Composite mortar transition layer and construction method

Abstract

A composite mortar transition layer is used between an ECC repairing layer and an original concrete interface, the composite mortar transition layer sequentially comprises a nanocrystal nucleus interface layer, a fiber reinforced transition layer and a self-repairing buffer layer, and the nanocrystal nucleus interface layer comprises 45-55 wt% of sulphoaluminate cement, 12-18 wt% of silica fume, 3-7 wt% of silicon carbide whiskers, 5-10 wt% of modified bentonite, 18-25 wt% of gradient grading aggregate and 2-15 wt% of functional materials; the fiber reinforced transition layer comprises 40-50 wt% of a composite cement matrix, 2-5 wt% of a fiber reinforced material and 12-18 wt% of an elastic particle filler; the self-repairing buffer layer comprises 55-65 wt% of magnesium phosphate cement, 5-10 wt% of a self-repairing functional material and 15-25 wt% of functional modified aggregate. The nanocrystal nucleus interface layer, the fiber-reinforced transition layer and the self-repairing buffer layer are arranged between the ECC repairing layer and the original concrete, through the three-order elastic modulus design of the nanocrystal nucleus interface layer, the fiber-reinforced transition layer and the self-repairing buffer layer, integration of bonding, crack resisting and repairing functions is achieved, the problem of interface stress concentration is solved, and the service life of the concrete is prolonged. And the problem of interlayer stripping is solved.

Description

Technical Field

[0001] The present invention relates to the field of concrete structure repair and reinforcement, and particularly to a composite mortar transition layer and a construction method thereof. Background Art

[0002] Engineered Cementitious Composites (ECC) is a new type of high-performance fiber-reinforced cement-based composite material. Due to its excellent mechanical properties, durability, and multiple cracking characteristics, ECC is widely used in the repair of concrete structures. The interfacial performance between the ECC repair layer and the original concrete is the key to affecting its repair effect.

[0003] There may be a problem of insufficient bonding force at the interface between the ECC repair layer and the original concrete, resulting in interface peeling and thus reducing the repair effect. This problem may stem from insufficient surface treatment during construction or poor performance of the adhesive used. In addition, there is usually a difference in the elastic modulus between the ECC repair layer and the original concrete, and stress concentration may occur at the interface. Especially under the action of load, stress concentration will lead to the generation and expansion of interface cracks, affecting the overall performance of the repair layer. Traditional construction methods often cannot effectively solve the problems of insufficient bonding force and stress concentration at the interface, resulting in poor repair effects and even possible secondary damage. Summary of the Invention

[0004] The present invention aims to solve the problems existing in the above-mentioned prior art, and provides a composite mortar transition layer, which can improve the interfacial performance between the ECC repair layer and the original concrete and enhance the repair effect.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: A composite mortar transition layer is used between the ECC repair layer and the original concrete interface. The composite mortar transition layer sequentially includes a nano-crystalline core interface layer, a fiber-reinforced transition layer, and a self-healing buffer layer. The nano-crystalline core interface layer includes the following components: 45-55 wt% of sulfoaluminate cement, 12-18 wt% of silica fume, 3-7 wt% of silicon carbide whiskers, 5-10 wt% of modified bentonite, 18-25 wt% of gradient graded aggregate, and 2-15 wt% of functional material; the fiber-reinforced transition layer includes the following components: 40-50 wt% of composite cement matrix, 2-5 wt% of fiber-reinforced material, and 12-18 wt% of elastic particle filler; the self-healing buffer layer includes the following components: 55-65 wt% of magnesium phosphate cement, 5-10 wt% of self-healing functional material, and 15-25 wt% of functional modified aggregate.

[0006] This solution sets a transition layer structure between the ECC repair layer and the original concrete, which successively includes a nanocrystalline nucleus interface layer, a fiber-reinforced transition layer, and a self-repair buffer layer from the base layer to the surface layer. On the one hand, it can alleviate the elastic modulus difference between the original concrete interface and the ECC, reducing the interfacial stress concentration; on the other hand, it inhibits the crack propagation caused by the interlayer shrinkage stress; on the third hand, it endows the interface with self-repair ability to improve durability.

[0007] Preferably, the functional material includes one or more of an auxiliary agent, recycled aggregate, nano-aerogel, antique color slurry, a lithium salt two-component coagulation promoting system, cubic boron nitride, or tungsten carbide.

[0008] Preferably, the fiber-reinforced transition layer is provided with a mechanical anchoring structure. The mechanical anchoring structure includes layer-by-layer implanted anchor bolts with a diameter of 0.2 - 0.5 mm and a density of 20 - 30 pieces / m 2 , the implantation depth of the anchor bolts is 50 - 70% of the single-layer thickness, and the surface of the anchor bolts has spiral grooves with a pitch of 0.1 - 0.3 mm and a groove depth of 20 - 50 μm.

[0009] Preferably, the fiber-reinforcing material includes one or more of basalt fiber, polypropylene fiber, carbon fiber, sisal fiber, or polyethylene fiber.

[0010] Preferably, the elastic particle filler is rubber powder or polyurethane particles with a particle size of 0.1 - 0.5 mm.

[0011] Preferably, the self-repairing functional material includes microencapsulated repair agents or responsive materials for realizing crack repair or stress buffering.

[0012] Preferably, the microencapsulated repair agent is sodium alginate microencapsulated chloride ion capturer, special microcapsules for vibration environment, microencapsulated underwater curing agent coated with polydopamine, acrylic resin microcapsules, or pH-sensitive microcapsules; the shape of the responsive material is a thermosensitive shape memory polymer, a solar-triggered thermosensitive repair system, or a zircon powder - magnesium phosphate - zinc borate composite ceramic material.

[0013] Preferably, the triggering mechanism of the microencapsulated repair agent includes at least one of the following: physical triggering, the capsules rupture when the crack width ≥ 0.05 mm; chemical triggering, the repair agent is released when the environmental pH value changes ≥ 1.5; temperature triggering, controlled release is achieved within the range of 40 - 60 °C.

[0014] The construction method of the composite mortar transition layer includes the following steps: S1. Base surface activation treatment: Pretreat the base surface by physical or chemical methods to form an activated interface; S2. Construction of the nanocrystalline nucleus interface layer: Spray or inject composite mortar on the activated interface to form a nanocrystalline nucleus interface layer; S3. Construction of fiber-reinforced transition layer: implant anchor bolts or fibers on the nanocrystalline nucleus interface layer, and fix the anchor bolts by combining ultrasonic vibration or laser welding. S4. Construction of self-healing buffer layer: set a buffer layer containing self-healing functional materials on the fiber-reinforced transition layer.

[0015] Preferably, in the above S3, ultrasonic vibration compacts with ultrasonic waves of a frequency of 15 - 25 kHz, the vibration time is 30 - 60 s per square meter, and the amplitude is controlled within the range of 0.02 - 0.05 mm.

[0016] The beneficial effects of the present invention include: (1) Through the three-order elastic modulus design of the nanocrystalline nucleus interface layer - fiber-reinforced transition layer - self-healing buffer layer, the nanocrystalline nucleus interface layer provides elastic modulus gradient transition and chemical bond enhancement, the fiber transition layer constructs a three-dimensional crack-blocking network, breaking through the limitation of the traditional two-dimensional fiber distribution, and the self-healing buffer layer fills the ability cracks through the self-healing mechanism, improving the durability; integrating the three mechanisms of the bonding of the nanocrystalline nucleus interface layer, the blocking of the fiber-reinforced transition layer, and the repair of the self-healing buffer layer in the transition layer structure, realizing the integration of the bonding - crack-blocking - repair functions, reducing the problem of interfacial stress concentration, and completely solving the problem of interlayer peeling.

[0017] (2) The synergistic effect of nanoscale silicon carbide whiskers and millimeter-scale mechanical anchor bolts forms a three-dimensional bridging structure, improving the interfacial shear strength.

[0018] (3) The microcapsule system releases the repair liquid in the microcapsules when the crack propagates, enabling the structure to fill the cracks immediately under the condition of no maintenance, extending the service life, and reducing the maintenance cost. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the transition layer structure between the ECC repair layer and the original concrete interface; Figure 2 It is a schematic diagram of the mechanical anchoring structure of the fiber-reinforced transition layer.

[0020] Description of the reference numerals: 1. Original concrete interface; 2. Nanocrystalline nucleus interface layer; 3. Fiber-reinforced transition layer; 31. Anchoring structure; 311. Anchor bolt; 4. Self-healing buffer layer; 5. ECC repair layer. Detailed Embodiments

[0021] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific embodiments, structures, features and their effects according to the present invention as follows.

[0022] Refer toFigure 1 As shown in the figure, the present invention provides a composite mortar transition layer for the interface between the ECC repair layer 5 and the original concrete interface 1. The composite mortar transition layer sequentially includes a nanocrystalline nucleus interface layer 2, a fiber-reinforced transition layer 3, and a self-healing buffer layer 4.

[0023] Referring to Figure 2 As shown in the figure, the fiber-reinforced transition layer 3 can be provided with a mechanical anchoring structure 31. The mechanical anchoring structure 31 includes anchor pins 311 with a diameter of 0.2 - 0.5 mm implanted between layers, and the density is 20 - 30 pieces / m 2 , the implantation depth of the anchor pins 311 is 50 - 70% of the single-layer thickness, and the surface of the anchor pins 311 has spiral grooves with a pitch of 0.1 - 0.3 mm and a groove depth of 20 - 50 μm.

[0024] Example 1 In the tidal difference area of a pier column of a certain cross-sea bridge, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Base surface activation treatment: First, use a 35 MPa high-pressure water jet (1.5 mm nozzle) to accurately remove biological attachments to form a uniform rough interface with Ra = 1.8 mm, then spray a 0.5% silane coupling agent ethanol solution (0.25 kg / m 2 coverage rate), let it stand for 45 min to construct a hydrophobic film, and finally use -0.08 MPa vacuum adsorption to remove residual droplets to achieve a base surface moisture content ≤ 2.5%; S2. Construction of the nanocrystalline nucleus interface layer 2: In the nanocrystalline nucleus interface layer 2, a composite formula (52 wt% sulfoaluminate cement + 16 wt% silica fume + 7 wt% silicon carbide whiskers + 22.5 wt% gradient sand + 2.5 wt% additives) is adopted, and it is formed in three times by double-gun cross spraying at 0.7 MPa (cumulative thickness 2.8 mm). After final setting, it is cured with artificial seawater with a salinity of 3.5% covering a permeable membrane for 72 h; S3. Construction of the fiber-reinforced transition layer 3: First, implant Φ0.4 mm 316L stainless steel micro-anchor pins 311 in the fiber-reinforced transition layer 3 to form an anchoring network, and combine a 0.25 MPa pre-stress and 20 kHz ultrasonic vibration (30 s / m 2 ), then scrape and apply basalt fiber mortar in layers (1.5 mm per layer), and finally use a steel needle rolling brush to form a 0.3 mm deep directional groove to enhance the interlayer bite; S4. Construction of the self-healing buffer layer 4: The self-healing buffer layer 4 is incorporated with sodium alginate microencapsulated chloride ion capturer (92% coating rate) and degassed by -0.09 MPa vacuum stirring.

[0025] Implementation effect: Chloride ion diffusion coefficient at 180 d: 1.2×10-12 m 2 / s, adhesion strength retention rate after 1000h salt spray test: 94%, no peeling after 500 tidal cycles.

[0026] Example 2 In the repair of a certain subway tunnel lining, the transition layer structure of the present invention and its construction method are adopted, which specifically include the following steps: S1. Base surface activation treatment: First, clean the surface with a 30MPa water jet, and use a laser rangefinder to detect the flatness (deviation ≤ 3mm / m). Then spray 1% nano-TiO 2 activator, and perform ultraviolet photocatalytic pretreatment for 20 minutes; S2. Construction of the nano-crystalline nucleus interface layer 2: First, pretreat the recycled aggregate: soak the recycled aggregate in a 5% hydrochloric acid solution to remove impurities in the recycled aggregate, and dry it with 200°C hot air to make the water content of the recycled aggregate as low as 0.3%. Then use the dry spraying method for construction, control the water content of the material mixed with the recycled aggregate at 6 - 8%, keep the spraying distance at 50cm, and control the rebound rate within 12%; S3. Construction of the fiber-reinforced transition layer 3: Pre-weave basalt fiber and polypropylene fiber into a mesh (mesh size 5mm × 5mm) according to a mass ratio of 4:1, and use a manipulator to lay the mesh for positioning (accuracy ±1mm). Then spray mortar for penetration filling (penetration ≥ 95%); S4. Construction of the self-repairing buffer layer 4: Use special microcapsules for the vibration environment (wall thickness 5μm) as the functional material, and use 80Hz high-frequency vibration to compact it during the construction operation. On this basis, cover and paste a damping isolation membrane (loss factor ≥ 0.15).

[0027] Implementation effect: After the vibration fatigue test, the crack width ≤ 0.08mm, the deformation coordination degree between the repair system and the existing lining ≥ 92%, and the construction efficiency is improved: the single-day repair area reaches 15m 2 .

[0028] Example 3 In the repair of a certain high-temperature industrial building, the transition layer structure of the present invention and its construction method are adopted, which specifically include the following steps: S1. Base surface activation treatment: First, remove the matrix carbonized layer by 1200°C plasma flame treatment (travel speed 0.5 m / min), and synchronously complete the flame spraying of a 50μm alumina transition coating to construct a heat-resistant base; S2. Construction of the nano-crystalline nucleus interface layer 2: First, prepare the interface layer with an aluminate cement base material (temperature resistance ≥ 800°C) and silicon carbide whiskers (aspect ratio 30:1), and then perform 400°C / 1h thermal radiation curing through an infrared lamp array to form a whisker-oriented arrangement structure; S3. Construction of the fiber-reinforced transition layer 3: First, perform CVD deposition of a 200-nm-thick SiC coating on the carbon fiber (raising the oxidation-resistant temperature to 650 °C), then implant nickel-based alloy anchor pins 311 with a diameter of Φ0.5 mm, and fix the nickel-based alloy anchor pins 311 by laser welding; S4. Construction of the self-healing buffer layer 4: First, compound zircon powder (10 wt%) with magnesium phosphate cement, then add zinc borate flux and hot-press at 0.5 MPa / 600 °C to finally form a dense ceramicized surface.

[0029] Implementation effect: After 50 thermal shock cycles at 400 °C, the bond strength is 3.8 MPa, the high-temperature creep rate (200 °C / 28 d) ≤ 0.15%, and the thermal conductivity gradient is 0.8 to 1.2 W / (m·K).

[0030] Example 4 In the restoration of a building in a freeze-thaw area, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Substrate activation treatment: First, select an ethanol-based cleaning agent with a freezing point of -50 °C for substrate activation in an environment of -10 °C, and then use an electric blanket to preheat the substrate at a gradient of ≤2 °C / min to 5 °C to eliminate freeze-thaw damage to the substrate; S2. Construction of the nanocrystalline nucleus interface layer 2: First, use a dry ice-assisted spraying process (-78 °C atomization) to prepare an interface layer from a material mixed with nano-aerogel (dosage 3 wt%, thermal conductivity 0.018 W / m·K), and then cover it with an electric heating maintenance blanket to maintain low-temperature curing at 10 °C / 48 h to form a nano-closed pore structure; S3. Construction of the fiber-reinforced transition layer 3: First, premix polyurethane elastic particles with a particle size of 0.2 mm with mortar, incorporate an anti-freezing early-strength agent, and pour in layers, and then implant a temperature sensor to monitor the formation of internal ice crystals in real time; S4. Construction of the self-healing buffer layer 4: By incorporating acrylic resin microcapsules with a phase change temperature of -15 °C (loaded with nano-silver antibacterial agents), conduct a 2-mm artificial ice layer interface splitting test to verify that the release efficiency of the repair agent under -20 °C freeze-thaw cycles is ≥85%.

[0031] Implementation effect: The mass loss rate after 300 freeze-thaw cycles is ≤0.8%, the interface bond strength at -20 °C is 2.5 MPa, and the ice splitting stress release rate is ≥85%.

[0032] Example 5 In the protective restoration of a historical building, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Substrate activation treatment: Use a 0.1 MPa low-pressure soft brush for mechanical cleaning combined with 60 °C, 95% RH steam fumigation to gently soften the historical residual coating; S2. Construction of the nanocrystalline core interface layer 2: First, use an antique-colored slurry (5 wt% rice husk ash + 3 wt% ochre powder + modified lime base material), and then apply a thin layer by hand (thickness 1.2 mm ± 0.2 mm) to accurately replicate the texture of the original brick joints; S3. Construction of the fiber-reinforced transition layer 3: Use ancient lime mortar reinforced with sisal fibers (15 mm in length), and cooperate with a bamboo trowel and a 10 mm × 10 mm degradable polylactic acid anchoring mesh; S4. Construction of the self-healing buffer layer 4: Set a pH-responsive reversible interface, and achieve non-destructive peeling of the repair layer through pH-sensitive microcapsules (sodium hydroxide-sensitive microcapsules, 5% drug loading). After soaking in 12% NaOH solution for 2 h for verification, the interface peeling strength drops to 0.15 MPa.

[0033] Implementation effect: Color difference ∆E ≤ 3.5 (CIELab standard), air permeability: matching degree with existing masonry structures ≥ 95%, reversible reparability: can be peeled off without damage by soaking in NaOH solution.

[0034] Example VI In the application of a certain rapid repair project, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Substrate activation treatment: First, use 2.45 GHz microwave radiation (power density 5 W / cm 2 ) to implement substrate activation, rapidly reduce the moisture content of the substrate to less than 1% within 3 min, and simultaneously spray 8% nano-TiO 2 photocatalytic pretreatment agent, and activate the surface photo-induced hydrophilic property by ultraviolet irradiation for 10 min; S2. Construction of the nanocrystalline core interface layer 2: The interface layer adopts a lithium salt two-component coagulation-promoting system (Li 2 CO 3 : LiNO 3 = 3:1, dosage 8%), so that the sulfoaluminate cement achieves ultra-rapid setting in 5 min, and cooperate with 800 W microwave curing (final setting reached in 5 min); S3. Construction of the fiber-reinforced transition layer 3: Use visible light-responsive self-cleaning mortar (nano-TiO 2 , loaded with 3%), continuously lay fibers through a laying system (laying speed 2 m / min), and simultaneously heat the substrate to improve the bonding strength between the fiber and the interface; S4. Construction of the self-healing buffer layer 4: Configure a solar-triggered temperature-sensitive repair system (black body particle heat absorption efficiency 92%). When the ambient temperature reaches 40 °C, the microcapsules rupture and release the repair agent. After 2 h, emergency traffic verification is carried out (deformation amount 0.48 mm under a load of 50 kN / m 2 ).

[0035] Implementation effect: The 2-hour compressive strength reaches 20 MPa, the pollutant degradation rate under ultraviolet irradiation is 85% / 24 h, and the emergency traffic opening time is shortened to 6 h.

[0036] Example VII In the repair of erosion resistance and abrasion resistance of a certain water conservancy and hydropower project, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Base surface activation treatment: First, use a 40 MPa high-pressure water jet combined with 0.3 mm emery abrasive to deeply roughen the base surface (surface roughness Ra = 2.5 mm), and then spray a special underwater epoxy primer (rapid curing in 30 minutes) to form a high-strength initial bonding layer; S2. Construction of the nanocrystalline nucleus interface layer 2: Adopt a tungsten carbide reinforcement system (15% dosage, 50 μm particle size, 2200 HV hardness), and realize the instant mixing of cement-based material and nano-SiO 2 sol by a two-component underwater spraying system to directly form a dense structure with excellent erosion resistance and abrasion resistance in water; S3. Construction of the fiber-reinforced transition layer 3: Use ultra-high molecular weight polyethylene fibers (18 mm in length, 3.5 GPa tensile strength) to reinforce the mortar, and cooperate with nickel-titanium alloy shape memory anchor bolts 311 (generating a pre-compression stress of 0.5 MPa when restored by water) to construct a three-dimensional reinforcement network; S4. Construction of the self-healing buffer layer 4: Introduce a microencapsulated underwater curing agent coated with polydopamine (10% dosage), which can autonomously release a sulfoaluminate cement-silica sol composite slurry when cracks occur, realizing self-healing in the underwater environment.

[0037] Implementation effect: Erosion test at a flow velocity of 15 m / s (ASTM C1138), the mass loss rate ≤ 0.8 g / h, and the underwater bonding strength (28 d) ≥ 3.2 MPa (refer to the DL / T5193 standard).

[0038] Example VIII In the repair of a road anti-skid thin layer, the transition layer structure and its construction method of the present invention are adopted, which specifically include the following steps: S1. Base surface activation treatment: First, use a 2 kW high-power laser (scanning speed 0.5 m / s) to precisely melt-etch the base surface to form a regular micro-pit array with a diameter of 0.5 mm and a depth of 0.3 mm, and then inject a low-resistance graphene slurry (resistivity ≤ 10 Ω·cm) to construct a de-icing circuit base layer; S2. Construction of the nanocrystalline nucleus interface layer 2: First, incorporate 15% cubic boron nitride (thermal conductivity 400 W / m·K) into the nanocrystalline nucleus layer as a thermal conductivity enhancement phase, and then use a 2.45 GHz microwave (power density 8 W / cm 2 ) for 3 minutes of rapid curing to form a high-thermal conductivity structure layer; S3. Construction of the fiber-reinforced transition layer 3: First, use steel slag powder (specific surface area 450 m 2 / kg) to replace 40% of the cement, and incorporate 0.5 - 1 mm silicon carbide anti-slip aggregate. At the same time, implant resistance heating wires with a spacing of 20 mm (power density 200 W / m 2 ), to achieve the function of active ice melting; S4. Construction of the self-healing buffer layer 4: The buffer layer uses a temperature-sensitive shape memory polymer (phase change temperature -5°C), which automatically triggers the crack closure mechanism (self-closure rate ≥ 90%) when the temperature is below the freezing point.

[0039] Implementation effect: The pendulum friction coefficient (wet state) ≥ 0.65 (JT / T712 standard), and the ice melting rate in an environment of -20°C ≥ 3 mm / h.

[0040] Table 1 Embodiment Feature Content 1 Feature Content 2 Feature Content 3 Implementation Effect 1 Implementation Effect 2 Implementation Effect 3 One Auxiliary Agent 2.5wt% 316L Stainless Steel Micro Anchor + Basalt Fiber Sodium Alginate Microencapsulated Chloride Ion Trapping Agent <![CDATA[180d chloride ion diffusion coefficient: 1.2×10-12 m 2 / s]]> Bond Strength Retention Rate after 1000h Salt Spray Test: 94% No Peeling after 500 Tidal Cycles Two Recycled Aggregate Pre - woven Mesh of Basalt Fiber and Polypropylene Fiber (4:1) Special Microcapsules for Vibration Environment Crack Width ≤ 0.08mm after Vibration Fatigue Test Degree of Deformation Coordination between Repair System and Existing Lining ≥ 92% <![CDATA[Construction efficiency improvement: the daily repair area reaches 15m 2 > Three Silicon Carbide Whiskers (Aspect Ratio 30:1) Carbon Fiber + Φ0.5mm Nickel - based Alloy Anchor Zircon Powder - Magnesium Phosphate - Zinc Borate Composite Ceramic Material Bond Strength after 50 Thermal Shock Cycles at 400℃: 3.8MPa High - temperature Creep Rate (200℃ / 28d) ≤ 0.15% Thermal Conductivity Gradient: 0.8 to 1.2 W / (m·K) Four Nanoporous Aerogel Polyurethane Elastic Particles Acrylic Resin Microcapsules (Loaded with Nano - silver Antibacterial Agent) Mass Loss Rate ≤ 0.8% after 300 Freeze - Thaw Cycles Interface Bond Strength at - 20℃: 2.5MPa Ice Wedging Stress Release Rate ≥ 85% Five Antique - colored Slurry Sisal Fiber (15mm) + 10mm×10mm Degradable Polylactic Acid Anchoring Mesh Sodium Hydroxide - sensitive Microcapsules Color Difference ∆E ≤ 3.5 (CIELab Standard) Air Permeability: Compatibility with Existing Masonry Structure ≥ 95% Reversible Repairability: Can be Peeled off without Damage after Immersion in NaOH Solution Six <![CDATA[8% lithium salt two-component coagulation promoting system (Li 2 CO 3 :LiNO 3 =3:1)]]> <![CDATA[Visible light-responsive self-cleaning mortar (nano-TiO 2 , loaded with 3%) + fiber]]> Solar - triggered Thermosensitive Repair System (Black Body Particle Heat Absorption Efficiency 92%) 2h Compressive Strength Reaches 20MPa Pollutant Degradation Rate under UV Irradiation: 85% / 24h Emergency Traffic Opening Time Shortened to 6h Seven Tungsten Carbide Ultra - high Molecular Weight Polyethylene Fiber (18mm, 3.5GPa) + Nickel - Titanium Alloy Shape Memory Anchor Microencapsulated Underwater Curing Agent Coated with Polydopamine (10% Dosage) Abrasion Test at Flow Velocity of 15m / s (ASTMC1138) Mass Loss Rate ≤ 0.8g / h Underwater Bond Strength (28d) ≥ 3.2MPa (Refer to DL / T5193 Standard) Eight 15% Cubic Boron Nitride <![CDATA[Ground granulated blast-furnace slag (specific surface area: 450 m 2 / kg) + silicon carbide anti-slip aggregate (0.5 - 1 mm) + resistance heating wire (spacing 20 mm)]]> Thermosensitive Shape Memory Polymer Pendulum Friction Coefficient (Wet State) ≥ 0.65 (JT / T712 Standard) Ice Melting Rate at - 20℃ Environment ≥ 3mm / h Summary: According to the above key indicators for evaluating the interface performance, the above embodiments have received high scores in relevant key indicators (such as bond strength, deformation coordination degree, compressive strength, mass strength, friction coefficient, etc.). Therefore, by setting a transition layer between the ECC repair layer 5 and the original concrete interface 1, and integrating the functions of the nanocrystalline core interface layer 2 - fiber-reinforced transition layer 3 - self-healing buffer layer 4 into the same mechanism, the interface performance between the ECC repair layer 5 and the original concrete interface 1 can be improved.

[0041] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to form equivalent embodiments with equivalent changes, but as long as they do not depart from the technical content of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A composite mortar transition layer, used between an ECC repair layer (5) and an original concrete interface (1), characterized in that: The composite mortar transition layer comprises a nanocrystalline core interface layer (2), a fiber-reinforced transition layer (3) and a self-repairing buffer layer (4) in sequence, wherein the nanocrystalline core interface layer (2) comprises the following components: 45-55wt% of sulphoaluminate cement, 12-18wt% of silica fume, 3-7wt% of silicon carbide whiskers, 5-10wt% of modified bentonite, 18-25wt% of gradient graded aggregate, and 2-15wt% of functional material; the fiber-reinforced transition layer (3) comprises the following components: 40-50wt% of composite cement matrix, 2-5wt% of fiber-reinforced material, and 12-18wt% of elastic particle filler; and the self-repairing buffer layer (4) comprises the following components: 55-65wt% of magnesium phosphate cement, 5-10wt% of self-repairing functional material, and 15-25wt% of functional modified aggregate.

2. The composite mortar transition layer according to claim 1, characterized in that: The functional material comprises one or more of an additive, a recycled aggregate, a nano-aerogel, an antique color slurry, a lithium salt two-component accelerating coagulation system, cubic boron nitride or tungsten carbide.

3. The composite mortar transition layer according to claim 1, characterized in that: The fiber-reinforced transition layer (3) is provided with a mechanical anchoring structure (31), which comprises anchors (311) with a diameter of 0.2-0.5 mm implanted between the layers at a density of 20-30 per m 2 The anchor (311) is implanted to a depth of 50-70% of the thickness of a single layer, and the surface of the anchor (311) has a spiral groove with a pitch of 0.1-0.3 mm and a groove depth of 20-50 μm.

4. The composite mortar transition layer according to claim 1, characterized in that: The fiber reinforcement material includes one or more of basalt fiber, polypropylene fiber, carbon fiber, sisal fiber or polyethylene fiber.

5. The composite mortar transition layer according to claim 1, characterized in that: The elastic particle filler is rubber powder or polyurethane particles, and the particle size is 0.1-0.5 mm.

6. The composite mortar transition layer according to claim 1, characterized in that: The self-repairing functional material includes a microencapsulated repairing agent or a responsive material, which is used to achieve crack repair or stress buffering.

7. The composite mortar transition layer according to claim 6, characterized in that: The microencapsulated repair agent is a sodium alginate microencapsulated chloride ion capture agent, a microcapsule specially used for a vibration environment, a polydopamine-coated microencapsulated underwater curing agent, an acrylic resin microcapsule or a pH-sensitive microcapsule; the shape of the responsive material is a temperature-sensitive shape memory polymer, a solar-triggered temperature-sensitive repair system or a zircon powder-magnesium phosphate-zinc borate composite ceramic material.

8. The composite mortar transition layer according to claim 6, characterized in that: The triggering mechanism of the microencapsulated repair agent includes at least one of the following: physical triggering, the capsule ruptures when the crack width is ≥0.05 mm; chemical triggering, the repair agent is released when the environmental pH value changes by ≥1.5; Temperature triggered, controlled release is achieved in the range of 40-60℃.

9. The construction method of the composite mortar transition layer according to any one of claims 1 to 8 comprises the following steps: S1. Surface activation treatment: pre-treat the surface by physical or chemical methods to form an activated interface; S2. Construction of nanocrystalline core interface layer (2): forming the nanocrystalline core interface layer (2) by spraying or jetting composite mortar on the activated interface; S3, construction of fiber-reinforced transition layer (3): implanting anchors or fibers on the nanocrystalline core interface layer (2), and fixing the anchors by ultrasonic vibration or laser welding; S4. Construction of a self-repairing buffer layer (4): a buffer layer containing a self-repairing functional material is provided on the fiber-reinforced transition layer (3).

10. The construction method of the composite mortar transition layer according to claim 9, characterized in that: In S3, the ultrasonic vibration is carried out by using a frequency of 15-25kHz ultrasonic vibration for compaction, the vibration time is 30-60s per square meter, and the amplitude is controlled in the range of 0.02-0.05mm.

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