A method of repairing a building crack

Abstract

The application relates to the technical field of building construction, and discloses a building crack repairing method, which sequentially comprises the following steps: base cleaning, base solidification layer coating, leveling layer scraping and batching, leveling solidification layer coating, anti-crack layer compounding, reinforcing layer compounding, outer surface layer scraping and batching, and polishing; wherein the leveling layer scraping and batching adopts a material of a prepared putty; the prepared putty comprises a first mixed material and a second mixed material, the mass ratio of the first mixed material to the second mixed material is 1:3; the first mixed material comprises polyvinyl acetate emulsion and clean water, and the mass ratio of the polyvinyl acetate emulsion to the clean water is 1:3; and the second mixed material comprises indoor putty and white portland cement, and the mass ratio of the indoor putty to the white portland cement is 3:1. The building crack repairing method can improve the anti-crack effect of crack repairing and prolong the service life of the repaired anti-crack.

Description

Technical Field

[0001] This application relates to the field of building construction technology, and in particular to a method for repairing building cracks. Background Technology

[0002] Cracks of varying degrees frequently appear in building structures. Although some cracks may not reach the level of causing building collapse, structural cracks can lead to leakage, corrosion, and concrete carbonation, thereby reducing the durability of building components and even posing a serious potential threat to the safety and reliability of the structure. Therefore, building cracks should be repaired promptly to reduce the hidden dangers they cause.

[0003] Building crack repair methods typically involve surface covering, where cement slurry or epoxy putty is applied to seal the crack surface. However, once the cement slurry or epoxy putty has cured, the resulting seal is a rigid connection. When the repaired crack experiences stress due to thermal expansion and contraction or external forces, the seal is easily torn open, resulting in poor crack resistance. Therefore, polyester fiberglass cloth is often applied to the crack during repair. Polyester fiberglass cloth is a mixture of fiberglass and polyester, possessing the strength of fiberglass and the flexibility of polyester, which can improve the crack resistance after repair. However, applying polyester fiberglass cloth requires first cleaning the crack surface, followed by applying a base coat to level the crack before applying the cloth. The base coat, often made of putty powder, is prone to powdering, reducing the surface stability of the putty layer. This significantly weakens the bond strength between the polyester fiberglass cloth and the building structure, further reducing crack resistance. Summary of the Invention

[0004] In order to improve the crack resistance effect of crack repair and extend the service life of the repaired crack-resistant structure, this application provides a method for repairing building cracks.

[0005] This application provides a method for repairing building cracks, which adopts the following technical solution:

[0006] A method for repairing building cracks includes the following steps in sequence: substrate cleaning, substrate curing layer application, leveling layer application, leveling curing layer application, crack-resistant layer lamination, reinforcing layer lamination, surface layer application, and sanding; wherein, the leveling layer application uses a prepared putty material; the prepared putty includes a first mixture and a second mixture, the mass ratio of the first mixture and the second mixture being 1:3; the first mixture includes polyvinyl acetate emulsion and water, the mass ratio of the polyvinyl acetate emulsion and water being 1:3; the second mixture includes interior putty and white silicate cement, the mass ratio of the interior putty and white silicate cement being 3:1.

[0007] By employing the aforementioned technical solution, cleaning and curing the substrate before applying the leveling layer improves the density of the substrate surface and enhances interfacial adhesion. This strengthens the bond between the leveling putty and the substrate, reduces the likelihood of hollow areas, and minimizes the possibility of the leveling putty detaching due to hollowness. It also improves the crack resistance stability of the crack-resistant layer on top of the leveling layer, extending the service life of the repaired crack-resistant layer. Furthermore, the putty used for leveling layer application is a specialized putty, made by mixing white silicate cement, interior putty, polyvinyl acetate emulsion, and water. The interior putty and white silicate cement form a cross-linked system through the polyvinyl acetate emulsion. The three components work synergistically, exhibiting high molecular compatibility, which improves the putty's bonding strength and adhesion, reduces powdering, and minimizes cracking caused by excessive curing hardness of the leveling layer. This enhances the composite stability between the leveling layer and the crack-resistant layer, improving the crack repair effect and extending the service life of the repaired crack-resistant layer. Furthermore, after the leveling layer is scraped, a leveling curing layer is applied. The curing agent in the leveling curing layer can penetrate deep into the leveling layer, improve the compactness of the leveling layer, further reduce the powdering phenomenon of the leveling layer, improve the surface adhesion of the leveling layer, and improve the composite stability between the leveling layer and the crack-resistant layer.

[0008] Optionally, the crack-resistant layer includes an elastic layer and a plastic layer, with the elastic layer located between the leveling and curing layer and the plastic layer.

[0009] The crack-resistant layer described in this application employs a dual-layer structure consisting of an elastic layer and a plastic layer. During the cracking process, the cracking stress first passes through the elastic layer and then is fed back to the plastic layer. The elastic layer disperses the cracking stress, reducing the direct impact of the stress on the plastic layer and lowering the likelihood of cracking in the plastic layer, thus reducing surface cracking after crack repair. Simultaneously, the plastic layer has less elasticity than the elastic layer, allowing it to provide shaping and restraint assistance to the elastic layer, dispersing the stress on the elastic layer and reducing the decrease in elastic dispersion caused by excessive deformation. This improves the crack resistance of the crack-resistant layer and extends its service life.

[0010] Optionally, the elastic layer is a fully polyester-lined elastic fabric.

[0011] Elastic fabric is a type of woven fabric with elasticity, achieved through a rib knit structure. Polyester fully lined elastic fabric, also known as polyester elastic fabric, not only possesses high elasticity but also high strength, high impact resistance, and resistance to abrasion and corrosion. Therefore, it can effectively disperse cracking stress and is easy to install, less affected by environmental factors during construction.

[0012] Optionally, the plastic layer is a polyester-cotton fabric.

[0013] Polyester-cotton blended fabric is a textile made primarily of polyester, using 65%-67% polyester and 33%-35% cotton blended yarns. It features high fiber strength, dimensional stability, good abrasion resistance, and a smooth surface for easy composite applications. Furthermore, in the construction process of the aforementioned building crack repair method, a reinforcing layer is laminated onto the polyester-cotton fabric. This lamination involves applying putty and then pressing the reinforcing layer into the putty layer. Once the putty layer is completely dry, the lamination is complete. During this process, because polyester fibers are hydrophobic and the polyester-cotton fabric has low water absorption, the low water absorption rate of the putty layer applied to it reduces the drying speed of the putty and the rate of moisture evaporation. This ensures sufficient moisture for the putty surface to cure, reducing powdering caused by poor curing due to water loss. This improves the composite stability of the reinforcing layer on the polyester-cotton fabric (crack-resistant layer), enhances the crack-resistant reinforcement effect, improves the stability of the crack repair structure, and ultimately improves the crack repair effect.

[0014] Optionally, a buffer layer may be applied between the elastic layer and the leveling and curing layer.

[0015] Through the above technical solution, during the crack fission process, the sudden cracking stress will first pass through the buffer layer and then be fed back to the elastic layer. The buffer layer buffers the sudden release of cracking stress, reduces the direct impact of cracking stress on the elastic layer, reduces the possibility of excessive deformation of the elastic layer, thereby improving the crack resistance effect and extending the crack resistance service life.

[0016] Optionally, the buffer layer is a hot melt adhesive layer, and the coating amount of the hot melt adhesive layer is 140 g / m². 2 -160g / m 2 .

[0017] Through the above technical solution, the hot melt adhesive layer is positioned between the elastic layer and the leveling and curing layer in a fully coated form, effectively acting as a buffer. It is important to note that when using the hot melt adhesive layer as a buffer, the required coating thickness is relatively high. If the hot melt adhesive layer is too thin, it will only achieve the desired adhesive bonding effect and will not provide a buffering effect. However, a thicker hot melt adhesive layer does not necessarily result in better buffering. An excessively thick layer will create an excessively thick adhesive layer between the leveling and curing layer and the elastic layer. For hot melt adhesives with insufficient cohesion, this can actually lead to a decrease in bond strength, resulting in reduced stability of the composite structure, decreased stability of the crack repair structure, and reduced crack resistance.

[0018] Optionally, the crack-resistant layer composite includes crack-resistant layer prefabrication and crack-resistant layer bonding; the crack-resistant layer prefabrication involves first bonding an elastic layer and a plastic layer together, and then bonding a buffer layer onto the side of the elastic layer away from the plastic layer to obtain the crack-resistant layer; the crack-resistant layer bonding involves applying a composite adhesive layer onto a leveling and curing layer, and then bonding the crack-resistant layer obtained from the crack-resistant layer prefabrication onto the composite adhesive layer.

[0019] By using the above technical solution, the buffer layer, elastic layer and plastic layer are prefabricated into one unit, which improves the controllability of the composite operation, reduces the number of composite procedures in the construction of building crack repair, reduces the construction difficulty, improves the on-site construction efficiency, and at the same time, it can also reduce the impact of construction environmental factors on the composite effect between the buffer layer, elastic layer and plastic layer.

[0020] Optionally, the anti-crack layer composite is prepared by applying a first composite adhesive layer to the surface of the leveling and curing layer, then attaching an elastic layer on the first composite adhesive layer, then applying a second composite adhesive layer on the elastic layer, and finally attaching a plastic layer on the second composite adhesive layer.

[0021] On-site composite construction of crack-resistant layers is suitable for situations where there are few cracks to be repaired and the amount of construction is small, and it is convenient to use local materials.

[0022] Optionally, the reinforcing layer is an alkali-resistant glass fiber mesh.

[0023] Alkali-resistant fiberglass mesh is made from medium-alkali or alkali-free woven fiberglass fabric as a base, treated with an alkali-resistant coating. It boasts advantages such as high strength, good adhesion, excellent conformability, and superior positioning. Alkali-resistant fiberglass mesh can serve as an outer layer skeleton, improving the strength of the outer layer, thereby increasing the strength at crack repair sites and enhancing crack resistance.

[0024] Optionally, the width of the leveling layer is 1-3 mm wider than the width of the crack-resistant layer, the width of the reinforcing layer is 200 mm wider than the width of the crack-resistant layer, and the crack-resistant layer is located in the middle of the reinforcing layer and also in the middle of the leveling layer.

[0025] With the above technical solution, the width of the leveling layer and the reinforcing layer is greater than that of the crack-resistant layer. After the crack repair construction is completed, the crack-resistant layer is located between the leveling layer and the reinforcing layer, and the crack-resistant layer is covered by the leveling layer and the reinforcing layer. This reduces the exposure of the crack-resistant layer's bonding gaps, protects the bonding gaps of the crack-resistant layer, and improves the bonding stability of the crack-resistant layer. At the same time, the surface smoothness of the crack repair location can also be improved by covering it with the reinforcing layer.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. A special putty is used for leveling the layer, resulting in a high-strength, non-powdering, and smooth surface. This improves the composite stability between the leveling layer and the crack-resistant layer, enhancing the crack-resistant effect of the repair and extending its service life. 2. The plastic layer of the crack-resistant layer uses polyester-cotton fabric. During the construction of the building crack repair method, a reinforcing layer is composited on top of the polyester-cotton fabric. This is achieved by applying putty and then pressing the reinforcing layer into it. Once the putty is completely dry, the reinforcing layer is complete. Because polyester fibers are hydrophobic and the polyester-cotton fabric has low water absorption, the low water absorption rate of the putty layer applied to it reduces the drying speed and evaporation rate of the putty layer. This ensures sufficient moisture for curing, reducing powdering caused by poor curing due to water loss. This improves the composite stability of the reinforcing layer on the polyester-cotton fabric (crack-resistant layer), enhances the crack-resistant reinforcement effect, improves the stability of the crack repair structure, and ultimately improves the crack repair effect. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the crack-resistant layer structure obtained in Example 5 of this application.

[0029] Figure 2 This is a schematic diagram of the crack repair structure in Embodiment 1 of this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Wall; 11. Wall base layer; 2. Crack; 21. Joint filler; 3. Base curing layer; 4. Leveling layer; 5. Leveling curing layer; 6. Composite adhesive layer; 7. Crack-resistant layer; 71. Plastic layer; 72. Elastic layer; 73. Adhesive layer; 74. Buffer layer; 75. Peelable layer; 76. Vent hole; 8. Composite putty layer; 9. Reinforcing layer; 10. Outer surface layer. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0032] This application discloses a method for repairing building cracks.

[0033] Preparation Example

[0034] Preparation Example 1

[0035] A method for preparing putty includes the following steps:

[0036] The first mixture was obtained by stirring and mixing polyvinyl acetate emulsion and water at a mass ratio of 1:3 for 3 minutes; the polyvinyl acetate emulsion was Baita brand polyvinyl acetate emulsion BT-03.

[0037] The second mixture was prepared by mixing interior putty and white silicate cement at a mass ratio of 3:1 for 3 minutes. The interior putty was interior wall leveling putty from Runxiang New Building Materials Co., Ltd., and the white silicate cement was 325# white silicate cement.

[0038] Add the second mixture to the first mixture, with a mass ratio of 1:3 between the first and second mixtures, and stir for 5 minutes to obtain the desired putty.

[0039] The stirring during the preparation process can be done by hand or by machine, as long as the mixing effect is fully achieved. In this preparation example, machine stirring is used.

[0040] Preparation Example 2

[0041] A method for preparing putty, which differs from preparation example 1 in that the second mixture in preparation example 2 is only for indoor use.

[0042] Preparation Example 3

[0043] A method for preparing putty, which differs from preparation example 1 in that the first mixture in preparation example 3 is only water.

[0044] Preparation Example 4

[0045] A method for preparing putty, which differs from preparation example 1 in that the first mixture in preparation example 4 is only water, and the second mixture is only indoor putty.

[0046] Preparation Example 5

[0047] refer to Figure 1 A method for preparing a crack-resistant layer, comprising the following steps in sequence:

[0048] Polyester-cotton fabric is selected as the plastic layer 71. Hot melt adhesive is applied to one side of the plastic layer 71 to form an adhesive layer 73 on one side of the plastic layer. The amount of hot melt adhesive applied is 120 g / m². 2 The hot melt adhesive is a synthetic resin.

[0049] Polyester fully lined elastic fabric is selected as the elastic layer 72, and the elastic layer 72 is flatly attached to the adhesive layer 73, that is, the elastic layer 72 is bonded and composited with the plastic layer 71 through the adhesive layer 73.

[0050] Hot melt adhesive is applied to the side of the polyester fully lined elastic fabric away from the polyester-cotton fabric to form a cushioning layer 74 on the side of the polyester fully lined elastic fabric away from the polyester-cotton fabric. The amount of hot melt adhesive applied is 140 g / m². 2 The hot melt adhesive is a synthetic resin.

[0051] A peelable layer 75 is laminated on the side of the buffer layer 74 away from the polyester fully lined elastic fabric. The peelable layer 75 is the release paper, thus obtaining the desired crack-resistant layer.

[0052] Laser drilling is performed on the crack-resistant layer to form vent holes 76 that penetrate the plastic layer 71, adhesive layer 73, elastic layer 72, buffer layer 74, and peelable layer 75. Multiple vent holes 76 are arranged in a rectangular array on the crack-resistant layer. The spacing between adjacent vent holes 76 can be 15 mm. The vent holes 76 provide venting paths for the crack-resistant layer during its application in repairing building cracks, improving the smoothness and adhesion between the crack-resistant layer and the building structure, thereby increasing the bonding strength of the crack-resistant layer and enhancing its crack-resistant application effect.

[0053] Preparation Example 6

[0054] A method for preparing a crack-resistant layer differs from preparation example 5 in that the plastic layer 71 is replaced with an elastic layer 72 in preparation example 6.

[0055] Preparation Example 7

[0056] A method for preparing a crack-resistant layer differs from preparation example 5 in that the elastic layer 72 is replaced with a plastic layer 71 in preparation example 7.

[0057] Preparation Example 8

[0058] A method for preparing a crack-resistant layer differs from preparation example 5 in that the plastic layer 71 in preparation example 8 is made of cotton cloth.

[0059] Preparation Example 9

[0060] A method for preparing a crack-resistant layer differs from that in Preparation Example 5 in that the hot melt adhesive coating amount of the buffer layer 74 in Preparation Example 9 is 120 g / m². 2 .

[0061] Preparation Example 10

[0062] A method for preparing a crack-resistant layer differs from that in Preparation Example 5 in that the hot melt adhesive coating amount of the buffer layer 74 in Preparation Example 10 is 150 g / m². 2 .

[0063] Preparation Example 11

[0064] A method for preparing a crack-resistant layer differs from that in Preparation Example 5 in that the hot melt adhesive coating amount of the buffer layer 74 in Preparation Example 11 is 160 g / m². 2 .

[0065] Preparation Example 12

[0066] A method for preparing a crack-resistant layer differs from that in Preparation Example 5 in that the hot melt adhesive coating amount of the buffer layer 74 in Preparation Example 11 is 180 g / m².2 .

[0067] Example

[0068] Example 1

[0069] refer to Figure 2 A method for repairing building cracks includes the following steps:

[0070] Base cleaning: Remove and clean the original wall base layer 11 on the surface of wall 1. The wall base layer 11 specifically refers to the original decorative putty layer; and fill the cracks 2 in the wall 2 with 21.

[0071] Base curing layer application: Apply one coat of curing agent to the cleaned base to form base curing layer 3. The drying time after roller application is 2 hours. Base curing improves the strength of the base and reduces the possibility of hollowing and peeling after subsequent leveling layer application. The curing agent used is from Fujian Keli Building Materials Technology Co., Ltd., with a water resistance of 96H (GB / T 1733-93) and an adhesion to concrete slab greater than 3.5MPa (GB / T 5210-2006).

[0072] Leveling layer application: Apply a thin layer of the prepared putty obtained in Example 1 onto the base curing layer 3 to level the base and form the leveling layer 4. The thickness of the thin layer should be controlled at 5mm. If it is too thin, the wall surface will be uneven; if it is too thick, it will affect the subsequent construction. After the leveling layer 4 dries, first use 120-grit sandpaper for initial sanding, then use 240-grit sandpaper for further sanding, and finally use 320-grit sandpaper for polishing and cleaning impurities. By sanding layer by layer, the surface of the leveling layer 4 becomes smoother and more uniform, thereby improving the bonding strength between the leveling layer 4 and the crack-resistant layer 7.

[0073] Leveling and curing layer coating: Apply one coat of curing agent to the leveling layer 4 to form the leveling and curing layer 5 on the leveling layer. The drying time after roller coating is 2 hours. The curing agent penetrates and cures the leveling layer, improving the surface strength of the leveling layer.

[0074] Crack-resistant layer bonding: Apply composite adhesive to the leveling and curing layer 5 to form a composite adhesive layer 6 on the leveling and curing layer 5. The width of the composite adhesive layer 6 is 20 mm wider than the width of the crack-resistant layer 7. The composite adhesive used is the composite adhesive from Fujian Keli Building Materials Technology Co., Ltd. The viscosity of the composite adhesive is greater than 88 mPas (GB / T 2794-2013), and the 180° peel strength is greater than 40 N / 25 mm (JC / T 548-2016). The crack-resistant layer should be bonded within 72 hours of applying the composite adhesive. The crack-resistant layer 7 is the crack-resistant layer obtained in Preparation Example 5. After peeling off the release paper 75 of the crack-resistant layer 7, the crack-resistant layer 7 is bonded to the middle position of the composite adhesive layer 6, and the crack-resistant layer 7 is centered along the center of the crack 2 in the wall 1. After bonding, the surface of the crack-resistant layer 7 should be free of bubbles and wrinkles.

[0075] Reinforcing layer composite: The reinforcing layer 9 is made of alkali-resistant glass fiber mesh. After the crack-resistant layer 7 is composited, a thin layer of the prepared putty of Preparation Example 1 is applied to the crack-resistant layer 7 to form a composite putty layer 8 on the crack-resistant layer. Then, the alkali-resistant glass fiber mesh is pressed into the composite putty layer 8. The composite putty layer 8 is completed when it is completely dry. The width of the reinforcing layer 9 is 200 mm greater than the width of the crack-resistant layer 7, and the crack-resistant layer 7 is located in the middle of the reinforcing layer 9.

[0076] Surface layer application and sanding: Apply a thin layer of the prepared putty of Preparation Example 1 onto the reinforcing layer 9 to form the surface layer 10 on the reinforcing layer 9. After the putty dries completely, sand the surface layer 10.

[0077] Example 2

[0078] A method for repairing building cracks. The difference between this embodiment and embodiment 1 is that the construction operation of the crack-resistant layer composite is different from that in embodiment 1.

[0079] Example 2 describes a method for repairing building cracks, including a crack-resistant composite layer, wherein the crack-resistant composite layer is as follows:

[0080] Polyester-lined elastic fabric and polyester-cotton fabric are selected as crack-resistant layers. The width of the polyester-lined elastic fabric is the same as that of the polyester-cotton fabric. A composite adhesive is applied to the leveling and curing layer to form a first composite adhesive layer. The width of the first composite adhesive layer is 20mm wider than the width of the polyester-lined elastic fabric. The polyester-lined elastic fabric is first attached to the first composite adhesive layer, with the polyester-lined elastic fabric located in the middle of the first composite adhesive layer and aligned with the center of the crack. Then, a second composite adhesive layer is applied to the side of the polyester-lined elastic fabric away from the leveling layer. The width of the second composite adhesive layer is 20mm wider than the width of the polyester-cotton fabric. The polyester-cotton fabric is attached to the second composite adhesive layer, with the polyester-cotton fabric located in the middle of the second composite adhesive layer and aligned with the center of the crack. The crack-resistant layer composite construction is now complete.

[0081] Example 3

[0082] A method for repairing building cracks. The difference between this embodiment and Embodiment 2 is that, in order to improve the bonding strength between the polyester fully lined elastic fabric and the polyester-cotton fabric during construction, adhesive is applied to the polyester fully lined elastic fabric and the polyester-cotton fabric before bonding the polyester fully lined elastic fabric and the first composite adhesive layer, and before bonding the polyester-cotton fabric and the second composite adhesive layer.

[0083] To eliminate the need for on-site adhesive coating of polyester-lined elastic fabrics and polyester-cotton fabrics, thus improving the convenience of on-site construction, in other embodiments, the polyester-lined elastic fabrics and polyester-cotton fabrics used may be pre-prepared with adhesive. Specifically, one side of the polyester-lined elastic fabric is coated with an adhesive layer, and release paper is laminated on the adhesive layer; the other side of the polyester-cotton fabric is coated with an adhesive layer, and release paper is laminated on the adhesive layer. Therefore, during construction, since the polyester-lined elastic fabric and adhesive layer are pre-coated with adhesive, only the release paper needs to be peeled off for direct bonding and application. The adhesive used can be a hot melt adhesive, and the coating amount of the adhesive layer for the polyester-lined elastic fabric is controlled at 140g / m². 2 -160g / m 2 .

[0084] Performance testing

[0085] Detection methods

[0086] Experiment 1: Test of putty appearance and powdering phenomenon

[0087] Using a cutting saw, a 15mm thick fiber-reinforced cement board was cut into multiple 10cm×10cm test blocks. The prepared putty prepared in Preparation Examples 1-4 was applied to each fiber-reinforced cement test block, and Preparation Examples 1-4 were marked accordingly, thus completing the preparation of the putty test specimens for Preparation Examples 1-4. After applying the prepared putty of Preparation Example 1 to each fiber-reinforced cement test block, the crack-resistant layer of Preparation Examples 5-12 was composited according to the steps of the building crack repair method, and the prepared putty of Preparation Example 1 was applied to the crack-resistant layer of Preparation Examples 5-12, thus completing the preparation of the putty test specimens for Preparation Examples 5-12.

[0088] After the putty has dried, observe whether there are any surface defects such as cracks. Touch the surface of the putty with your hand and observe how much powder sticks to your hand. The more obvious the powder sticking to your hand, the more serious the powdering phenomenon and the more obvious the powdering phenomenon, indicating that the putty structure is not strong enough.

[0089] The test results are shown in Table 1 below.

[0090]

[0091]

[0092] Table 1. Results of Appearance and Powdering Tests

[0093] A comparison of the appearance and powdering results of Preparation Examples 1-4 shows that, compared to Preparation Examples 2-4, Preparation Example 1 achieved a balanced and harmonious putty performance through specific proportions and compositions, resulting in a good brushing effect. This is mainly because the uneven matching between the components in Preparation Examples 2-4 led to problems such as excessively fast or uneven drying speeds after application, resulting in poor appearance and powdering.

[0094] Based on the comparison of the appearance and powdering results of Preparation Examples 5-12, it can be seen that when the plastic layer of the crack-resistant putty coating obtained in Preparation Example 1 is coated with a polyester-cotton fabric, the putty coating effect on Preparation Examples 5-7 and 9-12, where the plastic layer is obviously polyester-cotton fabric, is good. However, the putty coating effect on Preparation Example 8, where the plastic layer is cotton fabric, is significantly worse. This is mainly because cotton fabric has better water absorption than polyester-cotton fabric, which makes the putty coated on it dry too quickly and unevenly, thus affecting the putty coating effect.

[0095] Experiment 2: Testing of the physical properties of the crack-resistant layer

[0096] The physical properties of the crack-resistant layers prepared in Examples 5-11 were tested. The physical property test items and crack repair and crack resistance technical requirements are shown in Table 2 below, and the test results are shown in Table 3 below.

[0097]

[0098] Table 2. Test Items for Physical Properties of Crack-Resistant Layer

[0099]

[0100]

[0101] Table 3. Test results of physical properties of crack-resistant layers. According to the test results of physical properties of crack-resistant layers, it can be seen that the comprehensive physical properties of crack-resistant layers prepared in Examples 5, 10 and 11, which use polyester full-lined elastic fabric, polyester-cotton fabric and buffer layer, are the best, and all can meet the required crack-resistant technical requirements.

[0102] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for repairing building cracks, characterized in that, The process includes the following steps in sequence: substrate cleaning, substrate curing layer (3) application, leveling layer (4) scraping, leveling curing layer (5) application, crack-resistant layer (7) composite, reinforcing layer (9) composite, outer surface layer (10) scraping and sanding; wherein, the leveling layer (4) scraping uses a prepared putty material; the prepared putty includes a first mixture and a second mixture, the mass ratio of the first mixture and the second mixture is 1:3; the first mixture includes polyvinyl acetate emulsion and water, the mass ratio of the polyvinyl acetate emulsion and water is 1:3; the second mixture includes indoor putty and white silicate cement, the mass ratio of the indoor putty and white silicate cement is 3:1; The crack-resistant layer (7) includes an elastic layer (72) and a plastic layer (71), wherein the elastic layer (72) is located between the leveling and curing layer (5) and the plastic layer (71); The anti-cracking layer (7) composite includes the prefabrication of the anti-cracking layer (7) and the bonding of the anti-cracking layer (7); The crack-resistant layer (7) is prefabricated by selecting polyester-cotton fabric as the plastic layer (71), and applying hot melt adhesive to one side of the plastic layer (71) to form an adhesive layer (73) on one side of the plastic layer (71). The amount of hot melt adhesive applied to the adhesive layer (73) is 120 g / m². 2 The hot melt adhesive for the adhesive layer is a synthetic resin; then, polyester fully lining elastic fabric is selected as the elastic layer (72), and the elastic layer (72) is bonded to the plastic layer (71) through the adhesive layer (73); then, hot melt adhesive is applied to the side of the elastic layer (72) away from the plastic layer (71) to form a buffer layer (74) on the side of the elastic layer (72) away from the plastic layer (71), and the amount of hot melt adhesive applied to the buffer layer (74) is 140g / m². 2 -160g / m 2 The hot melt adhesive of the buffer layer is a synthetic resin; a peelable layer (75) is laminated on the side of the buffer layer (74) away from the elastic layer (72), which is the release paper, thus obtaining the desired crack-resistant layer (7); laser perforation is performed on the crack-resistant layer (7) to form vent holes (76) that penetrate the plastic layer (71), elastic layer (72), buffer layer (74) and peelable layer (75) on the crack-resistant layer. The anti-crack layer (7) is pasted by applying a composite adhesive layer (6) on the leveling and curing layer (5), and then peeling off the release paper of the anti-crack layer (7) obtained by the pre-made anti-crack layer, and pasting the anti-crack layer (7) onto the composite adhesive layer (6). The reinforcing layer (9) is an alkali-resistant glass fiber mesh.

2. The method for repairing building cracks according to claim 1, characterized in that: The width of the leveling layer (4) is 1-3 mm greater than the width of the crack-resistant layer (7), and the width of the reinforcing layer (9) is 200 mm greater than the width of the crack-resistant layer (7). The crack-resistant layer (7) is located in the middle of the reinforcing layer (9) and also in the middle of the leveling layer (4).

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