Construction process of bi-component nano acrylate modified concrete grouting material

Abstract

The invention discloses a construction process of a bi-component nano acrylate modified concrete grouting material, the grouting material is an A-B bi-component system, and the 28d compressive strength of the grouting material is greater than or equal to 80MPa; according to the construction process, a multi-dimensional information fused defect accurate diagnosis system is constructed, a scene-divided preprocessing process is designed for three defects of microcracks, interface void and bolt hole leakage, and a grouting system composed of a double-liquid grouting pump, an 18-element static mixer and a dynamic pressure feedback module is matched. Dynamic regulation and control of grouting pressure, flow and setting time are achieved, and the self-repairing function of the material is activated by controlling the pH value of a crack area; meanwhile, a special process adjustment scheme is formulated for a severe environment, and a three-stage quality detection system of process detection-short-term effect-long-term tracking is established; the material can be suitable for repairing 0.1-0.5 mm micro-cracks of a heavy-load concrete structure, filling interface void and treating bolt hole leakage, and is particularly suitable for severe construction environments such as low temperature of-5 DEG C to 10 DEG C and high humidity of which the relative humidity is greater than 85%.

Description

Technical Field

[0001] This invention belongs to the field of concrete grouting material construction technology, and more specifically, relates to a construction process for a two-component nano-acrylate modified concrete grouting material. Background Technology

[0002] Two-component nano-acrylate modified concrete grouting material, with its excellent properties such as nano-phase reinforcement and self-healing, has shown broad application prospects in the fields of repairing micro-cracks (0.1-0.5mm), filling interface voids, and treating bolt hole leakage in heavy-duty concrete structures (such as bridge main beams, tunnel segments, and high-rise building beams and columns). This material can achieve a 28-day compressive strength of ≥80MPa and a 7-day crack repair rate of ≥85%, and can be adapted to harsh construction environments such as low temperatures of -5℃ to 10℃ and high humidity of >85%.

[0003] However, this type of material possesses characteristics such as low viscosity (component A viscosity 55-65 mPa·s, component B viscosity 25-35 mPa·s) and a setting time that can be flexibly adjusted within the range of 30s-60min. Furthermore, the activation of its self-healing function depends on specific environmental conditions, which places far higher demands on the precision of construction process parameters and the adaptability to different scenarios compared to traditional grouting materials. Currently, existing construction processes are difficult to match the performance characteristics of this material, exhibiting the following core technical deficiencies: Mismatched grouting parameters lead to significant grout loss or pipe blockage issues: Existing processes do not design grouting pressure, flow rate, and setting time parameters specifically for the low viscosity, fast setting, and adjustable characteristics of the materials. This can easily result in grout loss rates exceeding 20% ​​during construction, or blockage of grouting pipelines due to excessively rapid setting, severely impacting construction efficiency and repair effectiveness. Poor sealing and penetration effect of grouting for microcracks: When constructing for microcracks of 0.1-0.5mm, there is a lack of special grouting sealing devices. Conventional grouting needles cannot form an effective seal with the crack borehole, resulting in the grout penetration depth generally being ≤30mm, which cannot achieve sufficient filling of the deep part of the crack. Insufficient activation of self-healing function and low repair efficiency: The existing process does not accurately control the pH value of the crack seepage area (the material needs to trigger the rupture of self-healing microcapsules in an environment of pH≤6.0), which makes it difficult for the material's self-healing performance to be fully utilized. The 7-day crack repair rate is usually <60%, which cannot meet the material design standards. Poor process versatility and limited construction efficiency: The existing process has not established a standardized construction process for different types of defects. For different concrete defects such as cracks, voids, and leaks, it is necessary to frequently change and adjust the construction equipment, resulting in a daily repair area of ​​≤50m² and a secondary repair rate of ≥15%, which is difficult to meet the needs of large-scale engineering repair. Poor adaptability to harsh environments: In harsh construction environments such as low temperature and high humidity, the existing process has no targeted adjustment plan, which can easily lead to problems such as reduced grout fluidity, slow curing of sealant, and insufficient curing of grout. The process stability deviation is >10%, which cannot guarantee the construction quality.

[0004] In summary, there is an urgent need to develop a construction process that is highly compatible with the performance of two-component nano-acrylate modified concrete grouting materials and can be precisely controlled according to different scenarios, so as to maximize the performance of the materials and meet the engineering needs of repairing defects in heavy-duty concrete structures. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a construction process for a two-component nano-acrylate modified concrete grouting material. By constructing a complete process system encompassing precise defect diagnosis, scenario-specific pretreatment, dynamic grouting, post-treatment curing, and three-level quality inspection, this process leverages the core performance characteristics of the two-component nano-acrylate modified concrete grouting material: low viscosity, rapid setting, adjustable properties, and self-healing capabilities. Compared to existing construction processes, it possesses significant technical advantages: Firstly, it maximizes the material's performance, achieving a 28-day compressive strength utilization rate ≥95% and a 7-day crack self-healing rate ≥85%, overcoming the technical pain point of insufficient activation of self-healing function in traditional processes. Secondly, through specialized grouting needles and sealing technology, it overcomes the bottleneck of repairing 0.1mm-level micro-cracks, achieving a sealed seal. With a success rate of ≥95% and a grout penetration depth of ≥50mm, it significantly outperforms traditional processes in sealing and penetration. Thirdly, it incorporates specialized adjustments for harsh environments such as low temperatures and high humidity, ensuring process stability deviations of ≤10% and broadening its adaptability to various construction environments. Fourthly, it establishes standardized construction processes categorized by defect type, increasing the daily repair area to ≥100m² and reducing the secondary repair rate to ≤3%, significantly improving construction efficiency and reducing rework costs. Fifthly, relying on a three-tiered quality inspection system to guarantee construction quality extends the service life of repaired heavy-duty concrete structures by 15-20 years, significantly improving long-term structural durability and effectively meeting the engineering needs for micro-crack repair, interface void filling, and bolt hole leakage control in heavy-duty concrete structures such as bridge main beams, tunnel segments, and high-rise building beams and columns.

[0006] To achieve the above objectives, one aspect of the present invention provides a construction process for a two-component nano-acrylate modified concrete grouting material. The two-component nano-acrylate modified concrete grouting material is an A / B two-component system, with a volume ratio of A to B of 1:1. The viscosity of component A is 55-65 mPa·s, and the viscosity of component B is 25-35 mPa·s. The grouting material has a 28-day compressive strength ≥80 MPa. The construction process includes: S1. Precise Defect Diagnosis: High-definition endoscopes, ultrasonic detectors, and impact echometers are used to detect microcracks, interface voids, and bolt hole leaks, respectively, to obtain defect size and water seepage status parameters. S2. Pre-treatment by scenario: Perform surface treatment, drilling, and sealing / protection installation operations according to the defect type. Install special conical grouting needles for micro-cracks and perform epoxy sealing. Install grouting nozzles with check valves for interface voids. Install PTFE protective sleeves for bolt hole leakage. S3, Dynamic Grouting: The grouting system consists of a dual-liquid grouting pump, an 18-element static mixer and a dynamic pressure feedback module. The grouting pressure, flow rate and setting time parameters are adjusted according to the type of defect. At the same time, process adjustments are made for harsh environments. S4. Post-grouting treatment and curing: Remove the grouting pipeline and seal the hole according to the grout setting time. Implement the corresponding curing plan according to the construction environment. Maintain a specific humidity environment in the self-healing area to ensure that the microcapsules are fully broken and CaCO3 is generated to complete the self-healing. S5. Quality Inspection and Acceptance: Establish a three-level inspection system including process inspection, short-term effect inspection, and long-term follow-up inspection to ensure that the construction quality meets the acceptance standards.

[0007] Furthermore, the microcracks mentioned in step S1 are cracks with a width of 0.1-0.5 mm, and the specific steps for accurate defect diagnosis are as follows: A high-definition endoscope was used to scan along the concrete surface and mark the direction, length L, and width w of the cracks. The crack depth d is detected using an ultrasonic detector, and the crack volume V = L × w × d is calculated. A humidity sensor is used to detect the humidity in the crack area. When the humidity is greater than 90%, it is determined to be a water seepage crack. The width w, depth d, and water seepage status of the crack are recorded simultaneously.

[0008] Furthermore, the specific steps for accurate diagnosis of interface void defects in step S1 are as follows: The suspected delamination area was scanned using an impact echo meter. When the wave velocity in the detected area was <3000m / s, it was preliminarily determined to be an interface delamination area. Infrared thermal imagers were used to detect the temperature difference in the preliminarily identified void areas. If the temperature difference between the void area and the surrounding normal concrete area was greater than 2°C, the extent of the void area was further confirmed. By combining the detection results of the shock echo meter and the infrared thermal imager, the specific range of the interface delamination is marked, the delamination area S is determined, the average thickness h of the delamination area is calculated, and it is determined whether there is water accumulation inside the delamination area.

[0009] Furthermore, the specific steps for accurate diagnosis of bolt hole leakage defects in step S1 are as follows: First, seal the bolt holes, then pressurize the holes to 0.44-0.55 MPa and maintain this pressure for 28-32 minutes. Record the pressure changes in real time and calculate the pressure drop ΔP. An endoscope with a diameter ≤5mm is inserted into the bolt hole to observe the distribution and width w1 of the cracks in the hole wall. The leakage level is determined based on the crack width, where w1≤1mm is micro-leakage and w1>1mm is severe leakage. By combining the pressure drop ΔP data and the borehole wall crack width w1, the severity of bolt hole leakage can be determined.

[0010] Furthermore, the specific operations for microcrack pretreatment in step S2 are as follows: For dry cracks, dust is blown away with high-pressure air and oil is wiped off with acetone; for wet cracks, water is first pumped out with a mini water pump and then dried with a hot air gun until the surface humidity is ≤70%; for concrete spalling areas at both ends and intersections of cracks, quick-setting repair mortar with an initial setting time of ≤15min and a compressive strength of ≥30MPa in 24h is used for repair, and the height difference between the repair surface and the original structure is ≤2mm. A dedicated directional drilling machine with a positioning accuracy of ±0.3mm and a rotation speed of 0-3000r / min is used. The drilling parameters are adjusted according to the crack width. Specifically, for cracks of 0.1-0.2mm, the drilling distance is 15-20mm from the crack edge, the hole diameter is 6mm, the hole depth is crack depth d+20mm, and the hole spacing is 100-120mm; for cracks of 0.2-0.5mm, the drilling distance is 20-25mm from the crack edge, the hole diameter is 8mm, the hole depth is crack depth d+30mm, and the hole spacing is 120-150mm. The drilling is at a 45° angle to the crack direction, and the connection rate between the drilling and the crack is ≥95%. Insert a specialized grouting needle with a 1:5 taper at the front end, 4-6 0.8mm side holes with a spacing of 8-10mm into the pipe wall, into the drill hole to a position matching the depth of the crack. After the needle is inserted into the drill hole, inject epoxy sealant with an initial setting time of 30 minutes into the hole opening. The sealant layer thickness should be ≥5mm. After curing for 2 hours, fix the needle and seal the hole opening. Conduct a sealing test with a pressure of 0.3MPa for 5 minutes. No leakage indicates that the test is qualified.

[0011] Furthermore, the specific operations for the interface de-emptying preprocessing in step S2 are as follows: Based on the impact echo meter test results, the boundary of the voided area was marked with an ink line with a deviation of ≤5mm. The surface laitance of the voided area was cleaned with an 80-grit angle grinder to expose the fresh concrete surface; the area of ​​the fresh concrete surface was ≥90% of the voided area. Drill holes in a quincunx pattern 48-52mm inside the boundary of the voided area. The holes need to penetrate the voided layer and be spaced 300-400mm apart. Install grouting nozzles with check valves and use expansion bolts to fix the grouting nozzles to prevent them from falling off during grouting; The specific procedures for the bolt hole leakage pretreatment in step S2 are as follows: Use a torque wrench to loosen the bolt at 50% of the design torque to avoid damaging the threads. Then use a wire brush that matches the bolt hole to clean the rust on the hole wall. After blowing with high-pressure air, use acetone to rinse the hole wall to remove rust. Drill at least 3 angled holes evenly around the bolt hole, with an angle of 15-20° to the axis of the bolt hole, and ensure that they are connected to the bolt hole; Install a PTFE protective sleeve with a thickness of 1.5-2.5mm and an inner diameter matching the bolt inside the bolt hole. Fill the gap between the protective sleeve and the hole wall with water-swellable rubber with an expansion rate of 200% and which completes expansion in 7 days to prevent the grout from contaminating the bolt threads.

[0012] Furthermore, in step S3, the flow rate adjustment range of the dual-liquid grouting pump in the grouting system is 0.1-2 L / min with a flow rate accuracy of ±0.01 L / min, the pressure adjustment range is 0-10 MPa with a pressure accuracy of ±0.05 MPa, and components A and B are independently metered with a ratio deviation ≤2%. The static mixer has 18 mixing elements and a mixing efficiency of ≥98%. The dynamic pressure feedback module includes a pressure sensor with a response time of ≤0.1s and a PLC control system. It can preset the pressure threshold and automatically reduce the flow rate to 50% of the initial value when the grouting pressure reaches 1.2 times the set value.

[0013] Furthermore, the parameters and operational requirements for dynamic grouting of microcracks in step S3 are as follows: For dry cracks, the setting time should be controlled at 20-30 min, the grouting pressure at 0.2-0.3 MPa, the flow rate at 0.2-0.3 L / min, and the target grout diffusion radius at 30-40 mm. For wet cracks, the setting time should be controlled at 10-15 min, the grouting pressure at 0.3-0.5 MPa, the flow rate at 0.3-0.5 L / min, and the target grout diffusion radius at 40-50 mm. The initial grouting pressure rises slowly at a rate of 0.05 MPa / min. When the pressure reaches 1.2 times the set value, the flow rate automatically drops to 50% of the initial value. When the grouting volume reaches 1.5 times the theoretical calculated volume of the crack, maintain the pressure at 0.2 MPa for 10 minutes. Grouting should be stopped when the pressure drop during the pressure holding period is ≤0.05MPa and grout seepage occurs in adjacent grouting holes; 24 hours after the dry crack grouting was completed, deionized water was sprayed on the crack surface to maintain the area humidity at ≥90% for 3 days, triggering the rupture of the self-healing microcapsules. The parameters and operational requirements for the interface de-cavitation grouting are as follows: Grouting sequence for interface delamination: adopt "bottom to top, intermittent skipping" to avoid grout short circuit; The setting time is controlled to be a long setting time of 30-40 minutes; the initial grouting pressure is set to 0.3 MPa, corresponding to an initial grouting flow rate of 0.5 L / min; when grout seeps out of a certain grouting hole, the grouting pressure of that hole needs to be reduced to 0.1 MPa, and grouting continues until grout seeps out of all grouting holes, indicating that the voided area has been filled. One hour after the initial grouting is stopped, all grouting holes need to be replenished a second time. The replenishment pressure is 0.2 MPa, the replenishment flow rate is 0.3 L / min, and the replenishment volume is 10%-15% of the total initial grouting volume. The parameters and operational requirements for the grouting of the bolt holes are as follows: A low-pressure, slow-injection grouting method is adopted; The setting time should be controlled to a medium setting time of 5-8 minutes; The grouting pressure is set to 0.2-0.3 MPa, corresponding to a grouting flow rate of 0.1-0.2 L / min; When the expansion of the PTFE protective sleeve inside the bolt hole is observed through an endoscope, and the grouting pressure stabilizes at 0.3 MPa and remains at that pressure for 5 minutes without significant decrease, grouting can be stopped. 24 hours after grouting is completed and the grout has fully cured, tighten the bolts with a torque wrench to the designed torque, with a torque deviation of ≤5%. The process adjustments for harsh environments mentioned in step S3 include: In a low-temperature environment of -5℃ to -10℃, components A and B are placed in a 50℃ constant temperature box for 2 hours before grouting to raise the material temperature to 15-20℃, while extending the grout setting time by 20-30% and increasing the grouting pressure by 0.1MPa. In high humidity environments with relative humidity > 85%, increase the number of times the concrete surface is wiped with acetone to 2-3 times to ensure that the surface is free of moisture; use fast-setting epoxy sealant; after grouting is completed, cover with a 0.1mm thick waterproof membrane and cure for 14 days.

[0014] Furthermore, the post-grouting treatment and curing described in step S4 includes: The timing of grout pipe removal is determined according to the grout setting time. After removal, epoxy mortar is used to seal the opening, with a sealing depth of ≥20mm and flush with the original structure. Remove excess grout from the surface after grouting; under normal conditions, use water spraying at 20-25℃ for curing, 3 times a day, for a curing cycle of 7 days; under low temperature conditions, cover with thermal insulation cotton to keep the curing temperature ≥5℃; under high humidity conditions, cover with waterproof membrane. The curing cycle for both types of harsh environments is 14 days. For self-healing areas, humidity should be checked weekly within 7 days after grouting and maintained at ≥80%.

[0015] Furthermore, the requirements for the three-level inspection system for quality inspection and acceptance in step S5 are as follows: During process testing, the flow ratio of components A and B is monitored in real time using a dual-liquid pump flow sensor to ensure it is 1:1 with a deviation of ≤2%. Grouting pressure and flow rate are recorded every 5 minutes with a deviation of ≤10%. Ultrasonic testing shows that the connectivity between grouting holes and cracks is ≥95%. In short-term performance testing, 7-28 days after grouting, the surface showed no dampness or leakage, the pore openings were smoothly sealed, the closure rate of 0.1-0.2mm cracks was ≥90%, the closure rate of 0.2-0.5mm cracks was ≥85%, the compressive strength after 28 days of core sampling was ≥80MPa, the interfacial bond strength after pull-out testing was ≥5MPa, and the strength recovery rate after 7 days of curing for manually cut 0.3mm microcracks was ≥85%. During long-term monitoring, after 1 year, ultrasonic testing showed an internal density of ≥95% with no voids; after 2 years, infrared thermal imaging showed a temperature difference of ≤1℃ with no voids; and after 3 years, 0.5MPa water pressure was maintained for 30 minutes with no leakage and no secondary cracking in the self-repairing area.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) By dynamically adjusting key parameters such as grouting pressure, flow rate, and setting time, and precisely controlling the environmental conditions for activating the self-healing function, the present invention enables the 28-day compressive strength utilization rate of the two-component nano-acrylate modified concrete grouting material to be ≥95%, which is much higher than the 70%-80% of the traditional process; and the self-healing rate of the material cracks at 7 days is ≥85%, which can solve the technical pain point of self-healing rate <60% under the traditional process, and give full play to the nano-reinforcement and self-healing characteristics of the material.

[0017] (2) The present invention uses a special grouting needle for microcracks with a front taper of 1:5 and a side hole of a specific specification on the pipe wall. Combined with a standardized epoxy sealing process, it can achieve a grouting and sealing success rate of ≥95% for microcracks of 0.1mm level and a grout penetration depth of ≥50mm. Compared with the penetration depth of ≤30mm under the traditional process, it can significantly improve the filling effect of deep microcracks and ensure a closure rate of ≥90% for microcracks of 0.1-0.2mm and a closure rate of ≥85% for microcracks of 0.2-0.5mm.

[0018] (3) The present invention has designed a special process adjustment scheme for harsh construction environments such as low temperature (-5℃-10℃) and high humidity (relative humidity > 85%), so that the process stability deviation is ≤10%, and it can be stably constructed in the temperature range of -5℃-40℃ and in high humidity environment. It can solve the problems of insufficient slurry fluidity, slow sealing and curing, and poor slurry forming quality in harsh environments of the existing process.

[0019] (4) This invention addresses three typical concrete defects: microcracks, interface voids, and bolt hole leakage. It constructs a standardized construction process for different scenarios, eliminating the need for frequent adjustments to construction equipment and achieving a daily repair area of ​​≥100m², which is more than twice the repair efficiency of the traditional process of ≤50m² per day. At the same time, the standardization of the process results in a secondary repair rate of ≤3%, which is much lower than the repair rate of ≥15% of the traditional process, thereby significantly reducing the cost of rework.

[0020] (5) This invention establishes a three-level quality inspection system of “process inspection - short-term effect - long-term tracking”. After long-term tracking and inspection, the internal density of the concrete structure repaired by this process is ≥95% after 1 year of ultrasonic testing and there are no voids. After 2 years, the infrared temperature difference is ≤1℃ and there are no voids. After 3 years of water pressure test, there is no leakage and no secondary cracking in the self-repair area. It can extend the service life of heavy-duty concrete structures by 15-20 years. Compared with the traditional process, the service life extension period is only 5-8 years, and the durability improvement effect is significant. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the network structure characteristics of a two-component nano-acrylate modified concrete grouting material according to an embodiment of the present invention. Figure 2 This is a schematic flowchart illustrating the preparation method of a two-component nano-acrylate modified concrete grouting material according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] One aspect of the present invention provides a two-component nano-acrylate modified concrete grouting material (such as... Figure 1As shown, the grouting material is prepared by mixing component A (main phase) and component B (functional initiator phase) in a volume ratio of 1:1. Component A, by mass parts, includes: 20-35 parts of calcium acrylate-magnesium acrylate composite monomer, 8-15 parts of nano-modified filler, 5-10 parts of silicon precursor, 0.1-0.5 parts of crosslinking agent, 3-8 parts of thickener, 1.0-3.0 parts of accelerator, 0.2-0.8 parts of pH adjuster, and 40-60 parts of deionized water. Component B, by mass parts, includes: 0.8-2.5 parts of initiator, 0.05-0.3 parts of composite catalyst, and 0.5-1.5 parts of dispersion stabilizer. The grouting material comprises 3-8 parts of pH-responsive microcapsules, 10-20 parts of liquid metal-coated steel fiber suspension, and 30-50 parts of deionized water; the initiator is composed of ammonium persulfate (APS) and potassium persulfate (KPS) in a 2:1 mass ratio; the grouting material has a 28-day compressive strength ≥80MPa, flexural strength ≥8MPa, interfacial bond strength ≥5MPa, a 7-day repair rate of 0.3mm cracks ≥85%, and a mass loss ≤1% after 300 freeze-thaw cycles; the strength change after 6 months of storage at 25℃ is ≤10%; the VOC content is ≤1g / L according to GB18583-2008 standard, and the raw material LD50 is ≤1g / L according to acute oral toxicity test. 50 >5000mg / kg.

[0024] Further, in component A, the mass ratio of calcium acrylate to magnesium acrylate in the calcium-magnesium acrylate composite monomer is 2:1-3:1, and the degree of neutralization is 92-96%; the preparation parameters for the calcium-magnesium acrylate composite monomer are: reacting acrylic acid with calcium hydroxide and magnesium hydroxide at 35-40℃ for 60-90 min, stirring speed 300 r / min, and pH controlled at 7.5-8.5; the nano-modified filler includes 3-5 parts of modified graphene, 3-6 parts of nano-metakaolin, and 2-4 parts of silicon carbide whiskers; the preferred mass ratio of the modified graphene, nano-metakaolin, and silicon carbide whiskers is 3:3:2; the modified graphene is TiO2 intercalated and modified with a particle size of 20-30 nm and a specific surface area ≥800 m². 2 / g; the modified graphene preparation includes: mixing expanded graphite with 98% concentrated sulfuric acid at a ratio of 1:30, adding potassium permanganate at a ratio of 1:1 and reacting for 1 hour, terminating with hydrogen peroxide at a ratio of 1:3, sonicating at 120-140℃ for 2 hours, adding carbon tetrachloride-butyl titanate at a ratio of 1:1, and hydrothermally heating at 130℃ for 2 hours; the nano-metakaolin has a specific surface area ≥200m². 2 / g; the silicon carbide whiskers have a diameter of 0.5-1μm, a length of 10-20μm, and an aspect ratio of 20-40; the silicon precursor is composed of tetraethyl orthosilicate (TEOS) and silica sol with a solid content of 30% in a 1:2 mass ratio, with a gel time of ≥48h at 25℃ and a hydrolysis rate of ≥90% (24h at 25℃); the crosslinking agent is composed of N,N'-methylenebisacrylamide (MBA) and divinylbenzene (DVB) in a 5:1 mass ratio, wherein MBA is used for rapid crosslinking (crosslinking degree ≥60% within 1h), and DVB is used to improve aging resistance; the tackifier is an acrylic ternary polymer with a solid content of 42-45%, a particle size of 100-200nm, and a minimum film-forming temperature ≤5℃. The copolymer emulsion, after being mixed with acrylate monomers and allowed to stand for 72 hours without stratification, is used to improve the stability of component A (storage period ≥ 6 months) and reduce flowability loss (≤ 10% in 30 min). The accelerator is composed of triethanolamine (TEA) and calcium formate in a 3:1 mass ratio, where TEA is used to accelerate the decomposition of the initiator (increasing the reaction rate by 2-3 times), and calcium formate is used to improve early strength (3-day strength ≥ 50 MPa). The pH adjuster is a 10% sodium hydroxide / potassium hydroxide aqueous solution, used to adjust the pH of component A to 8.0-9.0 to optimize the hydrolysis rate of the silicon precursor. The deionized water has a conductivity ≤ 10 μS / cm, is free of impurities, and the water-to-binder ratio of component A is 0.3-0.4. Furthermore, the initiator in component B is composed of ammonium persulfate (APS) and potassium persulfate (KPS) in a mass ratio of 2:1. APS has high activity (capable of initiating at temperatures ranging from 5 to 40°C), while KPS exhibits good thermal stability. The combined initiation efficiency is ≥95%, and it dissolves completely within 30 minutes at 25°C. The composite catalyst is composed of ferrous sulfate (FeSO4) and sodium bisulfite (NaHSO3) in a mass ratio of 1:3, and is activated by Fe... 2+ The initiator decomposition activation energy is reduced, and NaHSO3 inhibits oxygen polymerization. The dispersant stabilizer is composed of polyethylene glycol 400 (PEG400) and sodium dodecylbenzenesulfonate (SDBS) in a 2:1 mass ratio. PEG400 stabilizes the nanofiller through steric hindrance (agglomeration rate ≤5%), and SDBS stabilizes the steel fibers through electrostatic repulsion (settling rate ≤0.1mm / h). The dispersant stabilizer has a compatibility of ≥99% with component B (no precipitation). The pH-responsive microcapsules have a particle size of 3-5μm, and the shell ruptures within 5 minutes at pH ≤6.0, releasing CaO to generate CaCO3 (7-day filling rate ≥90%, filling rate is detected by weighing method). The liquid metal-coated steel fiber suspension has steel fibers with a diameter of 0.2-0.3mm, a length of 6-10mm, and a tensile strength ≥2800MPa. The coating is a gallium indium tin alloy with a thickness of 80±10nm.

[0025] Further, the preparation process of the pH-responsive microcapsules is as follows: calcium oxide (CaO, particle size ≤5μm) and tartaric acid (slow-release agent) are ground at a mass ratio of 10:1 in a ball mill at 300rpm and an agate ball-to-material ratio of 5:1 for 6 hours, and then vacuum dried at 60℃ for 12 hours until the moisture content is ≤0.5% to obtain the core material; methyl methacrylate (MMA) and acrylic acid (AA) are ground at a mass ratio of 4:1, with 1% potassium persulfate added, and prepolymerized at 35℃ under nitrogen protection for 30 minutes to obtain the shell material; the core material and shell material are ground at a mass ratio of 3:1, ultrasonicated at 350W for 30 minutes until D50=3-5μm and PDI≤0.3, and then spray-dried under nitrogen protection at an inlet temperature of 180℃ and an outlet temperature of 85℃, sprayed with KH-560 (1.5%), and cured at a programmed temperature of 80-110℃ for 45 minutes until the shell thickness is 500-800nm.

[0026] Further, the preparation of the liquid metal-coated steel fiber suspension includes: degreasing the steel fibers by ultrasonication with acetone at 300W for 15 minutes, removing the oxide layer by acid washing with 5% hydrochloric acid for 30 seconds, washing with water until pH=7, drying at 100℃ for 2 hours, and detecting that the residual chloride ion content on the surface of the steel fibers is ≤0.06%; mixing the coated steel fibers with deionized water at a mass ratio of 1:1, adding 0.5% SDBS, and ultrasonicating at 200-250W and 25kHz for 20 minutes to obtain the suspension, with a sedimentation amount of ≤5% after 24 hours; Furthermore, before forming the final grouting material, components A and B need to be prepared separately using specialized processes and stored independently to ensure that each functional component maintains its activity and dispersibility before mixing. Component A (main phase): With calcium acrylate-magnesium acrylate composite monomers as the core of the organic matrix, it is formed by stepwise composite nano-modified fillers (modified graphene, nano-kaolin, silicon carbide whiskers) and silicon precursors, followed by pH adjustment and aging, to form a uniform "organic-nano-inorganic" premixed system. It is stored at 25°C in a nitrogen-protected storage tank (oxygen content ≤0.5%) to ensure that the viscosity change is ≤10% within 6 months, and the nano-filler particle size is maintained at 20-50nm (deviation ≤5%) to avoid organic phase degradation or nano-agglomeration. Component B (functional initiating phase): With the initiator as the core, it is compounded with a composite catalyst, dispersant stabilizer, pH-responsive microcapsules and liquid metal-coated steel fiber suspension. The stability of the initiator is controlled by pH adjustment (2.0-3.0). It is stored at 25°C in a light-proof storage tank (transmittance ≤10%) to ensure that the initiation efficiency decreases by ≤5% within 6 months, the microcapsule breakage rate is ≤2%, and the 24-hour sedimentation of steel fibers is ≤5%, so as to avoid the failure of functional components. When synthesizing the grouting material, components A and B are mixed in a 1:1 volume ratio (this can be precisely controlled using a metering pump in industrial applications). During mixing, mechanical stirring (1000 r / min, stirring for 30 s) achieves uniform dispersion, simultaneously triggering chemical reactions and functional activation, ultimately forming a two-component nano-acrylate modified concrete grouting material. The grouting material meets the following three core indicators: "construction compatibility," "mechanical properties," and "long-term stability." Construction adaptability: Initial flowability 30-60s, flowability loss ≤15% within 30min, can be smoothly poured into cracks or defects in concrete structures; Mechanical properties: 28d compressive strength ≥80MPa, flexural strength ≥8MPa, interfacial bond strength ≥5MPa, meeting the requirements for heavy-duty structure repair; Long-term stability: Strength change ≤10% after 6 months of storage at 25℃, and environmental performance meets green building material standards (VOC ≤1g / L, raw material LD50). 50 >5000mg / kg).

[0027] Furthermore, the nano-modified filler in component A, the pH-responsive microcapsules in component B, and the liquid metal-coated steel fiber suspension all require special pretreatment to ensure dispersibility and functional retention in subsequent preparation processes. The pretreatment process for the nano-modified filler includes: Preliminary mixing: Modified graphene, nano-kaolin, and silicon carbide whiskers are added to a high-speed mixer at 800 r / min in a mass ratio of 3:3:2 and mixed for 10 min to break up the initial agglomeration and reduce the particle size from 1000 nm to below 500 nm. Coupling agent modification: Add 3-5% KH-570 coupling agent (diluted with 50% ethanol to reduce surface tension) to the total mass of the nano-modified filler, heat to 60-65℃, stir at 500r / min for 30min to graft the coupling agent onto the surface of the nanoparticles, with a grafting rate ≥80%, and perform infrared spectroscopy at 1080cm. -1 The characteristic peaks of Si-OC are obvious; Ultrasonic refining: Transfer to an ultrasonic disperser (350W power, 25kHz frequency) and sonicate for 40 minutes. Take samples every 10 minutes during this period and use a laser particle size analyzer to detect the particle size. Control the particle size within 20-50nm with a deviation of ≤5%. If the particle size exceeds the standard, sonicate for an additional 5 minutes to avoid excessive sonication that could lead to the decomposition of the coupling agent. Drying and storage: Vacuum drying at 60℃ (vacuum degree -0.09MPa) for 2 hours, grinding through a 200-mesh sieve to remove agglomerates, to obtain nano-modified fillers with a particle size of 20-50nm and a particle size distribution deviation of ≤5%; sealed storage at 25℃ and humidity ≤30% to prevent moisture absorption and agglomeration.

[0028] The pH-responsive microcapsule pretreatment process includes: Sieving and impurity removal: pH-responsive microcapsules with a particle size of 3-5 μm are passed through a 100-mesh sieve to remove aggregates >150 μm, and the proportion of microcapsules with a particle size of 3-5 μm is ≥95%; Surface coating: Surface coating is performed using a polyethylene glycol 600 (PEG600) aqueous solution at 0.5-0.8% of the total mass of pH-responsive microcapsules. The mixture is stirred at low speed (100 r / min) for 10 min to form a protective film on the surface of the microcapsules. Drying: Dry at 40℃ with forced air for 30 minutes until the moisture content is ≤1%; observe and test with an optical microscope at 400x magnification to obtain pH-responsive microcapsules with a breakage rate of ≤2%; The pretreatment process for the liquid metal coated steel fiber suspension includes: The steel fibers were degreased by ultrasonic treatment with acetone at 300W for 15 minutes, pickled with 5% hydrochloric acid for 30 seconds to remove the oxide layer, washed with water until pH=7, and dried at 100℃ for 2 hours. The residual chloride ion content on the surface of the steel fibers was found to be ≤0.06%. Liquid metal-coated steel fibers were mixed with deionized water at a mass ratio of 1:1, and sodium dodecylbenzene sulfonate (SDBS) was added at a mass ratio of 0.5% of the total mass of the mixture. The mixture was then ultrasonically treated at 200-250W and 25kHz for 20 minutes to obtain a liquid metal-coated steel fiber suspension. Dispersion test: Take a small amount of suspension and use a laser particle size analyzer to test the steel fiber dispersion to ensure ≥90%, that is, the proportion of a single fiber is ≥90%; if the dispersion is insufficient, add 0.1% SDBS and sonicate (200-250W) for 5 minutes. Stability test: The suspension was allowed to stand for 24 hours to ensure that the sedimentation amount was ≤5%; if the sedimentation amount exceeded the standard, the ultrasonic time was adjusted to 25 minutes (to enhance the surface charge density and the absolute value of the zeta potential was ≥30mV). like Figure 2 As shown, the second aspect of this invention provides a construction process for a two-component nano-acrylate modified concrete grouting material. This process uses "defect diagnosis - pretreatment - dynamic grouting - functional activation - quality verification" as its core flow, and achieves synergy between the material and construction through "scenario-specific parameter design + dedicated equipment adaptation + self-healing trigger control." Specifically, the construction process includes five stages: precise defect diagnosis, scenario-specific pretreatment, dynamic grouting, post-grouting treatment and curing, and quality inspection and acceptance. S1. Precise defect diagnosis includes: for three types of defects in concrete structures—microcracks, interface voids, and bolt hole leaks—corresponding detection equipment is used to obtain key parameters of the defects. Specifically, microcracks are detected using a high-definition endoscope with a resolution of 1080P and a magnification of 50-200x, a 2-5MHz ultrasonic detector, and a humidity sensor with an accuracy of ±2%RH; interface voids are detected using an impact echo meter with a sampling frequency of 100kHz and an infrared thermal imager with a resolution of 640×512; and bolt hole leaks are detected using a water pressure tester with a range of 0-2MPa and an endoscope with a diameter ≤5mm. S2. Pre-treatment by scenario: Perform surface treatment, drilling, and sealing / protection installation operations according to the defect type. Microcracks need to be installed with special conical grouting needles and epoxy sealing. Interface voids need to be installed with grouting nozzles with check valves. Bolt hole leakage needs to be installed with polytetrafluoroethylene protective sleeves. S3. Dynamic grouting includes: a grouting system consisting of a dual-liquid grouting pump, an 18-element static mixer and a dynamic pressure feedback module, which adjusts the grouting pressure, flow rate and setting time parameters according to the defect type, and performs process adjustments for harsh environments. S4. Post-grouting treatment and maintenance include: dismantling the grouting pipeline and sealing the hole according to the grout setting time; implementing the corresponding maintenance plan according to the construction environment; and maintaining a specific humidity environment in the self-healing area. S5. Quality inspection and acceptance includes: establishing a three-level inspection system of process inspection, short-term effect inspection, and long-term follow-up inspection to ensure that the construction quality meets the acceptance standards.

[0029] Furthermore, step S1 establishes a "multi-dimensional information fusion diagnosis" method for common defects in concrete structures (cracks, interface voids, bolt hole leakage) to provide a basis for matching process parameters; the microcracks mentioned in step S1 are cracks with a width of 0.1-0.5mm, and the specific steps for accurate diagnosis of these defects are as follows: A high-definition endoscope was used to scan along the concrete surface and mark the direction, length L, and width w of the cracks. The crack depth d is detected using an ultrasonic detector, and the crack volume V = L × w × d is calculated. A humidity sensor is used to detect the humidity in the crack area. When the humidity is greater than 90%, it is identified as a water seepage crack. The width w, depth d, and water seepage status (dry / wet) of the crack are recorded simultaneously. Furthermore, the specific steps for accurate diagnosis of defects in the interface voids (such as steel-concrete bonding surfaces and bearing pads) mentioned in step S1 are as follows: The suspected voiding area was scanned using an impact echo meter with a grid spacing of 200mm×200mm. When the wave velocity in the detected area was <3000m / s, it was preliminarily determined to be an interface voiding area. The temperature difference of the preliminarily identified void area was detected using an infrared thermal imager with a resolution of 640×512. If the temperature difference between the area and the surrounding normal concrete area is greater than 2℃, the range of the void area is further confirmed. By combining the detection results of the impact echo meter and the infrared thermal imager, the specific range of interface delamination is marked, the delamination area S is determined, the average thickness h of the delamination area is calculated, and it is determined whether there is water accumulation inside the delamination area, which provides a key basis for subsequent pretreatment and grouting process parameter matching. Furthermore, the specific steps for accurate diagnosis of bolt hole leakage defects in step S1 are as follows: First, the bolt holes are sealed, then pressure is applied into the holes to 0.45-0.55MPa (preferably 0.5MPa), and this pressure is maintained for 28-32 minutes (preferably 30 minutes). The pressure changes are recorded in real time and the pressure drop ΔP is calculated to determine the leakage status of the bolt holes. An endoscope with a diameter ≤5mm is inserted into the bolt hole to observe the distribution and width w1 of the cracks in the hole wall. The leakage level is determined based on the crack width, where w1≤1mm is micro-leakage and w1>1mm is severe leakage. By combining the pressure drop ΔP data and the hole wall crack width w1, the severity of bolt hole leakage is determined, providing a precise basis for subsequent targeted pretreatment and grouting process parameter setting; Furthermore, step S2 designs a "surface treatment-drilling-sealing" process for different defect types, primarily addressing the problems of "slurry leakage" and "blockage of seepage channels"; the specific operations for microcrack pretreatment in step S2 are as follows: (1) Surface cleaning: Dry cracks are cleaned by blowing away dust with 0.8MPa high-pressure air and then wiping away oil stains with acetone; wet cracks are first drained by pumping out water with a 0.5L / min micro water pump, and then dried with a hot air gun at 50-60℃ and 2m / s until the surface humidity is ≤70%; the concrete spalling areas at both ends and intersections of the cracks are repaired with fast-setting repair mortar with an initial setting time of ≤15min and a compressive strength of ≥30MPa in 24h, and the height difference between the repair surface and the original structure is ≤2mm; (2) Drilling operation: A special directional drilling machine with a positioning accuracy of ±0.3mm and a speed of 0-3000r / min is used. The drilling parameters are adjusted according to the crack width. For cracks of 0.1-0.2mm, the drilling distance is 15-20mm from the crack edge, the hole diameter is 6mm, the hole depth is the crack depth d+20mm, and the hole spacing is 100-120mm; for cracks of 0.2-0.5mm, the drilling distance is 20-25mm from the crack edge, the hole diameter is 8mm, the hole depth is the crack depth d+30mm, and the hole spacing is 120-150mm. The drilling is at a 45° angle to the crack direction, and the connection rate between the drilling and the crack is ≥95%. (1) Grouting pipe installation and sealing: Insert a special grouting needle with a front taper of 1:5 and 4-6 (preferably 4) 0.8mm side holes with a spacing of 8-10mm (preferably 8mm) into the drill hole to a position that matches the depth of the crack (ensure that the side holes of the needle tube wall can be aligned with the crack area to provide a channel for grout penetration). After the needle is inserted into the drill hole, inject epoxy sealant with an initial setting time of 30min into the hole opening. The sealant layer thickness is ≥5mm. After curing for 2 hours, fix the needle and seal the hole opening. Perform a sealing test with a pressure of 0.3MPa for 5min. If there is no leakage, it is considered qualified. Furthermore, the specific operations of the interface de-emptying preprocessing described in step S2 are as follows: (1) Based on the test results of the impact echo meter, mark the boundary of the voided area with ink lines with a deviation of ≤5mm, and use an 80-mesh abrasive wheel angle grinder to clean the surface laitance of the voided area to expose the fresh concrete surface; wherein, the area of ​​the fresh concrete surface is ≥90% of the voided area; (2) Drill holes in a quincunx pattern at a distance of 48-52mm (preferably 50mm) from the boundary of the voided area. The hole diameter is 10mm and the hole depth needs to penetrate the voided layer (confirmed by ultrasonic testing, generally 50-100mm). The hole spacing is 300-400mm (adjusted according to the voided area S; when S < 1m², the hole spacing is 300mm, and when S > 1m², the hole spacing is 400mm). (3) Install grouting nozzles with check valves (e.g., inner diameter 6mm, check pressure 0.2MPa), and use expansion bolts to fix the grouting nozzles to prevent them from falling off during grouting; Furthermore, the specific operations for the bolt hole leakage pretreatment described in step S2 are as follows: (1) Use a torque wrench to remove the bolt at 50% of the design torque to avoid damaging the threads. Then use a wire brush that matches the bolt hole to clean the rust on the hole wall. After blowing with 0.6MPa high-pressure air, use acetone to rinse the hole wall to remove rust. (2) Drill at least 3 inclined holes evenly around the bolt hole. The diameter of the inclined hole is 8mm and the depth is 100-120mm. The angle between the inclined hole and the axis of the bolt hole is 15-20° and it must be ensured that the inclined hole is connected to the bolt hole. (3) Install a polytetrafluoroethylene protective sleeve with a thickness of 1.5-2.5mm (preferably 2mm) and an inner diameter matching the bolt inside the bolt hole. Fill the gap between the protective sleeve and the hole wall with water-swellable rubber with an expansion rate of 200% and which completes expansion in 7 days to prevent the grout from contaminating the bolt threads. Furthermore, based on the "two-component, fast-setting and adjustable, nano-reinforced" characteristics of the grouting material, step S3 designs a grouting scheme of "dynamic parameter control + special device adaptation" to ensure uniform grout diffusion, no loss, and activation of self-healing function: The technical parameters of the grouting system described in step S3 are as follows: The flow rate of the dual-liquid grouting pump is adjustable from 0.1 to 2 L / min with a flow rate accuracy of ±0.01 L / min, and the pressure is adjustable from 0 to 10 MPa with a pressure accuracy of ±0.05 MPa. Components A and B are metered independently with a ratio deviation of ≤2%. It is used to accurately control the ratio and delivery volume of components A and B to avoid performance degradation caused by ratio imbalance. The static mixer has 18 mixing elements made of 304 stainless steel, with a mixing efficiency of ≥98%, an inlet / outlet inner diameter of 8mm, and a length of 200mm; it is used to ensure uniform mixing of components A and B (uneven mixing will cause local condensation time deviation >30%). The dynamic pressure feedback module includes a pressure sensor with a response time of ≤0.1s and a PLC control system. It can preset the pressure threshold and automatically reduce the flow rate to 50% of the initial value when the grouting pressure reaches 1.2 times the set value; this is used to avoid damage to the concrete structure (such as segment cracking) caused by overpressure. The microcrack grouting needle has a 1:5 taper at the front end and four 0.8mm side holes with an 8mm spacing between them on the tube wall; it is suitable for 0.1mm cracks and has a sealing success rate of ≥95%; it is used to solve the problem of grouting and sealing microcracks and improve the penetration depth. Grouting system connection: Component A storage tank → Dual liquid pump A channel → Static mixer → Grouting pipe; Component B storage tank → Dual liquid pump B channel → Static mixer → Grouting pipe; Dynamic pressure feedback module is connected in series at the front end of the grouting pipe (to monitor grouting pressure in real time). Step S3: Based on the defect type and material setting time characteristics (adjustable from 30s to 60min), design a dynamic control scheme for grouting pressure, flow rate, and sequence. The parameters and operational requirements for the dynamic grouting of microcracks are as follows: Initial parameter settings (based on crack width and seepage status): Adjust the setting time according to crack type. For dry cracks (0.1-0.2mm), the setting time is controlled at 20-30min, the grouting pressure is 0.2-0.3MPa, the flow rate is 0.2-0.3L / min, and the target grout diffusion radius is 30-40mm; for wet cracks (0.2-0.5mm), the setting time is controlled at 10-15min, the grouting pressure is 0.3-0.5MPa, the flow rate is 0.3-0.5L / min, and the target grout diffusion radius is 40-50mm. Pressure rise phase: In the initial stage of grouting, the pressure rises slowly from the initial value at a rate of 0.05 MPa / min. When the pressure reaches 1.2 times the set value, the flow rate automatically drops to 50% of the initial value (to avoid overpressure leading to crack propagation). Pressure holding stage: When the grouting volume reaches 1.5 times the theoretical calculated volume of the crack, maintain the pressure at 0.2 MPa for 10 minutes (to promote grout penetration and uniform distribution of microcapsules). End point determination: Grouting is stopped when the pressure drop during the pressure holding period is ≤0.05MPa and grout seepage occurs in adjacent grouting holes (indicating that the crack has been filled); Self-healing activation control: 24 hours after the grouting of dry cracks is completed, deionized water is sprayed on the crack surface to make the area humidity ≥90% and maintain it for 3 days (simulating the seepage environment, making the pH of the crack area ≤6.0, triggering the microcapsule rupture to release CaO and activate self-healing). The self-healing microcapsule rupture is triggered; no additional treatment is required for wet cracks (natural seepage already meets the pH conditions). The parameters and operational requirements for the interface de-cavitation grouting are as follows: Grouting sequence for interface voids: adopt "from bottom to top, intermittent skipping" (e.g., hole number 1-2-3-4-5, the sequence is 1→3→5→2→4) to avoid grout short circuit (i.e., grout flows directly out from the grouting hole at the lower level, while the voided area at the higher level is not effectively filled). Core dynamic grouting parameters: Setting time: Controlled to a long setting time of 30-40 minutes to ensure that the slurry has sufficient time to spread evenly and fill the large area of ​​voids. Initial grouting pressure: set to 0.3MPa, corresponding to an initial grouting flow rate of 0.5L / min; when grout seeps out of a certain grouting hole, the grouting pressure of that hole needs to be reduced to 0.1MPa, and grouting should continue until grout seeps out of all grouting holes, at which point the voided area is considered to be filled; Secondary grouting: One hour after the first grouting is stopped, all grouting holes need to be grouted a second time. The grouting pressure is 0.2MPa, the grouting flow rate is 0.3L / min, and the grouting volume is 10%-15% of the total volume of the first grouting. This is to compensate for the volume shrinkage that occurs during the solidification process of the grout and to ensure that the voided areas are filled densely. Additional adjustments for adapting to harsh environments include: if in a high-humidity (relative humidity > 85%) harsh environment, a 0.1mm thick waterproof membrane must be covered for curing after grouting is completed, and the curing period is extended to 14 days to prevent rainwater from seeping in and affecting the curing effect of the grout; The parameters and operational requirements for the grouting of the bolt holes are as follows: The low-pressure, slow-injection grouting method is adopted to avoid cracking of the bolt hole wall due to excessive grouting pressure, which would further aggravate the leakage problem. Core grouting parameters: Setting time: A medium setting time of 5-8 minutes can effectively prevent the grout from flowing out along the bolt thread gaps and ensure that the grout quickly forms and seals the leakage channels in the hole. Grouting pressure: set to 0.2-0.3MPa, corresponding to a grouting flow rate of 0.1-0.2L / min. Low-pressure slow injection can make the grout fill the cracks in the hole wall evenly. Endpoint determination: When the PTFE protective sleeve inside the bolt hole begins to expand as observed by endoscopy, and the grouting pressure stabilizes at 0.3 MPa and remains at that pressure for 5 minutes without significant decrease, grouting can be stopped. 24 hours after grouting is completed, once the grout has fully cured, tighten the bolts with a torque wrench to the designed torque, ensuring that the torque deviation is ≤5% to guarantee the stability of the bolt connection. If the environment is harsh such as high humidity, cover with a 0.1mm thick waterproof membrane after grouting and cure for 14 days to prevent external moisture from seeping in and affecting the curing effect of the grout. Furthermore, the process adjustment requirements for the harsh environment described in step S3 are as follows: In low-temperature environments (-5℃ to 10℃), before grouting, components A and B are placed in a 50℃ constant temperature chamber for 2 hours to raise the material temperature to 15-20℃ (to avoid viscosity increase of >20% due to low temperature). At the same time, the grout setting time is extended by 20-30% (e.g., from 10 min to 12-13 min), and the grouting pressure is increased by 0.1 MPa (to compensate for the decrease in grout fluidity caused by low temperature). In high humidity environments (relative humidity > 85%), increase the number of times the concrete surface is wiped with acetone to 2-3 times to ensure that the surface is free of moisture; use fast-setting epoxy sealant (initial setting time 15 min) to avoid slow curing of the sealant due to high humidity; after grouting is completed, cover with a 0.1 mm thick waterproof membrane and cure for 7 days (to prevent rainwater from seeping in and affecting curing). Furthermore, the specific requirements for post-grouting treatment and curing described in step S4 are as follows: Grouting pipe removal: Determine the timing of grouting pipe removal according to the grout setting time. After removal, use epoxy mortar to seal the hole opening with a sealing depth of ≥20mm and flush with the original structure. Surface cleaning and curing: Remove excess grout from the surface after grouting (do this 24 hours later to avoid damaging the cured grout); under normal conditions, use water spraying at 20-25℃ for curing, 3 times a day, for a curing cycle of 7 days; under low temperature conditions, cover with insulation cotton to maintain a curing temperature ≥5℃; under high humidity conditions, cover with a waterproof membrane. The curing cycle for both types of harsh environments is 14 days. Within 7 days after grouting, the humidity of the self-healing area should be checked weekly and maintained at ≥80% to ensure that the microcapsules fully rupture and generate CaCO3 to complete the self-healing process.

[0030] Furthermore, step S5 establishes a three-tiered inspection system of "process inspection - short-term effect - long-term tracking" to ensure construction quality; the requirements for the three-tiered inspection system for quality inspection and acceptance are as follows: During process testing, the flow ratio of components A and B is monitored in real time using a dual-liquid pump flow sensor to ensure it is 1:1 with a deviation of ≤2%. Grouting pressure and flow rate are recorded every 5 minutes with a deviation of ≤10%. Ultrasonic testing shows that the connectivity between grouting holes and cracks is ≥95%. In short-term performance testing, 7-28 days after grouting, the surface showed no dampness or leakage, the pore openings were smoothly sealed, the closure rate of 0.1-0.2mm cracks was ≥90%, the closure rate of 0.2-0.5mm cracks was ≥85%, the compressive strength after 28 days of core sampling was ≥80MPa, the interfacial bond strength after pull-out testing was ≥5MPa, and the strength recovery rate after 7 days of curing for manually cut 0.3mm microcracks was ≥85%. During long-term monitoring, after 1 year, ultrasonic testing showed an internal density of ≥95% with no voids; after 2 years, infrared thermal imaging showed a temperature difference of ≤1℃ with no voids; and after 3 years, 0.5MPa water pressure was maintained for 30 minutes with no leakage and no secondary cracking in the self-repairing area.

[0031] This invention provides a construction process for a two-component nano-acrylate modified concrete grouting material, belonging to the field of concrete structure repair construction technology. It is suitable for repairing 0.1-0.5mm microcracks, filling interface voids, and treating bolt hole leakage in heavy-load concrete structures (bridge main beams, tunnel segments, and high-rise building beams and columns), and is particularly suitable for harsh construction environments such as -5℃ to 10℃ low temperatures and relative humidity >85%. This process uses "defect diagnosis - pretreatment - dynamic grouting - functional activation - quality verification" as its core flow, constructing a multi-dimensional information fusion-based precise defect diagnosis system. It designs scenario-specific pretreatment processes for three types of defects: microcracks, interface voids, and bolt hole leakage. A grouting system consisting of a dual-liquid grouting pump, an 18-element static mixer, and a dynamic pressure feedback module is provided to achieve dynamic control of grouting pressure, flow rate, and setting time. The self-healing function of the material is activated by controlling the pH value of the crack area. Simultaneously, a special process adjustment plan is developed for harsh environments, establishing a three-level quality inspection system of "process detection - short-term effect - long-term tracking." This invention solves the shortcomings of traditional processes, such as high slurry loss rate, poor sealing and penetration effect of microcracks, insufficient self-healing activation, low construction efficiency, and weak adaptability to harsh environments. It achieves a material 28-day compressive strength utilization rate ≥95%, a 0.1mm microcrack penetration depth ≥50mm, a 7-day self-healing rate ≥85%, and increases the daily repair area to ≥100m². 2 With a secondary repair rate of ≤3%, the service life of the repaired structure can be extended by 15-20 years, while also ensuring construction precision, scenario adaptability, and durability.

[0032] The technical effects of the present invention will be further illustrated below through three embodiments: Example 1: Repair of microcracks (0.2-0.3mm) in the main girder of a bridge Project Overview: A highway bridge T-beam has been in service for 10 years, and dry cracks with a length of 3-5m and a width of 0.2-0.3mm have appeared in the web area. The concrete strength grade in this part is C50. Construction steps Defect diagnosis: The direction and size of the crack were marked using a 1080P high-definition endoscope. The crack depth was measured to be 80mm using a 2-5MHz ultrasonic detector. The humidity sensor detected that the humidity in the crack area was 65%, which determined it to be a dry crack.

[0033] Pretreatment: First, blow away the dust on the crack surface with 0.8MPa high-pressure air, then wipe away the oil stains with acetone; use a special directional drilling machine to drill holes with parameters of 20mm from the crack edge, 8mm diameter, 110mm depth (crack depth + 30mm), and 120mm spacing, with the drilling angle at 45° to the crack direction; install a special grouting needle with a front taper of 1:5, inject epoxy sealant (adhesive layer thickness ≥ 5mm) with an initial setting time of 30min into the hole, and after curing for 2 hours, pass the sealing test by holding the sealant at 0.3MPa for 5 minutes; Dynamic grouting: The grout setting time is controlled at 15 min, the grouting pressure is set at 0.3-0.4 MPa, the flow rate is 0.4 L / min, and the grouting volume is 1.2 times the theoretical volume of the crack. After reaching the grouting volume, the pressure is maintained at 0.2 MPa for 10 min. Grouting is stopped after grout seepage occurs from adjacent grouting holes. 24 h after grouting is completed, deionized water is sprayed on the crack surface to make the area humidity ≥90%, and the self-healing function is activated after 3 days. Maintenance: Spray water with clean water at 20-25℃ 3 times a day for maintenance, with a maintenance cycle of 7 days.

[0034] Test results: The crack closure rate reached 92% after 7 days, and the interfacial bond strength was 5.6 MPa. Core samples taken at 28 days showed a compressive strength of 86.3 MPa and a self-healing rate of 89%. After one year, ultrasonic testing showed an internal density of 98%, with no secondary cracking. Example 2: Repair of leakage in tunnel segment bolt holes (pressure drop 0.2MPa / 30min) Project Overview: The bolt holes of a subway tunnel segment have a diameter of 30mm and a leakage level of Class II (dripping). The water pressure test shows a pressure drop of 0.2MPa after 30 minutes, and the width of the crack in the hole wall observed by endoscopy is 0.8mm. Construction steps Defect diagnosis: The pressure drop of the bolt hole after 30 minutes of pressure holding was 0.2 MPa, as measured by a 0-2 MPa water pressure tester. An endoscope with a diameter ≤5 mm was used to confirm that the width of the crack in the hole wall was 0.8 mm, which was determined to be a micro-leakage. Pre-treatment: Remove the bolts using a torque wrench at 50% of the design torque; clean the rust from the hole walls with a matching wire brush; after blowing with 0.6MPa high-pressure air, rinse the hole walls with acetone; drill three evenly spaced 8mm diameter, 100mm deep, angled holes at 15-20° to the bolt hole axis around the bolt hole; install a 2mm thick PTFE protective sleeve inside the bolt hole, filling the gaps with water-swellable rubber (200% expansion rate); Dynamic grouting: Low-pressure slow grouting method is adopted, the grout setting time is controlled at 6 minutes, the grouting pressure is set at 0.25 MPa and the flow rate is 0.15 L / min. Grouting is stopped when the endoscope observes that the protective sleeve begins to expand and the pressure stabilizes at 0.3 MPa for 5 minutes without pressure drop. Curing and repositioning: Cover with a 0.1mm thick waterproof membrane for 7 days; 24 hours after grouting is completed, tighten the bolts to a design torque of 350 N·m, with a torque deviation of ≤5%; Test results: At 7 days, a 0.5MPa water pressure holding test was conducted for 30 minutes, and the pressure drop was ≤0.02MPa; at 6 months, there was no leakage in the bolt holes, and the bolt torque remained stable at 345N·m. Example 3: Void at the beam-column interface of a high-rise building (area 2m²) 2 (50mm thick) filler Project Overview: At the interface between the columns and beams of an office building frame, an impact echo meter and infrared thermal imager revealed a void area of ​​2 square meters. 2 Average thickness 50mm, no water accumulation; Construction steps Defect diagnosis: A 100kHz shock echo meter was used to scan a 200mm×200mm grid to confirm that the wave velocity in the void area was <3000m / s. Combined with the temperature difference >2℃ detected by a 640×512 resolution infrared thermal imager, the void boundary was marked (deviation ≤5mm) to clarify the void area and thickness. Pretreatment: Use an 80-mesh angle grinder to clean the surface laitance of the voided area, exposing ≥90% of the voided area of ​​fresh concrete surface; Drill holes in a quincunx pattern 50mm inside the boundary of the voided area, with a hole diameter of 10mm, a hole depth of 60mm (penetrating the voided layer), and a hole spacing of 300mm; Install grouting nozzles with a 6mm inner diameter and a check valve with a check pressure of 0.2MPa, and fix them with expansion bolts; Dynamic grouting: A bottom-up, intermittent grouting sequence is adopted, controlling the grout setting time to 35 minutes. The initial grouting pressure is 0.3-0.4 MPa, and the flow rate is 0.5 L / min. After grout seepage occurs in a certain hole, the pressure is reduced to 0.1 MPa until grout seepage occurs in all holes. One hour after the initial grouting is stopped, a second grouting is performed at a pressure of 0.2 MPa and a flow rate of 0.3 L / min, with the replenished grout volume being 12% of the initial grouting volume. Curing: Due to the high humidity environment, cover with a 0.1mm thick waterproof membrane for 14 days after grouting; Test results: At 28 days, the impact echo detection showed a void rate of ≤2% and an interfacial bonding strength of 5.2 MPa; at 2 years, the infrared thermal imager detected a temperature difference of ≤0.8℃ and no void phenomenon.

[0035] This invention achieves a material 28-day compressive strength utilization rate of ≥95% (compared to only 70-80% with traditional processes) and a self-repair rate of ≥85% (compared to <60% with traditional processes) through dynamic parameter control (pressure, flow rate, and setting time). This significantly improves material performance utilization. A specialized needle and sealing process enable penetration depth of ≥50mm into 0.1mm cracks, achieving a sealing success rate of ≥95% (compared to penetration depth ≤30mm and sealing success rate <80% with traditional processes). This breakthrough overcomes the bottleneck in micro-crack repair technology, enhancing sealing and penetration effects. This invention covers defects such as micro-cracks, voids, and leaks, and is adaptable to environments ranging from -5℃ to 40℃ and high humidity, with a process stability deviation of ≤10%. It exhibits strong adaptability to various scenarios, ensuring stable construction under harsh conditions. The daily repair area is ≥100m². 2 (Traditional process ≤50m) 2 The secondary repair rate is ≤3% (compared to ≥15% for traditional processes); it significantly improves construction efficiency and quality while reducing project rework costs; after 3 years of follow-up testing, there is no leakage or secondary cracking, and the service life of the structure is extended by 15-20 years (compared to 5-8 years for traditional processes), with a significant improvement in long-term durability.

[0036] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction process for a two-component nano-acrylate modified concrete grouting material, characterized in that: The two-component nano-acrylate modified concrete grouting material is an A / B two-component system with a volume ratio of 1:

1. The viscosity of component A is 55-65 mPa·s, and the viscosity of component B is 25-35 mPa·s. The grouting material has a 28-day compressive strength ≥80 MPa. The construction process includes: S1. Precise Defect Diagnosis: High-definition endoscopes, ultrasonic detectors, and impact echometers are used to detect microcracks, interface voids, and bolt hole leaks, respectively, to obtain defect size and water seepage status parameters. S2. Pre-treatment by scenario: Perform surface treatment, drilling, and sealing / protection installation operations according to the defect type. Install special conical grouting needles for micro-cracks and perform epoxy sealing. Install grouting nozzles with check valves for interface voids. Install PTFE protective sleeves for bolt hole leakage. S3. Dynamic grouting: The grouting system consists of a dual-liquid grouting pump, an 18-element static mixer and a dynamic pressure feedback module. The grouting pressure, flow rate and setting time parameters are adjusted according to the type of defect. At the same time, process adjustments are made for harsh environments. S4. Post-grouting treatment and curing: Remove the grouting pipeline and seal the hole according to the grout setting time. Implement the corresponding curing plan according to the construction environment. Maintain a specific humidity environment in the self-healing area to ensure that the microcapsules are fully broken and CaCO3 is generated to complete the self-healing. S5. Quality Inspection and Acceptance: Establish a three-level inspection system including process inspection, short-term effect inspection, and long-term follow-up inspection to ensure that the construction quality meets the acceptance standards.

2. The construction process of the two-component nano-acrylate modified concrete grouting material according to claim 1, characterized in that: The microcracks mentioned in step S1 are cracks with a width of 0.1-0.5 mm. The specific steps for accurate defect diagnosis are as follows: A high-definition endoscope was used to scan along the concrete surface and mark the direction, length L, and width w of the cracks. The crack depth d is detected using an ultrasonic detector, and the crack volume V = L × w × d is calculated. A humidity sensor is used to detect the humidity in the crack area. When the humidity is greater than 90%, it is determined to be a water seepage crack. The width w, depth d, and water seepage status of the crack are recorded simultaneously.

3. The construction process of a two-component nano-acrylate modified concrete grouting material according to claim 2, characterized in that: The specific steps for accurate diagnosis of interface void defects in step S1 are as follows: The suspected delamination area was scanned using an impact echo meter. When the wave velocity in the detected area was <3000m / s, it was preliminarily determined to be an interface delamination area. Infrared thermal imagers were used to detect the temperature difference in the preliminarily identified void areas. If the temperature difference between the void area and the surrounding normal concrete area was greater than 2°C, the extent of the void area was further confirmed. By combining the detection results of the shock echo meter and the infrared thermal imager, the specific range of the interface delamination is marked, the delamination area S is determined, the average thickness h of the delamination area is calculated, and it is determined whether there is water accumulation inside the delamination area.

4. The construction process of a two-component nano-acrylate modified concrete grouting material according to claim 3, characterized in that: The specific steps for accurate diagnosis of bolt hole leakage defects in step S1 are as follows: First, seal the bolt holes, then pressurize the holes to 0.44-0.55 MPa and maintain this pressure for 28-32 minutes. Record the pressure changes in real time and calculate the pressure drop ΔP. An endoscope with a diameter ≤5mm is inserted into the bolt hole to observe the distribution and width w1 of the cracks in the hole wall. The leakage level is determined based on the crack width, where w1≤1mm is micro-leakage and w1>1mm is severe leakage. By combining the pressure drop ΔP data and the borehole wall crack width w1, the severity of bolt hole leakage can be determined.

5. The construction process of a two-component nano-acrylate modified concrete grouting material according to any one of claims 1-4, characterized in that: The specific operations for microcrack pretreatment in step S2 are as follows: For dry cracks, dust is blown away with high-pressure air and oil stains are wiped off with acetone; for wet cracks, water is first pumped out with a mini water pump and then dried with a hot air gun until the surface humidity is ≤70%; for concrete spalling areas at both ends and intersections of cracks, quick-setting repair mortar with an initial setting time of ≤15min and a compressive strength of ≥30MPa in 24h is used for repair, and the height difference between the repair surface and the original structure is ≤2mm. A dedicated directional drilling machine with a positioning accuracy of ±0.3mm and a rotation speed of 0-3000r / min is used. The drilling parameters are adjusted according to the crack width. Specifically, for cracks of 0.1-0.2mm, the drilling distance is 15-20mm from the crack edge, the hole diameter is 6mm, the hole depth is crack depth d+20mm, and the hole spacing is 100-120mm; for cracks of 0.2-0.5mm, the drilling distance is 20-25mm from the crack edge, the hole diameter is 8mm, the hole depth is crack depth d+30mm, and the hole spacing is 120-150mm. The drilling is at a 45° angle to the crack direction, and the connection rate between the drilling and the crack is ≥95%. Insert a specialized grouting needle with a 1:5 taper at the front end, 4-6 0.8mm side holes with a spacing of 8-10mm into the pipe wall, into the drill hole to a position matching the depth of the crack. After the needle is inserted into the drill hole, inject epoxy sealant with an initial setting time of 30 minutes into the hole opening. The sealant layer thickness should be ≥5mm. After curing for 2 hours, fix the needle and seal the hole opening. Conduct a sealing test at 0.3MPa for 5 minutes. No leakage indicates that the test is qualified.

6. The construction process of a two-component nano-acrylate modified concrete grouting material according to claim 5, characterized in that: The specific operations for the interface de-emptying preprocessing in step S2 are as follows: Based on the impact echo meter test results, the boundary of the voided area was marked with an ink line with a deviation of ≤5mm. The surface laitance of the voided area was cleaned with an 80-grit angle grinder to expose the fresh concrete surface; the area of ​​the fresh concrete surface was ≥90% of the voided area. Drill holes in a quincunx pattern 48-52mm inside the boundary of the voided area. The holes need to penetrate the voided layer and be spaced 300-400mm apart. Install grouting nozzles with check valves and use expansion bolts to fix the grouting nozzles to prevent them from falling off during grouting; The specific steps for the bolt hole leakage pretreatment in step S2 are as follows: Use a torque wrench to loosen the bolt at 50% of the design torque to avoid damaging the threads. Then use a wire brush that matches the bolt hole to clean the rust on the hole wall. After blowing with high-pressure air, use acetone to rinse the hole wall to remove rust. Drill at least 3 angled holes evenly around the bolt hole, with an angle of 15-20° to the axis of the bolt hole, and ensure that they are connected to the bolt hole; Install a PTFE protective sleeve with a thickness of 1.5-2.5mm and an inner diameter matching the bolt inside the bolt hole. Fill the gap between the protective sleeve and the hole wall with water-swellable rubber with an expansion rate of 200% and which completes expansion in 7 days to prevent the grout from contaminating the bolt threads.

7. The construction process of a two-component nano-acrylate modified concrete grouting material according to claim 6, characterized in that, In step S3, the flow rate adjustment range of the dual-liquid grouting pump in the grouting system is 0.1-2 L / min with a flow rate accuracy of ±0.01 L / min, the pressure adjustment range is 0-10 MPa with a pressure accuracy of ±0.05 MPa, and components A and B are independently metered with a ratio deviation ≤2%. The static mixer has 18 mixing elements and a mixing efficiency of ≥98%. The dynamic pressure feedback module includes a pressure sensor with a response time of ≤0.1s and a PLC control system. It can preset the pressure threshold and automatically reduce the flow rate to 50% of the initial value when the grouting pressure reaches 1.2 times the set value.

8. The construction process of a two-component nano-acrylate modified concrete grouting material according to claim 7, characterized in that, The parameters and operational requirements for dynamic grouting of microcracks in step S3 are as follows: For dry cracks, the setting time should be controlled at 20-30 min, the grouting pressure at 0.2-0.3 MPa, the flow rate at 0.2-0.3 L / min, and the target grout diffusion radius at 30-40 mm. For wet cracks, the setting time should be controlled at 10-15 min, the grouting pressure at 0.3-0.5 MPa, the flow rate at 0.3-0.5 L / min, and the target grout diffusion radius at 40-50 mm. The initial grouting pressure rises slowly at a rate of 0.05 MPa / min. When the pressure reaches 1.2 times the set value, the flow rate automatically drops to 50% of the initial value. When the grouting volume reaches 1.5 times the theoretical calculated volume of the crack, maintain the pressure at 0.2 MPa for 10 minutes. Grouting should be stopped when the pressure drop during the pressure holding period is ≤0.05MPa and grout seepage occurs in adjacent grouting holes; 24 hours after the dry crack grouting was completed, deionized water was sprayed on the crack surface to maintain the area humidity at ≥90% for 3 days, triggering the rupture of the self-healing microcapsules. The parameters and operational requirements for the interface de-cavitation grouting are as follows: Grouting sequence for interface delamination: adopt "bottom to top, intermittent skipping" to avoid grout short circuit; The setting time is controlled to be a long setting time of 30-40 minutes; the initial grouting pressure is set to 0.3 MPa, corresponding to an initial grouting flow rate of 0.5 L / min; when grout seeps out of a certain grouting hole, the grouting pressure of that hole needs to be reduced to 0.1 MPa, and grouting continues until grout seeps out of all grouting holes, indicating that the voided area has been filled. One hour after the initial grouting is stopped, all grouting holes need to be replenished a second time. The replenishment pressure is 0.2 MPa, the replenishment flow rate is 0.3 L / min, and the replenishment volume is 10%-15% of the total initial grouting volume. The parameters and operational requirements for the grouting of the bolt holes are as follows: A low-pressure, slow-injection grouting method is adopted; The setting time should be controlled to a medium setting time of 5-8 minutes; The grouting pressure is set to 0.2-0.3 MPa, corresponding to a grouting flow rate of 0.1-0.2 L / min; When the expansion of the PTFE protective sleeve inside the bolt hole is observed through an endoscope, and the grouting pressure stabilizes at 0.3 MPa and remains at that pressure for 5 minutes without significant decrease, grouting can be stopped. 24 hours after grouting is completed and the grout has fully cured, tighten the bolts with a torque wrench to the designed torque, with a torque deviation of ≤5%. The process adjustments for harsh environments mentioned in step S3 include: In a low-temperature environment of -5℃ to -10℃, components A and B are placed in a 50℃ constant temperature box for 2 hours before grouting to raise the material temperature to 15-20℃, while extending the grout setting time by 20-30% and increasing the grouting pressure by 0.1MPa. In high humidity environments with relative humidity > 85%, increase the number of times the concrete surface is wiped with acetone to 2-3 times to ensure that the surface is free of moisture; use fast-setting epoxy sealant; after grouting is completed, cover with a 0.1mm thick waterproof membrane and cure for 14 days.

9. The construction process of a two-component nano-acrylate modified concrete grouting material according to any one of claims 1-4 and 6-8, characterized in that, The post-grouting treatment and curing described in step S4 includes: The timing of grouting pipe removal is determined according to the grout setting time. After removal, epoxy mortar is used to seal the hole opening, with a sealing depth of ≥20mm and flush with the original structure. Remove excess grout from the surface after grouting; under normal conditions, use water spraying at 20-25℃ for curing, 3 times a day, for a curing cycle of 7 days; under low temperature conditions, cover with thermal insulation cotton to keep the curing temperature ≥5℃; under high humidity conditions, cover with waterproof membrane. The curing cycle for both types of harsh environments is 14 days. For self-healing areas, humidity should be checked weekly within 7 days after grouting and maintained at ≥80%.

10. The construction process of a two-component nano-acrylate modified concrete grouting material according to any one of claims 1-4 and 6-8, characterized in that, The requirements for the three-level inspection system for quality inspection and acceptance in step S5 are as follows: During process testing, the flow ratio of components A and B is monitored in real time using a dual-liquid pump flow sensor to ensure it is 1:1 with a deviation of ≤2%. Grouting pressure and flow rate are recorded every 5 minutes with a deviation of ≤10%. Ultrasonic testing shows that the connectivity between grouting holes and cracks is ≥95%. In short-term performance testing, 7-28 days after grouting, the surface showed no dampness or leakage, the pore openings were smoothly sealed, the closure rate of 0.1-0.2mm cracks was ≥90%, the closure rate of 0.2-0.5mm cracks was ≥85%, the compressive strength after 28 days of core sampling was ≥80MPa, the interfacial bond strength after pull-out testing was ≥5MPa, and the strength recovery rate after 7 days of curing for manually cut 0.3mm microcracks was ≥85%. During long-term monitoring, after 1 year, ultrasonic testing showed an internal density of ≥95% with no voids; after 2 years, infrared thermal imaging showed a temperature difference of ≤1℃ with no voids; and after 3 years, 0.5MPa water pressure was maintained for 30 minutes with no leakage and no secondary cracking in the self-repairing area.

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