KR102485889B1 - Building crack repair method - Google Patents

Abstract

The invention relates to a method for repairing cracks in building structures and materials for repairing cracks in building structures applied to the method. The method for repairing cracks in building structures of the present invention is a mixture of isocyanurate, methylamine emulsion having a solid content of 25%, and triethylphosphine, 100 parts by weight of a complex emulsion, 60-85 parts by weight of methyl methacrylate, 55-85 parts by weight of polysiloxane 75 parts by weight, 40-85 parts by weight of polyoxyethylene ether, 38-63 parts by weight of methyl oleate, 32-55 parts by weight of methyl cyclopentane, 22-44 parts by weight of cyclohexanone and 11-33 parts by weight of silicone antifoaming agent are added. Building structure crack repair material preparation step of preparing the formed building structure crack repair material; A repair part surface treatment step of treating the surface of the repair part with the crack in order to repair the crack; A crack repair material application step of applying the building structure crack repair material to the repair portion where the surface treatment is completed; and a surface finishing operation step of performing a finishing operation on the surface to which the application of the building structure crack repair material is completed.

Description

Building structure crack repair method {Building crack repair method}

The present invention relates to a building structure crack repair method and a building structure crack repair material applied to the method, and more specifically, it is possible to repair cracks using a predetermined building structure crack repair material, thereby preventing cracks. It relates to a method for repairing cracks in building structures, which can significantly increase waterproofing efficiency according to repair, and materials for repairing cracks in building structures applied to the method.

Building structures constructed of concrete are subject to leaks and condensation due to cracks over time, which weakens durability and accelerates deterioration.

In particular, when such cracks occur on the roof floor, there is a problem in that there is a high possibility of leakage because rainwater is structurally easy to accumulate. Therefore, in order to prevent water leakage due to cracks, it can be said that construction to implement waterproofing by repairing cracks is essential.

In this regard, as a currently widely used waterproof construction method, a method using an asphalt sheet is known.

Asphalt sheet is a construction material impregnated or coated with straight asphalt and APP (Atactic Polypropylene) or SBS (Styrene Butadiene styrene) on a core material such as short fiber non-woven fabric, stretched film, or unstretched film.

As shown in FIG. 1, in the conventional waterproofing construction method using an asphalt sheet, a primer is applied to the surface of a slab (1) to form a primer layer (2), and liquid asphalt is applied on top of the primer layer (2). After forming the asphalt layer 3, a plurality of waterproof sheets 4 integrally formed with silica sand are provided on the upper part of the asphalt layer 3 and laid at regular intervals, and between the waterproof sheet 4 and the adjacent waterproof sheet The filling layer 5 is formed by filling the liquid asphalt.

Then, the asphalt tape 6 is attached so that the entire upper surface of the filling layer 5 and one corner of the waterproof sheet 4 are covered, and the asphalt tape 6 is coated with the same layer as the silica sand layer of the waterproof sheet 4 on top of the asphalt tape 6. When the silica sand layer 7 is formed by spraying silica sand to a height, and then the coating layer 8 is formed by applying a coating agent on top of the silica sand layer 7, the construction is completed.

However, the conventional waterproofing construction method as shown in FIG. 1 has a problem in that the process is complicated and time and manpower are wasted, and when heating asphalt, heating costs are incurred due to the use of oil, and environmental pollution is caused by the emission of carbon dioxide or harmful gases. There is a high possibility of safety accidents occurring during the operation of heating equipment.

In addition, in the conventional method of treating the parapet area in the waterproof construction of the rooftop slab, a member (cant strip) with a triangular cross section is inserted into the right angle part, a waterproof sheet is extended and adhered to the parapet area, and the upper part is water-repellent. There is a method of installing a protective wall after flashing, but this method has problems in that the process is complicated and defects occur frequently.

Accordingly, an alternative to solving the above problem is disclosed in FIG. 2 . Referring to FIG. 2, a rubberized asphalt sheet 10 is installed on the slab 1 so as to be spaced apart from the parapet 9 at a predetermined interval, and the molten asphalt between the parapet 9 and the rubberized asphalt sheet 10 ( 11), the rubberized asphalt tape 12 is bonded to surround the bottom of the rubberized asphalt sheet 10, the molten asphalt 11, and the parapet 9, and the rubberized asphalt tape 12 and the parapet A parapet treatment method of forming a coating waterproofing layer 13 on the pet 9 is known.

However, since this conventional parapet treatment method requires the use of molten asphalt 11 to form a waterproof layer, separate equipment is required and handling is inconvenient, and the rubberized asphalt tape 12 needs to be pre-manufactured. This is a very complicated, time- and manpower-consuming problem.

In the case of the prior art described above, although it responds to the waterproofing of building structures with its own technology, considering the fact that it is still evaluated that the efficiency is not good structurally or methodically, it is a building structure that deviated from the previous method. Technology development on crack repair methods is required.

Korean Intellectual Property Office Application No. 10-2015-0146599 Republic of Korea Intellectual Property Office Application No. 10-2016-0084902 Republic of Korea Intellectual Property Office Application No. 10-2016-0128256 Korean Intellectual Property Office Application No. 20-1991-0017438

An object of the present invention is to apply a method and method for repairing cracks in building structures, which can repair cracks using a predetermined material for repairing cracks in building structures, thereby significantly increasing the waterproofing efficiency according to the repair of cracks compared to the prior art. To provide a building structure crack repair material.

For the above purpose, 100 parts by weight of isocyanurate, 25% solids methylamine emulsion and triethylphosphine mixed emulsion, 60-85 parts by weight of methyl methacrylate, 55-75 parts by weight of polysiloxane, polyoxy Building structure crack repair material formed by adding 40-85 parts by weight of ethylene ether, 38-63 parts by weight of methyl oleate, 32-55 parts by weight of methylcyclopentane, 22-44 parts by weight of cyclohexanone and 11-33 parts by weight of silicone defoamer Building structure crack repair material preparation step to prepare; A repair part surface treatment step of treating the surface of the repair part with the crack in order to repair the crack; A crack repair material application step of applying the building structure crack repair material to the repair portion where the surface treatment is completed; and a surface finishing operation step of performing a finishing operation on the surface to which the application of the building structure crack repair material is completed.

During the surface treatment of the repaired area, the lifted and aged areas are treated with a metal brush, knife, or sear, while the old coating, dust, and foreign substances on the surface to be coated can be removed and cleaned.

The crack repairing material application step may include applying the building structure crack repairing material at least twice to the surface treatment-completed repairing part using a dedicated spatula; and a re-applying step of re-applying the entire surface including the repair portion after applying the building structure crack repair material at least twice.

When performing the surface finishing operation, the surface to which the building structure crack repair material is applied may be pressed at a predetermined angle using a dedicated spatula before the building structure crack repair material is cured.

On the other hand, for the above purpose, 100 parts by weight of isocyanurate, 25% solids methylamine emulsion and triethylphosphine mixed emulsion, 60-85 parts by weight of methyl methacrylate, 55-75 parts by weight of polysiloxane, Characterized in that 40-85 parts by weight of polyoxyethylene ether, 38-63 parts by weight of methyl oleate, 32-55 parts by weight of methyl cyclopentane, 22-44 parts by weight of cyclohexanone and 11-33 parts by weight of silicone antifoaming agent are added It is also achieved by building structure crack repair materials.

According to the present invention, it is possible to repair cracks using a predetermined building structure crack repair material, so that the waterproofing efficiency according to the repair of cracks can be significantly increased compared to the prior art.

1 and 2 are views for explaining a building structure waterproof construction structure according to the prior art.
Figure 3 is a flow chart of a building structure crack repair method according to an embodiment of the present invention.
Figure 4 is a flow chart of a building structure crack repair method according to another embodiment of the present invention.
5 is a physical property comparison table of a sealant made of a modified polymer and a sealant using an acrylic emulsion as a crack repair material for building structures according to another embodiment of the present invention.
6 is a chart comparing the advantages and disadvantages of modified sealant and acrylic sealant.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention.

However, since the description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as being limited by the embodiments described in the text.

For example, since the embodiments can be modified and have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea.

In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, the scope of the present invention should not be construed as being limited thereto.

In this specification, this embodiment is provided to make the disclosure of the present invention complete, and to completely inform those skilled in the art of the scope of the invention to which the present invention belongs. And the invention is only defined by the scope of the claims.

Thus, in some embodiments, well-known components, well-known operations and well-known techniques have not been described in detail in order to avoid obscuring the interpretation of the present invention.

On the other hand, the meaning of the terms described in the present invention is not limited to the dictionary meaning, and should be understood as follows.

It should be understood that when an element is referred to as “connected” to another element, it may be directly connected to the other element, but other elements may exist in the middle. On the other hand, when an element is referred to as being “directly connected” to another element, it should be understood that no intervening elements exist. Meanwhile, other expressions describing the relationship between components, such as “between” and “immediately between” or “adjacent to” and “directly adjacent to” should be interpreted similarly.

Singular expressions should be understood to include plural expressions unless the context clearly dictates otherwise, and terms such as “comprise” or “having” refer to a described feature, number, step, operation, component, part, or It should be understood that it is intended to indicate that a combination exists, and does not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise.

Terms defined in commonly used dictionaries should be interpreted as consistent with meanings in the context of related art, and cannot be interpreted as having ideal or excessively formal meanings unless explicitly defined in the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the embodiments, the same reference numerals are assigned to the same components, and descriptions of the same reference numerals are omitted in some cases.

(one embodiment)

Figure 3 is a flow chart of a building structure crack repair method according to an embodiment of the present invention.

Referring to this drawing, the present invention can repair cracks using a predetermined building structure crack repair material, so that the waterproof efficiency according to the repair of cracks can be significantly increased than before, and the construction as shown in FIG. In addition to the structure crack repair method, the scope of the right may be applied to the building structure crack repair material for performing this.

Building structure crack repair method according to an embodiment of the present invention includes a building structure crack repair material preparation step (S10), a repair part surface treatment step (S20), a crack repair material application step (S30) and a surface finishing operation step (S40). can include

Building structure crack repair material preparation step (S10) is isocyanurate, 25% solid content methylamine emulsion and triethylphosphine mixed 100 parts by weight of the complex emulsion, methyl methacrylate 60-85 parts by weight, polysiloxane 55 -75 parts by weight, polyoxyethylene ether 40-85 parts by weight, methyl oleate 38-63 parts by weight, methyl cyclopentane 32-55 parts by weight, cyclohexanone 22-44 parts by weight and silicone antifoaming agent 11-33 parts by weight added This is the process of preparing the building structure crack repair material.

This building structure crack repair material is for repairing cracks on the surface of concrete structures, and is a multi-purpose crack repair material having three functions: sealing, adhesion, and gap filling.

Since silicone, that is, silicone antifoaming agent, is contained in building structure crack repair materials, it is suitable for elasticity (elastic recovery), UV resistance, temperature, weather, etc. there is.

In particular, the building structure crack repair material having the above physical properties provides excellent weather resistance and high elasticity, and provides excellent adhesion to most building materials.

In addition, it has excellent weather, temperature, and UV resistance, so it can work in bad weather outside environments, and has high value as a non-staining, waterproof, and eco-friendly product. In particular, the storage function is excellent.

These building structure crack repair materials can be used exclusively for internal and external crack repair and waterproofing of cracks in concrete structures, but are also used for non-polluting snow material sealing and repair purposes, joint applications requiring paintability, and adhesion and sealing of interior and exterior finishing materials. can also be utilized.

Isocyanurate provides a function of adsorption and adhesion to concrete, etc., and when mixed with the compositions, it speeds up the reaction rate so that the compositions are converted into prepolymers within a short period of time and terminates the reaction.

The methyl amine emulsion is obtained by reacting methanol or dimethyl ether with ammonia in the presence of a heterogeneous catalyst to continuously synthesize methyl amine, wherein the catalyst is a solid component including a microporous material and one or more binders, and the binder Compounds suitable as organosilicon binders include monomeric, oligomeric or polymeric silanes, alkoxysilanes, acyloxysilanes, oximeinosilanes, halosilanes, aminoxysilanes, aminosilanes, amidosilanes, silazanes or silicones, and the like; , It provides water resistance and alkali resistance in response to changes in the expansion and contraction of concrete structures.

Here, the methylamine emulsion has a solid content of 25% by weight, and through this, it is good to fill the crack space when the crack repair agent is applied or injected into the crack part of the concrete structure.

Triethylphosphine, as a substance that determines the reaction time with the compositions and provides adsorption function, provides stress cracking resistance to concrete structures.

The complex emulsion, in which isocyanurate, methylamine emulsion and triethylphosphine are mixed, is mixed in a volume ratio of 3.5: 3: 2.5, respectively. Since properties such as viscosity and viscosity are changed and workability, alkali resistance, and water resistance are deteriorated, it is preferable to have a critical significance of the volume ratio in the limited range as described above.

Methyl methacrylate is a reactive resin made to have a double carbon bond through a polymerization reaction process of acrylic acid and methyl methacrylic acid ester. It has excellent weather resistance, which is a property of enduring, and improves adhesion strength and toughness by suppressing corrosion caused by external environment changes and enabling integration by penetrating into the surface of structures.

Here, methyl methacrylate is mixed in an amount of 60-85 parts by weight based on 100 parts by weight of the complex emulsion. , In the case of exceeding the above weight part, curing is performed at an early time, so that the composition does not penetrate deep into the surface of the structure, and rather the adhesive strength is lowered, so that the wear resistance and weather resistance are greatly reduced. desirable.

Polysiloxane, when mixed with the above compositions, provides adhesion to the surface of the structure or a coating function, and is mixed in an amount of 55-75 parts by weight based on 100 parts by weight of the complex emulsion. If it is easily peeled off from the surface or the coating degree of the tangent gel becomes too small, and if the weight exceeds the above weight part, the adhesive force becomes strong, but the coating degree of the elastic gel becomes too large and the workability deteriorates. It is desirable that the wealth is maintained.

Polyoxyethylene ether is for improving the compressive strength of the coating layer, and it is preferable to provide high compressive strength through an ester value of 62-72 and an acid value of 2.0 or less. Polyoxyethylene ether is mixed in an amount of 40 to 85 parts by weight based on 100 parts by weight of the complex emulsion. If it is less than the above part by weight, the water repellency is lowered, and if it exceeds the above part by weight, the adhesiveness is lowered. It is preferable to keep the parts by weight in the same limited range.

Methyl oleate is used to improve the stirrability when mixing the above compositions, and 38-63 parts by weight is mixed with respect to 100 parts by weight of the complex emulsion. and waterproofness are lowered, and when the above parts by weight are exceeded, the viscosity of the compositions increases and they cannot penetrate deep into the surface of the structure, so the adhesive strength and abrasion resistance are lowered. Do.

Methylcyclopentane is intended to provide a function of improving the adhesive strength of a coating layer or coating layer, that is, mechanical properties, and is mixed in an amount of 32-55 parts by weight based on 100 parts by weight of the complex emulsion. The storage stability of is lowered, the adhesive strength of the coating layer or coating layer is lowered, and when the above parts by weight are exceeded, the viscosity of the mixture increases and the stirring property is lowered.

Cyclohexanone is to ensure that the mixture is smoothly sprayed or applied by a spraying device or coating device during construction of a coating layer or coating layer, and 22-44 parts by weight is mixed with respect to 100 parts by weight of the complex emulsion, less than the above part by weight In the case of, the adhesive strength is increased and the spraying workability is lowered, and when the above weight part is exceeded, the adhesive strength is lowered and the adhesive strength is lowered.

The silicone antifoaming agent is a material that suppresses bubbles generated during stirring of the mixtures to improve agitation, and is mixed in an amount of 11-33 parts by weight based on 100 parts by weight of the complex emulsion. The reaction of the compositions is suppressed, and if the amount is less than the above parts by weight, the foam suppression function is lowered and the stirring efficiency is lowered, so it is preferable to maintain the above limited parts by weight.

The repair part surface treatment step (S20) is a process of treating the surface of the repair part with cracks in order to repair the cracks.

At this time, the raised and aged parts can be surface treated with a metal brush, knife, or sear, while the old coating film, dust, and foreign substances on the surface to be coated can be removed and cleaned.

The crack repairing material application step (S30) is a process of applying the building structure crack repairing material to the repaired area where the surface treatment is completed.

The crack repair material application step (S30) includes the steps of applying the building structure crack repair material at least twice to the repair area where the surface treatment has been completed using a dedicated hera, and after applying the building structure crack repair material at least twice, A re-applying step of re-applying the entire surface including the site may be included.

Of course, if a re-applying step of re-coating the entire surface including the repaired area is performed, it is preferable in that perfect waterproofing can be implemented, but this step is not necessarily applied.

In other words, a method for repairing cracks in a building structure without a re-applying step of re-coating the entire surface including the repaired area should also be said to fall within the scope of the present invention.

The surface finishing operation step (S40) is a process of performing a finishing operation on the surface on which the application of the building structure crack repair material is completed.

In this case, the surface to which the building structure crack repair material is applied can be pushed and pressed at a certain angle using a dedicated spatula before the building structure crack repair material hardens.

Hereinafter, a method for repairing cracks in a building structure will be described in series.

First, a building structure crack repair material is prepared. In this case, 100 parts by weight of isocyanurate, 25% solid methylamine emulsion and triethylphosphine mixed emulsion, 60-85 parts by weight of methyl methacrylate, 55-75 parts by weight of polysiloxane, 40 parts by weight of polyoxyethylene ether -85 parts by weight, 38-63 parts by weight of methyl oleate, 32-55 parts by weight of methyl cyclopentane, 22-44 parts by weight of cyclohexanone, and 11-33 parts by weight of silicone defoamer are added to make building structure crack repair materials. there is.

Next, in order to repair the crack, the surface of the repair part with the crack is treated. At this time, the raised and aged parts are treated with an iron brush, knife, or sear, while the old coating, dust, and foreign substances on the surface to be coated are removed and cleaned.

Next, a building structure crack repair material is applied to the repair part where the surface treatment is completed. In this case, the building structure crack repair material can be applied at least twice to the repair part where the surface treatment has been completed using a dedicated spatula.

Of course, after applying the building structure crack repair material at least twice, it is okay to proceed with the re-application step of re-coating the entire surface including the repair part.

Then, a finishing operation is performed on the surface on which the application of the building structure crack repair material is completed. At this time, before the building structure crack repair material hardens, the surface to which the building structure crack repair material is applied can be pushed and pressed at a certain angle using a dedicated spatula, and all processes can be completed by completing this step.

According to the present embodiment, which operates based on the structure as described above, cracks can be repaired using a predetermined building structure crack repair material, so that the waterproofing efficiency according to the crack repair can be significantly increased than before. do.

(another embodiment)

Figure 4 is a flow chart of a building structure crack repair method according to another embodiment of the present invention.

Referring to this figure, the building structure crack repair method according to this embodiment is also a building structure crack repair material preparation step (S10), repair part surface treatment step (S20), crack repair material application step (S30), and surface finishing work Step (S40) may be included. These methods are as described above. Therefore, redundant description is omitted.

However, in the case of this embodiment, before the surface finishing operation step (S40), the reinforcing fiber installation step (S31) and the resin composition coating step (S32) are further included in order.

The reinforcing fiber installation step (S31) is a process of installing the reinforcing fibers. As the reinforcing fiber, aramid fibers or aramid fibers coated with a resin composition may be used. That is, in the aramid fiber, the amide bond -CONH is bonded to an aromatic ring such as a benzene ring to form a polymeric polyamide. It has excellent tensile strength, toughness and heat resistance, and has high strength and high modulus of elasticity. Although it is a thin thread with a thickness of about 5 mm, it provides a large force enough to lift a 2-ton car. It does not burn or melt, and it is carbonized only when it exceeds 500℃. It is also considered the best plastic reinforcing material because it does not stretch no matter how much force is applied.

The resin composition coating step (S32) is urethane acrylate (urethane acrylate) 10 parts by weight, butyl acrylate (butyl acrylate) 10 parts by weight, lithium silicate (Li2O3Si) 3 parts by weight, polymethyl methacrylate (polymethyl methacrylate) 60 parts by weight This is a process of coating a resin composition composed of 15 parts by weight of 2-hydroxyl ethyl methacrylate and 2 parts by weight of sodium silicate (Na2SiO3·nH2O) on the reinforcing fibers. By coating a resin composition having these physical properties, it has excellent strength and adhesion, is non-reactive to salt damage and frost damage, maximizes the effect of heat shielding, and can complete repairs with excellent wear resistance.

Even if this embodiment is applied, cracks can be repaired using a predetermined building structure crack repair material, so the waterproofing efficiency according to the crack repair can be significantly increased compared to the prior art.

(another embodiment)

5 is a comparison table of physical properties of a sealant made of a modified polymer and a sealant using an acrylic emulsion as a crack repair material for building structures according to another embodiment of the present invention, and FIG. 6 compares the advantages and disadvantages of modified sealant and acrylic sealant it is a diagram

Referring to these drawings, the building structure crack repair material applied in this embodiment is Kaneka's S203H and 303H SAX260, a modified polymer having a solid content of 95% or more, 100 parts by weight of a modified polymer, 85 parts by weight of dioctyl terephthalate, an eco-friendly plasticizer, oxidized 1 part by weight of the inhibitor, 265 parts by weight of 5 microcalcium carbonate, and 5 parts by weight of the thickener were added, and the temperature was raised to 150 ° C. under vacuum and maintained for 1 hour to sufficiently remove moisture, and then cooled to about 50 ° C. at room temperature and dehumidifying agent 4 It can be prepared by adding parts by weight, 6 parts by weight of an adhesion enhancer, and 1 part by weight of dibutylene and stirring, followed by vacuum defoaming. The building structure crack repair material manufactured in this way may be referred to as a sealing and adhesive for construction.

The building structure crack repair material of this embodiment has physical properties as shown in FIG. 5 because a modified polymer solid content, that is, a modified sealant is used. For example, the crack repair material for building structures of the present embodiment, which is a modified sealant, and the conventional acrylic sealant have excellent paintability compared to general silicone.

In particular, in the case of acrylic sealant, it exhibits physical properties close to a plastic body rather than an elastic body. In addition, the construction structure crack repair material of this embodiment, which may melt and crumble when exposed to rainwater for a long time after construction, can solve all these problems.

Advantages and disadvantages of modified sealant and acrylic sealant can be grasped through FIG. 6 .

As described above, even if the crack repair of a building structure is performed using the building structure crack repair material, that is, the modified sealant, construction sealing and adhesive, the effect of the present invention that can significantly increase the waterproofing efficiency according to the crack repair can be provided. there is.

As such, the present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Accordingly, it should be said that such modifications or variations fall within the scope of the claims of the present invention.

S10; Construction structure crack repair material preparation step
S20; Repair part surface treatment step
S30; Crack repair material application step
S40; surface finish work

Claims (5)

Isocyanurate, 25% solid content methylamine emulsion and triethylphosphine mixed emulsion 100 parts by weight, methyl methacrylate 60-85 parts by weight, polysiloxane 55-75 parts by weight, polyoxyethylene ether 40- 85 parts by weight, 38-63 parts by weight of methyl oleate, 32-55 parts by weight of methyl cyclopentane, 22-44 parts by weight of cyclohexanone, and 11-33 parts by weight of silicone defoaming agent are added to prepare construction structure crack repair materials. Structure crack repair material preparation step;
A repair part surface treatment step of treating the surface of the repair part with the crack in order to repair the crack;
A crack repair material application step of applying the building structure crack repair material to the repair portion where the surface treatment is completed; and
Including a surface finishing operation step of performing a finishing operation on the surface to which the application of the building structure crack repair material is completed,
During the surface treatment step of the repair area, the lifted and aged parts are surface-treated with a metal brush, knife, or sear, while removing and cleaning the old film, dust, and foreign substances on the surface to be painted,
The crack repair material application step,
Applying the building structure crack repair material at least twice to the repaired area where the surface treatment has been completed using a dedicated spatula; and
A re-applying step of re-applying the entire surface including the repair part after applying the building structure crack repair material at least twice,
When the surface finishing step is performed, the surface to which the building structure crack repair material is applied is pushed and pressed at a predetermined angle using a dedicated herra before the building structure crack repair material is hardened. Method for repairing cracks.
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