aggregate cement concrete, which is composed of recycled aggregate component, river sand, water reducing agent, cement, auxiliary admixture and water, and does not contain active carbon capture agent and microencapsulated material. The mass percentage of each substance in the common recycled aggregate cement concrete is 45-50wt% of recycled aggregate component, 24-28wt% of river sand, 0.8-1.2wt% of water reducing agent, 15-18wt% of cement, 1.2-4.8wt% of auxiliary admixture, and 6-9wt% of water. The mass percentage of each substance in the recycled aggregate component is 40-60wt% of aggregate and 40-60wt% of recycled aggregate. The specific substances, the gradation of recycled aggregate, the gradation of aggregate, the gradation of river sand, etc. are all the same as those of Example One. The preparation process and process parameters of the common recycled aggregate cement concrete are also basically the same as those of Example One, except that the preparation steps of the active carbon capture agent and the microencapsulated material are deleted.

[0161] The compressive strength test, the splitting tensile strength test, the elastic modulus test, the SEM test and the XRD test were performed on the above five examples and two comparative examples, and the test equipment, test environment, test conditions, sample shape and size were the same.

[0162] After the test pieces were standardly cured for 28 days, the compressive strength test, the splitting tensile strength test and the elastic modulus test were performed, and the test temperature of the three tests was room temperature. The speed of the compressive strength test was 0.6MPa / s, the speed of the splitting tensile strength test was 0.06MPa / s, and the speed of the elastic modulus test was 0.5MPa / s. Three parallel tests were performed for each example and comparative example, and the average value was taken finally. The average value of the test results is shown in Table 1.

[0163] Table 1 Test results of compressive strength, splitting tensile strength and elastic modulus (average value)

[0164]

[0165] As can be seen from the test results in Table 1, the compressive strength, the splitting tensile strength and the elastic modulus of the long-acting carbon sequestration enhanced recycled aggregate cement concrete of the five examples are close to those of the natural aggregate cement concrete of Comparative Example One, and compared with the common recycled aggregate cement concrete of Comparative Example Two, the compressive strength is increased by at least 17.98%, the splitting tensile strength is increased by at least 41.78%, and the elastic modulus is increased by at least 25.25%. After the long-acting carbon sequestration, the long-acting carbon sequestration enhanced recycled aggregate cement concrete of the five examples improves the strength of the cement concrete, that is, the recycled aggregate is fully utilized, and the mechanical properties are ensured to be close to those of the natural aggregate cement concrete.

[0166] After the test pieces were standardly cured for 28 days and exposed outdoors for 6 months, the SEM test and the XRD test were performed, respectively. Figure 5SEM photos of the long-term carbon sequestration enhanced recycled aggregate cement concrete specimen of Example 1 after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months. Figure 6 SEM photos of the ordinary recycled aggregate cement concrete specimen of Comparative Example 2 after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months.

[0167] From Figure 5 and Figure 6 It can be seen that in the ordinary recycled aggregate cement concrete of Comparative Example 2, the interface transition zone is relatively weak, the mechanical fracture section increases with time, the carbonation process is slow, the ettringite filling in the crack is limited, and there is unhydrated Ca(OH)2 and hydrated calcium silicate C-S-H. In contrast, although the long-term carbon sequestration enhanced recycled aggregate cement concrete of Example 1 also has cracks, it benefits from the improvement of carbon capture capacity, CO2 penetration promotes the reaction of cement components and recycled aggregate to generate calcium carbonate, which can effectively repair pores and cracks; after 6 months of outdoor exposure, the carbonation continues, C-S-H becomes the dominant reactant, and is converted into cubic calcium carbonate and fine needle ettringite, further filling the interface cracks. With the decrease of carbonation reactants, the carbon sequestration capacity gradually tends to be saturated; this process demonstrates the self-repairing and carbon fixation mechanism of long-term carbon sequestration enhanced recycled aggregate cement concrete under carbonation.

[0168] Figure 7 XRD photos of the long-term carbon sequestration enhanced recycled aggregate cement concrete specimen of Example 1 after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months; Figure 8 XRD photos of the ordinary recycled aggregate cement concrete specimen of Comparative Example 2 after standard curing for 28 days and outdoor exposure for 6 months, wherein: (a) is standard curing for 28 days, (b) is outdoor exposure for 6 months. The vertical coordinate in the figure is the diffraction intensity, which is proportional to the content of the substance. From Figure 7 and Figure 8 It can be seen that with the extension of outdoor exposure time, the content of CaCO3 in the ordinary recycled aggregate cement concrete of Comparative Example 2 increases; in contrast, the content of CaCO3 in the long-term carbon sequestration enhanced recycled aggregate cement concrete of Example 1 is higher at the same stage, which indicates that it has good carbon capture and carbon sequestration capacity, and the proportion of CaCO3 continues to increase after 6 months of outdoor exposure, which indicates that it has long-term carbon sequestration capacity.

[0169] In the above examples and comparative examples, the raw materials such as aggregate, cement, auxiliary admixture, river sand, water reducing agent, etc. are purchased from Beijing Municipal Road and Bridge Building Material Group Co., Ltd.; the recycled aggregate is purchased from Beijing Urban Green Source Environmental Protection Technology Co., Ltd., mainly from construction waste generated by the demolition of concrete buildings within a 30-kilometer range of the disposal site, which is processed into low-brick mixed construction waste recycled aggregate in the processing plant; and the raw materials used for preparing the active carbon capture agent and microencapsulated material are purchased from Aladdin Reagent Co., Ltd.

[0170] Particular note: The technical solutions of the present application involve many parameters, and the synergistic effect between each parameter needs to be considered in order to obtain the beneficial effects and significant progress of the present application. Moreover, the value range of each parameter in the technical solution is obtained through a large number of tests, and for each parameter and the mutual combination of each parameter, the inventors have recorded a large amount of test data, and due to the limited space, the specific test data is not disclosed here.

[0171] It is not difficult for those skilled in the art to understand that the enhanced recycled aggregate cement concrete based on long-acting carbon sequestration and the preparation method of the present application include any combination of the parts shown in the summary of the application and the specific embodiments part of the present application specification and the drawings, and due to the limited space and in order to make the specification concise, each scheme formed by these combinations is not described one by one. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A long-term carbon sequestration based enhanced recycled aggregate cement concrete, characterized in that: The percentage of each component in the reinforced recycled aggregate cement concrete by mass is as follows: recycled aggregate 45-50 wt%, activated carbon scavenger 2-5 wt%, microencapsulated material 1-2 wt%, river sand 24-28 wt%, water-reducing agent 0.8-1.2 wt%, cement 15-18 wt%, auxiliary admixtures 1.2-4.8 wt%, and water 6-9 wt%. The percentage of each substance added to the activated carbon scavenger by mass is as follows: 40-50 wt% modified magnesium oxide, 20-30 wt% calcium hydroxide, 10-20 wt% silicate, 5-10 wt% catalyst, 5-10 wt% industrial solid waste, and 1-3 wt% trace reinforcing agent; The percentage of each substance added to the calcium hydroxide component by mass is as follows: calcium hydroxide 95-98.5 wt%, metal oxide 1-3 wt%, and rare earth element 0.5-2 wt%; the metal oxide is Al2O3 and / or Fe2O3, the rare earth element is Ce and / or La, and the particle size of the calcium hydroxide, the metal oxide, and the rare earth element is 0.1-1 μm. The silicate includes any one or more of anhydrous sodium silicate, potassium silicate, and sodium-potassium composite silicate; the catalyst includes any one or more of titanium dioxide, zirconium dioxide, magnesium aluminum layered double hydroxide, and hydrated magnesium aluminate carbonate; the industrial solid waste includes any one or more of steel slag, carbide slag, fly ash, desulfurized gypsum, red mud, and glass slag; the trace reinforcing agent is a lithium-based compound and / or a manganese-based compound, wherein the lithium-based compound includes any one or more of lithium carbonate, lithium hydroxide, and lithium chloride, and the manganese-based compound includes any one or more of manganese dioxide, manganese chloride, and potassium manganate.

2. The enhanced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 1, characterized in that: The percentage of each substance added to the recycled aggregate component by mass is 40-60 wt% of aggregate and 40-60 wt% of recycled aggregate; the aggregate includes any one or more of limestone, basalt, granite and diabase; the recycled aggregate is recycled aggregate from low-concrete brick-concrete construction waste, and its brick-concrete content is 5-10 wt%.

3. The enhanced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 2, characterized in that: The aggregate includes four particle size grades, with each grade accounting for the following percentage of the aggregate's mass: 8-11 wt% for particles larger than or equal to 19 mm, 34-50 wt% for particles 16-19 mm, 35-51 wt% for particles 9.5-16 mm, and 4-6 wt% for particles 4.75-9.5 mm. The recycled aggregate also includes four particle size grades, with each grade accounting for the following percentage of the recycled aggregate's mass: 8-11 wt% for particles larger than or equal to 19 mm, 34-50 wt% for particles 16-19 mm, 35-51 wt% for particles 9.5-16 mm, and 4-6 wt% for particles 4.75-9.5 mm.

4. The enhanced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 3, characterized in that: The percentage of each substance added to the microencapsulated material by mass is as follows: chitosan 20-30 wt%, polylactic acid 50-60 wt%, and silica microspheres 20-30 wt%, with the mass ratio of chitosan to polylactic acid being 1:2.2-3, and the particle size of the silica microspheres being 0.01-10 μm.

5. The reinforced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 4, characterized in that: The river sand comprises eight particle size grades, with each grade accounting for the following percentage of the river sand's mass: 4.75-9.5mm 7-9wt%, 2.36-4.75mm 3-5wt%, 1.18-2.36mm 10-16wt%, 0.6-1.18mm 15-25wt%, 0.3-0.6mm 25-35wt%, 0.15-0.3mm 20-30wt%, 0.075-0.15mm 4-6wt%, and 0-0.075mm 4-6wt%.

6. The reinforced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 5, characterized in that: The water-reducing agent is a polycarboxylate superplasticizer, the cement is PO 42.5 ordinary Portland cement, and the auxiliary admixtures include any one or more of fly ash, slag powder, and silica fume.

7. A method for preparing reinforced recycled aggregate cement concrete based on long-term carbon sequestration, characterized in that: The method for preparing the reinforced recycled aggregate cement concrete based on long-term carbon sequestration as described in any one of claims 1-6 comprises the following steps in sequence. Step 1: Prepare the recycled aggregate components, activated carbon scavenger, and microencapsulated materials according to the designed material ratios and process parameters; Step 2: Weigh the recycled aggregate components, activated carbon capture agent, microencapsulated material, river sand of various particle sizes, water-reducing agent, cement, auxiliary admixtures, and water according to the designed material ratio and set aside. Step 3: Add a portion of the activated carbon scavenger to the microencapsulation material and stir evenly to encapsulate the activated carbon scavenger inside the microencapsulation material, forming a microcapsule raw material liquid; use spray drying to disperse the microcapsule raw material liquid into fine droplets, and rapidly evaporate the solvent in a high-temperature hot air stream to polymerize and solidify the solid substances in the microcapsule raw material liquid, forming microcapsule particles; Step 4: Put the recycled aggregate components and the remaining activated carbon scavenger into a mechanical mixer and mix them. After mixing evenly, remove the mixture of recycled aggregate components and activated carbon scavenger from the mechanical mixer for later use. Step 5: In sequence, put the river sand of each particle size, cement, recycled aggregate components and activated carbon capture agent mixture, and auxiliary admixtures into the mixing pot and mix them. After mixing evenly, set aside for later use. Step 6: Mix water and water-reducing agent in a container to form a mixed solution of water and water-reducing agent; put the mixed solution of water and water-reducing agent into a mixing pot and mix it together with the materials in the mixing pot. After mixing evenly, carbon sequestration-based reinforced recycled aggregate cement concrete slurry is obtained. Step 7: Remove the carbon sequestration-based reinforced recycled aggregate cement concrete slurry from the mixing pot and place it in a storage container, while simultaneously mixing it manually. After manual mixing is completed, carbon sequestration-based reinforced recycled aggregate cement concrete slurry is filled into the specimen molding mold, and the upper surface of the slurry in the specimen molding mold is leveled with a scraper. Then, some microcapsule particles are evenly sprinkled on the upper surface of the slurry, and the upper surface of the microcapsule particles is leveled with a scraper. Step 8: Place the specimen molding mold on the electric vibration table, start the electric vibration table, and begin vibration molding. If a depression occurs during vibration molding, add carbon sequestration-based reinforced recycled aggregate cement concrete slurry to the depression. After vibration molding is completed, let the specimen molding mold and the slurry inside stand for a certain period of time before demolding. Then place it in a standard curing chamber for curing to obtain carbon sequestration-based reinforced recycled aggregate cement concrete specimens. Step 9: Dissolve the remaining microcapsule particles in anhydrous ethanol to form a suspension; stir the suspension evenly and coat it evenly on the outer surface of the carbon sequestration-based reinforced recycled aggregate cement concrete specimen to obtain the long-term carbon sequestration-based reinforced recycled aggregate cement concrete specimen.

8. The method for preparing reinforced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 7, characterized in that: In step one, the preparation process of the recycled aggregate component is as follows: First, the construction waste generated from the demolition of concrete buildings is crushed and washed, and then screened according to the designed particle size range to obtain recycled aggregate of each particle size range; then, the recycled aggregate of each particle size range is weighed according to the designed material ratio, and carbonation pretreatment is performed, that is, the recycled aggregate of each particle size range is soaked in a 5% sodium carbonate solution, the sodium carbonate solution just covering the recycled aggregate of each particle size range, the soaking temperature is room temperature, and the soaking time is 1- After soaking for 2 hours, melamine is added to the sodium carbonate solution and recycled aggregates of various particle sizes and stirred. The amount of melamine added is 0.5-1 wt% of the total mass of the recycled aggregates. The stirring temperature is room temperature and the stirring time is 0.5-1 hours. After stirring, the carbonation pretreatment of the recycled aggregates is completed. Finally, according to the designed material ratio, the aggregates of various particle sizes are weighed and mixed evenly with the recycled aggregates of various particle sizes after carbonation pretreatment to obtain the recycled aggregate composition.

9. The method for preparing reinforced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 8, characterized in that: In step one, the preparation process of the activated carbon scavenger is as follows: First, modified magnesium oxide is prepared by placing magnesium oxide in a calcining furnace for low-temperature calcination at 700-900℃ for 3-5 hours. The calcined magnesium oxide is then washed and purified. The purified magnesium oxide is then dried in an oven at 80-100℃ for 2-3 hours. Alkaline carbonates are added to the dried magnesium oxide and mixed thoroughly to obtain modified magnesium oxide. The amount of alkaline carbonate added is 1-3 wt% of the mass of the modified magnesium oxide. The alkaline carbonates include lithium carbonate, potassium carbonate, and carbonates. The process involves: first, preparing one or more of cesium; second, preparing a calcium hydroxide component by uniformly mixing calcium hydroxide, metal oxides, and rare earth elements at room temperature according to the designed material ratio; then, uniformly mixing modified magnesium oxide, calcium hydroxide component, silicate, catalyst, industrial solid waste, and trace reinforcing agent at room temperature according to the designed material ratio, and ball milling the mixed material to obtain a solid powder with a particle size of less than 5 μm; finally, drying the solid powder in an oven at a temperature of 80-100℃ for 2-3 hours. After drying, an activated carbon scavenger can be obtained. In step one, the preparation process of the microencapsulated material is as follows: First, chitosan, polylactic acid, and silica microspheres are weighed according to the designed material ratio and set aside; then, chitosan and polylactic acid are mixed evenly and dissolved in anhydrous ethanol to form a solution, the mass of anhydrous ethanol being 20-30 times the total mass of chitosan and polylactic acid; finally, silica microspheres are added to the solution and stirred evenly to obtain the microencapsulated material.

10. The method for preparing reinforced recycled aggregate cement concrete based on long-term carbon sequestration according to claim 9, characterized in that: In step three, the mass of the activated carbon scavenger is 40-50 wt% of the total mass of the activated carbon scavenger, the temperature of the high-temperature hot air stream is 150-200℃, and the particle size of the microcapsule particles is 100-120 μm. In step four, the remaining activated carbon scavenger has a mass of 50-60 wt% of the total activated carbon scavenger mass; the mechanical mixer is set to room temperature, a stirring speed of 120-180 rpm, and a stirring time of 4-6 min. In step five, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40-60 rpm, and the mixing time is 60-90 seconds. In step six, the mixing temperature of the mixing pot is room temperature, the mixing speed is 40-60 rpm, and the mixing time is 3-4 min; In step seven, the manual mixing temperature is room temperature, and the mixing time is 1-2 minutes; the length, width, and height of the inner cavity of the specimen molding mold are 100 mm; the mass of the partial microcapsule particles is 20-30 wt% of the total mass of the microcapsule particles. In step eight, the settling temperature is room temperature, the settling time is 24 hours, and the curing time is 28 days. In step nine, the mass of the remaining microcapsule particles is 70-80 wt% of the total mass of the microcapsule particles, and the mass of the anhydrous ethanol is 20-30 times the mass of the remaining microcapsule particles.

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