CN113427611B

CN113427611B - Method for repairing surface of prefabricated concrete member

Info

Publication number: CN113427611B
Application number: CN202110745218.XA
Authority: CN
Inventors: 吴继东; 朱凤敏; 刘沛祺; 黄沛均; 商玉宽; 韦林清
Original assignee: Dongguan Jianan Group Co ltd
Current assignee: Dongguan Jianan Group Co ltd
Priority date: 2021-07-01
Filing date: 2021-07-01
Publication date: 2022-08-09
Anticipated expiration: 2041-07-01
Also published as: CN113427611A

Abstract

The application relates to the field of concrete member surface repair, in particular to a method for repairing the surface of a prefabricated concrete member, which comprises the following steps: cleaning the concrete at the loose part on the peripheral side of the hole of the precast concrete member; cleaning the inner surface of the chiseled position, and coating a leakage-proof agent after air drying; coating an isolation coating on the surface of the template, preparing a special template after the isolation coating is cured, and fixing the special template at the chiseling position of the prefabricated concrete member; pouring concrete into the chiseling position on the prefabricated concrete member, and tamping to be compact; after the concrete is solidified, continuing to maintain for a period of time until the concrete reaches a certain strength, removing the special template, detecting the flatness of the chiseled-out position, and filling and leveling the remaining positions to the original size by using a filling and leveling material after the flatness meets the requirements; and after the filling material is completely dried and hardened, polishing the repaired surface smoothly. The method and the device can improve the problem that the newly poured concrete surface easily generates new surface defects when the formwork is dismantled.

Description

Method for repairing surface of prefabricated concrete member

Technical Field

The application relates to the field of repairing surface defects of concrete members, in particular to a method for repairing the surface of a prefabricated concrete member.

Background

The prefabricated concrete member is a prefabricated concrete member product which is prefabricated for on-site assembly, such as a prefabricated slab used as a floor slab.

The prefabricated concrete member is formed by supporting the prefabricated concrete member without leaving a template, and after the prefabricated concrete member is hardened and maintained, the template on the outer side of the prefabricated concrete member for shaping the concrete member is removed, so that the prefabricated concrete member can be obtained.

However, due to the fluctuation of the quality of the raw materials, the metering error or insufficient stirring, the newly mixed concrete is easily separated into the characteristics of segregation, bleeding, dryness, hardening and the like and poor workability, so that the surface of the prefabricated concrete member is easily cracked or honeycombed and other defects. Therefore, in order to ensure the quality of the precast concrete member, after the formwork supported on the surface of the precast concrete member is removed, the surface of the precast concrete member is usually repaired.

At present, aiming at a hole with a large depth, a template is generally required to be erected to support a position to be repaired, then concrete with the same strength is poured into the position to be repaired, and finally a filling material is used for filling the position to the original surface to repair the surface defects of the precast concrete component.

However, because the problem of excessive binding force between poured concrete and the formwork is often caused, when the formwork on the outer side of the precast concrete member is removed, the surface of the poured concrete is easy to fall off, so that a new surface defect problem is caused.

Disclosure of Invention

In order to solve the problem that a newly generated surface defect is easy to generate on the surface of the newly poured concrete when a formwork is removed, the application provides a method for repairing the surface of the precast concrete member.

The method for repairing the surface of the precast concrete member adopts the following technical scheme:

the method for repairing the surface of the precast concrete member comprises the step of processing a hole with the depth of more than 100mm, wherein the step of processing the hole with the depth of more than 100mm comprises the following steps:

cleaning the concrete at the loose part on the peripheral side of the hole of the precast concrete member;

cleaning the inner surface of the chiseled position with water, air-drying, uniformly coating the leakproof agent, and performing the next operation after the leakproof agent surface is dry;

uniformly coating an isolation coating on the surface of the template, obtaining a special template after the isolation coating is cured, and then fixing the special template on the chiseling position of the prefabricated concrete member;

pouring concrete with the same strength as the precast concrete member into the chiseling position on the precast concrete member, and compacting;

after the concrete is solidified, continuing to maintain for a period of time until the concrete reaches a certain strength, removing the special template, detecting the flatness of the chiseled-out position, and filling and leveling the remaining positions to the original size by using a filling and leveling material after the flatness meets the requirements;

after the filling material is completely dried and hardened, polishing the repaired surface smoothly;

the isolation coating is prepared from the following raw materials in parts by weight:

acrylic resin: 30-40 parts of

Ester solvent: 80 to 90 portions of

Polyester fiber: 1-2 parts of

Quartz sand: 3-6 parts of

Dispersing agent: 1-3 parts.

By adopting the technical scheme, before the template is fixed, the isolating coating is sprayed on the template, and under the matching action of the polyester fiber and the quartz sand in the isolating coating, the wear-resisting effect of the isolating coating poured between the concrete and the template can be improved, and meanwhile, the stripping force between the poured concrete and the template can be reduced, so that the surface of the concrete cannot be easily damaged when the template is removed.

Optionally, the length of the polyester fiber is 4-6mm, and the breaking strength is 2-4 CN/detx.

By adopting the technical scheme, the polyester fiber with the length of 4-6mm and the breaking strength of 2-4CN/detx has better dispersion performance in the isolation coating.

Optionally, the particle size range of the quartz sand is 20-40 nm.

By adopting the technical scheme, when the particle size range of the quartz sand is 20-40nm, the particle size of the quartz sand is proper, and the quartz sand can be promoted to be uniformly dispersed in the isolation coating.

Optionally, the ester solvent is one or two of butyl acrylate and ethyl acetate.

By adopting the technical scheme, the acrylic resin can be well dissolved in butyl acrylate or ethyl acetate, the butyl acrylate or the ethyl acetate has volatility, and the isolation coating is solidified on the template along with the volatilization of the butyl acrylate or the ethyl acetate.

Optionally, the dispersant is a silane coupling agent, and the silane coupling agent is any one or a combination of several of KH550, KH560 and KH 570.

By adopting the technical scheme, under the action of the silane coupling agent KH550, KH560 or KH570, the polyester fibers and the quartz sand can be uniformly dispersed into the film-forming substance, so that the isolation coating with stable performance is obtained.

Optionally, the release coating further comprises 6-9 parts by weight of maleic anhydride modified rosin glyceride and 0.1-0.4 part by weight of sulfonated castor oil.

By adopting the technical scheme, when the maleic anhydride modified rosin glyceride and the sulfonated castor oil are matched for use, the wear resistance of the isolation coating is further improved, the stripping force between the concrete and the template is further reduced, and the effect of conveniently detaching the template and protecting the surface of the concrete is achieved.

Optionally, the preparation method of the release coating comprises the following steps:

s1, adding acrylic resin into an ester solvent, and stirring to dissolve the acrylic resin into the ester solvent to obtain a film-forming substance;

s2, adding polyester fiber, quartz sand, a dispersing agent, maleic anhydride modified rosin glyceride and sulfonated castor oil into the film forming substance, and stirring until the mixture is uniformly dispersed to obtain the isolation coating.

By adopting the technical scheme, the uniform isolation coating can be obtained, and the isolation coating prepared by adopting the method has the characteristics of simple steps and low equipment requirement.

Optionally, the spraying thickness of the isolation coating is 0.5-1.0 mm.

By adopting the technical scheme, when the spraying thickness of the isolation coating is controlled to be 0.5-1.0mm, the spraying thickness of the isolation coating is proper, so that the isolation coating can be firmly attached to the template, namely, the isolation coating cannot be easily separated from the template when concrete is filled, and the special template is convenient to disassemble.

Optionally, the method for repairing the surface defect of the precast concrete member further includes processing the surface defect with the depth of less than 100mm, and the processing of the surface defect with the depth of less than 100mm includes the following steps:

chiseling the concrete around the surface defect position of the precast concrete member, and cleaning the loose part;

repairing the chiseled position by using a repairing material to ensure that all gaps are filled and compacted, and then troweling;

filling the remaining positions with a filling material and sliding the filling material to the original size about 20min after the repair material is filled;

and after the filling material is completely dried and hardened, polishing the repaired surface smoothly.

By adopting the technical scheme, for the surface defect with the depth less than 100mm, the surface is restored to be smooth without leakage after the position of the surface defect is repaired by adopting the method.

In summary, the present application includes at least one of the following beneficial technical effects:

1. before the template is fixed, a layer of isolating coating is sprayed on the template, under the matching action of polyester fibers and quartz sand in the isolating coating, the wear-resisting effect of the isolating coating poured between the concrete and the template can be improved, and meanwhile, the stripping force between the poured concrete and the template can be reduced, so that the surface of the concrete cannot be easily damaged when the template is removed;

2. when maleic anhydride modified rosin glyceride and sulfonated castor oil are used in a matched mode, the wear resistance of the isolation coating is further improved, the stripping force between the concrete and the template is further reduced, and the effect of facilitating template removal and protecting the surface of the concrete is achieved.

Detailed Description

The present application will be described in further detail with reference to examples and comparative examples.

The raw materials in the application are all commercially available, wherein:

the acrylic resin is purchased from plastic raw materials Limited of Dingxin in Dongguan city, and the brand is MB-2952;

the polyester fiber with the length of 4mm and the breaking strength of 2CN/detx is purchased from Jiangsu Haide New materials Co.Ltd;

the polyester fiber with the length of 6mm and the breaking strength of 4CN/detx is purchased from Jiangsu Haide New materials Co.Ltd;

the maleic anhydride modified rosin glycerin ester is purchased from Shanghai Haiching industries Co., Ltd and is available under the trade name of Lewis 29-M.

Examples

Example 1

The embodiment discloses a method for repairing the surface of a precast concrete component, wherein the method specifically comprises the following steps aiming at the treatment of a hole with the depth of more than 100 mm:

(1a) and (3) chiseling the periphery of the hole of the prefabricated concrete member by using a percussion drill or an iron hammer, and then removing the loose part of concrete.

(2a) And cleaning the inner surface of the chiseled position of the prefabricated concrete member by using clear water, air-drying for 3min, uniformly coating the leakproof agent, and performing the next operation after the surface of the leakproof agent is dry. In this example, the preparation method of the leak preventive is as follows:

mixing the white glue and clear water according to the volume ratio of 1.5:1, and then uniformly stirring to obtain the leak preventive.

(3a) Uniformly coating a layer of isolation coating with the thickness of 0.5mm on the surface of the template, obtaining a special template after the isolation coating is cured, and then fixing the special template on the chiseling position of the prefabricated concrete member. The preparation method of the barrier coating of the embodiment comprises the following steps:

s1, adding 30kg of acrylic resin into 80kg of butyl acrylate, and stirring to dissolve the acrylic resin into the butyl acrylate to obtain a film-forming substance;

s2, adding 1kg of polyester fiber with the length of 4mm and the breaking strength of 2CN/detx, 3kg of quartz sand with the particle size range of 20-40nm and 1kgKH550 into the film-forming substance, and stirring until the materials are uniformly dispersed to obtain the isolation coating.

(4a) And pouring concrete with the same strength as the prefabricated concrete components into the chiseling position, and tamping to be compact.

(5a) And after the concrete is solidified, continuing to maintain for a period of time until the concrete reaches a certain strength, removing the special template, detecting the flatness of the chiseled position, and filling and leveling the remaining positions to the original size by using a leveling material after the flatness meets the requirement. In this example, the preparation steps of the leveling material are as follows:

adding 40kg of Auditare SC216-OP into 14 liters of white cement, stirring by using an electric stirrer until the materials are uniform and have no blocks, and then standing for 5min to obtain a filling material, wherein the filling material needs to be used up within 30 min.

After the filling material was completely dry and hard, the repaired surface was polished smooth with water-sandpaper.

In addition, the method specifically comprises the following steps aiming at the treatment of the surface defects with the depth of less than 100 mm:

(1b) and chiseling concrete around the surface defect of the precast concrete member by using an iron hammer, and cleaning the loosened part.

(2b) And cleaning the inner surface of the chiseled position of the prefabricated concrete member by using clear water, air-drying for 3min, uniformly coating the leakproof agent, and performing the next operation after the surface of the leakproof agent is dry. The leakproof agent adopted in the step is the same as that adopted in the step.

(3b) And repairing the chiseled position by using a repairing material to ensure that all gaps are filled and compacted, and then trowelling by using a curette. In this embodiment, the preparation method of the repair material is as follows:

adding 25kg Audiem NS612 into 3.3L clear water, stirring with electric stirrer until no lump exists, standing for 5min to obtain the repairing material, and using up the repairing material within 20 min.

(4b) And filling the remaining positions with a filling material and sliding the filling material to the original size about 20min after the repair material is filled. The leveling material used in this step is the same as above.

(5b) After the filling material was completely dry and hard, the repaired surface was polished smooth with water-sandpaper.

Example 2

The difference between the method for repairing the surface of the precast concrete member and the embodiment 1 is that:

the isolation coating has different raw material ratios, and specifically comprises the following components:

adding 40kg of acrylic resin into 90kg of butyl acrylate, and stirring to dissolve the acrylic resin in ethyl acetate to obtain a film-forming substance;

2kg of polyester fiber with the length of 6mm and the breaking strength of 4CN/detx, 6kg of quartz sand with the particle size range of 20-40nm and 3kg of KH560 are added into the film-forming substance and stirred until the film-forming substance is uniformly dispersed, thus obtaining the isolating coating.

Example 3

in the preparation of the release coating, 6.1kg of glycerol ester of maleic anhydride modified rosin was also mixed in step S2.

Example 4

in the preparation of the barrier coating, 6.1kg of sulfonated castor oil was also mixed in step S2.

Example 5

in the preparation of the barrier coating, 6kg of maleic anhydride modified rosin glycerin ester and 0.1kg of sulfonated castor oil were further mixed in the step of S2.

Example 6

in the preparation of the barrier coating, 9kg of maleic anhydride modified rosin glycerin ester and 0.4kg of sulfonated castor oil were further mixed in the step of S2.

Comparative example

Comparative example 1

(3a) the template in the step is not sprayed with an isolation material.

Comparative example 2

the quartz sand in the step S2 was replaced with an equal amount of polyester fiber.

Comparative example 3

the polyester fiber in the step S2 was replaced with an equal amount of quartz sand.

Performance test

Experiment 1

After the precast concrete units of examples 1 to 6 and comparative examples 1 to 3 were maintained and removed from the forms of examples 1 to 6 and comparative examples 1 to 3 in the same environment, the concrete at the repaired position was observed for the occurrence of the concrete crack or the concrete fall-off, and the results are shown in table 1 below.

Experiment 2

The isolation coatings prepared in examples 1 to 6 and comparative examples 2 to 3 were respectively sprayed on 8 wood boards with the same shape, size and material, the thickness of the coating was 2 μm, the templates coated with the isolation materials were dried and cured under the same conditions to obtain sample plates 1 to 8, the isolation coatings on the sample plates were tested for wear resistance according to GB/T23988 + 2009 "paint wear resistance determination shakeout method", and the results were recorded in table 2 below.

Experiment 3

Respectively spraying the isolation coatings prepared in the embodiments 1-6 and the comparative examples 2-3 on 8 wood templates with consistent shapes, sizes and materials, wherein the thickness of the coating is 0.5mm, and then drying and curing the templates coated with the isolation materials under the same condition to obtain sample plates 1-8; and then, paving a layer of concrete with consistent thickness on the sample plates 1-8, curing the sample plates paved with the concrete under the same condition until the sample plates are hardened, and testing the stripping force between the template and the concrete sample block. The release coatings used on panels 1-8 were the release coatings prepared in examples 1-6 and comparative examples 2-3, respectively.

TABLE 1 surface condition of repaired precast concrete member after removal of formwork

TABLE 2 abrasion resistance of the barrier coatings in examples 1-6 and comparative examples 2-3

Item	Example 1	Example 2	Example 3	Example 4
					Abrasion resistance/(L/mum)	4.62	4.68	4.64	4.66
Item	Example 5	Example 6	Comparative example 2	Comparative example 3
					Abrasion resistance/(L/mum)	5.32	5.36	1.88	2.64

TABLE 3 Peel Performance test

Item	Sample plate 1	Sample plate 2	Template 3	Sample plate 4	Sample plate 5
						Peel force/KN	2.35	2.31	2.34	2.32	2.03
Item	Template 6	Template 7	Sample plate 8	Control group
						Peel force/KN	1.98	4.04	3.24	4.68

Note: the control panels were not coated with release coating and the other treatment steps were identical to the other panels.

Combining the data in example 1, comparative examples 1-3, experiment 1, and table 1, it can be seen that example 1 differs from comparative examples 1-3 in the release coating on the stencil; as can be seen from the data in table 1, when the polyester fiber and the silica sand are simultaneously added to the insulating coating, the problem of damage to the concrete when the formwork is removed can be reduced by the synergistic combination of the polyester fiber and the silica sand.

By combining the data in example 1, comparative examples 2 to 3, experiments 2 to 3 and tables 2 to 3, it can be seen that after the polyester fibers and the quartz sand are simultaneously added into the isolation coating, not only the wear-resistant effect of the isolation coating can be improved, but also the stripping force between the concrete and the template can be reduced, so that the surface of the concrete cannot be easily damaged when the template is removed.

Combining the data in examples 1 and 3-5, experiments 2-3, and tables 2-3, it can be seen that when maleic anhydride modified rosin glycerin ester and sulfonated castor oil are added to the release coating at the same time, the wear resistance of the release coating is further improved under the cooperation of the maleic anhydride modified rosin glycerin ester and the sulfonated castor oil, and the stripping force between the concrete and the formwork is further reduced, which has the effects of facilitating the removal of the formwork and protecting the surface of the concrete.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The method for repairing the surface of the precast concrete member is characterized by comprising the following steps: the method comprises the following steps of processing holes with the depth of more than 100mm, wherein the processing of the holes with the depth of more than 100mm comprises the following steps:

cleaning the inner surface of the chiseled position with water, uniformly coating the anti-leakage agent after air drying, and performing the next operation after the surface of the anti-leakage agent is dry;

acrylic resin: 30-40 parts of

Ester solvent: 80 to 90 portions of

Polyester fiber: 1-2 parts of

Quartz sand: 3-6 parts of

Dispersing agent: 1-3 parts of

The length of the polyester fiber is 4-6mm, and the breaking strength is 2-4 CN/detx.

2. The method for repairing the surface of a precast concrete member according to claim 1, wherein: the particle size range of the quartz sand is 20-40 nm.

3. The method for repairing the surface of a precast concrete member according to claim 1, wherein: the ester solvent is one or two of butyl acrylate and ethyl acetate.

4. The method for repairing the surface of a precast concrete member according to claim 1, wherein: the dispersing agent is a silane coupling agent, and the silane coupling agent is any one or a combination of KH550, KH560 and KH 570.

5. The precast concrete member surface repairing method according to any one of claims 1 to 4, wherein: the release coating also comprises 6-9 parts by weight of maleic anhydride modified rosin glyceride and 0.1-0.4 part by weight of sulfonated castor oil.

6. The method for repairing the surface of a precast concrete unit according to claim 5, wherein: the preparation method of the isolation coating comprises the following steps:

7. The method for repairing the surface of a precast concrete member according to claim 1, wherein: the spraying thickness of the isolation coating is 0.5-1.0 mm.

8. The method for repairing the surface of a precast concrete member according to claim 1, wherein: the method for repairing the surface defect of the precast concrete member further comprises the step of treating the surface defect with the depth of less than 100mm, wherein the step of treating the surface defect with the depth of less than 100mm comprises the following steps: