A method for treating cracking prevention structure of steel structure insulation board wall

Abstract

The present invention relates to the technical field of building wall panel construction, and provides a method for treating a crack-proof structure of a steel structure insulation panel wall, comprising the following steps: Step 1: Welding U-shaped metal clips on both sides of a steel structure column, providing a serrated protrusion on the inner side of the U-shaped metal clip, and coating the inner wall with a neutral silicone structural adhesive; Step 2: Embedding a polyurethane insulation board into the U-shaped metal clip, applying pressure and curing it with a hydraulic press to form a flexible transition layer; Step 3: Cutting grooves at the joints of adjacent insulation boards. This method solves the problem that joint treatment relies on a single material, which cannot take into account both bonding strength and deformation coordination; and even lacks rigid-flexible composite reinforcement measures for long panels. In addition, a multi-level anti-cracking system has not been constructed, and local stress concentration will still cause microcracks to expand.

Description

Technical Field

[0001] The invention relates to the technical field of building wall panel construction, in particular to a method for treating a crack-proof structure of a steel structure insulation panel wall. Background Art

[0002] With the rapid development of prefabricated buildings, steel-structured insulated panel walls are widely used due to their lightweight, high strength, and easy construction. However, the poor synergistic deformation capacity of steel structures and insulation panels makes them susceptible to cracking in joints under wind loads, temperature fluctuations, and foundation settlement. This leads to a decrease in insulation performance and loss of the finishing layer, severely restricting their application in engineering projects.

[0003] In the prior art, the invention patent with announcement number CN103089012B discloses a method of dispersing stress using U-shaped clips and polymer mortar, but does not solve the problem of flexural cracking in the middle of long plates; the invention patent with announcement number CN104775541B proposes a combination of glass fiber mesh cloth and caulking tape to prevent cracking, but does not consider the elastic deformation characteristics of the steel structure; the invention patent with announcement number CN101793097B uses slag-silver powder filler, but its flexibility is insufficient and it is difficult to adapt to the dynamic deformation of the steel structure.

[0004] In addition, the traditional method relies on a single material for joint treatment, which cannot take into account both bonding strength and deformation coordination; it even lacks rigid-flexible composite reinforcement measures for long plates. In addition, a multi-level anti-cracking system has not been constructed, and local stress concentration will still cause microcracks to expand. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for anti-cracking structural treatment of steel structure insulation board walls, which solves the problem that joint treatment relies on a single material and cannot take into account both bonding strength and deformation coordination; it even lacks rigid and flexible composite reinforcement measures for long plates. In addition, a multi-level anti-cracking system has not been constructed, and local stress concentration will still cause microcracks to expand.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for treating a steel structure insulation board wall to prevent cracking, comprising the following steps:

[0008] Step 1: Weld U-shaped metal clips on both sides of the steel structure column. Set a serrated protrusion on the inner side of the U-shaped metal clip, and apply a neutral silicone structural adhesive with an elastic modulus of 0.8-0.9 MPa on the inner wall. The adhesive layer thickness is 2.5-3 mm.

[0009] Step 2: Embed the polyurethane insulation board into the U-shaped metal clamp, apply 6-6.5MPa pressure through a hydraulic press and maintain the pressure for 35-40 minutes, and cure for 30-45 hours to form a flexible transition layer;

[0010] Step 3: Cut grooves at the joints of adjacent insulation boards. The grooves are V-shaped or inverted trapezoidal grooves, and fill the grooves with polymer mortar.

[0011] Step 4: Cover the surface of the unset mortar with alkali-resistant glass fiber mesh cloth, pressing it into the mortar layer to a depth of 2 / 3 of the thickness;

[0012] Step 5: Use a wedge-shaped jack to install the upper insulation board, and the laser positioning instrument controls the verticality deviation to 0.8mm / m;

[0013] Step 6: Spray the elastic waterproof coating on the joint surface, which forms a continuous film layer after drying, with a dry film thickness of 0.8mm;

[0014] Step 7: Install EPDM rubber elastic gaskets on the contact surface between the insulation board and the steel beam;

[0015] Step 8: Add an H-shaped steel reinforcement rib in the center of the back of the insulation board and connect it with an embedded clip;

[0016] Step 9: Hang galvanized steel mesh on the insulation board surface, and lay a 3mm thick rubber isolation pad between the steel mesh and the insulation board;

[0017] Step 10: Check for cracks after 7 days of curing, and inject epoxy resin micro-slurry to repair cracks with a width greater than 0.1mm.

[0018] Furthermore, the U-shaped metal clip in step one is made of 304 stainless steel, and the serrated protrusions include unidirectional serrations or bidirectional staggered serrations.

[0019] Furthermore, the neutral silicone structural adhesive in step 1 has an elongation at break of 450%, and the jagged protrusions form continuous wavy patterns on the surface of the adhesive layer.

[0020] Furthermore, in step 3, when the groove is a V-groove, the V-groove has a depth of 35 mm and a width of 12 mm;

[0021] When the groove is an inverted trapezoidal groove, the groove depth of the inverted trapezoidal groove is 1 / 3 of the plate thickness, the upper width of the inverted trapezoidal groove is 15mm, and the lower width is 10mm.

[0022] Furthermore, the polymer mortar ratio in step three is: 100 kg of cement, 150 kg of fine sand, 8 kg of EVA glue powder, 0.8 kg of nano-silica, and 45 kg of water.

[0023] Furthermore, the embedded buckle spacing in step eight is 380 mm, and the tensile strength is 12 MPa.

[0024] Furthermore, the dynamic stiffness of the seismic isolation cushion layer in step nine is 8 MPa, the galvanized steel wire mesh weighs 160 g / m², and the surface of the mesh is coated with KH-550 coupling agent.

[0025] Furthermore, the elastic gasket described in step seven is in the shape of an "I", with a stress relief hole with a diameter of 20 mm opened every 600 mm in the longitudinal direction, and the hole is filled with silicone sealant; when the length of the insulation board is ≥4m, a prestressed carbon fiber belt is added to the back.

[0026] Furthermore, the elastic waterproof coating in step six is ​​a polyurethane-acrylate or water-based fluorocarbon coating.

[0027] Furthermore, the epoxy resin micro-slurry ratio in step 10 is 100 kg of epoxy resin, 30 kg of curing agent, and 15 kg of nano-calcium carbonate, and the slurry fluidity is 220 mm.

[0028] The present invention provides a method for treating a steel structure insulation board wall to prevent cracking, which has the following beneficial effects:

[0029] This invention incorporates serrated protrusions on the inside of U-shaped metal clips, creating a synergistic effect between the protrusions and the polymer mortar, enhancing interfacial shear strength. Combined with elastic gaskets and seismic isolation pads, this allows the steel structure insulation panel wall system to remain crack-free even at ±5mm displacement. This three-level protection system, encompassing interfacial bonding, intermediate transition, and surface layer protection, reduces the probability of cracking to below 3% over a 50-year period, an 80% reduction compared to existing technologies. Furthermore, by replacing overall thickening with local reinforcement using H-shaped ribs, material usage is reduced by 25%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be combined with Figure 1 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] Example 1: This example discloses a method for treating a steel structure insulation board wall to prevent cracking, comprising the following steps:

[0033] Step 1: The steel structure columns (H-shaped steel columns) are made of Q355B material and have a cross-sectional area of ​​H300mm × 150mm × 6mm × 5mm. U-shaped metal clamps made of 304 stainless steel with a wall thickness of 3mm are welded on both sides of the steel structure columns. Serrated protrusions are machined on the inside of the U-shaped metal clamps. In this embodiment, the serrations are unidirectional, with a height of 1.5mm and a spacing of 12mm. The inner surface of the U-shaped metal clamps is coated with a neutral silicone structural adhesive with an elastic modulus of 0.8MPa, an elongation at break of 450%, and a thickness of 2.5mm. The serrations increase the adhesive contact area and form a continuous ripple on the adhesive surface. The high elasticity of the neutral silicone structural adhesive absorbs the dynamic deformation stress between the steel structure and the insulation board, preventing interfacial debonding.

[0034] Step 2: The insulation board is a polyurethane insulation board with a thickness of 100mm. It is embedded in the U-shaped metal clip. A hydraulic press is used to apply a pressure of 6MPa and maintain the pressure for 35 minutes to make the neutral silicone structural adhesive evenly fill the gap. It is cured for 30 hours. The pressure ensures that there is no hollowing in the adhesive layer. The temperature and humidity are controlled during the curing stage. The curing conditions are 25℃ and RH60%. A flexible transition layer is formed after curing. After testing, the shear strength is increased to 2.6MPa, while the traditional method is 1.2MPa.

[0035] Step 3: Cut grooves at the joints of adjacent insulation boards. The grooves are V-shaped grooves. The V-shaped grooves increase the contact surface of the filling. The groove depth is 35mm and the groove width is 12mm. The polymer mortar is filled in the grooves. The specific ratio is: 100kg cement, 150kg fine sand, 8kg EVA glue powder, 0.8kg nano-silica, and 45kg water. The added nano-silica can effectively improve the crack resistance of the mortar. After testing, the flexural strength reaches 8.5MPa, which is 40% higher than the ordinary mortar in the existing technology.

[0036] Step 4: Cover the mortar with alkali-resistant glass fiber mesh cloth before it sets. The weight is 160g / m² and KH-550 coupling agent is applied. The mesh cloth is 120mm wide and overlapped 60mm. The pressing depth is 2 / 3 of the mortar layer thickness. The mesh cloth forms a bidirectional tensile layer. The added coupling agent enhances the bonding strength with the mortar. The actual test shows that the peel strength is ≥1.5kN / m.

[0037] Step 5: Use a 5° wedge-shaped jack to install the upper insulation board with a jacking force of 2.8 kN. Calibrate the verticality deviation of the laser positioning instrument to 0.8 mm / m to ensure that the mortar overflows and is scraped flat at the joint. The wedge-shaped jacking method eliminates the installation gap, and the laser positioning ensures the straightness of the joint and reduces stress concentration.

[0038] Step 6: Spray polyurethane-acrylate elastic waterproof coating (solid content 65%, elongation 350%) on the joint surface. After drying, a continuous film layer is formed with a dry film thickness of 0.8mm. The coating can adapt to ±5mm displacement deformation and has a waterproof moisture permeability of 0.1g / (m²·h), preventing moisture intrusion from causing frost heave and cracking.

[0039] Step 7: Install an elastic gasket made of EPDM rubber on the contact surface between the insulation board and the steel beam. The thickness of the elastic gasket is 4mm and the compression rate is 25%. The elastic gasket is bonded to the steel structure with epoxy adhesive. The elastic gasket buffers the vibration transmission of the steel structure and reduces the probability of micro cracks on the contact surface.

[0040] Step 8: In this embodiment, the insulation board is 4.5m long, and an H-shaped steel reinforcement rib is added in the center with a height of 150mm and a spacing of 1.0m. The H-shaped steel reinforcement rib is connected to the insulation board through embedded clips with a spacing of 380mm and a tensile strength of 12MPa.

[0041] Furthermore, H-shaped steel reinforcement ribs are used to suppress the bending deformation in the middle of the plate, reducing the deflection value from L / 250 of the traditional method to L / 500; thereby more effectively controlling the bending deformation of the plate and reducing cracks.

[0042] Step 9: The surface of the insulation board is fully covered with galvanized steel wire mesh with a mesh size of 10mm×10mm and a gram weight of 160g / m². The surface of the mesh is coated with KH-550 coupling agent. A 3mm thick rubber isolation pad is laid between the galvanized steel wire mesh and the insulation board. The dynamic stiffness of the isolation pad is 8MPa and it is fixed with self-tapping screws at a spacing of 180mm. The isolation pad disperses the external impact load and the steel wire mesh improves the crack resistance of the surface layer. After testing, the impact toughness is increased by 30%.

[0043] Step 10: After 7 days of curing, use a crack observation instrument to detect and inject epoxy resin micro-slurry into cracks with a width of more than 0.1mm. The epoxy resin micro-slurry ratio is: 100kg epoxy resin, 30kg curing agent, and 15kg nano-calcium carbonate. After repair, the re-inspection is qualified. Nano-calcium carbonate enhances the fluidity and permeability of the slurry. Among them, the fluidity is 220mm. After actual testing, the micro-crack closure rate is ≥95%.

[0044] After testing, the effects of this embodiment are as follows:

[0045]

[0046] This embodiment, through the collaborative design of "flexible interface + rigid reinforcement + multi-level protection," solves the problem of cracking in the joints of steel structure insulation panels caused by deformation due to material differences. In actual project application (a steel structure factory with an area of ​​5,000 square meters), acceptance testing showed a crack incidence rate of only 1.2%, significantly lower than the 18.5% rate of traditional processes, demonstrating excellent economic efficiency.

[0047] Example 2: This example is basically the same as Example 1, except that the inner side of the U-shaped metal clip is laser-engraved with bidirectional staggered serrations with a depth of 1.3 mm and a spacing of 10 mm.

[0048] Neutral silicone structural adhesive is applied on the bidirectional staggered zigzag pattern with a thickness of 3mm;

[0049] The bidirectional staggered serrations create continuous wavy patterns on the surface of the adhesive layer, which increases the effective bonding area by 30%. The resulting wavy adhesive layer creates a "spring effect" when under pressure. Tests have shown that the dynamic shear strength is increased to 2.8MPa. The low elastic modulus (<1MPa) of the neutral silicone structural adhesive can absorb the ±4mm differential deformation between the steel structure and the insulation board.

[0050] Example 3: This example discloses a method for treating a steel structure insulation board wall to prevent cracking, comprising the following steps:

[0051] Step 1: Weld U-shaped metal clips on both sides of the steel structure column (H-shaped steel column, specifications: specifications H400×200×8×12). The U-shaped metal clips are made of 304 stainless steel and the wall thickness of the U-shaped metal clips is 3mm; and laser engrave bidirectional staggered serrations on the inside of the U-shaped metal clips. The bidirectional staggered serrations are 1.2mm deep and 10mm apart. The inner wall of the U-shaped metal clip is coated with neutral silicone structural adhesive. The elastic modulus of the neutral silicone structural adhesive is 0.9MPa and the adhesive coating thickness is 3mm. Continuous wavy patterns are formed on the colloid surface formed by the neutral silicone structural adhesive. The serrations increase the effective bonding area by 30%. The wavy adhesive layer forms a "spring effect" when under pressure, and the dynamic shear strength is increased to 2.85MPa.

[0052] Step 2: Use a 120mm thick polyurethane insulation board, embed U-shaped metal clips, and use a hydraulic press to apply uniform pressure at 6.5MPa for 40 minutes. During the curing stage, the temperature and humidity are controlled at 25℃ and RH60%, and the curing time is 45 hours. Synchronous jacking is used to eliminate local stress concentration. The void ratio of the adhesive layer is tested to be <0.5%, and the actual test is 0.45%. The peel strength is ≥3.5kN / m (GB / T7124 test).

[0053] Step 3: Cut grooves at the joints of adjacent insulation boards. The grooves are inverted trapezoidal grooves with a depth of 1 / 3 of the board thickness, an upper width of 15 mm, and a lower width of 10 mm. At the same time, the side walls of the inverted trapezoidal grooves are sandblasted to a roughness of Ra = 50 μm to create an "anchor effect" in the inverted trapezoidal grooves. Fill the inverted trapezoidal grooves with polymer mortar, specifically including:

[0054] Bottom layer: cement-based penetrating crystalline waterproof mortar (thickness 10mm, water-cement ratio 0.28), mixed with 1.5% nano-alumina (particle size 15nm);

[0055] Middle layer: polymer anti-cracking mortar (ratio: P.O42.5 cement 100kg, quartz sand 150kg, redispersible latex powder 8kg, polypropylene fiber 0.5kg, water 45kg), thickness 15mm;

[0056] Surface layer: spraying ultra-high performance mortar (compressive strength 120MPa) containing steel fiber (length 12mm, diameter 0.2mm, dosage 2%), thickness 10mm.

[0057] Nano-alumina improves the capillary density of the waterproof mortar, and the steel fiber mortar makes the joint's impact energy absorption value reach 15J. The nano-modified mortar is filled in a layered manner. After field testing, the pull-out strength is increased to 9.8kN, which is significantly improved compared with the V-groove in Example 1.

[0058] Step 4: Cover the surface of the inverted trapezoidal groove with alkali-resistant glass fiber mesh cloth. There are two layers of alkali-resistant glass fiber mesh (lower layer 160g / m², upper layer 300g / m²). The mesh cloth is 120mm wide and overlapped 80mm. The pressing depth accounts for 2 / 3 of the total thickness of the mortar layer. Coat the surface with coupling agent KH-550 (coating amount 8g / m²).

[0059] Step 5: Use a laser locator to control the vertical deviation of the joint to 0.7 mm / m. When installing the upper insulation board, use a 5° wedge-shaped jack with a lifting force of 2.8 kN to ensure that the polymer mortar is filled and overflows.

[0060] Step 6: Spray water-based fluorocarbon elastic coating (solid content 70%, elongation 400%) on the joint surface with a dry film thickness of 0.8mm, and apply it in two cross-coatings; after coating, cover it with self-repairing nano-coating (containing microcapsule repair agent with a diameter of 50-100μm) to form a functional layer with a thickness of 20μm. The fluorocarbon coating has a UV aging resistance level of ASTMG154 and no powdering after 3000 hours. The microcapsules rupture and release epoxy resin when the cracks on the contact surface expand, achieving self-healing of cracks with a width of ≤0.05mm.

[0061] Step 7: An I-shaped EPDM rubber pad (5mm thick, 60HA Shore hardness) is placed on the contact surface between the insulation board and the steel beam. A stress relief hole (20mm in diameter) is opened every 600mm in the longitudinal direction with a compression rate of 25%. The stress relief hole is filled with silicone sealant. The insulation board in this embodiment is 5m long. When the insulation board is ≥4m, a prestressed carbon fiber tape (50mm in width, 1.2mm in thickness, and 10kN in pretension) is added to the back of the insulation board and connected to the steel structure through a stainless steel clamp. The stress relief hole allows the gasket to deform in three dimensions when under pressure to compensate for the thermal expansion of the steel structure by ±3mm. The carbon fiber tape applies a reverse bending moment to control the maximum deflection of the insulation board within L / 600 (laser scanning detection).

[0062] Step 8: Add H-shaped steel reinforcement ribs to the center of the insulation board. The rib height is 180mm, and the rib spacing is 1.0m. The ribs are connected to the board body with embedded clips (tensile strength 12MPa) to suppress deflection in the middle of the board. The deflection value is ≤L / 600. The rib height is calculated as 120mm plate thickness × 1.5.

[0063] Step 9: Cover the surface of the insulation board with galvanized steel mesh (mesh size 10mm×10mm), lay a 3mm thick rubber isolation pad (dynamic stiffness 8MPa) between the insulation board, and fix it with self-tapping screws, with adjacent screws spaced 180mm apart.

[0064] Step 10: After 7 days of curing, use a crack observation instrument to detect and inject epoxy resin micro-slurry (ratio: epoxy resin 100kg, curing agent 30kg, nano calcium carbonate 15kg) into cracks with a width of more than 0.1mm. The slurry fluidity is 220mm. After repair, the re-inspection is qualified.

[0065] The implementation effect verification is shown in the following table:

[0066]

[0067] In this embodiment, the inverted trapezoidal groove and layered caulking process increase the shear strength to 3.2 MPa.

[0068] It should be noted that, in actual applications, when the thickness of the insulation board is ≤100mm, a V-shaped groove is used; when the thickness is greater than 100mm, an inverted trapezoidal groove is used.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating cracking prevention of steel structure insulation board wall, characterized in that: The following steps are involved: Step 1: Weld U-shaped metal clips on both sides of the steel structure column. Set a serrated protrusion on the inner side of the U-shaped metal clip, and apply a neutral silicone structural adhesive with an elastic modulus of 0.8-0.9 MPa on the inner wall. The adhesive layer thickness is 2.5-3 mm. Step 2: Embed the polyurethane insulation board into the U-shaped metal clamp, apply 6-6.5MPa pressure through a hydraulic press and maintain the pressure for 35-40 minutes, and cure for 30-45 hours to form a flexible transition layer; Step 3: Cut grooves at the joints of adjacent insulation boards. The grooves are V-shaped or inverted trapezoidal grooves, and fill the grooves with polymer mortar. Step 4: Cover the surface of the unset mortar with alkali-resistant glass fiber mesh cloth, pressing it into the mortar layer to a depth of 2 / 3 of the thickness; Step 5: Use a wedge-shaped jack to install the upper insulation board, and the laser positioning instrument controls the verticality deviation to 0.8mm / m; Step 6: Spray the elastic waterproof coating on the joint surface, which forms a continuous film layer after drying, with a dry film thickness of 0.8mm; Step 7: Install EPDM rubber elastic gaskets on the contact surface between the insulation board and the steel beam; Step 8: Add an H-shaped steel reinforcement rib in the center of the back of the insulation board and connect it with an embedded clip; Step 9: Hang galvanized steel mesh on the insulation board surface, and lay a 3mm thick rubber isolation pad between the steel mesh and the insulation board; Step 10: Check for cracks after 7 days of curing, and inject epoxy resin micro-slurry to repair cracks with a width greater than 0.1mm.

2. A method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: The U-shaped metal clip in step 1 is made of 304 stainless steel, and the serrated protrusions include unidirectional serrations or bidirectional staggered serrations.

3. A method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: The neutral silicone structural adhesive in step 1 has an elongation at break of 450%, and the jagged protrusions form continuous wavy patterns on the surface of the adhesive layer.

4. A method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: In step three, when the groove is a V-shaped groove, the V-shaped groove has a depth of 35 mm and a width of 12 mm; when the groove is an inverted trapezoidal groove, the groove depth of the inverted trapezoidal groove is 1 / 3 of the plate thickness, the upper width of the inverted trapezoidal groove is 15 mm, and the lower width is 10 mm.

5. The method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: The polymer mortar ratio in step 3 is: 100 kg of cement, 150 kg of fine sand, 8 kg of EVA glue powder, 0.8 kg of nano-silica, and 45 kg of water.

6. A method for treating cracking prevention structure of a steel structure insulation board wall according to claim 1, characterized in that: The embedded buckles described in step eight have a spacing of 380 mm and a tensile strength of 12 MPa.

7. A method for treating crack prevention structure of a steel structure insulation board wall according to claim 1, characterized in that: The dynamic stiffness of the isolation cushion layer in step nine is 8 MPa, the weight of the galvanized steel wire mesh is 160 g / m², and the surface of the mesh is coated with KH-550 coupling agent.

8. The method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: The elastic gasket described in step seven is in the shape of an "I" character, with a stress relief hole of 20mm in diameter opened every 600mm in the longitudinal direction, and the hole is filled with silicone sealant; when the length of the insulation board is ≥4m, a prestressed carbon fiber belt is added to the back.

9. The method for treating a steel structure insulation board wall against cracking according to claim 1, characterized in that: The elastic waterproof coating in step six is ​​a polyurethane-acrylate or water-based fluorocarbon coating.

10. A method for treating crack prevention structure of a steel structure insulation board wall according to claim 1, characterized in that: In step 10, the epoxy resin micro-paste ratio is 100 kg of epoxy resin, 30 kg of curing agent, and 15 kg of nano-calcium carbonate, and the slurry fluidity is 220 mm.

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