Method for improving performance of disassembled concrete part based on multi-stage synergistic repair and product thereof

Abstract

The invention provides a method for improving the performance of a disassembled concrete part based on multi-stage synergistic repair and a product thereof, and belongs to the technical field of resource utilization of building wastes. The method comprises the following steps of: performing pulse vacuum impregnation and carbonization curing on a repaired disassembled concrete part; wherein the pulse vacuum impregnation is carried out in a repairing solution containing nano silicon dioxide particles, and the impregnation process comprises at least two times of alternate circulation of negative pressure and normal pressure. According to the method, in-situ performance repairing and direct recycling are conducted on large concrete components such as beams, plates and columns generated in the building and structure disassembling process, the concrete components are disassembled through pulse vacuum impregnation and gradient temperature and humidity coupling carbonization, the penetration depth and uniformity of a repairing material are remarkably improved, the carbonization reaction efficiency and quality are remarkably improved, and the repairing cost is reduced. Therefore, the overall performance of the disassembled component is obviously and reliably improved.

Description

Technical Field

[0001] This invention belongs to the field of construction waste resource utilization technology, and in particular relates to a method for improving the performance of dismantled concrete components based on multi-level collaborative repair and its products. Background Technology

[0002] Currently, the recycling of construction waste mainly focuses on crushing waste concrete to prepare recycled aggregates for use in the production of new concrete. However, this approach suffers from problems such as cumbersome processes, high energy consumption, and insufficient durability of new concrete due to the deterioration of recycled aggregate performance. Existing technologies, exemplified by patent application CN119954428A, primarily rely on chemical impregnation to improve the quality of recycled aggregates. While this improves the performance of recycled concrete to some extent, it does not break free from the "crushing-recycling" technological framework.

[0003] Concrete components disassembled using precise cutting and static crushing methods still retain load-bearing capacity and durability, possessing the potential for direct and holistic reuse. However, in actual engineering projects, the service life of the disassembled concrete, the service environment, and the cutting operations all cause cumulative damage (such as microcracks), leading to performance degradation (such as strength reduction). Data shows that the width of microcracks in disassembled components can reach 0.1-0.5 mm, with a strength reduction of 15%-30%, affecting their direct reuse. How to effectively repair these "quasi-waste" components that still possess basic structural forms to meet the performance requirements for reuse is a pressing and economically and environmentally valuable technical challenge in the field of building recycling. Existing concrete repair technologies mostly use organic or inorganic materials such as epoxy resin and ordinary silane to fill internal cracks, but they still have the following drawbacks: ① Insufficient penetration depth (usually ≤3 mm), resulting in limited improvement in the durability of the repaired component; ② Long curing period (≥14 days), resulting in low efficiency; ③ High carbon sequestration in the repair methods, failing to achieve carbon footprint reduction. Therefore, developing a technology that can perform in-depth, uniform, and efficient repair of disassembled concrete components and significantly improve their overall performance is of great engineering significance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method and product for improving the performance of dismantled concrete components based on multi-level collaborative repair. This invention targets large concrete components such as beams, slabs, and columns generated during the dismantling of buildings and structures, enabling in-situ performance repair and direct reuse. By using pulsed vacuum impregnation and gradient temperature and humidity coupled carbonization to dismantle the concrete components, the penetration depth and uniformity of the repair material, as well as the efficiency and quality of the carbonization reaction, are significantly improved, thereby achieving a significant and reliable improvement in the overall performance of the dismantled components.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for improving the performance of disassembled concrete components based on multi-level collaborative repair, including the steps of pulse vacuum impregnation and carbonation curing of the disassembled concrete components to be repaired; The pulsed vacuum impregnation is carried out in a repair solution containing nano-silica particles, and the impregnation process includes at least two alternating cycles of negative pressure and normal pressure.

[0006] Furthermore, the pulsed vacuum impregnation specifically includes: first, placing the disassembled concrete component to be repaired in a vacuum environment with a vacuum degree of not less than -0.09MPa for 20-40 minutes, injecting the repair solution in the vacuum environment, and then restoring it to an atmospheric pressure environment for 10-20 minutes; repeating the cycle 2-4 times.

[0007] Furthermore, in the repair solution containing nano-silica particles, the average particle size of the nano-silica particles is 10nm-30nm, and their mass accounts for 2%-15% of the total mass of the repair solution.

[0008] Furthermore, the repair solution containing nano-silica particles also includes a high-efficiency dispersant; preferably, the high-efficiency dispersant is a polycarboxylate high-efficiency water-reducing agent.

[0009] Furthermore, the carbonization curing is carried out in an environment where the pressure is not lower than atmospheric pressure and the carbon dioxide concentration is higher than the carbon dioxide concentration in the air.

[0010] Furthermore, the carbonization curing is carried out in an environment with a pressure of 0.1 MPa and a relative humidity of 50%-70%, and the purity of the carbon dioxide gas introduced is not less than 60%.

[0011] Furthermore, after pulse vacuum impregnation and before carbonization curing, a step of natural curing of the impregnated parts is also included.

[0012] Furthermore, prior to pulsed vacuum impregnation, a pretreatment step is included for the disassembled concrete components, the pretreatment comprising cleaning and / or drying.

[0013] Furthermore, the temperature of the drying step is 60°C-80°C.

[0014] More specifically, this invention provides a method for improving the performance of disassembled concrete components based on multi-level collaborative repair, which specifically includes the following steps: (1) Pre-treatment of disassembled concrete components: Based on the size characteristics of the disassembled concrete components, the components are cut into disassembled concrete components using a diamond saw blade cutting machine. The surface of the cut components is washed with a high-pressure water gun to remove surface laitance and dust. Then the components are placed in a constant temperature curing chamber at 60-80℃ and dried for 72 hours to allow the internal free water to vaporize and improve the impregnation efficiency of the nano silica solution. Among them, the dimensions of disassembled concrete components must meet the dimensional requirements in clause GB / T21144 of the national standard; (2) Preparation of high-stability and high-permeability repair solution: Nano silica sol, polycarboxylate high-efficiency water-reducing agent (as dispersant) are mixed with water and subjected to high-speed shearing and ultrasonic dispersion for 30 minutes to prepare a uniform and stable repair solution with a nano silica particle solid content of 2-15%. Among them, the nano silica sol is an industrially produced nano silica solution with a pH value of 9-11; (3) Pulse vacuum impregnation with nano-silica repair solution: The disassembled concrete parts to be repaired, which were pretreated in step (1), are placed in a vacuum impregnation chamber and subjected to the following pulse cycle: a) Evacuate the chamber to a vacuum level ≤ -0.09 MPa and maintain this level for 20-40 minutes; b) Inject the nano-silica repair solution prepared in step (2) to completely immerse the component; c) Remove the vacuum to atmospheric pressure and maintain it for 10-20 minutes; d) Repeat steps a) and c) 2-4 times to create a pulse effect, forcing the repair solution to penetrate into the component; e) After completing the pulse cycle, continue immersion for 1-2 hours in an environment with a vacuum degree ≤ -0.09MPa, and then remove the component; (4) Natural curing: The components impregnated in step (3) are cured at room temperature for 7 days; (5) Carbonation curing: Place the component obtained in step (4) into a carbonation reactor with a controllable environment and process it in the following stages: first, evacuate to -0.08MPa, then introduce CO2 gas with a purity of ≥99%, and maintain the internal pressure of the reactor at 0.1MPa and the humidity at 50%-70% for 24 hours during the carbonation process to complete the improvement of the performance of the disassembled concrete component.

[0015] After performance improvement, disassembling concrete components can ensure no structural cracks (crack width < 0.2 mm). When the strength is > 30 MPa, it can be directly used in non-load-bearing structures (such as walls and retaining structures) or secondary load-bearing structures (such as floor slab filling layers).

[0016] The present invention also provides a performance-enhanced dismantled concrete component, which is prepared according to the above method.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: 1. Significantly Improved Penetration Depth and Uniformity: Pulsed vacuum impregnation, through repeated cycles of negative pressure and normal pressure, can "press" the nano-slurry into deeper and finer pores and cracks, solving the technical pain point of difficult repair of core areas of large components. At the same time, the highly efficient dispersant added to the slurry ensures that the nanoparticles do not agglomerate during the penetration process, further improving the uniformity of the repair.

[0018] 2. Significantly improve carbonization efficiency and repair strength: The temperature and humidity coupled carbonization process creates the optimal "gas-liquid-solid" three-phase reaction interface for the main carbonization reaction. Compared with traditional carbonization, the reaction rate is increased by 5-10 times, and the compressive strength of the repaired component is significantly improved.

[0019] 3. High efficiency and direct utilization: This invention retains the core two-step method of "impregnation-carbonation", which directly processes the dismantled concrete component units, avoiding the complex processing procedures of crushing, screening and producing concrete products from the demolished waste concrete, and can be directly reused. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a process flow diagram of the method for improving the performance of disassembled concrete components based on multi-level collaborative repair in an embodiment of the present invention. Detailed Implementation

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

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

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

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

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

[0026] This invention provides a method for improving the performance of disassembled concrete components based on multi-level collaborative repair, including the steps of pulse vacuum impregnation and carbonation curing of the disassembled concrete components to be repaired; Pulsed vacuum impregnation is carried out in a repair solution containing nano-silica particles, and the impregnation process includes at least two alternating cycles of negative pressure and normal pressure.

[0027] This invention, based on a multi-level synergistic repair method for improving the performance of dismantled concrete components, differs from existing crushing-recycled aggregate technologies. It is the first to propose a comprehensive repair scheme for dismantled concrete components (beams, slabs, columns, etc.) involving pulsed vacuum impregnation (containing nano-silica) and carbonization curing. This addresses the pain point of dismantled components being unable to be directly reused due to micro-cracks (0.1-0.5mm) and strength reduction (15%-30%), achieving in-situ performance repair and direct reuse of quasi-waste materials, thus possessing both economic and environmental value. During the process, the "negative pressure-normal pressure alternating cycle" of pulsed vacuum impregnation forces the nano-silica slurry into the deep, fine pores of the component, solving the problem of difficult repair in the core areas of large components. Carbonization curing and the nano-slurry create a synergistic effect, significantly improving the uniformity of the repair material's penetration and the quality of the carbonization reaction, ultimately achieving a reliable improvement in the overall performance (strength and durability) of the component. This avoids the shortcomings of existing single repair technologies (such as epoxy resin filling) with a penetration depth ≤3mm and limited durability improvement.

[0028] In a preferred embodiment of the present invention, pulsed vacuum impregnation specifically includes: first, placing the disassembled concrete component to be repaired in a vacuum environment with a vacuum degree not lower than -0.09 MPa for 20-40 minutes; then injecting the repair solution under vacuum; and finally restoring to normal pressure for 10-20 minutes; repeating this cycle 2-4 times. This process ensures that air inside the component is fully expelled during each negative pressure stage, creating pore space for solution penetration; the normal pressure stage promotes the solution to more fully fill the pores, avoiding problems such as insufficient negative pressure leading to air residue or too few cycles resulting in shallow penetration, or too many cycles resulting in energy waste. This further enhances the deep penetration effect of the repair solution and provides a uniform material basis for the subsequent carbonization reaction.

[0029] In a preferred embodiment of the present invention, the repair solution containing nano-silica particles has an average particle size of 10nm-30nm and a mass accounting for 2%-15% of the total mass of the repair solution. The repair solution also includes a high-efficiency dispersant; preferably, the high-efficiency dispersant is a polycarboxylate superplasticizer. Specifically, the preparation method of the repair solution containing nano-silica particles includes the following steps: mixing nano-silica sol, polycarboxylate superplasticizer (as a dispersant), and water, and then dispersing the mixture by high-speed shearing and ultrasonication for 30 minutes to prepare a uniform and stable repair solution with a nano-silica particle solid content of 2-15%; wherein the nano-silica sol is an industrially produced nano-silica solution with a pH value of 9-11, an average particle size of 30nm, and a concentration of 30wt.%. The small particle size of 10-30nm nano-silica particles ensures that they can penetrate the tiny cracks (0.1-0.5mm) in the disassembled components, preventing large-diameter particles from clogging the pores. A mass ratio of 2%-15% balances the repair strength requirements with solution fluidity; too low a ratio results in insufficient strength improvement after repair, while too high a ratio increases solution viscosity, leading to agglomeration and hindering uniform penetration, ultimately impacting component strength. Adding a high-efficiency dispersant (such as polycarboxylate superplasticizer) to the nano-silica solution effectively prevents nanoparticle agglomeration during impregnation, avoiding pore blockage and compromised penetration uniformity, ensuring uniform distribution of nano-silica throughout the component. Uniformly distributed nanoparticles can fully combine with subsequent carbonization reaction products (such as calcium carbonate), preventing localized performance differences and further improving the overall density of the component.

[0030] For example, in this embodiment of the invention, the preparation method of the nano-repair solution with a solid content of 5% is as follows: 2 kg of nano-silica sol with an average particle size of 30 nm and a concentration of 30 wt.%, and 40 g of polycarboxylate superplasticizer are weighed and added to 10 kg of water. After high-speed stirring and ultrasonic dispersion for 30 minutes, a nano-repair solution with a solid content of 5% is obtained. Wherein, the solid content in the nano-silica sol = 2 kg × 30 wt.% = 0.6 kg (solid silica), and the polycarboxylate superplasticizer is generally considered a solid additive according to the formula, i.e., 0.04 kg. The total solid mass in the system = 0.6 kg + 0.04 kg = 0.64 kg, and the total mass of the system = 2 kg nano-silica sol + 0.04 kg superplasticizer + 10 kg water = 12.04 kg. The calculated solid content = 0.64 / 12.04 ≈ 5%. The calculations in other embodiments are performed according to this method.

[0031] In a preferred embodiment of the present invention, carbonization curing is carried out in an environment with a pressure not lower than atmospheric pressure and a carbon dioxide concentration higher than that of air. More specifically, carbonization curing is carried out in an environment with a pressure of 0.1 MPa and a relative humidity of 50%-70%, and the purity of the introduced carbon dioxide (CO2) gas is not less than 60%. The present invention specifies "carbonization pressure ≥ atmospheric pressure and CO2 concentration higher than air", which overcomes the low efficiency of natural carbonization (CO2 concentration in air is only 0.03%). The high CO2 concentration increases the concentration of reactants in the reaction environment, and the pressure ≥ atmospheric pressure promotes the penetration of CO2 into the interior of the component, accelerates the carbonization reaction rate of nano-silica and cement hydration products (such as calcium hydroxide), and solves the problem of long curing cycles in traditional methods.

[0032] In a preferred embodiment of the invention, after pulsed vacuum impregnation and before carbonization curing, a natural curing step is included for the impregnated component, specifically curing at room temperature for 7 days. Adding a natural curing step after pulsed vacuum impregnation allows the repair solution to fully diffuse and stably adhere within the component, avoiding problems such as uneven solution distribution and excessive localized reaction that can occur if the component directly enters the carbonization stage. Simultaneously, it allows excess solution on the component surface to dry or penetrate evenly, providing a more stable interface for the subsequent carbonization reaction, ensuring uniform carbonization across the entire surface, and further improving the stability of the repaired component's performance (e.g., reducing the range of strength fluctuations).

[0033] In a preferred embodiment of the present invention, before pulse vacuum impregnation, a pretreatment step of the disassembled concrete component is included. The pretreatment includes cleaning and / or drying, wherein the drying temperature is 60℃-80℃. Specifically, this includes: according to the size characteristics of the disassembled existing concrete component, using a diamond saw blade cutting machine to cut the component into disassembled concrete parts; washing the surface of the cut parts with a high-pressure water gun to remove surface laitance and dust; and then placing the parts in a constant temperature curing chamber at 60-80℃ for 72 hours to dry them, allowing the internal free water to vaporize and improving the impregnation efficiency of the nano-silica solution; wherein the size of the disassembled concrete part must meet the size requirements in the national standard GB / T21144 (size 100×100×100mm).

[0034] The disassembled concrete components processed according to the embodiments of the present invention can be ensured to be free of structural cracks (crack width < 0.2 mm) and have a strength > 30 MPa. They can be directly used in non-load-bearing structures (such as walls and retaining structures) or secondary load-bearing structures (such as floor slab filling layers).

[0035] In this embodiment of the invention, the compressive strength and water absorption rate are tested according to GB-T 50081-2019 Test Methods for Physical and Mechanical Properties of Concrete; the porosity is tested according to GB / T 21650.1-2008 Determination of Pore Size Distribution and Porosity of Solid Materials by Mercury Intrusion Porosimetry and Gas Adsorption Method Part 1: Mercury Intrusion Porosimetry.

[0036] All raw materials used in the embodiments of this invention were purchased commercially.

[0037] In this embodiment of the invention, normal pressure refers to standard atmospheric pressure, specifically 101.325 kPa, and normal temperature refers to "23 ± 0.5 °C".

[0038] The process flow diagram of the method for improving the performance of disassembled concrete components based on multi-level collaborative repair in this embodiment of the invention is shown below. Figure 1 .

[0039] The technical solution of the present invention will be further illustrated by the following embodiments.

[0040] Example 1 A method for improving the performance of disassembled concrete components based on multi-level collaborative repair specifically includes the following steps: (1) Pretreatment of disassembled concrete components: Take a benchmark disassembled concrete test block. The benchmark disassembled concrete test block is a cubic concrete component (100×100×100mm) cut after bearing 0.7 times the compressive strength load. After rinsing the surface, place it in a constant temperature drying oven at 60℃ for 72 hours. (2) Preparation of high-stability and high-permeability repair solution: Weigh 2 kg of nano silica sol with an average particle size of 30 nm and a concentration of 30 wt.% and 40 g of polycarboxylate high-efficiency water-reducing agent, add them to 10 kg of water, and disperse them by high-speed stirring and ultrasonication for 30 minutes to obtain a nano repair solution with a solid content of 5%. (3) Pulse vacuum impregnation with nano-silica repair solution: The disassembled concrete parts to be repaired, which were pretreated in step (1), are placed in a vacuum impregnation chamber and subjected to the following pulse cycle: a) Evacuate the chamber to -0.095 MPa and maintain this vacuum for 30 minutes; b) Inject the nano-repair solution composite solution prepared in step (2) to completely immerse the component; c) Remove the vacuum to atmospheric pressure and maintain it for 15 minutes; d) Repeat steps a) and c) 3 times to create a pulse effect, forcing the repair solution to penetrate into the component; e) After completing the pulse cycle, continue immersion in a vacuum environment of -0.095MPa for 1.5 hours, and then remove the component; (4) Natural curing: After the component was soaked in step (3), it was then taken out and the residual solution was wiped off with a cloth. The concrete surface was covered with plastic film and placed in a curing room at a temperature of 23±0.5℃ for 7 days. (5) Carbonation curing: Place the component obtained in step (4) into a carbonation reactor with a controllable environment. First, evacuate to -0.08MPa, then introduce CO2 gas with a purity of ≥99% to make the gas pressure inside the carbonation reactor reach 0.1MPa. Use saturated KCl solution to maintain the humidity inside the reactor at 70±5% for 24 hours to complete the improvement of the performance of the disassembled concrete component.

[0041] Example 2 A method for improving the performance of disassembled concrete components based on multi-level collaborative repair specifically includes the following steps: (1) Pretreatment of disassembled concrete components: Take a benchmark disassembled concrete test block. The benchmark disassembled concrete test block is a cubic concrete component (100×100×100mm) cut after bearing 0.7 times the compressive strength load. After rinsing the surface, place it in a constant temperature drying oven at 80℃ for 72 hours. (2) Preparation of high-stability and high-permeability repair solution: Weigh 0.57 kg of nano silica sol with an average particle size of 30 nm and a concentration of 30 wt.%, and 40 g of polycarboxylate high-efficiency water-reducing agent, add them to 10 kg of water, and disperse them by high-speed stirring and ultrasonication for 30 minutes to obtain a nano repair solution with a solid content of 2%. (3) Pulse vacuum impregnation with nano-silica repair solution: The disassembled concrete parts to be repaired, which were pretreated in step (1), are placed in a vacuum impregnation chamber and subjected to the following pulse cycle: a) Evacuate the chamber to -0.095 MPa and maintain this vacuum for 40 minutes; b) Inject the nano-repair solution composite solution prepared in step (2) to completely immerse the component; c) Remove the vacuum to atmospheric pressure and maintain it for 20 minutes; d) Repeat steps a) and c) 4 times to create a pulse effect, forcing the repair solution to penetrate into the component; e) After completing the pulse cycle, continue immersion in a vacuum environment of -0.095MPa for 1 hour, and then remove the component; (4) Natural curing: After the component was soaked in step (3), it was then taken out and the residual solution was wiped off with a cloth. The concrete surface was covered with plastic film and placed in a curing room at a temperature of 23±0.5℃ for 7 days. (5) Carbonation curing: Place the component obtained in step (4) into a carbonation reactor with a controllable environment. First, evacuate to -0.08MPa, then introduce CO2 gas with a purity of ≥99% to make the gas pressure inside the carbonation reactor reach 0.1MPa and the temperature 25℃. Use saturated KCl solution to maintain the humidity inside the reactor at 70±5% for 24 hours to complete the improvement of the performance of the disassembled concrete component.

[0042] Example 3 A method for improving the performance of disassembled concrete components based on multi-level collaborative repair specifically includes the following steps: (1) Pretreatment of disassembled concrete components: Take a benchmark disassembled concrete test block. The benchmark disassembled concrete test block is a cubic concrete component (100×100×100mm) cut after bearing 0.7 times the compressive strength load. After rinsing the surface, place it in a constant temperature drying oven at 70℃ for 72 hours. (2) Preparation of high-stability and high-permeability repair solution: Weigh 9.77 kg of nano silica sol with an average particle size of 30 nm and a concentration of 30 wt.%, 40 g of polycarboxylate high-efficiency water-reducing agent, add it to 10 kg of water, and disperse it by high-speed stirring and ultrasonication for 30 minutes to obtain a nano repair solution with a solid content of 15%. (3) Pulse vacuum impregnation with nano-silica repair solution: The disassembled concrete parts to be repaired, which were pretreated in step (1), are placed in a vacuum impregnation chamber and subjected to the following pulse cycle: a) Evacuate the chamber to -0.095 MPa and maintain this vacuum for 20 minutes; b) Inject the nano-repair solution composite solution prepared in step (2) to completely immerse the component; c) Remove the vacuum to atmospheric pressure and maintain it for 10 minutes; d) Repeat steps a) and c) twice to create a pulse effect, forcing the repair solution to penetrate into the component; e) After completing the pulse cycle, continue immersion in a vacuum environment of -0.095MPa for 2 hours, and then remove the component; (4) Natural curing: After the component was soaked in step (3), it was then taken out and the residual solution was wiped off with a cloth. The concrete surface was covered with plastic film and placed in a curing room at a temperature of 23±0.5℃ for 7 days. (5) Carbonation curing: Place the component obtained in step (4) into a carbonation reactor with a controllable environment. First, evacuate to -0.08MPa, then introduce CO2 gas with a purity of ≥99% to make the gas pressure inside the carbonation reactor reach 0.1MPa and the temperature 20℃. Use saturated KCl solution to maintain the humidity inside the reactor at 70±5% for 24 hours to complete the improvement of the performance of the disassembled concrete component.

[0043] Comparative Example 1 Same as Example 1, except that steps (2) and (3) are omitted, specifically: (1) Pretreatment of disassembled concrete components: Take a benchmark disassembled concrete test block. The benchmark disassembled concrete test block is a cubic concrete component (100×100×100mm) cut after bearing 0.7 times the compressive strength load. After rinsing the surface, place it in a constant temperature drying oven at 60℃ for 72 hours. (2) Natural curing: Cover the concrete surface of the component obtained in step (1) with plastic film and place it in a curing room with a temperature of 23±0.5℃ for 7 days; (3) Carbonization curing: Place the component obtained in step (2) into a carbonization reactor with a controllable environment. First, evacuate to -0.08MPa, then introduce CO2 gas with a purity of ≥99% to make the gas pressure inside the carbonization reactor reach 0.1MPa. Use saturated KCl solution to maintain the humidity inside the reactor at 70±5% for 24 hours.

[0044] Comparative Example 2 Same as Example 1, except that step (5) is omitted, specifically: (1) Pretreatment of disassembled concrete components: Take a benchmark disassembled concrete test block. The benchmark disassembled concrete test block is a cubic concrete component (100×100×100mm) cut after bearing 0.7 times the compressive strength load. After rinsing the surface, place it in a constant temperature drying oven at 60℃ for 72 hours. (2) Preparation of high-stability and high-permeability repair solution: Weigh 2 kg of nano silica sol with an average particle size of 30 nm and a concentration of 30 wt.% and 40 g of polycarboxylate high-efficiency water-reducing agent, add them to 10 kg of water, and disperse them by high-speed stirring and ultrasonication for 30 minutes to obtain a nano repair solution composite solution with a solid content of 5%. (3) Pulse vacuum impregnation with nano-silica repair solution: The disassembled concrete parts to be repaired, which were pretreated in step (1), are placed in a vacuum impregnation chamber and subjected to the following pulse cycle: a) Evacuate the chamber to -0.095 MPa and maintain this vacuum for 30 minutes; b) Inject the nano-repair solution composite solution prepared in step (2) to completely immerse the component; c) Remove the vacuum to atmospheric pressure and maintain it for 15 minutes; d) Repeat steps a) and c) 3 times to create a pulse effect, forcing the repair solution to penetrate into the component; e) After completing the pulse cycle, continue immersion in a vacuum environment of -0.095MPa for 1.5 hours, and then remove the component; (4) Natural curing: The component after being soaked in step (3) is then taken out and the residual solution is wiped off with a cloth. The concrete surface is covered with plastic film and placed in a curing room at a temperature of 23±0.5℃ for 7 days.

[0045] Performance testing After removing the disassembled concrete components obtained in the examples and comparative examples, they were dried in an oven at 80°C for 24 hours. The concrete specimens were then removed, and their compressive strength, water absorption, and porosity were tested. The original benchmark disassembled concrete specimens were used as controls. The results are shown in Table 1.

[0046]

[0047] As shown in Table 1, the compressive strength of Example 1 is 52.7 MPa, representing increases of 35.1%, 8.0%, and 7.3% compared to the baseline disassembled concrete, Comparative Example 1, and Comparative Example 2, respectively. Simultaneously, the water absorption rate of Example 1 is significantly lower than the baseline group, decreasing by 20% and 28.6% compared to Comparative Example 1 and Comparative Example 2, respectively. Furthermore, the porosity of Example 1 is also significantly lower than that of the baseline group and Comparative Example 1, and comparable to Comparative Example 2. This indicates that the present invention can significantly improve the mechanical properties and density of disassembled concrete components after service, laying the foundation for direct reuse. Notably, the compressive strength of Example 1 (52.7 MPa) is significantly higher than the simple sum of Comparative Example 1 (carbonation only, 48.8 MPa) and Comparative Example 2 (impregnation only, 49.1 MPa), and the reduction in water absorption and porosity also far exceeds expectations. This fully demonstrates a significant synergistic enhancement effect between nano-silica impregnation and accelerated carbonation, resulting in a non-linear performance improvement, which is precisely the inventiveness of this invention compared to existing single repair technologies.

[0048] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for improving the performance of disassembled concrete components based on multi-level collaborative repair, characterized in that, This includes the steps of pulse vacuum impregnation and carbonation curing of the disassembled concrete components to be repaired; The pulsed vacuum impregnation is carried out in a repair solution containing nano-silica particles, and the impregnation process includes at least two alternating cycles of negative pressure and normal pressure.

2. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 1, characterized in that, The pulsed vacuum impregnation specifically includes: first, placing the disassembled concrete component to be repaired in a vacuum environment with a vacuum degree of not less than -0.09MPa for 20-40 minutes, injecting the repair solution in the vacuum environment, and then restoring it to the normal pressure environment for 10-20 minutes; repeating the cycle 2-4 times.

3. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 1, characterized in that, In the repair solution containing nano-silica particles, the average particle size of the nano-silica particles is 10nm-30nm, and the mass accounts for 2%-15% of the total mass of the repair solution.

4. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 3, characterized in that, The repair solution containing nano-silica particles also includes a highly efficient dispersant.

5. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 1, characterized in that, The carbonization curing is carried out in an environment where the pressure is not lower than atmospheric pressure and the carbon dioxide concentration is higher than the carbon dioxide concentration in the air.

6. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 5, characterized in that, The carbonization curing is carried out in an environment with a pressure of 0.1 MPa and a relative humidity of 50%-70%, and the purity of the carbon dioxide gas introduced is not less than 60%.

7. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 1, characterized in that, The process includes a natural curing step for the impregnated parts after pulse vacuum impregnation and before carbonization curing.

8. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 1, characterized in that, Prior to pulsed vacuum impregnation, a pretreatment step is included for the disassembled concrete components, which includes cleaning and / or drying.

9. The method for improving the performance of disassembled concrete components based on multi-level collaborative repair according to claim 8, characterized in that, The temperature of the drying step is 60℃-80℃.

10. A performance-enhanced concrete dismantling component, characterized in that, Prepared by the method according to any one of claims 1-9.

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