Construction method for coating existing structural column with fair-faced concrete thin shell

Abstract

The invention discloses a construction method for wrapping an existing structural column with a fair-faced concrete thin shell, and relates to the technical field of building construction.The construction method comprises the steps that the column wall of the existing structural column is coated with a hydration heat hydrophobic dredging layer to prevent the existing structural column from absorbing water of subsequently poured concrete; laying an anti-cracking net on the column wall; an outer wrapping formwork is installed outside the existing structural column, so that an annular cavity is formed between the outer wrapping formwork and the column wall; a concrete pumping pipe is arranged at the top of the annular cavity, concrete is poured in a spiral pushing mode from bottom to top, the concrete is poured at a preset height every time, and in the pouring process, a vibrator and the concrete pouring rhythm synchronously conduct spiral moving high-frequency low-amplitude vibration; and meanwhile, a vibrator is installed on the outer wall of the outer wrapping formwork for vibration so as to discharge free gas in the concrete. The problems that the bare concrete thin shell wrapping the outer side of the existing structural column is prone to cracking, and the one-time forming quality difficulty is large are solved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method for wrapping an existing structural column with a thin shell of fair-faced concrete. Background Art

[0002] In the structural design of building projects, in order to improve the appearance quality or structural performance of the building without destroying the original structure, a thin layer of fair-faced concrete is added to the periphery of the original structure. This method can be applied to the renovation and upgrading of old buildings, and can also be used in the design of new buildings. Through innovative construction technology, it can be done in one go to achieve both aesthetics and practicality. However, wrapping a thin layer of fair-faced concrete on the outside of the existing structural columns is quite difficult in terms of construction operation.

[0003] Generally speaking, the exposed concrete wall wrapped on the outside of the existing structural column is designed to be thin, and the existing structural column is relatively high. The existing structure is covered with an exposed concrete thin shell, which requires high rigidity for the large-section column formwork reinforcement. The exposed thin shell concrete needs to follow the shape of the existing structure, which makes reinforcement difficult and easy to expand the mold. The height of the existing structural column is high, and the free bubbles in the concrete slurry are difficult to discharge, resulting in the accumulation of pores on the surface of the structure. The cavity between the formwork and the existing structural column is narrow, and the steel mesh and embedded pipelines in the formwork are complexly interwoven. Especially at the corners of the structure, the flow of concrete slurry is obstructed, affecting the uniform distribution of concrete aggregate and slurry, resulting in honeycomb pockmarks, holes, and easy cracking of the exposed thin shell structure.

[0004] Therefore, it is very difficult to ensure the quality of the concrete thin shell during the concrete pouring process, especially when casting the concrete thin shell on the outside of the existing structural column and achieving the clear water effect of one-time molding. Summary of the invention

[0005] In order to overcome the defects of the prior art, a construction method for wrapping an existing structural column with a thin shell of fair-faced concrete is provided to solve the problem that the thin shell of fair-faced concrete wrapped on the outside of the existing structural column is easy to crack and difficult to form in one time.

[0006] In order to achieve the above object, a construction method for wrapping an existing structural column with a thin shell of fair-faced concrete is provided, comprising the following steps:

[0007] Coating a hydrated thermal hydrophobic drainage layer on the column wall of an existing structural column to prevent the existing structural column from absorbing moisture from subsequently poured concrete;

[0008] Laying an anti-crack net on the column wall;

[0009] Installing an external formwork on the exterior of the existing structural column so that an annular cavity is formed between the external formwork and the column wall;

[0010] A concrete pumping pipe is arranged at the top of the annular cavity, and the concrete is poured from bottom to top in a spiral manner. Each time the concrete is poured to a preset height, during the pouring process, the vibrator is moved in a spiral manner in synchronization with the concrete pouring rhythm to perform high-frequency and low-amplitude vibration. At the same time, a vibrator is installed on the outer wall of the outer formwork to vibrate to discharge free gas in the concrete.

[0011] Furthermore, the hydrated thermal hydrophobic conductive layer is a waterproof penetration crystal.

[0012] Furthermore, the anti-cracking net is a metal anti-cracking net.

[0013] Furthermore, the existing structural column is a square column, and the external formwork has a second side surface corresponding to the four first side surfaces of the existing structural column.

[0014] Furthermore, the preset height is 40 to 50 cm.

[0015] Furthermore, the vibrator is a miniature high-frequency low-amplitude rubber-head vibrator.

[0016] Furthermore, there are multiple vibrators, and the multiple vibrators are arranged along the circumferential direction of the outer template.

[0017] Furthermore, the vibrator is an attached vibrator.

[0018] The beneficial effect of the present invention is that the construction method of the present invention for wrapping the existing structural column with a thin shell of plain concrete, by adding a hydration heat hydrophobic diversion layer on the interface between the new and old concrete, forms an isolation layer between the new and old concrete, so as to prevent the cast-in-place thin shell from absorbing moisture by the existing concrete column during the molding process, resulting in dehydration cracking or hydration heat cracking. By adopting the method of directional quantitative spiral casting + high-frequency low-amplitude internal and external spiral vibration, the problem of narrow cavity and many corners between the existing structural column and the formwork, the flow of concrete is blocked, and the density of the concrete structure is affected. In addition, by adopting a miniature high-frequency low-amplitude rubber-head vibrator, the problem of regional limitation of vibration in a narrow space is solved; by hanging an attached vibrator on the outside of the formwork to vibrate and exhaust from bottom to top, the problem of difficulty in discharging free bubbles in thin-walled concrete is solved.

[0019] The construction method of wrapping the existing structural column with a thin shell of fair-faced concrete of the present invention is a set of scientific and systematic operating processes, which not only solves a series of difficulties and problems in the construction of wrapping the existing structural column with a thin shell of fair-faced concrete, but also realizes the one-time optimization of wrapping the existing structural column with a thin shell of fair-faced concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0021] Figures 1 to 3 The present invention is a schematic diagram of the steps of a construction method for wrapping an existing structural column with a thin shell of fair-faced concrete according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] Reference Figures 1 to 3 As shown, the present invention provides a construction method for enclosing an existing structural column with a thin shell of plain concrete, comprising the following steps:

[0025] S1. Coating a hydrated thermal hydrophobic drainage layer on the column wall of the existing structural column 1 to prevent the existing structural column 1 from absorbing moisture from the subsequently poured concrete.

[0026] In this embodiment, the existing structural columns are supported between two upper and lower adjacent existing structural floors.

[0027] Before constructing the hydrated thermal hydrophobic diversion layer, the surface of the existing structural column is cleaned. After the surface of the existing structural column is cleaned, the hydrated thermal hydrophobic diversion layer is coated on the surface of the existing structural column 1.

[0028] As a preferred embodiment, the hydrated thermal hydrophobic drainage layer is a waterproof permeable crystal. Specifically, the hydrated thermal hydrophobic drainage layer is formed by spraying a permeable crystal waterproof material on the surface of an existing structural column.

[0029] The construction method of wrapping an existing structural column with a thin shell of plain concrete of the present invention forms an isolation layer between the new and old concretes by adding a hydration heat hydrophobic drainage layer on the interface of the new and old concretes, so as to prevent the cast-in-place thin shell from absorbing moisture by the existing concrete column during the molding process, thereby causing dehydration cracking or hydration heat cracking.

[0030] S2. Lay anti-crack net 2 on the column wall.

[0031] After the hydration thermal hydrophobic drainage layer is formed, an anti-cracking net is installed on the column wall of the existing structure so that the anti-cracking net is wrapped around the existing structural column.

[0032] As a preferred implementation, the anti-cracking net 2 is a metal anti-cracking net.

[0033] S3. Install the outer formwork 3 on the outside of the existing structural column 1 so that an annular cavity is formed between the outer formwork 3 and the column wall.

[0034] See also Figure 1 In this embodiment, the existing structural column 1 is a square column. The outer shell template 3 has a second side surface corresponding to the four first side surfaces of the existing structural column 1. Specifically, the outer shell template includes four side templates and a column hoop. Each side template is arranged opposite to each side surface of the existing structural column. A gap is formed between the template and the side surface of the existing structural column. The column hoop is sleeved on the outside of the four side templates.

[0035] In this embodiment, the template is a shaped steel template. The inner wall of the shaped steel template is polished and cleaned, then sprayed with a release agent and dried in the sun for 24 hours.

[0036] S4. The concrete pumping pipe 7 is arranged at the top of the annular cavity, and the concrete is poured in a spiral manner from bottom to top. Each time the concrete is poured to a preset height, during the pouring process, the vibrator 4 is synchronously moved in a spiral manner with the concrete pouring rhythm to perform high-frequency and low-amplitude vibration. At the same time, a vibrator 5 is installed on the outer wall of the outer formwork 3 to vibrate to discharge free gas in the concrete.

[0037] In this embodiment, concrete is poured into the annular cavity through a concrete micro-delivery pump and a concrete pumping pipe.

[0038] Specifically, the concrete pumping pipe of the concrete micro-delivery pump is arranged at the top of the annular cavity, and the spiral propulsion pouring is performed with the annular cavity folding surface as a unit. The pouring amount is controlled during the pouring process. The pouring amount is detected by the pouring surface through the micro rubber head vibrator each time, and measured by the scale on the soft shaft of the vibrator. The preset height of each pouring is 40 to 50 cm. In this embodiment, the preset height is 50 cm.

[0039] The concrete slurry is poured into the annular cavity between the existing structural column and the external formwork through a concrete micro-delivery pump.

[0040] As a preferred embodiment, the vibrator is a micro high-frequency low-amplitude rubber-head vibrator. The micro rubber-head vibrator performs spiral movement and high-frequency low-amplitude vibration in sync with the pouring rhythm during the pouring of concrete slurry.

[0041] As a preferred implementation, there are multiple vibrators 5 , and the multiple vibrators 5 are arranged along the circumferential direction of the outer template 3 .

[0042] In this embodiment, the vibrator 5 is an attached vibrator.

[0043] Multiple attached vibrators are installed on the outer wall of the formwork and vibrated during the pouring of concrete slurry to discharge free gas in the concrete slurry and reduce the pores on the surface of the thin shell of plain concrete.

[0044] A few days after the concrete slurry is poured, the formwork is removed to form a thin shell of plain concrete 6.

[0045] Finally, the fair-faced concrete protective agent is applied to the outer wall of the fair-faced concrete shell to form a protective film.

[0046] The construction method of wrapping an existing structural column with a thin shell of plain concrete of the present invention forms an isolation layer between the new and old concretes by adding a hydration heat hydrophobic drainage layer on the interface of the new and old concretes, so as to prevent the cast-in-place thin shell from absorbing moisture by the existing concrete column during the molding process, resulting in dehydration cracking or hydration heat cracking. By adopting a directional quantitative spiral casting + high-frequency low-amplitude internal and external spiral vibration method, the problem of narrow cavity and many corners between the existing structural column and the formwork, which hinders the flow of concrete and affects the density of the concrete structure is solved. In addition, by adopting a miniature high-frequency low-amplitude rubber-head vibrator, the problem of vibration being limited to a small space is solved; by hanging an attached vibrator on the outside of the formwork to vibrate and exhaust from the bottom up, the problem of free bubbles in thin-walled concrete being difficult to discharge is solved.

[0047] The construction method of wrapping the existing structural column with a thin shell of fair-faced concrete of the present invention is a set of scientific and systematic operating processes, which not only solves a series of difficulties and problems in the construction of wrapping the existing structural column with a thin shell of fair-faced concrete, but also realizes the one-time optimization of wrapping the existing structural column with a thin shell of fair-faced concrete.

[0048] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A construction method for wrapping an existing structural column with a thin shell of fair-faced concrete, characterized in that: The following steps are involved: Coating a hydrated thermal hydrophobic drainage layer on the column wall of an existing structural column to prevent the existing structural column from absorbing moisture from subsequently poured concrete; Laying an anti-crack net on the column wall; Installing an external formwork on the exterior of the existing structural column so that an annular cavity is formed between the external formwork and the column wall; A concrete pumping pipe is arranged at the top of the annular cavity, and the concrete is poured from bottom to top in a spiral manner. Each time the concrete is poured to a preset height, during the pouring process, the vibrator is moved in a spiral manner in synchronization with the concrete pouring rhythm to perform high-frequency and low-amplitude vibration. At the same time, a vibrator is installed on the outer wall of the outer formwork to vibrate to discharge free gas in the concrete.

2. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1 is characterized in that: The hydration heat hydrophobic diversion layer is waterproof and permeable crystal.

3. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1, characterized in that: The anti-cracking net is a metal anti-cracking net.

4. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1, characterized in that: The existing structural column is a square column, and the outer shell formwork has a second side surface corresponding to the four first side surfaces of the existing structural column.

5. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1 is characterized in that: The preset height is 40 to 50 cm.

6. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1, characterized in that: The vibrator is a miniature high-frequency low-amplitude rubber-head vibrator.

7. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 1, characterized in that: There are multiple vibrators, and the multiple vibrators are arranged along the circumferential direction of the outer template.

8. The construction method of wrapping an existing structural column with a thin shell of fair-faced concrete according to claim 7 is characterized in that: The vibrator is an attached vibrator.

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