Inorganic adhesive suitable for repairing outer wall and outer wall reconstruction construction method

Abstract

The application belongs to the field of cement-based inorganic adhesive, and relates to an inorganic adhesive suitable for repairing outer walls and a method for reconstructing outer walls, wherein the adhesive comprises the following raw materials in mass parts: 20-30 parts of Portland cement, 8-12 parts of nano-metakaolin, 10-14 parts of quartz powder, 2-3 parts of long glass fiber modified by sulfur-containing silane coupling agent, 4-6 parts of short glass fiber modified by epoxy silane coupling agent, 0.5-2 parts of hydroxypropyl methyl cellulose, 8-12 parts of water-based epoxy emulsion with a solid content of 30-40%, 5-7 parts of polyaluminum phosphate, 0.2-0.5 parts of polycarboxylate superplasticizer, and 0.1-0.3 parts of silicone defoaming agent. The construction method is used for laying steel wire mesh on the repaired and smoothed outer wall, and the inorganic adhesive is used to bond the outer wall thermal insulation layer, the steel wire mesh and the anti-cracking putty layer into an integrated whole, the adhesive has good bonding strength, weather resistance against freeze-thaw cycles, good toughness, and will not crack or bulge.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cement-based inorganic adhesive, and particularly relates to an inorganic adhesive suitable for external wall repair and an external wall reconstruction construction method. BACKGROUND

[0002] At present, many building external walls have been used for more than 30 years, and there are common phenomena of external wall cracking, hollowing, water seepage and peeling on the wall surface, which not only affects the appearance, but also has certain safety hazards. Therefore, the external wall repair and reconstruction work of old communities is imminent, and is also the direction of future development of the building industry.

[0003] CN113653354A discloses an external wall reconstruction construction method. The technology of this patent requires batched mortar treatment after full paving of the wall surface with stainless steel mesh, which requires that the batched mortar treatment material not only has good adhesion to the wall surface insulation layer and the stainless steel mesh in the inner layer of the stainless steel mesh, but also has certain toughness, so that the repaired external wall will not crack under dry and wet conditions or under high and low temperature conditions. However, the existing inorganic adhesive materials such as ceramic treasure cannot simultaneously meet the foregoing requirements.

[0004] CN118703116A discloses a montmorillonite-based high-performance inorganic adhesive. The patent changes the structure and performance of montmorillonite by combining silicates, phosphates and aluminates with montmorillonite, thereby improving the adhesion, water resistance and high temperature resistance of the inorganic adhesive. In addition, mixing gypsum, aluminum oxide and silicon dioxide can increase the tensile strength and bending strength of the inorganic adhesive. However, the inorganic adhesive of this patent lacks toughness and is difficult to adapt to the stress caused by temperature changes or structural deformation of the external wall, which can easily cause the external wall to crack again.

[0005] CN115700230A discloses an interface agent for enhancing the adhesion performance of the interface between new and old concrete. The main component of the interface agent of this patent is cement, although polymer emulsion is added for toughening, the brittleness is still large, and cracks are still likely to occur when the temperature changes and the structure deforms. Moreover, the interface agent of this patent has poor compatibility with non-concrete materials such as stainless steel mesh, resulting in general overall strength. In addition, the polyacrylate and polyvinyl acetate used in this patent are prone to degradation under wet and hot conditions, resulting in a decrease in adhesion.

[0006] CN104628350A discloses a binder for raw soil building surfaces. This patent uses water glass as the main gel material, which is prone to swelling in freeze-thaw cycles after solidification, resulting in loose structure and even pulverization, which can cause the adhesive layer to crack or even peel off. The water glass combined with sand lacks toughness and is prone to cracking or peeling when the external wall changes in temperature or is subjected to stress. In addition, the binder of this patent does not consider the adaptability of various substrates, resulting in insufficient adhesion. SUMMARY

[0007] In view of the fact that the prior art lacks an inorganic adhesive with excellent comprehensive performance suitable for repairing external walls, which has good adhesion to building external wall insulation layers, stainless steel and anti-cracking putty, and has freeze-thaw cycle resistance and weather resistance, and has a high mechanical strength retention rate in freeze-thaw cycle aging and does not crack or bulge. In addition, the adhesive provided by the present application has little corrosion on stainless steel mesh (does not contain acid and does not contain chloride). Specifically, the present application achieves the above-mentioned purposes by the following technical solutions:

[0008] An inorganic adhesive suitable for repairing external walls, comprising the following raw materials by mass: 20-30 parts of Portland cement, 8-12 parts of nano-metakaolin, 10-14 parts of quartz powder, 2-3 parts of sulfur-containing silane coupling agent modified long glass fiber, 4-6 parts of epoxy silane coupling agent modified short glass fiber, 0.5-2 parts of hydroxypropyl methyl cellulose, 8-12 parts of water-based epoxy emulsion with a solid content of 30-40%, 5-7 parts of polyaluminum phosphate, 0.2-0.5 parts of polycarboxylic acid water reducer, and 0.1-0.3 parts of silicone defoamer.

[0009] Further, the strength of the Portland cement is 42.5 MPa or more, such as 42.5 MPa, 52.5 MPa; the size of the nano-metakaolin is 50-200 nm, the water-reducing rate of the polycarboxylic acid water reducer is 25-30%; the quartz powder is 20-40 mesh; the silicone defoamer is selected from at least one of BYK-A530, BYK-141, Wacker 47, Wacker SRE, and Wacker 850E. Preferably, the nano-metakaolin is activated by calcining at 700-900°C for 1-2h.

[0010] Further, the solid epoxy equivalent of the water-based epoxy emulsion is 480-530 g / mol, and is specifically selected from at least one of E11 and E13 produced by Jiangsu Xingfeng Chemical Technology Co., Ltd., E-pos1025 produced by Changzhou Quanrui Polymer New Material Co., Ltd., PZ 3961 produced by Huntsman, USA, and 3EE109W and 3EE102W produced by Foshan Gaoming Tongde Chemical Co., Ltd.

[0011] Further, the sulfur-containing silane coupling agent modified long glass fiber is obtained by a preparation method comprising the following steps: immersing the long glass fiber in an alcohol-water solution containing a sulfur-containing silane coupling agent, modifying by immersion under heating conditions, taking out, washing, and drying to obtain the sulfur-containing silane coupling agent modified long glass fiber.

[0012] Further, the long glass fiber has a length of 5-10 mm and a diameter of 10-20 μm; the sulfur-containing silane coupling agent is at least one selected from a mercapto silane coupling agent and bis-[γ-(triethoxysil)propyl]tetrasulfide (Si-69), the mercapto silane coupling agent is selected from 3-mercaptopropyl triethoxysilane (KH-580), 3-mercaptopropyl trimethoxysilane (KH-590); the mass concentration of the sulfur-containing silane coupling agent in the alcohol aqueous solution is 3-5 wt%, the alcohol aqueous solution is a mixed solution of C1-3 alcohol and water in a volume ratio of 6-8:1-2, the C1-3 alcohol is at least one selected from methanol, ethanol and propanol; the impregnation under heating is impregnation at 40-50℃ for 2-4 h, and the washing is washing with C1-3 alcohol.

[0013] Preferably, the sulfur-containing silane coupling agent is a compound of a mercapto silane coupling agent and bis-[γ-(triethoxysil)propyl]tetrasulfide in a mass ratio of 3-5:1. After the long glass fiber surface is modified by the above compound of a sulfur-containing silane coupling agent, the bonding strength and the freeze-thaw cycle resistance of the adhesive can be improved at the same time. The complex is formed by the mercapto group and the metal ion, and the polysulfide metal complex is formed by the four sulfur bonds (-S4-) in Si-69 and the metal ion, which further enhances the interface bonding capacity. The above two different sulfur-containing silane coupling agents form a network complement through the mercapto group (-SH) and the four sulfur bonds (-S4-) as crosslinking points, respectively, break through the performance bottleneck of the traditional single coupling agent, and are particularly suitable for the complex stress and environmental challenge scene in the building exterior wall repair

[0014] Further, the epoxy silane coupling agent modified short glass fiber is obtained by a preparation method comprising the following steps: impregnating the short glass fiber in an alcohol aqueous solution of an epoxy silane coupling agent, completing the modification under heating, taking out and washing, and drying to obtain the epoxy silane coupling agent modified short glass fiber.

[0015] Further, the short glass fiber has a length of 0.5-1 mm and a diameter of 1-3 μm; the epoxy silane coupling agent is selected from 3-glycidyloxypropyl trimethoxysilane (KH-560), 3-(2,3-epoxypropoxy)propyl triethoxysilane (KH-561), 3-(2,3-epoxypropoxy)propyl methyl dimethoxysilane (KH-563), and 3-[(2,3)-epoxypropoxy]propyl methyl dimethoxysilane (KH-564); the mass concentration of the epoxy silane coupling agent in the alcohol aqueous solution is 3-5 wt%, the alcohol aqueous solution is a mixed solution of C1-3 alcohol and water in a volume ratio of 6-8:1-2, the C1-3 alcohol is at least one selected from methanol, ethanol and propanol; the impregnation under heating is impregnation at 40-50℃ for 2-4 h, and the washing is washing with C1-3 alcohol.

[0016] The application further provides a preparation method of the inorganic adhesive suitable for repairing the outer wall.

[0017] (1) uniformly mix silicate cement, nano metakaolin, quartz powder and polyaluminum phosphate to obtain dry materials;

[0018] (2) uniformly mix polycarboxylate superplasticizer into water-based epoxy emulsion to obtain wet materials;

[0019] (3) uniformly mix the wet materials and the dry materials, add long glass fibers modified by sulfur-containing silane coupling agent and short glass fibers modified by epoxy-based silane coupling agent, add hydroxypropyl methyl cellulose and silicone defoaming agent, and uniformly mix them by stirring.

[0020] Further, the mixing mode of the dry materials in step (1) is not particularly limited, such as a high-speed mixer and a double-planetary stirrer, at a rotating speed of 200-400 rpm and for 5-20 min; the mixing mode of the wet materials in step (2) and the mixing mode of the wet materials and the dry materials in step (3) are not particularly limited, such as stirring, at a rotating speed of 100-200 rpm; the long glass fibers modified by sulfur-containing silane coupling agent and the short glass fibers modified by epoxy-based silane coupling agent are added in batches, such as 3-5 batches, to ensure uniform dispersion of the glass fibers; and the vacuum defoaming treatment is carried out at a vacuum degree of -0.05 MPa to -0.1 MPa, at a low speed of 50-100 rpm for 10-30 min to eliminate residual bubbles.

[0021] The application uses a silicate cement and nano metakaolin composite system as a gel material, and through a series of physical and chemical actions and cementation with other materials, combines the building outer wall insulation layer, stainless steel and anti-cracking putty into an integral whole to enhance the mechanical strength. The nano metakaolin can enhance the compactness and later strength, but the amount thereof should not be too much, because it is a high-activity material that can accelerate hydration and too short initial setting time is not conducive to construction operation. In addition, excessive filling of pores by nano particles can lead to a decrease in flexibility and easily cause cracks. The cellulose ether can play a water-retaining and thickening role to ensure the operability of construction. The application uses the water-based epoxy emulsion and long and short glass fibers modified by two kinds of silane coupling agents to play a synergistic role, and at the same time, endows the adhesive with excellent flexibility to ensure that it will not crack; the adhesive has good adhesive strength for the building outer wall insulation layer, stainless steel and anti-cracking putty, and ensures the overall strength of the repaired building outer wall. The two kinds of glass fibers with different lengths simultaneously provide macroscopic and microscopic anti-cracking performance, and the bonding force between different interfaces forms a firm interface among the three materials. The long fibers modified by mercapto groups can form a chemical bond with metal ions in cement and nano metakaolin, such as Ca 2+The modified short fibers are dispersed in the matrix, filling the pores of the long fibers, optimizing stress distribution and forming a multi-scale crack-resistant network. Using aminosilane coupling agents instead of mercaptosilane coupling agents can also achieve these goals, but their weather resistance is inferior to that of mercaptosilane coupling agents. Polyaluminum phosphate acts as a curing agent, accelerating the curing of cement while ensuring proper coagulation even at low temperatures. Furthermore, polyaluminum phosphate can also form -SH complexes with mercaptosilane coupling agents to modify the long glass fibers, further enhancing interfacial bonding.

[0022] The present invention further provides an exterior wall reconstruction construction method, which comprises the following steps:

[0023] (S1) After the damaged outer wall is repaired and made flat and complete, a stainless steel mesh is laid on the outer wall obtained and fixed with fixing parts;

[0024] (S2) The stainless steel mesh is disconnected at the separation seams between layers, and the disconnected locations are reinforced;

[0025] (S2) cutting the separation seam to the structural layer and sealing it with structural adhesive;

[0026] (S4) applying the aforementioned inorganic adhesive to form an inorganic adhesive layer, wherein the inorganic adhesive layer completely covers the stainless steel mesh and the fixing member, so that the outer wall and the stainless steel mesh are bonded together;

[0027] (S5) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer;

[0028] (S6) Optionally, coating is applied on the anti-cracking putty layer, or other decorative layers are added.

[0029] Preferably, the stainless steel mesh is laid from top to bottom in step 1) along the exterior wall, continuously from the top of the highest floor of the building to the bottom of the lowest floor. The stainless steel mesh has a wire thickness of 2-5 mm and a mesh size of 100-200 mm. The fixings are secured using stainless steel screws arranged in a plum blossom pattern with spacing no greater than 50 cm.

[0030] Preferably, the width of the separation seam in step 2) is 2-4 mm; the disconnected position is reinforced by driving stainless steel screws at intervals of 20-100 cm within 2 cm from the disconnected portion of the stainless steel mesh.

[0031] The present invention further provides an exterior wall reconstruction construction method, which comprises the following steps:

[0032] (P1) After the damaged exterior wall is repaired and made flat and complete, partition joints are set between the floors, the partition joints are cut to the structural layer, and structural adhesive is applied to seal the walls;

[0033] (P2) Lay the stainless steel mesh from top to bottom and fix it with fixing parts; disconnect the stainless steel mesh at the separation seam between layers.

[0034] (P3) applying the aforementioned inorganic adhesive to form an inorganic flame retardant adhesive layer so that the outer wall and the stainless steel mesh are bonded together;

[0035] (P4) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer;

[0036] (P5) Optionally, coating is applied on the anti-cracking putty layer, or other decorative layers are added.

[0037] Preferably, the width of the separation seam in step (P1) is 2-4 mm; the stainless steel mesh laid from top to bottom in step (P2) is laid along the surface of the outer wall, from the top of the highest floor of the building to the bottom of the lowest floor of the building without interruption. The wire thickness of the stainless steel mesh is 2-5 mm, and the mesh size is 100-200 mm; the fixing parts are fixed by stainless steel screws arranged in a plum blossom shape with a spacing of no more than 50 cm. In step (P2), within a range of 2 cm from the disconnection point of the stainless steel mesh, stainless steel screws are driven in at intervals of 20-100 cm for reinforcement;

[0038] The present invention further provides an exterior wall reconstruction construction method, which comprises the following steps:

[0039] (T1) After the damaged exterior wall is repaired and made flat and complete, partition joints are set between the floors, the partition joints are cut to the structural layer, and structural adhesive is applied to seal the walls;

[0040] (T2) Pre-cut stainless steel mesh is laid continuously from top to bottom on the exterior walls of each floor, avoiding separation seams during the laying process and fixed with fixings;

[0041] (T3) applying the aforementioned inorganic adhesive to form an inorganic flame retardant adhesive layer so that the outer wall and the stainless steel mesh are bonded together;

[0042] (T4) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer;

[0043] (T5) Optionally, coating is applied on the anti-cracking putty layer, or other decorative layers are added.

[0044] Preferably, the width of the separation joint in step (T1) is 2-4 mm; the fixing in step (T2) is carried out by arranging the stainless steel screws in a plum blossom shape with a spacing of not more than 50 cm; in step (T2), the wire thickness of the stainless steel mesh is 2-5 mm, and the mesh hole is 100-200 mm; in step (T2), within a range of 2 cm from the edge of the stainless steel mesh, stainless steel screws are punched at intervals of 20-100 cm for reinforcement.

[0045] Preferably, after the anti-cracking putty layer or the anti-cracking mortar layer is scraped, a plum blossom-shaped hole is drilled to reach the structural layer at an interval of 0.2-3 m, the diameter of the hole is 2-5 cm, and a breather disc is installed in the hole, so that the moisture in the structural layer can be immediately discharged from the breather disc.

[0046] The inorganic binder of the present application is reasonably matched, and the external wall insulation layer, the stainless steel mesh, and the anti-cracking putty in the external wall reinforcement and reconstruction are well bonded together by the inorganic binder of the present application. The inorganic binder of the present application has excellent toughness and good bonding force for the three different materials of the external wall insulation layer, the stainless steel mesh, and the anti-cracking putty, and also has excellent freeze-thaw cycle resistance and weather resistance. The reconstructed building external wall treated by the inorganic binder of the present application has high overall strength and cracking resistance, and meets the requirements of the reconstruction project of old building external walls. DETAILED DESCRIPTION

[0047] The technical solutions of the present application are further explained and described below with specific examples.

[0048] Example 1

[0049] (A) Long glass fibers (length 8 mm, diameter 15 μm) were immersed in a 5 wt% sulfur-containing silane coupling agent ethanol aqueous solution (ethanol: water = 8:2, v / v), the sulfur-containing silane coupling agent was 3-mercaptopropyl triethoxysilane (KH-580), the temperature was raised to 40°C, and the modification was completed by immersing for 4 h. The modified long glass fibers were obtained by taking out, washing with ethanol, and drying.

[0050] (B) Short glass fibers (length 0.6 mm, diameter 2 μm) were immersed in a 5 wt% epoxy silane coupling agent ethanol aqueous solution (ethanol: water = 8:2, v / v), the epoxy silane coupling agent was KH-560, the temperature was raised to 40°C, and the modification was completed by immersing for 4 h. The modified short glass fibers were obtained by taking out, washing with ethanol, and drying.

[0051] (1) 25 parts by mass of R42.5 grade Portland cement, 10 parts by mass of nano metakaolin (activated by calcination at 800°C for 1 h) with a size of about 100 nm, 12 parts by mass of 20-mesh quartz powder, and 6 parts by mass of polyaluminum phosphate were mixed uniformly by a double-planet mixer at a rotation speed of 300 rpm for 10 min to obtain a dry mixture;

[0052] (2) 0.3 parts by mass of polycarboxylic acid water reducer (water-reducing rate 28.6%) was added to 10 parts of water-based epoxy emulsion PZ 3961, and stirred and mixed uniformly to obtain a wet mixture;

[0053] (3) The wet mixture and the dry mixture were mixed uniformly by a mixer, 2.2 parts by mass of long glass fibers modified by the sulfur-containing silane coupling agent prepared in step (A) and 5 parts by mass of short glass fibers modified by the epoxy silane coupling agent prepared in step (B) were added in three batches with an interval of 10 min, 0.2 parts by mass of hydroxypropyl methyl cellulose and 0.2 parts by mass of silicone defoaming agent BYK-141 were finally added, and the mixture was stirred and mixed uniformly, and then vacuum degassing treatment was performed at a vacuum degree of -0.08 MPa and a rotation speed of 50 rpm for 30 min to eliminate residual bubbles, thereby obtaining the product inorganic binder.

[0054] Example 2

[0055] The other conditions were the same as in Example 1, except that in step (1), the raw materials were 30 parts by mass of R42.5 grade Portland cement, 12 parts by mass of nano metakaolin with a size of about 100 nm, 14 parts by mass of 20-mesh quartz powder, and 7 parts by mass of polyaluminum phosphate. In step (3), the amount of long glass fibers modified by the sulfur-containing silane coupling agent was 3 parts by mass, and the amount of short glass fibers modified by the epoxy silane coupling agent was 6 parts by mass.

[0056] Example 3

[0057] The other conditions were the same as in Example 1, except that in step (1), the raw materials were 20 parts by mass of R42.5 grade Portland cement, 8 parts by mass of nano metakaolin with a size of about 100 nm, 10 parts by mass of 20-mesh quartz powder, and 5 parts by mass of polyaluminum phosphate. In step (3), the amount of long glass fibers modified by the sulfur-containing silane coupling agent was 2 parts by mass, and the amount of short glass fibers modified by the epoxy silane coupling agent was 4 parts by mass.

[0058] Example 4

[0059] The other conditions were the same as in Example 1, except that in step (A), the sulfur-containing silane coupling agent was bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69).

[0060] Example 5

[0061] Other conditions are the same as example 1, the difference is that in step (A), the sulfur-containing silane coupling agent is KH-580 and Si-69 according to the mass ratio of 3:1.

[0062] Example 6

[0063] Other conditions are the same as example 1, the difference is that in step (A), the sulfur-containing silane coupling agent is KH-580 and Si-69 according to the mass ratio of 5:1.

[0064] Example 7

[0065] Other conditions are the same as example 1, the difference is that in step (A), the sulfur-containing silane coupling agent is KH-580 and Si-69 according to the mass ratio of 1:1.

[0066] Comparative example 1

[0067] Other conditions are the same as example 1, the difference is that in step (1), the amount of nano-metakaolin is 6 parts by mass.

[0068] Comparative example 2

[0069] Other conditions are the same as example 1, the difference is that in step (1), the amount of nano-metakaolin is 14 parts by mass.

[0070] Comparative example 3

[0071] Other conditions are the same as example 1, the difference is that step (A) is cancelled, no sulfur-containing silane coupling agent is added to modify the long glass fiber in step (3), and the amount of epoxy silane coupling agent modified short glass fiber is changed to 7.2 parts by mass.

[0072] Comparative example 4

[0073] Other conditions are the same as example 1, the difference is that step (B) is cancelled, no epoxy silane coupling agent is added to modify the short glass fiber in step (3), and the amount of sulfur-containing silane coupling agent modified long glass fiber is changed to 7.2 parts by mass.

[0074] Comparative example 5

[0075] (A1) The long glass fiber (length 8 mm, diameter 15 μm) was immersed in a 5 wt% epoxy silane coupling agent aqueous ethanol solution (ethanol: water = 8:2, v / v), the epoxy silane coupling agent was KH-560, and the modification was completed by heating to 40℃ for 4h, then washed with ethanol, dried to obtain epoxy silane coupling agent modified long glass fiber.

[0076] (B) Short glass fibers (length 0.6 mm, diameter 2 μm) were dipped in a 5 wt% solution of sulfur-containing silane coupling agent (3-mercaptopropyltriethoxysilane (KH-580)) in an ethanol / water mixture (ethanol:water = 8:2, v / v) and left to soak for 4 h at 40 °C. The modified short glass fibers were removed, washed with ethanol and dried.

[0077] (1) 25 parts by mass of Portland cement of grade R42.5, 10 parts by mass of nano-pulverized metakaolin with a size of about 100 nm, 12 parts by mass of 20-mesh quartz powder, and 6 parts by mass of polyaluminum phosphate were mixed by a double planetary mixer at a rotation speed of 300 rpm for 10 min to obtain a dry mixture;

[0078] (2) 0.3 parts by mass of polycarboxylic acid water reducer (water-reducing rate 28.6%) was added to the aqueous epoxy emulsion PZ 3961 and mixed to obtain a wet mixture;

[0079] (3) The wet mixture and the dry mixture were mixed by a mixer, 2.2 parts by mass of the epoxy silane coupling agent-modified long glass fibers obtained in step (A) and 5 parts by mass of the sulfur-containing silane coupling agent-modified short glass fibers obtained in step (B) were added in three batches with an interval of 10 min, and 0.2 parts by mass of hydroxypropyl methylcellulose and silicone defoaming agent BYK-141 were finally added. The mixture was mixed and vacuum degassed at a vacuum degree of -0.08 MPa and a rotation speed of 50 rpm for 30 min to eliminate residual air bubbles, to obtain the product inorganic binder.

[0080] That is, compared with Example 1, Comparative Example 5 is a reversal of the epoxy silane coupling agent and the sulfur-containing silane coupling agent.

[0081] Comparative Example 6

[0082] Other conditions were the same as in Example 1, except that in step (A), the sulfur-containing silane coupling agent was replaced by amino silane coupling agent KH550 to obtain amino silane coupling agent-modified long glass fibers. In step (3), the sulfur-containing silane coupling agent-modified long glass fibers were also replaced by amino silane coupling agent-modified long glass fibers.

[0083] Test Example

[0084] The binders in the above examples and comparative examples were tested for the following properties, and the results are shown in Table 1.

[0085] 28d tensile and shear bond strength test refers to JC / T 547-2017C, building exterior wall insulation layer / stainless steel test 28d tensile bond strength a; anti-cracking putty / stainless steel test 28d shear bond strength b. The tensile bond strength a test method is to take 5 cm x 5 cm square of building exterior wall insulation layer and stainless steel plate respectively, with a thickness of 2 cm. The inorganic adhesive is evenly applied between the building exterior wall insulation material and the stainless steel plate with a thickness of 5 mm, and cured at 25°C, 80RH% for 28 days. The electronic universal testing machine is used to test the tensile bond strength. The mechanical strength retention rate is that after the sample is subjected to freeze-thaw cycle of-20°C / 4h, 60°C / 4h for 50 times, the strength test is carried out again, and the retention rate is calculated. For example, the tensile bond strength a retention rate calculation formula is a1 / a0x100%, wherein a0 is the tensile bond strength before freeze-thaw cycle, and a1 is the tensile bond strength after freeze-thaw cycle.

[0086] The building exterior wall insulation material formula is 100 parts by mass of 42.5R Portland cement, 13 parts of fly ash, 20 parts of quartz sand, 10 parts of nano calcium carbonate with a size of 200 nm, 7.2 parts of polypropylene fiber, 1.3 parts of basalt fiber, and 0.8 parts of polycarboxylate superplasticizer. After the raw materials are mixed uniformly according to the mass ratio, they are poured into a mold to form, the mold is removed after initial setting, and cured to reach the strength, then cut into square blocks according to the size requirements.

[0087] The 28d shear bond strength b is that the inorganic adhesive layer is formed by applying 5mm thick inorganic adhesive on the stainless steel plate, and then the anti-cracking putty (anti-cracking putty powder for building exterior wall AS-08) is directly scraped on the inorganic adhesive layer, with a thickness of 1-2mm each time, and the outer putty thickness reaches 5mm after 3-5 times of scraping, and the interval between each scraping is ≥4h. The shear bond strength of the anti-cracking putty / stainless steel is tested after standing for 28 days. The shear bond strength b retention rate is that after the sample is subjected to freeze-thaw cycle of-20°C / 4h, 60°C / 4h for 50 times, the shear bond strength b test is carried out again, and the retention rate is calculated.

[0088] The fracture toughness is that the inorganic adhesive is poured into a mold, and cured at 25°C, 80RH% for 28 days to form a sample. The fracture toughness is tested by the single-edge notched beam method according to ASTM C1421. The fracture toughness retention rate is that after the sample is subjected to freeze-thaw cycle of-20°C / 4h, 60°C / 4h for 50 times, the fracture toughness test is carried out again, and the retention rate is calculated.

[0089] Table 1 Inorganic adhesive performance test

[0090] .

[0091] Application Example 1

[0092] The following is the building exterior wall reconstruction of an old community, the steps are as follows:

[0093] (S1) The damaged exterior wall is repaired and leveled to obtain an exterior wall body, and a stainless steel mesh (wire thickness 4mm, mesh hole 160mm) is laid along the surface of the exterior wall body, from the top of the highest floor to the bottom of the lowest floor, and is fixed by stainless steel screws arranged in a plum blossom shape with a spacing of not more than 50cm;

[0094] (S2) The stainless steel mesh is disconnected at the partition joint between the layers, and the width of the partition joint is 4mm. Within 2cm from the disconnected part of the stainless steel mesh, stainless steel screws are inserted at intervals of 50cm;

[0095] (S3) The partition joint is cut to the structural layer, and structural glue is sealed;

[0096] (S4) Apply the inorganic adhesive of Example 5 to form an inorganic adhesive layer, which completely covers the stainless steel mesh and the fixing part, so that the exterior wall body and the stainless steel mesh are bonded together;

[0097] (S5) A crack-resistant putty layer is applied on the inorganic adhesive layer;

[0098] (S6) Apply paint on the crack-resistant putty layer.

[0099] Application Example 2

[0100] The following is the building exterior wall reconstruction of an old community, the steps are as follows:

[0101] (P1) After the damaged exterior wall is repaired and leveled to obtain an exterior wall body, a partition joint is provided between the layers of the floor, and the width of the partition joint is 4mm. The partition joint is cut to the structural layer, and structural glue is sealed;

[0102] (P2) Lay a stainless steel mesh (wire thickness 4mm, mesh hole 160mm) from top to bottom along the surface of the exterior wall body, from the top of the highest floor to the bottom of the lowest floor, and fix it by stainless steel screws arranged in a plum blossom shape with a spacing of not more than 50cm. The laid stainless steel mesh is disconnected at the partition joint between the layers, and within 2cm from the disconnected part of the stainless steel mesh, stainless steel screws are inserted at intervals of 50cm for reinforcement;

[0103] (P3) Apply the inorganic adhesive of Example 5 to form an inorganic fire-retardant adhesive layer, so that the exterior wall body and the stainless steel mesh are bonded together;

[0104] (P4) A crack-resistant putty layer is applied on the inorganic adhesive layer;

[0105] (P5) The anti-cracking putty layer is added to the decorative layer.

[0106] Application Example 3

[0107] The following is the building exterior wall reconstruction of an old community, the steps are as follows:

[0108] (T1) The damaged exterior wall is repaired to be flat and complete, and the exterior wall body obtained after the repair is provided with a separation joint between the floors, the width of the separation joint is 4 mm, the separation joint is cut to the structural layer, and the structural glue is sealed;

[0109] (T2) A stainless steel mesh (wire thickness 4 mm, mesh hole 160 mm) of a pre-cut size is continuously laid on the exterior wall body of each floor from top to bottom, stainless steel screws are fixed in the range within 2 cm from the edge of the stainless steel mesh at intervals of 20-100 cm for reinforcement, and the stainless steel screws are arranged in a plum blossom shape with a spacing of not more than 50 cm in the laying process to avoid the separation joint;

[0110] (T3) The inorganic flame-retardant adhesive of Example 5 is applied to form an inorganic adhesive layer, so that the exterior wall body and the stainless steel mesh are bonded as a whole;

[0111] (T4) An anti-cracking putty layer is applied on the inorganic adhesive layer;

[0112] (T5) A coating is applied on the anti-cracking putty layer.

Claims

1. An inorganic adhesive suitable for exterior wall repair, characterized in that: The raw materials include the following parts by weight: 20-30 parts of Portland cement, 8-12 parts of nano-metakaolin, 10-14 parts of quartz powder, 2-3 parts of sulfur-containing silane coupling agent modified long glass fiber, 4-6 parts of epoxy silane coupling agent modified short glass fiber, 0.5-2 parts of hydroxypropyl methylcellulose, 8-12 parts of water-based epoxy emulsion with a solid content of 30-40%, 5-7 parts of polyaluminum phosphate, 0.2-0.5 parts of polycarboxylic acid water reducer, 0.1-0.3 parts of silicone disinfectant. Foaming agent; the sulfur-containing silane coupling agent is selected from at least one of a mercaptosilane coupling agent and bis-[γ-(triethoxysilyl)propyl]tetrasulfide, the mercaptosilane coupling agent is selected from 3-mercaptopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane; the epoxysilane coupling agent is selected from 3-glycidoxypropyltrimethoxysilane, 3-(2,3-epoxypropyloxy)propyltriethoxysilane and 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane.

2. The inorganic adhesive suitable for exterior wall repair according to claim 1, characterized in that: The strength of silicate cement is above 42.5 MPa; the size of nano-metakaolin is 50-200 nm; the water reduction rate of polycarboxylate water reducer is 25-30%; the quartz powder is 20-40 mesh; and the organosilicon defoamer is selected from at least one of BYK-A530, BYK-141, Wacker 47, Wacker SRE, and Wacker 850E.

3. The inorganic adhesive suitable for exterior wall repair according to claim 1, characterized in that: The solid epoxy equivalent weight of waterborne epoxy emulsion is 480-530 g / mol.

4. The inorganic adhesive suitable for exterior wall repair according to claim 1, characterized in that: The sulfur-containing silane coupling agent modified long glass fiber is obtained by a preparation method comprising the following steps: immersing the long glass fiber in an alcohol aqueous solution of the sulfur-containing silane coupling agent, immersing under heating conditions to complete the modification, taking out, washing, and drying to obtain the sulfur-containing silane coupling agent modified long glass fiber; the long glass fiber has a length of 5-10 mm and a diameter of 10-20 μm.

5. The inorganic adhesive suitable for exterior wall repair according to claim 1, characterized in that: The sulfur-containing silane coupling agent is a compound of a mercaptosilane coupling agent and bis-[γ-(triethoxysilyl)propyl]tetrasulfide in a mass ratio of 3-5:

1.

6. The method for preparing the inorganic adhesive suitable for exterior wall repair according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Portland cement, nano-metakaolin, quartz powder, and polyaluminum phosphate are uniformly mixed to obtain a dry material; (2) adding the polycarboxylate water-reducing agent to the aqueous epoxy emulsion and mixing them uniformly to obtain a wet material; (3) Mix the wet material and the dry material evenly, add the long glass fiber modified by the sulfur-containing silane coupling agent and the short glass fiber modified by the epoxy silane coupling agent, add hydroxypropyl methylcellulose and the silicone defoaming agent, stir and mix evenly, and perform vacuum degassing.

7. The preparation method according to claim 6, characterized in that In step (3), the sulfur-containing silane coupling agent modified long glass fiber and the epoxy silane coupling agent modified short glass fiber are added in batches; the vacuum degassing treatment is carried out at a vacuum degree of -0.05 MPa to -0.1 MPa, with low-speed stirring at 50-100 rpm for 10-30 minutes.

8. A construction method for exterior wall reconstruction, characterized in that: After the exterior wall is repaired and leveled, a stainless steel mesh is laid, and the stainless steel mesh is completely covered with the inorganic adhesive according to any one of claims 1 to 5 to form an inorganic adhesive layer, and an anti-cracking putty layer or an anti-cracking mortar layer is applied on the inorganic adhesive layer.

9. The exterior wall reconstruction construction method according to claim 8, characterized in that: One of the following methods A, B, and C; Method A includes the following steps: (S1) After the damaged outer wall is repaired and made flat and complete, a stainless steel mesh is laid on the outer wall, and fixed with fixing parts; (S2) The stainless steel mesh is disconnected at the separation seams between layers, and the disconnected locations are reinforced; (S2) cutting the separation seam to the structural layer and sealing it with structural adhesive; (S4) applying the inorganic adhesive to form an inorganic adhesive layer, wherein the inorganic adhesive layer completely covers the stainless steel mesh and the fixing member, so that the outer wall and the stainless steel mesh are bonded together; (S5) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer; (S6) optionally, applying a coating on the anti-cracking putty layer, or adding other decorative layers; Method B comprises the following steps: (P1) After the damaged exterior wall is repaired and made complete, partition joints are set between the floors, the partition joints are cut to the structural layer, and structural adhesive is applied to seal the walls; (P2) Lay the stainless steel mesh from top to bottom and fix it with fixing parts; disconnect the stainless steel mesh at the separation seam between layers. (P3) applying the inorganic adhesive to form an inorganic flame retardant adhesive layer so that the outer wall and the stainless steel mesh are bonded together; (P4) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer; (P5) optionally, applying a coating on the anti-cracking putty layer, or adding other decorative layers; Method C comprises the following steps: (T1) After the damaged exterior wall is repaired and made flat and complete, partition joints are set between the floors, the partition joints are cut to the structural layer, and structural adhesive is applied to seal the walls; (T2) Pre-cut stainless steel mesh is laid continuously from top to bottom on the exterior walls of each floor, avoiding separation seams during the laying process and fixed with fixings; (T3) applying the inorganic adhesive to form an inorganic flame retardant adhesive layer so that the outer wall and the stainless steel mesh are bonded together; (T4) applying an anti-cracking putty layer or an anti-cracking mortar layer on the inorganic binder layer; (T5) Optionally, coating is applied on the anti-cracking putty layer, or other decorative layers are added.

10. The exterior wall reconstruction construction method according to claim 8 or 9, characterized in that: After applying the anti-cracking putty layer or anti-cracking mortar layer, plum blossom-shaped holes with a spacing of 0.2-3m are drilled to reach the structural layer. The diameter of the holes is 2-5cm. A breathable plate is installed in the hole so that the moisture in the structural layer can be discharged immediately from the breathable plate.