Traditional dwelling timber frame joint reinforcing, fireproofing and corrosion-proofing integrated treatment method

Abstract

This application discloses an integrated method for strengthening and fireproofing / corrosion prevention of joints in traditional residential timber structures, belonging to the field of traditional building protection and timber structure strengthening technology. The method includes: drilling a micropore array at a preset hole spacing in the joint strengthening area based on moisture content distribution data and coating type information; injecting supercritical carbon dioxide fluid into the joint through the micropore array to open the pore structure of the wood; adaptively adjusting the mixing parameters of a two-component moisture-curing polyurethane-epoxy hybrid adhesive according to the moisture content distribution data, and adding molecular sieve powder to the adjusted adhesive to form a modified injection material; injecting the modified injection material into the joint through the micropore array, allowing it to penetrate into the pores and microcracks of the wood and cure; and installing a prefabricated composite functional panel on the outside of the joint, ensuring its anti-corrosion slow-release layer adheres to the substrate of the timber frame joint.

Description

Technical Field

[0001] This application relates to the field of traditional building preservation and timber structure reinforcement technology, and more specifically, to an integrated treatment method for strengthening the joints of traditional residential timber frames and providing fireproofing and corrosion protection. Background Technology

[0002] Traditional dwellings, as an important part of historical and cultural heritage, widely adopt timber frame structures as their main load-bearing structure, characterized by flexible construction, good seismic performance, and distinct regional cultural features. However, due to long-term exposure to complex natural environments, timber frame joints are susceptible to various factors such as humid heat cycles, insect and fungal erosion, material aging, and fire risks. This leads to problems such as crack expansion, reduced load-bearing capacity, and loosening of connections at the joints, thereby affecting the overall structural safety and service life of traditional dwellings.

[0003] Existing methods for reinforcing timber frame joints mainly include external steel reinforcement, resin injection repair, and surface anti-corrosion coating. While external steel reinforcement can improve the load-bearing capacity of the joint to some extent, it also presents problems such as increased self-weight, poor harmony with traditional architectural styles, and localized stress concentration. Resin injection, although capable of filling and repairing cracks, has limited adaptability to high-moisture-content timber, leading to poor interfacial bonding, uneven internal penetration, and subsequent delamination. Surface anti-corrosion and flame-retardant treatments mostly remain on the outer layer of the timber, failing to provide deep protection for the internal pores and micro-cracks of the joint.

[0004] Furthermore, traditional timber frame joints are exposed to constant temperature and humidity fluctuations, resulting in significant non-uniformity in the moisture content distribution within the timber. Existing reinforcement techniques typically employ fixed-ratio materials and a single injection method, lacking the ability to adaptively regulate the moisture content of the timber. This leads to unstable curing performance and penetration of the injection materials. Simultaneously, joint reinforcement, fireproofing, and anti-corrosion treatments often involve separate construction processes, resulting in prolonged construction periods and potential issues such as interface mismatch, insufficient sealing, and synergistic failures between different functional layers. These shortcomings make it difficult to meet the comprehensive requirements for structural stability and durability under the long-term service conditions of traditional residential buildings.

[0005] In addition, after the existing node protection structure is completed, it is mostly accepted by manual visual inspection or partial sampling inspection. There is a lack of comprehensive testing methods for the integrity of the sealing layer, the bonding status of the functional panels and internal hollow defects. It is difficult to detect potential leakage, delamination or internal defects in time, thus affecting the safety and protection effect of subsequent use.

[0006] In summary, how to achieve deep and efficient reinforcement of traditional residential timber frame joints in complex water-bearing environments, while taking into account fire resistance, corrosion resistance, sealing and long-term stable service performance, and improving the ability to detect internal defects and control construction quality, has become an urgent technical problem to be solved. Summary of the Invention

[0007] In order to overcome a series of defects in the existing technology, the purpose of this application is to provide an integrated method for strengthening and fireproofing / corrosion protection of the joints of traditional residential wooden frames, which includes the following steps: Based on moisture content distribution data and coating type information, a micropore array is drilled in the node reinforcement area according to a preset hole spacing, and supercritical carbon dioxide fluid is injected into the node through the micropore array to open the wood pore structure. The mixing ratio parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive were adaptively adjusted based on the moisture content distribution data, and molecular sieve powder was added to the adjusted adhesive to form a modified injection material. Modified infusion material is injected into the node through a microporous array, allowing it to penetrate into the wood pores and microcracks and solidify into shape. Prefabricated composite functional panels are installed on the outside of the nodes to ensure that the anti-corrosion slow-release layer adheres to the base of the timber frame node.

[0008] Furthermore, the method for drilling a micro-hole array according to a preset hole spacing is as follows: Based on the moisture content distribution data, the node areas of the wooden components to be reinforced are divided into moisture content zones. Different micropore spacing parameters are set according to different moisture content zoning types to form a differentiated pore layout scheme; Based on the aforementioned differentiated hole layout scheme, a low-speed, high-torque pneumatic micro-drill is used for micro-hole array drilling.

[0009] Furthermore, the method of injecting supercritical carbon dioxide fluid into the node via a micropore array is as follows: Dry nitrogen gas at a pressure of 0.2 MPa was used to pre-purge the micropore channels for a period of not less than 30 seconds to remove residual moisture and drilling debris from the channels. The sealed injection connectors are fixed one by one to the openings of each micropore and connected to the constant pressure carbon dioxide supply system through pipelines to construct a closed injection channel; The carbon dioxide fluid is pressurized at a rate not exceeding 0.5 MPa / min and simultaneously heated to above 31.1°C to bring the carbon dioxide to a supercritical state before being injected under stable pressure. A staged pressure injection strategy is used for permeation treatment to achieve further permeation and extraction into the pores; After injection, a gradient depressurization process is performed at a depressurization rate not exceeding 0.3 MPa / min; After depressurization, the patency of the micropore array is tested using 0.05MPa dry nitrogen gas, and the pore continuity is determined based on the pressure drop rate. At the same time, abnormal pores are marked and unblocked.

[0010] Furthermore, the method for adaptively adjusting the mixing ratio parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive based on moisture content distribution data is as follows: The average moisture content of the area to be reinforced is calculated based on the moisture content distribution data, and the corresponding adhesive mixing parameters are determined according to the average moisture content range. When the average moisture content is less than 12%, a formula with a polyurethane prepolymer to epoxy resin mass ratio of 40:60 is adopted, and the amount of curing agent is set to 25% of the epoxy component mass; When the average moisture content is in the range of 12% to 20%, the mass ratio of polyurethane prepolymer to epoxy resin is adjusted to 55:45, and the amount of curing agent is adjusted to 20% of the mass of epoxy component. When the average moisture content exceeds 20%, the mass ratio of polyurethane prepolymer to epoxy resin is further adjusted to 70:30, and an additional 3% to 5% silane coupling agent is added to the total adhesive solution.

[0011] Furthermore, the method for injecting modified infusion material into the node via a microporous array is as follows: The micropore array is divided into an upper injection zone, a middle injection zone, and a lower injection zone according to its spatial location. Injection is carried out sequentially from the lower injection zone to the upper injection zone, so that the subsequent injection pressure drives the residual bubbles in the previous injection zone to escape upward. During the injection process in each zone, the initial injection pressure is set to 0.3-0.5 MPa based on the node size and channel length, and the injection operation is performed on each micropore in sequence. When adhesive overflow occurs in a microwell, record the total amount injected into the corresponding well, seal the microwell, and switch to the adjacent microwell to continue injection. For holes where the amount of overflow adhesive is less than 30% of the estimated injection amount, a second injection should be performed 2 to 4 hours after the first injection is completed and the adhesive has initially set. The pressure of the second injection should not exceed 1.5 times the pressure of the first injection. During the injection process, the pressure change curve of each micropore is monitored in real time. When the pressure drops suddenly, the injection is paused and the presence of cross-holes or leakage of adhesive is detected. After all injections are completed, the mixture should be left to cure at room temperature for no less than 72 hours. After 24 hours of curing, a preliminary curing uniformity test should be conducted using the hammering sound method. Abnormal areas should be marked and included in subsequent reinforcement treatment.

[0012] Furthermore, the integrated processing method also includes: Nickel-titanium alloy shape memory bolts are used to connect and fix the prefabricated composite functional panels, and the martensitic phase transformation recovery is triggered by heating, so that it applies a uniform preload force within a preset range to the prefabricated composite functional panels. Apply a premixed elastic MS sealant containing anti-corrosion components to the joint between the edge of the prefabricated composite functional panel and the node of the timber frame to form a continuous sealing layer.

[0013] Furthermore, the preparation method of the elastic MS sealant is as follows: MS sealant base material is selected, and anti-corrosion components are introduced according to a preset ratio. The anti-corrosion components include nano zinc oxide, 8-hydroxyquinoline copper complex and organosilicon quaternary ammonium salt. Nano zinc oxide was surface modified with silane coupling agent KH-560, and modified nano zinc oxide with a particle size of 20-50 nm was added to MS sealant base material at a ratio of 2%-3% of the total mass of sealant to form a modified nano zinc oxide initial mixture system. The modified nano zinc oxide initial mixture system was dispersed using a high-speed disperser at a speed of 2000-3000 rpm for 15 min to form a uniformly dispersed nanocomposite system. The 8-hydroxyquinoline copper complex and the organosilicon quaternary ammonium salt were pre-dissolved in propylene glycol solvent at a mass ratio of 3:2 to form an anti-corrosion mixed solution. The anti-corrosion mixed solution was then added to the nanocomposite uniform dispersion system and mixed and stirred to form a premixed modified MS sealant system. The 8-hydroxyquinoline copper complex accounted for 1% to 1.5% of the total mass of the sealant, and the organosilicon quaternary ammonium salt accounted for 0.5% to 1% of the total mass of the sealant.

[0014] Furthermore, the method for applying elastic MS sealant to the joint between the edge of the precast composite functional panel and the timber frame node is as follows: Masking tape is applied to both sides of the joint between the edge of the precast composite functional panel and the node of the wooden frame to define the boundary of the sealant application. Dust removal treatment is performed on the joint base surface, and a corresponding primer is applied according to the base material to improve the interfacial adhesion performance between the sealant and the base. During the drying process of the primer, polyethylene foam rods are inserted into the bottom of the joint to control the thickness and filling depth of the sealant joint. After the primer has dried, use a pneumatic caulking gun to continuously inject elastic MS sealant into the joint to form a continuous sealant layer inside the joint. The injected elastic MS sealant is compacted and shaped to ensure a tight bond between the elastic MS sealant and the substrate on both sides of the joint. After the shaping is completed, remove the masking tape and cure the joint area to complete the joint sealing construction.

[0015] Furthermore, the integrated processing method also includes: Based on simultaneous detection of infrared thermal imaging and acoustic response, the sealing performance of the continuous sealing layer and the bonding status of the functional board are jointly judged to determine whether the preset acceptance criteria are met. If the requirements are not met, a supplementary sealing and reinforcement process for the joint area will be triggered until the preset acceptance standards are met. If the conditions are met, the timber frame node is deemed to have completed integrated reinforcement, fireproofing, and corrosion protection.

[0016] Furthermore, the method for jointly determining the sealing performance of the continuous sealing layer and the bonding status of the functional panels based on simultaneous detection of infrared thermal imaging and acoustic response is as follows: Establish testing conditions for continuous sealing layers and functional board node areas to form infrared thermal imaging testing conditions, acoustic response testing conditions, and airtightness testing conditions. The node region is heated, and an infrared thermal image sequence is acquired during the cooling process after heating is stopped. The temperature decay characteristics in the infrared thermogram sequence were analyzed to identify hollow areas and abnormal bonding areas on the back of the functional board. The functional board surface is subjected to point-by-point tapping excitation according to the grid spacing, and the corresponding acoustic response signals are collected simultaneously. Characteristic analysis of the resonant frequency and attenuation coefficient in the acoustic response signal is performed to determine the range of hollowness and bonding status of the functional board; A leak detection medium is coated on the surface of the continuous sealing layer, and a positive pressure airflow is applied to the back side of the sealing layer to detect the location of leakage in the continuous sealing layer. For areas inaccessible on the back side of the sealing layer, infrared thermal imaging is used to identify localized areas of abnormal temperature caused by leakage, in order to help determine the location of the leakage. The results of infrared thermal imaging, acoustic response, and airtightness testing are comprehensively analyzed, and the sealing performance of the continuous sealing layer and the bonding status of the functional panel are jointly determined based on preset thresholds.

[0017] Compared with the prior art, this application has the following beneficial effects: This application achieves a synergistic improvement in the deep reinforcement, fire resistance, corrosion resistance, and long-term sealing stability of traditional residential wooden frame joints through supercritical carbon dioxide pore opening, moisture content adaptive modification injection, and synergistic sealing reinforcement with composite functional panels. Attached Figure Description

[0018] Figure 1This is a flowchart illustrating an integrated method for strengthening, fireproofing, and corrosion protection of nodes in traditional residential wooden structures, as disclosed in an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the water content partitioning layout of the micropore array in the embodiments of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some embodiments of this invention, but not all embodiments.

[0021] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] The embodiments and directional terms described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figure 1 As shown, a method for integrating reinforcement, fireproofing, and corrosion protection of traditional residential wooden frame joints includes the following steps: Layered moisture content testing was conducted on the nodes of the timber frame to be reinforced, and the types of historical coatings on the surface and shallow layers were identified to obtain moisture content distribution data and coating type information. Based on moisture content distribution data and coating type information, a micropore array is drilled in the node reinforcement area according to a preset hole spacing, and supercritical carbon dioxide fluid is injected into the node through the micropore array to open the wood pore structure. The mixing ratio parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive were adaptively adjusted based on the moisture content distribution data, and molecular sieve powder was added to the adjusted adhesive to form a modified injection material. Modified infusion material is injected into the node through a microporous array, allowing it to penetrate into the wood pores and microcracks and solidify into shape. Prefabricated composite functional panels are installed on the outside of the nodes to ensure that the anti-corrosion slow-release layer is in contact with the base of the timber frame node; Nickel-titanium alloy shape memory bolts are used to connect and fix the prefabricated composite functional panels, and the martensitic phase transformation recovery is triggered by heating, so that it applies a uniform preload force within a preset range to the prefabricated composite functional panels. Apply premixed elastic MS sealant with anti-corrosion components to the joint between the edge of the prefabricated composite functional panel and the node of the wooden frame to form a continuous sealing layer. Based on simultaneous detection of infrared thermal imaging and acoustic response, the sealing performance of the continuous sealing layer and the bonding status of the functional board are jointly judged to determine whether the preset acceptance criteria are met. If the requirements are not met, a supplementary sealing and reinforcement process for the joint area will be triggered until the preset acceptance standards are met. If the conditions are met, the timber frame node is deemed to have completed integrated reinforcement, fireproofing, and corrosion protection.

[0024] The method for integrating reinforcement, fireproofing, and corrosion protection of traditional residential wooden frame joints described in this application accurately obtains the internal moisture content gradient distribution and interface state parameters of the joints through layered moisture content detection and historical coating type identification, providing a reliable data basis for subsequent differentiated configuration of micropore layout and adhesive ratio; it achieves efficient opening of the wood pore structure through supercritical carbon dioxide fluid injection, creating favorable conditions for deep penetration of modified injection materials; and it significantly enhances the adhesion adaptability and curing stability of the injection material at high moisture content interfaces by adaptively adjusting the polyurethane-epoxy hybrid adhesive ratio and introducing molecular sieve modification. By coordinating the installation of prefabricated composite functional panels and nickel-titanium alloy shape memory bolts, the functions of fire prevention, corrosion prevention, and structural load-bearing are integrated, and the preload force is ensured to be uniform and controllable. The long-term airtightness and bonding reliability of the node interface are ensured by the continuous sealing layer of elastic MS sealant and the joint acceptance and testing mechanism of infrared thermal imaging-acoustic response. On this basis, the structural reinforcement and fire prevention and corrosion prevention functions of the timber frame node are systematically integrated, thereby significantly improving the structural strength, fire resistance and corrosion resistance of traditional residential timber frame nodes, meeting the high-standard engineering requirements of cultural relic protection and historical building restoration.

[0025] Furthermore, the method for conducting layered moisture content testing on the joints of the reinforced timber frame is as follows: The surface of the timber frame node to be inspected is divided into grids, and a TDR multi-depth probe array is deployed according to the grid spacing to determine the spatial position of each inspection point; Based on the spatial location of the measurement points, a near-infrared spectral scanner was used to scan the surface of the nodes point by point with a scanning step of no more than 20 mm. The intensity of the characteristic absorption peaks of water in the 1450 nm and 1940 nm bands was extracted, and the near-shallow water content data in the depth range of 0 to 5 mm was obtained by inversion based on the partial least squares regression model. The time-domain reflectance signals corresponding to the 10mm, 25mm and 40mm depth layers were collected by TDR multi-depth probes, and the time-domain reflectance signals were analyzed to obtain the water content data of the corresponding depth layers, and TDR layered water content data were constructed. The shallow water content data and the TDR stratified water content data are fused according to spatial location and depth level to construct a water content gradient distribution matrix; The ambient temperature and humidity parameters are collected synchronously, and the moisture content gradient distribution matrix is ​​compensated and corrected based on the ambient temperature to obtain moisture content distribution data.

[0026] The layered moisture content detection method described in this application achieves multi-scale, multi-depth three-dimensional detection of moisture content from the surface to the deep layers of timber frame nodes through point-by-point scanning of near-infrared spectroscopy and coordinated deployment of a TDR multi-depth probe array. High-precision moisture content data for the near-shallow and mid-deep layers are obtained through partial least squares regression models and time-domain reflectometry. A moisture content gradient distribution matrix is ​​constructed by fusing spatial location and depth-level data to comprehensively characterize the three-dimensional distribution pattern of moisture content within the nodes. Environmental temperature compensation correction eliminates the systematic bias of temperature changes on the moisture content detection results, thereby significantly improving the accuracy and reliability of the moisture content distribution data and providing high-quality input parameters for subsequent micropore layout design and adaptive adjustment of adhesive ratios.

[0027] Furthermore, the method for drilling a micro-hole array according to a preset hole spacing is as follows: Based on the moisture content distribution data, the node area of ​​the wooden component to be reinforced is divided into high moisture content area, medium moisture content area and low moisture content area. Different micropore spacing parameters were set according to different moisture content zones. Specifically, the micropore spacing was 30–40 mm for high moisture content zones, 40–60 mm for medium moisture content zones, and 60–80 mm for low moisture content zones, to create differentiated pore placement schemes. Figure 2 As shown; Based on the aforementioned differentiated hole layout scheme, a low-speed, high-torque pneumatic micro-drill is used for micro-hole array drilling. The micro-hole diameter is 1.5–3.0 mm, the drilling depth does not exceed 2 / 3 of the thickness of the wood component section, and the angle between the drilling direction and the wood fiber direction is 15°–30°.

[0028] The micro-hole array drilling method described in this application employs a three-level zoning strategy based on moisture content distribution data to set differentiated micro-hole spacing for high, medium, and low moisture content zones. This achieves precise matching between the density of the grouting channels and the moisture content state of the nodes, avoiding localized insufficient grouting or excessive damage caused by uniform hole spacing. By controlling the micro-hole diameter within the range of 1.5–3.0 mm using a low-speed, high-torque pneumatic micro-drill, mechanical damage to wood fibers during drilling is effectively reduced. By limiting the drilling depth to within 2 / 3 of the cross-sectional thickness and setting an inclination angle of 15°–30°, the connectivity of the channels is ensured while protecting the core load-bearing area of ​​the wood component cross-section, thereby significantly improving the spatial coverage uniformity of the grouting channels and the structural integrity of the nodes.

[0029] Furthermore, the method of injecting supercritical carbon dioxide fluid into the node via a micropore array is as follows: Dry nitrogen gas at a pressure of 0.2 MPa was used to pre-purge the micropore channels for a period of not less than 30 seconds to remove residual moisture and drilling debris from the channels. The sealed injection connectors are fixed one by one to the openings of each micropore and connected to the constant pressure carbon dioxide supply system through pipelines to construct a closed injection channel; The carbon dioxide fluid is pressurized at a rate not exceeding 0.5 MPa / min and simultaneously heated to above 31.1°C to bring the carbon dioxide to a supercritical state before being injected under stable pressure. A staged pressure injection strategy was adopted for permeation treatment. In the first stage, the injection was maintained at a pressure of 8-10 MPa for 15-20 min to achieve initial permeation into the macropores. In the second stage, the pressure was increased to 10-12 MPa and maintained for 10-15 min while keeping the temperature stable to achieve further permeation and extraction into the pores. After injection, a gradient depressurization process is performed at a depressurization rate not exceeding 0.3 MPa / min to avoid microcracks inside the wood caused by rapid depressurization. After depressurization, the patency of the micropore array is tested using 0.05MPa dry nitrogen gas, and the pore continuity is determined based on the pressure drop rate. At the same time, abnormal pores are marked and unblocked.

[0030] The supercritical carbon dioxide fluid injection method described in this application removes residual moisture and debris from the pores through pre-purging with dry nitrogen, creating clean channel conditions for the uniform penetration of the supercritical fluid. Controlled pressurization and simultaneous heating ensure the stable entry of carbon dioxide into the supercritical state, fully leveraging its low viscosity and high diffusivity mass transfer advantages. A two-stage gradient pressurization strategy achieves preliminary filling of macroscopic pores and deep penetration and extraction of residual impurities from micropores, significantly improving the openness of the wood's pore structure. Gradient depressurization control effectively avoids microcracks inside the wood caused by rapid depressurization, protecting the structure of the wood component. Post-injection pore patency testing and abnormal pore marking ensure that the entire micropore array is effectively connected, thus laying a reliable pore foundation for the subsequent deep and uniform penetration of modified injection materials.

[0031] Furthermore, the method for adaptively adjusting the mixing ratio parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive based on moisture content distribution data is as follows: The average moisture content of the area to be reinforced is calculated based on the moisture content distribution data, and the corresponding adhesive mixing parameters are determined according to the average moisture content range. When the average moisture content is less than 12%, a formula with a mass ratio of polyurethane prepolymer to epoxy resin of 40:60 is adopted, and the amount of curing agent is set to 25% of the mass of epoxy component, so as to give full play to the high-strength adhesive performance of epoxy component. When the average moisture content is in the range of 12% to 20%, the mass ratio of polyurethane prepolymer to epoxy resin is adjusted to 55:45, and the amount of curing agent is adjusted to 20% of the mass of epoxy component, so as to improve the adaptability of the adhesive to the damp interface. When the average moisture content exceeds 20%, the mass ratio of polyurethane prepolymer to epoxy resin is further adjusted to 70:30, and an additional 3% to 5% of silane coupling agent is added to form a stable chemical bond structure at the high moisture content interface.

[0032] The adaptive adjustment method for adhesive ratio described in this application establishes a quantitative correspondence between the average moisture content range and the mass ratio of polyurethane-epoxy components, thereby achieving precise adaptation of the injection material composition to the moisture content state of the wood interface. Under low moisture content conditions, the high-strength adhesive performance of the epoxy component is given priority. Under medium moisture content conditions, the wetting and penetration ability of the adhesive to the moist interface is enhanced by increasing the proportion of polyurethane. Under high moisture content conditions, the proportion of polyurethane is further increased and a silane coupling agent is introduced to construct a stable covalent chemical bond layer at the moisture-containing interface. Through the systematic switching of the three-level ratio strategy, curing defects and bonding failures caused by mismatch between the adhesive formulation and the interface moisture content are effectively avoided. Thus, high-quality interfacial bonding between the injection material and the pore walls of the wood can be achieved under different moisture content conditions, significantly improving the mechanical properties and durability of the reinforced structure.

[0033] Furthermore, the method of adding molecular sieve powder to the adjusted adhesive solution to form a modified injection material is as follows: Select 3A or 4A type synthetic zeolite molecular sieve powder and control its particle size to the range of 5 to 15 μm; The synthetic zeolite molecular sieve powder was activated at 120℃ for no less than 4 hours. After activation, it was placed in a dry and sealed environment for later use. The amount of molecular sieve powder added was determined based on the moisture content distribution data. The base amount was 3% of the total mass of the adhesive solution, and it was adjusted by increasing by 1% for every 5% increase in the average moisture content of the nodes. The total amount of molecular sieve powder added did not exceed 8% of the total mass of the adhesive solution. The activated molecular sieve powder was added to the adjusted adhesive solution and stirred for no less than 5 minutes at 500-800 rpm using a planetary mixer to form a uniformly dispersed system. Aluminum hydroxide micro powder, accounting for 1% to 2% of the total mass, is added simultaneously during the stirring process to obtain the modified injection material.

[0034] The method for preparing the aforementioned molecular sieve-modified injection material in this application involves selecting 3A or 4A type synthetic zeolite molecular sieves with a particle size of 5–15 μm and subjecting them to thorough activation treatment. This enables the molecular sieves to efficiently adsorb residual moisture within the pores, thereby eliminating the adverse interference of free water in the interface of damp wood on the curing process of the adhesive. By dynamically adjusting the molecular sieve dosage based on the average moisture content of the nodes, a precise match between the water absorption capacity and the interface moisture content is achieved. Uniform dispersion treatment using a planetary mixer ensures that the molecular sieve particles are evenly distributed in the adhesive system, avoiding local curing defects caused by agglomeration. Simultaneous introduction of aluminum hydroxide micropowder enhances the flame retardant properties and thermal stability of the modified injection material, thereby significantly improving the curing quality of the injection material at high moisture content wood interfaces and enhancing the mechanical reliability and fire resistance durability of the reinforced structure.

[0035] Furthermore, the method for injecting modified infusion material into the node via a microporous array is as follows: The micropore array is divided into an upper injection zone, a middle injection zone, and a lower injection zone according to its spatial location. Injection is carried out sequentially from the lower injection zone to the upper injection zone, so that the subsequent injection pressure drives the residual bubbles in the previous injection zone to escape upward. During the injection process in each zone, the initial injection pressure is set to 0.3-0.5 MPa based on the node size and channel length, and the injection operation is performed on each micropore in sequence. When adhesive overflow occurs in a microwell, record the total amount injected into the corresponding well, seal the microwell, and switch to the adjacent microwell to continue injection. For holes where the amount of overflow adhesive is less than 30% of the estimated injection amount, a second injection should be performed 2 to 4 hours after the first injection is completed and the adhesive has initially set. The pressure of the second injection should not exceed 1.5 times the pressure of the first injection. During the injection process, the pressure change curve of each micropore is monitored in real time. When the pressure drops suddenly, the injection is paused and the presence of cross-holes or leakage of adhesive is detected. After all injections are completed, the mixture should be left to cure at room temperature for no less than 72 hours. After 24 hours of curing, a preliminary curing uniformity test should be conducted using the hammering sound method. Abnormal areas should be marked and included in subsequent reinforcement treatment.

[0036] The modified grouting material injection method described in this application divides the micropore array into upper, middle, and lower injection zones and adopts a bottom-up injection sequence. The combined effect of gravity and injection pressure drives residual air bubbles within the pores to continuously escape upwards, effectively reducing porosity defects within the grouting body. By setting the initial injection pressure based on the node size and pore length, it ensures the modified grouting material penetrates the wood's micropores and microcracks at an appropriate pressure. Through overflow monitoring and a secondary injection mechanism, areas with insufficient filling during the initial injection are promptly compensated. Real-time pressure curve monitoring during the injection process identifies and addresses abnormalities such as cross-holes or external leakage. A combined quality control process, including 72-hour static curing and 24-hour initial setting uniformity testing, ensures the modified grouting material achieves complete, continuous, and uniform curing within the wood frame nodes, thereby significantly improving the internal density of the grouting and the overall mechanical properties of the reinforced structure.

[0037] Furthermore, the prefabricated composite functional panel comprises, from the outside in, a fireproof surface layer, a structural load-bearing core layer, and a corrosion-resistant slow-release layer, with the structure and function of each layer as follows: The fireproof surface layer is an intumescent inorganic fireproof board with a thickness of 3-5mm. Its matrix is ​​made of calcium silicate fiber reinforced cement material and is internally mixed with a composite intumescent flame retardant system of ammonium polyphosphate and pentaerythritol. When the temperature exceeds 200℃, the expansion ratio of the fireproof surface layer is not less than 10 times to form a dense heat-insulating carbonized layer. The load-bearing core layer of the structure is a bamboo fiber reinforced polymer-based composite board with a thickness of 8-12 mm, wherein the volume fraction of bamboo fiber is 40%-50%; after alkali treatment and surface modification treatment with silane coupling agent, the bamboo fiber has a bending strength of not less than 80 MPa, an elastic modulus of not less than 8 GPa, and has the elastic deformation coordination ability to match the wooden frame. The anti-corrosion slow-release layer is a microcapsule-loaded functional coating with a thickness of 1-2 mm. The microcapsules use melamine-formaldehyde resin as the wall material and encapsulate a composite anti-corrosion agent of zinc borate and zinc oxide nanoparticles with a mass ratio of 1:1. When the wood frame joints are in a humid environment or a microbial erosion environment, the microcapsules will break down and release the anti-corrosion agent to achieve a continuous slow-release anti-corrosion effect for no less than 10 years. The prefabricated composite functional panels are processed into L-shaped, T-shaped or cross-shaped structures according to the node geometry during the factory prefabrication process, and are selected according to the node type during on-site installation so that the splicing seams avoid the main stress transmission area.

[0038] The prefabricated composite functional panel described in this application integrates fire resistance, structural reinforcement, and corrosion protection into a single component through a three-layer functional composite design consisting of a fire-resistant surface layer, a structural load-bearing core layer, and a corrosion-resistant slow-release layer, achieving integrated installation. The fire-resistant surface layer forms a dense, heat-insulating carbonized layer with an expansion ratio of not less than 10 times at high temperatures, effectively blocking heat conduction to the timber frame. The structural load-bearing core layer, with a bending strength of not less than 80 MPa, an elastic modulus of not less than 8 GPa, and elastic deformation coordination capabilities matching the timber frame, bears the structural load transfer in the joint area. The corrosion-resistant slow-release layer, through a microcapsule responsive cell-wall breaking mechanism, continuously releases composite anti-corrosion active agents in humid and microbial erosion environments, achieving long-term corrosion protection for not less than 10 years. By prefabricating various joint adaptation forms such as L-shaped, T-shaped, or cross-shaped joints in the factory, it ensures that the splicing seams avoid the main stress areas, thereby improving the overall fire resistance, structural load-bearing capacity, and long-term corrosion resistance of the timber frame joints.

[0039] Furthermore, the preparation method of the elastic MS sealant is as follows: MS sealant base material is selected, and anti-corrosion components are introduced according to a preset ratio. The anti-corrosion components include nano zinc oxide, 8-hydroxyquinoline copper complex and organosilicon quaternary ammonium salt. Nano zinc oxide was surface modified with silane coupling agent KH-560, and modified nano zinc oxide with a particle size of 20-50 nm was added to MS sealant base material at a ratio of 2%-3% of the total mass of sealant to form a modified nano zinc oxide initial mixture system. The modified nano zinc oxide initial mixture system was dispersed using a high-speed disperser at a speed of 2000-3000 rpm for 15 min to form a uniformly dispersed nanocomposite system. The 8-hydroxyquinoline copper complex and the organosilicon quaternary ammonium salt were pre-dissolved in propylene glycol solvent at a mass ratio of 3:2 to form an anti-corrosion mixed solution. The anti-corrosion mixed solution was then added to the nanocomposite uniform dispersion system and mixed and stirred to form a premixed modified MS sealant system. The 8-hydroxyquinoline copper complex accounted for 1% to 1.5% of the total mass of the sealant, and the organosilicon quaternary ammonium salt accounted for 0.5% to 1% of the total mass of the sealant.

[0040] The preparation method of the aforementioned elastic MS sealant in this application constructs a multi-mechanism synergistic anti-corrosion system by introducing three anti-corrosion components: nano-zinc oxide, 8-hydroxyquinoline copper complex, and organosilicon quaternary ammonium salt. This system covers inorganic antibacterial, metal-organic complex antibacterial, and organosilicon quaternary ammonium salt long-lasting bactericidal functions, respectively. The nano-zinc oxide is surface-modified using the silane coupling agent KH-560, significantly improving the interfacial compatibility between the nanoparticles and the sealant matrix. High-speed dispersion at 2000–3000 rpm ensures uniform distribution of the nano-zinc oxide in the sealant matrix, preventing uneven anti-corrosion performance due to particle agglomeration. The 8-hydroxyquinoline copper complex and organosilicon quaternary ammonium salt are pre-dissolved in propylene glycol solvent and then mixed in stepwise to ensure uniform dispersion and compatibility stability of the organic anti-corrosion active components. This endows the elastic MS sealant with excellent elastic sealing performance while possessing long-lasting and broad-spectrum anti-corrosion and antibacterial capabilities, meeting the anti-corrosion and sealing requirements of timber frame joint areas under long-term humid conditions.

[0041] Furthermore, the method for applying elastic MS sealant to the joint between the edge of the precast composite functional panel and the timber frame node is as follows: Masking tape is applied to both sides of the joint between the edge of the precast composite functional panel and the node of the wooden frame to define the boundary of the sealant application. Dust removal treatment is performed on the joint base surface, and a corresponding primer is applied according to the base material to improve the interfacial adhesion performance between the sealant and the base. During the drying process of the primer, polyethylene foam rods are inserted into the bottom of the joint to control the thickness and filling depth of the sealant joint. After the primer has dried, use a pneumatic caulking gun to continuously inject elastic MS sealant into the joint to form a continuous sealant layer inside the joint. The injected elastic MS sealant is compacted and shaped to ensure a tight bond between the elastic MS sealant and the substrate on both sides of the joint. After the shaping is completed, remove the masking tape and cure the joint area to complete the joint sealing construction.

[0042] The sealant application method described in this application defines the application boundary using masking tape, ensuring neat sealant seam lines and clear edges. Dust removal and targeted primer application to the joint surface significantly enhance the interfacial bonding strength between the elastic MS sealant and the two dissimilar substrates of wood and functional boards. Polyethylene foam rods control the sealant filling depth, enabling precise control of sealant dosage and joint cross-sectional dimensions, ensuring the sealant's elastic deformation performance under stress. Continuous injection using a pneumatic caulking gun combined with compaction and shaping ensures the sealant fully fills the joint and adheres tightly to both substrates, eliminating interfacial air gaps and voids. This forms a continuous sealing layer with excellent elastic sealing and anti-corrosion / antibacterial functions, effectively resisting external moisture penetration and microbial erosion, ensuring long-term airtightness and durability of the timber frame joint area.

[0043] Furthermore, the method for jointly determining the sealing performance of the continuous sealing layer and the bonding status of the functional panels based on simultaneous detection of infrared thermal imaging and acoustic response is as follows: Establish testing conditions for continuous sealing layers and functional board node areas to form infrared thermal imaging testing conditions, acoustic response testing conditions, and airtightness testing conditions. The node region is heated, and an infrared thermal image sequence is acquired during the cooling process after heating is stopped. The temperature decay characteristics in the infrared thermogram sequence were analyzed to identify hollow areas and abnormal bonding areas on the back of the functional board. The functional board surface is subjected to point-by-point tapping excitation according to the grid spacing, and the corresponding acoustic response signals are collected simultaneously. Characteristic analysis of the resonant frequency and attenuation coefficient in the acoustic response signal is performed to determine the range of hollowness and bonding status of the functional board; A leak detection medium is coated on the surface of the continuous sealing layer, and a positive pressure airflow is applied to the back side of the sealing layer to detect the location of leakage in the continuous sealing layer. For areas inaccessible on the back side of the sealing layer, infrared thermal imaging is used to identify localized areas of abnormal temperature caused by leakage, in order to help determine the location of the leakage. The results of infrared thermal imaging, acoustic response, and airtightness testing are comprehensively analyzed, and the sealing performance of the continuous sealing layer and the bonding status of the functional panel are jointly determined based on preset thresholds.

[0044] The aforementioned joint acceptance testing method integrates three non-destructive testing methods—infrared thermal imaging, acoustic response, and airtightness testing—to form a multi-dimensional cross-verification mechanism. Infrared thermal imaging accurately identifies hollow areas and abnormal bonding areas on the back of the functional panel by analyzing the temperature decay characteristics during the cooling process. Acoustic response testing quantitatively determines the range of hollow areas and bonding quality of the functional panel through point-by-point tapping excitation and characteristic analysis of resonant frequency and attenuation coefficient. Airtightness testing, combined with the application of leak detection medium and positive pressure airflow, directly locates the leakage position of the sealing layer and uses infrared thermal imaging to assist in identifying leakage points in inaccessible areas on the back side. Through comprehensive analysis of the three types of test results and joint judgment with preset thresholds, a comprehensive and accurate evaluation of the sealing performance of the continuous sealing layer and the bonding status of the functional panel is achieved, thereby significantly reducing the risk of missed inspections during acceptance and ensuring that the quality of the integrated reinforcement and fireproofing / corrosion protection of the timber frame joints meets the preset engineering standards.

[0045] Furthermore, the supplementary sealing and reinforcement process is specifically divided into the following three treatment scenarios: In the first scenario, when there is localized leakage in the continuous sealing layer, the original sealant should be cut off along the leakage section. The cutting area should cover at least 50mm beyond each end of the leakage section. After the cutting is completed, the base coat should be reapplied and the foam rod should be filled. The elastic MS sealant should be reapplied according to the original construction process. After curing for 24 hours, the air tightness test should be carried out again. The second scenario involves localized hollow areas on the functional panel, where the hollow area does not exceed 15% of the area of ​​a single functional panel. In this case, a 5mm diameter injection hole is drilled in the center of the hollow area. Low-viscosity epoxy resin is injected into the hollow cavity through an injection needle at a pressure of 0.2–0.3 MPa until stable overflow of resin appears in adjacent areas. After the resin injection is completed, bolts are used to assist in pressure curing. Acoustic testing is then performed to verify the curing process. The third scenario is when the hollow area of ​​a functional panel exceeds 15% of the area of ​​a single functional panel or when the functional panel separates completely from the node substrate. In this case, the functional panel is removed directly, and the substrate is re-polished, cleaned, and treated with an interface agent. Then, a new precast composite functional panel is installed and the complete acceptance and testing process is repeated.

[0046] The supplementary sealing and reinforcement process described in this application employs precise treatment plans for three typical quality defects: localized leakage in the sealing layer, localized hollowing of functional panels, and overall separation of functional panels. This ensures a precise match between defect levels and treatment measures. For localized leakage defects, a repair method involving excision, extension, and re-applying the original process is used to ensure the continuity of the repaired sealant section with the surrounding intact sealing layer. For small-area hollowing defects, a method of injection filling and bolt-assisted pressure curing is used to restore the bonding quality without removing the functional panels, reducing repair costs and construction interference. For large-area hollowing or overall separation defects, a method of complete removal and replacement is used to ensure that the substrate interface quality of the reinstalled functional panels meets installation requirements. Through the organic connection of the three-level treatment process and the closed-loop re-inspection mechanism, all quality defects are ensured to be thoroughly addressed before acceptance, thereby guaranteeing the overall project quality of integrated reinforcement, fireproofing, and corrosion protection of timber frame nodes.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for integrating reinforcement, fireproofing, and corrosion prevention of joints in traditional residential wooden structures, characterized in that, Includes the following steps: Based on moisture content distribution data and coating type information, a micropore array is drilled in the node reinforcement area according to a preset hole spacing, and supercritical carbon dioxide fluid is injected into the node through the micropore array to open the wood pore structure. The mixing ratio parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive were adaptively adjusted based on the moisture content distribution data, and molecular sieve powder was added to the adjusted adhesive to form a modified injection material. Modified infusion material is injected into the node through a microporous array, allowing it to penetrate into the wood pores and microcracks and solidify into shape. Prefabricated composite functional panels are installed on the outside of the nodes to ensure that the anti-corrosion slow-release layer adheres to the base of the timber frame node.

2. The integrated processing method according to claim 1, characterized in that, The method for drilling a micro-hole array according to a preset hole spacing is as follows: Based on the moisture content distribution data, the node areas of the wooden components to be reinforced are divided into moisture content zones. Different micropore spacing parameters are set according to different moisture content zoning types to form a differentiated pore layout scheme; Based on the aforementioned differentiated hole layout scheme, a low-speed, high-torque pneumatic micro-drill is used for micro-hole array drilling.

3. The integrated processing method according to claim 1, characterized in that, The method of injecting supercritical carbon dioxide fluid into the node via a micropore array is as follows: Dry nitrogen gas at a pressure of 0.2 MPa was used to pre-purge the micropore channels for a period of not less than 30 seconds to remove residual moisture and drilling debris from the channels. The sealed injection connectors are fixed one by one to the openings of each micropore and connected to the constant pressure carbon dioxide supply system through pipelines to construct a closed injection channel; The carbon dioxide fluid is pressurized at a rate not exceeding 0.5 MPa / min and simultaneously heated to above 31.1°C to bring the carbon dioxide to a supercritical state before being injected under stable pressure. A staged pressure injection strategy is used for permeation treatment to achieve further permeation and extraction into the pores; After injection, a gradient depressurization process is performed at a depressurization rate not exceeding 0.3 MPa / min; After depressurization, the patency of the micropore array is tested using 0.05MPa dry nitrogen gas, and the pore continuity is determined based on the pressure drop rate. At the same time, abnormal pores are marked and unblocked.

4. The integrated processing method according to claim 1, characterized in that, The method for adaptively adjusting the mixing parameters of the two-component moisture-curing polyurethane-epoxy hybrid adhesive based on moisture content distribution data is as follows: The average moisture content of the area to be reinforced is calculated based on the moisture content distribution data, and the corresponding adhesive mixing parameters are determined according to the average moisture content range. When the average moisture content is less than 12%, a formula with a polyurethane prepolymer to epoxy resin mass ratio of 40:60 is adopted, and the amount of curing agent is set to 25% of the epoxy component mass; When the average moisture content is in the range of 12% to 20%, the mass ratio of polyurethane prepolymer to epoxy resin is adjusted to 55:45, and the amount of curing agent is adjusted to 20% of the mass of epoxy component. When the average moisture content exceeds 20%, the mass ratio of polyurethane prepolymer to epoxy resin is further adjusted to 70:30, and an additional 3% to 5% silane coupling agent is added to the total adhesive solution.

5. The integrated processing method according to claim 1, characterized in that, The method of injecting modified infusion material into the node via a microporous array is as follows: The micropore array is divided into an upper injection zone, a middle injection zone, and a lower injection zone according to its spatial location. Injection is carried out sequentially from the lower injection zone to the upper injection zone, so that the subsequent injection pressure drives the residual bubbles in the previous injection zone to escape upward. During the injection process in each zone, the initial injection pressure is set to 0.3-0.5 MPa based on the node size and channel length, and the injection operation is performed on each micropore in sequence. When adhesive overflow occurs in a microwell, record the total amount injected into the corresponding well, seal the microwell, and switch to the adjacent microwell to continue injection. For holes where the amount of overflow adhesive is less than 30% of the estimated injection amount, a second injection should be performed 2 to 4 hours after the first injection is completed and the adhesive has initially set. The pressure of the second injection should not exceed 1.5 times the pressure of the first injection. During the injection process, the pressure change curve of each micropore is monitored in real time. When the pressure drops suddenly, the injection is paused and the presence of cross-holes or leakage of adhesive is detected. After all injections are completed, the mixture should be left to cure at room temperature for no less than 72 hours. After 24 hours of curing, a preliminary curing uniformity test should be conducted using the hammering sound method. Abnormal areas should be marked and included in subsequent reinforcement treatment.

6. The integrated processing method according to claim 1, characterized in that, The integrated processing method further includes: Nickel-titanium alloy shape memory bolts are used to connect and fix the prefabricated composite functional panels, and the martensitic phase transformation recovery is triggered by heating, so that it applies a uniform preload force within a preset range to the prefabricated composite functional panels. Apply a premixed elastic MS sealant containing anti-corrosion components to the joint between the edge of the prefabricated composite functional panel and the node of the timber frame to form a continuous sealing layer.

7. The integrated processing method according to claim 6, characterized in that, The preparation method of elastic MS sealant is as follows: MS sealant base material is selected, and anti-corrosion components are introduced according to a preset ratio. The anti-corrosion components include nano zinc oxide, 8-hydroxyquinoline copper complex and organosilicon quaternary ammonium salt. Nano zinc oxide was surface modified with silane coupling agent KH-560, and modified nano zinc oxide with a particle size of 20-50 nm was added to MS sealant base material at a ratio of 2%-3% of the total mass of sealant to form a modified nano zinc oxide initial mixture system. The modified nano zinc oxide initial mixture system was dispersed using a high-speed disperser at a speed of 2000-3000 rpm for 15 min to form a uniformly dispersed nanocomposite system. The 8-hydroxyquinoline copper complex and the organosilicon quaternary ammonium salt were pre-dissolved in propylene glycol solvent at a mass ratio of 3:2 to form an anti-corrosion mixed solution. The anti-corrosion mixed solution was then added to the nanocomposite uniform dispersion system and mixed and stirred to form a premixed modified MS sealant system. The 8-hydroxyquinoline copper complex accounted for 1% to 1.5% of the total mass of the sealant, and the organosilicon quaternary ammonium salt accounted for 0.5% to 1% of the total mass of the sealant.

8. The integrated processing method according to claim 7, characterized in that, The method for applying elastic MS sealant to the joint between the edge of the precast composite functional panel and the timber frame node is as follows: Masking tape is applied to both sides of the joint between the edge of the precast composite functional panel and the node of the wooden frame to define the boundary of the sealant application. Dust removal treatment is performed on the joint base surface, and a corresponding primer is applied according to the base material to improve the interfacial adhesion performance between the sealant and the base. During the drying process of the primer, polyethylene foam rods are inserted into the bottom of the joint to control the thickness and filling depth of the sealant joint. After the primer has dried, use a pneumatic caulking gun to continuously inject elastic MS sealant into the joint to form a continuous sealant layer inside the joint. The injected elastic MS sealant is compacted and shaped to ensure a tight bond between the elastic MS sealant and the substrate on both sides of the joint. After the shaping is completed, remove the masking tape and cure the joint area to complete the joint sealing construction.

9. The integrated processing method according to claim 6, characterized in that, The integrated processing method further includes: Based on simultaneous detection of infrared thermal imaging and acoustic response, the sealing performance of the continuous sealing layer and the bonding status of the functional board are jointly judged to determine whether the preset acceptance criteria are met. If the requirements are not met, a supplementary sealing and reinforcement process for the joint area will be triggered until the preset acceptance standards are met. If the conditions are met, the timber frame node is deemed to have completed integrated reinforcement, fireproofing, and corrosion protection.

10. The integrated processing method according to claim 9, characterized in that, The method for jointly determining the sealing performance of continuous sealing layers and the bonding status of functional panels based on simultaneous detection of infrared thermal imaging and acoustic response is as follows: Establish testing conditions for continuous sealing layers and functional board node areas to form infrared thermal imaging testing conditions, acoustic response testing conditions, and airtightness testing conditions. The node region is heated, and an infrared thermal image sequence is acquired during the cooling process after heating is stopped. The temperature decay characteristics in the infrared thermogram sequence were analyzed to identify hollow areas and abnormal bonding areas on the back of the functional board. The functional board surface is subjected to point-by-point tapping excitation according to the grid spacing, and the corresponding acoustic response signals are collected simultaneously. Characteristic analysis of the resonant frequency and attenuation coefficient in the acoustic response signal is performed to determine the range of hollowness and bonding status of the functional board; A leak detection medium is coated on the surface of the continuous sealing layer, and a positive pressure airflow is applied to the back side of the sealing layer to detect the location of leakage in the continuous sealing layer. For areas inaccessible on the back side of the sealing layer, infrared thermal imaging is used to identify localized areas of abnormal temperature caused by leakage, in order to help determine the location of the leakage. The results of infrared thermal imaging, acoustic response, and airtightness testing are comprehensively analyzed, and the sealing performance of the continuous sealing layer and the bonding status of the functional panel are jointly determined based on preset thresholds.

Images