Construction segment concrete curing method for special-shaped main tower in winter

Abstract

The application discloses a kind of special-shaped main tower construction section concrete winter curing method, for climbing form device, the method comprises: the form outer thermal body is set in the outer side of the climbing form device;Each construction section is installed in section in the upper of the lower tower column in turn;Insulating shed frame is erected on the top of the construction section;The insulating shed frame is covered in the upper of the form outer thermal body, and the construction section is covered;Pouring concrete to the construction section;Steam health care is carried out to the inner box chamber of concrete in the construction section, to carry out winter curing to the concrete of the special-shaped main tower construction section.The application carries out steam health care to the concrete after initial setting by insulating shed frame and the form outer thermal body on climbing form device, prevents concrete from frozen expansion, crack, structural disease and other quality problems, guarantees the forming strength of concrete, ensures the winter construction quality of main tower concrete.

Description

Technical Field

[0001] This invention relates to the field of winter construction technology for main towers in high-altitude and cold regions, and particularly to a method for winter curing of concrete in construction segments of irregular-shaped main towers. Background Technology

[0002] Due to the excessive height of the main tower of the cable-stayed bridge, there is no mature experience to draw upon domestically or internationally regarding its winter insulation performance. To ensure the construction schedule, winter construction is unavoidable. The effectiveness of winter construction directly impacts the quality of the concrete work, making research on winter construction insulation technology particularly important. During winter construction, heating measures can easily lead to safety accidents, and inadequate anti-freezing and insulation measures can cause quality problems such as concrete frost heave, cracks, and structural defects, severely affecting the concrete's strength.

[0003] The International Recommendations on Winter Construction of Concrete (RILEM, hereinafter referred to as the "International Recommendations") were developed by R1LEM 39-BH Committee and adopted after discussions at the London Conference in 1981 and the Moscow Conference in 1984. It summarizes the experiences of various countries worldwide in winter construction techniques over the past 20 years. The Heilongjiang Provincial Institute of Low Temperature Building Science translated it based on the January 1988 Espu, Finland edition and presented it at the National Winter Construction Conference in 1989. The above content focuses on concrete mix design and the application of new materials, with less description of external insulation techniques.

[0004] Therefore, the key issues in the field of winter construction of cable-stayed bridges have attracted sufficient attention in the industry, and relevant research results have emerged continuously, solving a large number of practical problems in engineering projects. However, there is a lot of application of macro-control methods, but few application results in the field of special control. In particular, the problem of winter construction of the main tower of cable-stayed bridges has not been solved in depth and systematically, and the key technology system for winter construction has not yet been fully matured. Summary of the Invention

[0005] The main objective of this invention is to provide a method for winter curing of concrete in the construction segments of irregular main towers. This method aims to address the technical problems in the existing technology, where macroscopic control methods are widely used but specialized control methods are rarely applied. In particular, the problem of winter construction of cable-stayed bridge main towers has not been thoroughly and systematically solved, and the key technology system for winter construction is not yet fully mature.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for winter curing of concrete in construction segments of irregularly shaped main towers, using a climbing formwork device. The climbing formwork device is circumferentially framed around the construction segment and includes a climbing formwork, a climbing frame, and climbing equipment. The construction segment includes an initial segment, a current segment, and a target segment. The current segment is the next construction segment after the initial segment, and the target segment is the next construction segment after the current segment. The method includes:

[0008] A lower tower column is formed on the tower base; wherein, the lower tower column includes a bottom chamber;

[0009] An external insulation body is installed on the side of the climbing formwork device away from the construction segment; wherein the external insulation body is hung on the climbing formwork.

[0010] The climbing formwork device is used to construct the initial segment, and an insulated shed is erected on top of the initial segment;

[0011] A partition layer is provided inside the bottom chamber; wherein, the partition layer, the insulated frame, and the outer insulation body of the template together enclose a first insulated chamber that seals the initial segment.

[0012] Concrete is poured into the initial segment, and the insulation chamber is heated to steam cure the concrete of the initial segment.

[0013] After steam curing of the initial concrete segment is completed, the insulation frame and the partition layer are removed to obtain the initial shaped segment.

[0014] Above the initially formed segment, the climbing formwork device is raised to construct the current segment, and the heat-insulating shed is erected on top of the current segment;

[0015] The partition layer is provided within the initial forming segment; wherein, the partition layer, the heat-insulating frame, and the external heat-insulating body of the template together enclose a second heat-insulating chamber that seals the initial forming segment and the current segment.

[0016] Concrete is poured into the current segment, and the second insulation chamber is heated to steam cure the concrete of the current segment and the initially formed segment.

[0017] After steam curing of the concrete in the current segment and the concrete in the initial forming segment is completed, the insulation frame and the partition layer are removed to obtain the current forming segment.

[0018] Above the currently formed segment, the climbing formwork device is raised to construct the target segment, and the heat-insulating shed is erected on top of the target segment;

[0019] The partition layer is provided within the current forming segment; wherein, the partition layer, the heat-insulating frame, and the external heat-insulating body of the template together enclose a third heat-insulating chamber that seals the current forming segment and the target segment.

[0020] Concrete is poured into the current segment, and heat is supplied to the third insulation chamber to steam-cur the concrete of the target segment and the current forming segment;

[0021] After steam curing of the concrete in the target segment and the concrete in the currently formed segment is completed, the insulation frame and the partition layer are removed to obtain the irregular-shaped main tower.

[0022] The insulated shed frame covers the outer insulation body of the template.

[0023] Optionally, in the above-mentioned method for winter curing of concrete in the construction segment of the irregular main tower, the distance between the insulation shed and the top of the climbing formwork device is 20cm.

[0024] Optionally, in the above-mentioned method for winter curing of concrete in the construction segments of the irregular main tower, the partition layer is an aluminum silicate board.

[0025] Optionally, in the above-mentioned method for winter curing of concrete in the construction segments of the irregular main tower, before the step of using the climbing formwork device to construct the initial segment and erecting an insulation shed on top of the initial segment, the method further includes:

[0026] A miniature intelligent electric boiler is installed on the climbing frame;

[0027] Steam pipes are laid within the construction segment and connected to the miniature intelligent electric boiler to provide heat to the construction segment.

[0028] Optionally, in the above-mentioned method for winter curing of concrete in the construction segments of the irregular main tower, before the step of pouring concrete into the initial segment and heating the insulation chamber to steam-cur the concrete of the initial segment, the method further includes:

[0029] Set preset parameters for steam therapy to suit different stages of steam therapy;

[0030] According to the preset parameters, the construction segment is heated through the steam pipeline.

[0031] Optionally, in the above-mentioned method for winter curing of concrete in the construction segments of irregular main towers, the preset parameter is the heating rate, and the step of setting the preset parameters for steam curing to adapt to different stages of steam curing includes:

[0032] When the steam curing is in the heating stage, adjust the heating rate V1;

[0033] Among them, 6℃ / h≤V1≤10℃ / h.

[0034] Optionally, in the above-mentioned method for winter curing of concrete in irregular-shaped main tower construction segments, the preset parameter is temperature, and the step of setting preset parameters for steam curing to adapt to different stages of steam curing includes:

[0035] When the steam curing is in the constant temperature stage, adjust the temperature T;

[0036] Among them, 15℃≤T≤30℃.

[0037] Optionally, in the above-mentioned method for winter curing of concrete in the construction segments of irregular-shaped main towers, the preset parameter is the cooling rate, and the step of setting the preset parameters for steam curing to adapt to different stages of steam curing includes:

[0038] When the steam curing is in the cooling phase, adjust the cooling rate V2;

[0039] Where V2≤5℃ / h.

[0040] Optionally, in the above-mentioned method for winter curing of concrete in irregular-shaped main tower construction segments, the step of setting an external insulation body for the formwork on the side of the climbing formwork device away from the construction segment includes:

[0041] A wire mesh is installed on the side of the climbing formwork that is away from the construction segment;

[0042] An electric heat tracing cable is laid on the wire mesh;

[0043] Install glass wool insulation boards on the climbing template;

[0044] The glass wool insulation board covers the side of the electric heating tape away from the wire mesh to form a closed-structure external insulation body for the template.

[0045] Optionally, in the above-mentioned method for winter curing of concrete in irregular-shaped main tower construction segments, the step of setting an external insulation body for the formwork on the side of the climbing formwork device away from the construction segment includes:

[0046] A wooden I-beam is installed on the side of the climbing formwork opposite to the construction segment;

[0047] An electric heating cable is embedded in the wooden I-beam;

[0048] Install glass wool insulation boards on the climbing template;

[0049] The glass wool insulation board covers the side of the electric heating cable away from the wooden I-beam to form a closed-structure external insulation body for the template.

[0050] The above-described one or more technical solutions provided by this invention can have the following advantages or at least achieve the following technical effects:

[0051] This invention proposes a method for winter curing of concrete in irregularly shaped main tower construction segments. This method involves erecting an insulated shed on top of the formed upper tower column formwork and covering it with the external insulation of the formwork. Concrete is then poured onto the upper tower column formwork using a climbing formwork device to form the upper tower column segment. After this process, the formed upper tower column segment is steam-cured to prevent quality problems such as frost heave, cracking, and structural defects in the concrete, ensuring the concrete's forming strength. This method guarantees the winter construction quality of the main tower concrete in cold regions and solves the insulation problem at the top of the main tower under conditions of densely embedded steel reinforcement. It provides a reference for the winter construction technology system of cable-stayed bridge main towers. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a flowchart illustrating the method for winter curing of concrete in the construction segments of the irregular main tower according to the present invention.

[0054] Figure 2 This is a schematic diagram of the climbing formwork device involved in the present invention;

[0055] Figure 3 This is a schematic diagram of the structure of the insulated chamber involved in the present invention;

[0056] Figure 4 This is a cross-sectional structural diagram of the external insulation body involved in the present invention.

[0057] Explanation of icon numbers:

[0058] label name label name 100 Upper tower segment 200 Climbing formwork device 300 External insulation of template 400 Insulated shed 500 First Insulated Box 700 Vertical main reinforcement 600 perlite 310 Glass wool insulation board 320 Electric heat tracing tape 330 Wire mesh

[0059] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0061] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0062] In this invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. Furthermore, the meaning of "and / or" throughout the text includes three parallel options; for example, "A and / or B" includes option A, option B, or options where both A and B are satisfied.

[0063] In this invention, unless otherwise explicitly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements.

[0064] In this invention, if there are descriptions involving "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0065] In this invention, the use of suffixes such as "module," "component," "part," "unit," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" can be used interchangeably.

[0066] For those skilled in the art, the specific meanings of the above terms in this invention can be understood according to the specific circumstances. Furthermore, the technical solutions of the various embodiments can be combined with each other; however, this is based on the premise that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0067] The inventive concept of the present invention will be further explained below with reference to some specific embodiments.

[0068] This invention proposes a method for winter curing of concrete in the construction segments of irregularly shaped main towers.

[0069] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 This is a flowchart illustrating the method for winter curing of concrete in the construction segments of the irregular main tower according to the present invention. Figure 2 This is a schematic diagram of the climbing formwork device involved in the present invention; Figure 3 This is a schematic diagram of the structure of the insulated chamber involved in the present invention; Figure 4 This is a cross-sectional structural diagram of the external insulation body involved in the present invention.

[0070] In one embodiment of the present invention, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a method for winter curing of concrete in construction segments of an irregularly shaped main tower is provided. The method utilizes a climbing formwork device, which is circumferentially framed around the construction segment. The climbing formwork device includes a climbing template, a climbing frame, and climbing equipment. The construction segment includes an initial segment, a current segment, and a target segment. The current segment is the next construction segment after the initial segment, and the target segment is the next construction segment after the current segment. The method for winter curing of concrete in construction segments of an irregularly shaped main tower includes:

[0071] Step S100: Form a lower tower column on the tower base; wherein, the lower tower column includes a bottom chamber;

[0072] Step S200: Install an external insulation body 300 on the side of the climbing formwork device away from the construction segment; wherein, the external insulation body 300 is hung on the climbing formwork.

[0073] Step S300: Use the climbing formwork device to construct the initial segment and erect an insulated shed on top of the initial segment;

[0074] Step S400: A partition layer is installed in the bottom chamber; wherein, the partition layer, the insulation frame and the outer insulation body 300 of the template together enclose the first insulation chamber 500 that encloses the initial segment.

[0075] Step S500: Pour concrete into the initial segment and heat the first insulation chamber 500 to steam-cur the concrete of the initial segment.

[0076] Step S600: After steam curing the initial segment concrete, remove the insulation frame and partition layer to obtain the initial formed segment;

[0077] Step S700: Above the initially formed segment, use climbing equipment to climb the climbing formwork device to carry out construction on the current segment, and erect an insulated shed on top of the current segment;

[0078] Step S800: Set a partition layer within the initial forming segment; wherein, the partition layer, the insulation frame, and the external insulation body 300 of the template together enclose a second insulation chamber that seals the initial forming segment and the current segment.

[0079] Step S900: Pour concrete into the current segment and heat the second insulation chamber to steam-cur the concrete of the current segment and the initially formed segment;

[0080] Step S10: After steam curing the concrete of the current segment and the initial forming segment, remove the insulation scaffold and partition layer to obtain the current forming segment.

[0081] Step S11: Above the current formed segment, use climbing equipment to climb the climbing formwork device to carry out construction on the target segment, and erect an insulated shed on top of the target segment;

[0082] Step S12: Set up a partition layer within the current forming segment; wherein, the partition layer, the insulation frame, and the external insulation body 300 of the template together enclose a third insulation chamber that seals the current forming segment and the target segment.

[0083] Step S13: Pour concrete into the current segment and heat the third insulation chamber to steam-cur the concrete of the target segment and the current forming segment.

[0084] Step S14: After steam curing the concrete of the target segment and the concrete of the currently formed segment, remove the insulation scaffold and partition layer to obtain the irregular-shaped main tower.

[0085] The insulated shed frame covers the outer insulation body 300 of the template.

[0086] For ease of understanding, a specific implementation method is shown below:

[0087] The method for erecting the insulation shed is as follows: erect the shed on top of the construction segment; install steel mesh on the top of the shed; and install aluminum silicate board on the steel mesh to cover the top of the construction segment.

[0088] This plan is applicable to the winter construction of the main tower of the bridge project. In order to complete the construction on schedule while ensuring safety and quality, this plan is adopted for winter construction. This plan solves the problems of external insulation and internal curing of concrete during winter construction, and avoids quality problems caused by excessively low concrete temperature.

[0089] The main tower involved in this plan adopts a C55 reinforced concrete structure, is an irregularly shaped pylon, and the anchorage section is equipped with prestressed reinforced concrete and steel anchor boxes. It has a herringbone shape transversely and is divided into five parts from top to bottom: the tower crown, upper tower column, middle tower column, lower tower column, and tower base (using C40 concrete). The height above the bridge tower pier is 102.749m, and the tower base is 2m high. The height of the pylon above the bridge deck is 88m, with a height-to-span ratio of 0.64. The center-to-center distance between the left and right tower columns at the base is 47.82m. The tower crown is 6m wide transversely and 6.8m long longitudinally. At a height of 55m, it branches downwards into two tower columns, each 4.3m wide transversely. The centerline of the pylon structure gradually changes with a radius of curvature of 400.05m to a position 12m from the top of the tower base. The distance from 12m to the top of the tower base is a straight line. The base is 7.5m wide transversely and 8.5m long longitudinally.

[0090] The outer and inner cross-sections of the tower columns are both octagonal, with dimensions of 4.3m x 6.8m. The left and right tower columns merge at an elevation of 125.2m. The merging triangle is a hollow thin-walled structure connected by five transverse diaphragms. The thickness of the thin walls and diaphragms is 600mm.

[0091] The stay cables are anchored within the tower using steel anchor boxes, which are installed on the upper tower column. Stay cables 2 through 17 are all anchored to these steel anchor boxes. Each steel anchor box is 5.2m long, 1.8m wide, and ranges in height from 0.7m to 3.99m, with a base height of 0.7m. High-strength bolts are used to connect the anchor box segments on-site. The lowest point of each anchor box is anchored to a positioning steel bracket. The starting elevation of the anchor box is 118.400m, the top elevation is 158.050m, and the total height is 39.65m. The maximum lifting weight of the anchor box is 19t, and it is installed using a tower crane.

[0092] Main Tower Construction: The lower tower column is constructed using a flip-formwork method, while the middle and upper tower columns utilize HCB-100 hydraulic automatic climbing formwork technology. Two sets of hydraulic automatic climbing formwork machines are on-site, with symmetrical construction of the upstream and downstream tower columns. The formwork configuration height is 4.85m, with a 100mm lower cladding and an upward overhang of over 50mm. The vertical layer height varies depending on the slope. The tower column construction is divided into 24 segments, with a standard pouring height of 4.5m. For the tower column facing down the bridge, the scaffolding is scheduled to be installed after the fourth segment is poured; for the tower column facing up the bridge, the scaffolding is scheduled to be installed after the third segment is poured. The scaffolding on the side of the closure section is a modified version of the up-climbing scaffolding, with two scaffolding frames on each side. Closure Zone Construction: Embedded parts are installed in the tower column concrete, and corbels and steel supports are installed and poured simultaneously with the tower columns of the same height. Anchorage Zone Construction: The steel anchor boxes are hoisted and installed using a tower crane. The upper tower column's cable tower concrete construction is carried out simultaneously with the installation of the steel anchor boxes. After the concrete reaches the required strength, prestressing construction will proceed. Temporary active horizontal bracing construction: Three temporary active horizontal braces will be installed on the central tower column. Each brace will be installed using a tower crane after the tower column has been constructed to a certain segment, and the corresponding pre-jacking force will be applied according to the instructions.

[0093] The external insulation of the main tower is mainly implemented by the external insulation body 300 of the formwork. The external insulation body 300 is fixed to the outside of the climbing formwork device 200 and rises synchronously with the climbing formwork device 200. The top insulation body needs to be erected and dismantled for each section according to the construction progress. A 5cm*5cm steel wire mesh 330 is fixed to the outside of the formwork for the external insulation body 300. An electric heating cable 320 is laid in an S-shape on the steel wire mesh 330, and then glass wool insulation board 310 is fixed to form a closed insulation body. The external insulation body is at least 20cm higher than the top surface of the concrete. The top surface of the box duct is sealed with aluminum silicate board, at least 20cm higher than the top surface of the concrete, to ensure steam circulation on the top surface of the concrete. The gaps between the vertical main reinforcement bars 700 are sealed with aluminum silicate board and perlite 600 to reduce heat loss. Perlite 600 has a fire rating of Class A and a density of 80-250kg / m³. 3 Perlite 600 with a thermal conductivity of 0.045 W / (m2.K).

[0094] To achieve the desired external insulation effect and ensure the quality of concrete construction, extensive testing and data analysis were conducted to ensure that the external insulation system of the main tower met the requirements. First, a 5cm*5cm steel wire mesh 330 was fixed on the outer surface of the template, and electric heating tape 320 with a spacing of 15cm was fixed on the steel wire mesh 330. The specific insulation materials were steel wire mesh 330, electric heating tape and 10cm glass insulation board.

[0095] It should be noted that in this embodiment and other embodiments, a miniature intelligent electric boiler is used to heat the insulated chamber 500, with the following specifications: rated steam temperature: t = 154℃; rated steam pressure: P = 0.5MPa; boiler efficiency: η = 93.5%; total power consumption: 73KW; boiler installation dimensions (length * width * height): 600mm × 800mm × 1200mm.

[0096] The technical solution of this invention involves erecting an insulation shed 400 on top of the formed upper tower column template and covering the outer insulation body 300 of the template with the insulation shed 400. After the upper tower column template is formed by pouring concrete into it using a climbing formwork device 200 to form the upper tower column segment 100, the formed upper tower column segment 100 is steam-cured to prevent quality problems such as frost heave, cracking, and structural defects in the concrete, ensuring the forming strength of the concrete, ensuring the winter construction quality of the main tower concrete in cold regions, solving the insulation problem of the top of the main tower under the condition of densely pre-embedded vertical main reinforcement 700, and providing a reference for the winter construction technology system of cable-stayed bridge main towers.

[0097] In one embodiment, the distance between the insulated shed frame and the top of the climbing formwork device is 20cm.

[0098] Specifically, the outer insulation 300 is at least 20cm higher than the top surface of the concrete, i.e., the top surface of the initial segment, the current segment, or the target segment. The top surface of the box is sealed with aluminum silicate board, which is at least 20cm higher than the top surface of the concrete to ensure steam circulation on the top surface of the concrete. Moreover, while the concrete of the initial segment, the current segment, or the target segment is being steam cured, the construction of the vertical main reinforcement 700 can still be carried out on the next segment. This ensures the steam curing effect while avoiding affecting the construction progress, improving construction efficiency, and saving construction costs.

[0099] In one embodiment, to ensure the sealing effect, waterproof performance, and durability of the partition layer, the partition layer is made of aluminum silicate board.

[0100] In one embodiment, before the steps of constructing the initial segment using a climbing formwork device and erecting an insulated shed on top of the initial segment, the method for winter curing of the concrete of the top construction segment of the irregular main tower further includes:

[0101] Step F100: Install a miniature intelligent electric boiler on the climbing frame;

[0102] Step F200: Lay steam pipes within the construction segment and connect the steam pipes to a miniature intelligent electric boiler to provide heat to the construction segment.

[0103] Specifically, steam pipes are laid in the main tower chamber. After the concrete is poured, a simple shed is immediately erected on the top of the chamber and covered with insulation material. After the concrete has initially set, steam curing is carried out.

[0104] After the inner formwork of each tower segment is reinforced, a scaffold is erected 20cm above the top of the tower box chamber using φ48*3mm steel pipes, and φ20 steel mesh is installed with a mesh size of 20cm*20cm. Before pouring concrete, the top is encased with aluminum silicate board, and the spaces between the double rows of reinforcing bars are also encased in sections with aluminum silicate board. The gaps between the 700mm vertical main reinforcing bars can be filled with 600mm perlite to create a closed space inside the box chamber. When erecting the 400mm insulation scaffold, it must be 20cm higher than the top surface of the later poured concrete to allow steam circulation inside the box chamber, prevent the top concrete from freezing, and ensure the quality of the concrete. The top insulation material is fixed with φ12 steel mesh to prevent the insulation material from being missing due to wind.

[0105] It should be noted that the aluminum silicate board in this embodiment and other embodiments has a fire rating of Class A and a density of 150 kg / m³. 3 Alumina silicate board with a thermal conductivity of 0.035 W / (m2.K).

[0106] The main tower consists of a lower tower column and an upper tower column, heated by a miniature intelligent electric boiler that insulates the interior. The miniature intelligent electric boiler is mounted on the operating platform of the hydraulic climbing frame. Steam pipes (DN40mm rubber hoses) enter the main tower through the vent (φ100mm) of the lower tower column. All pipes on the outside of the tower columns are wrapped with insulation material. The interior chamber is sealed at both the top and bottom with aluminum silicate boards to ensure that two sections are always being cured.

[0107] Steam pipes are installed inside the main tower box chamber. After the concrete is poured, a simple scaffold is immediately erected on the top of the box chamber and covered with insulation material. After the concrete has initially set, steam curing is carried out to ensure that the temperature inside the main tower box chamber is above 10℃. Steam curing should be supervised by designated personnel. To prevent cracking of the concrete surface of the main tower, the heating and cooling rates should not exceed 10℃ / h, and the constant temperature should not exceed 30℃. The steam curing process is divided into three stages: heating, constant temperature, and cooling. During the steam curing process, the heating and cooling rates and the constant temperature should be strictly controlled to avoid excessive temperature differences between the inside and outside of the beam or excessively high constant temperatures, which could lead to concrete cracking and structural deformation. The curing period should not be less than 7 days.

[0108] In one embodiment, prior to the steps of pouring concrete into the initial segment and heating the insulation chamber to steam-cur the concrete of the initial segment, the winter curing method for the concrete of the irregular main tower construction segment further includes:

[0109] Step G100: Set the preset parameters for steam therapy to suit different stages of steam therapy;

[0110] Step G200: Heat the construction section through steam pipes according to preset parameters.

[0111] In one embodiment, the preset parameter is the heating rate. Setting preset parameters for steam curing to adapt to different stages of steam curing includes the following steps:

[0112] Step G110: When steam curing is in the heating stage, adjust the heating rate V1;

[0113] Among them, 6℃ / h≤V1≤10℃ / h.

[0114] Specifically, the temperature should be increased slowly, with high humidity and low temperature. The heating rate should be controlled at 6-8℃ / h for the first 2 hours and relaxed to 10℃ / h for the next 1-2 hours to avoid damage to the concrete structure caused by excessively rapid heating. The maximum temperature should not exceed 80℃.

[0115] In one embodiment, the preset parameter is temperature. Setting preset parameters for steam therapy to adapt to different stages of steam therapy includes the following steps:

[0116] Step G120: When the steam curing is in the constant temperature stage, adjust the temperature T;

[0117] Among them, 15℃≤T≤30℃.

[0118] Specifically, the temperature is strictly controlled within 15℃ to 30℃ to maintain a relatively consistent temperature throughout the main tower chamber, both inside and outside, avoiding excessive temperature differences between the internal and external surfaces of the structure and reducing damage to the concrete from localized thermal shock. The airtightness of the steam curing shed in the constant-temperature section is frequently checked to prevent steam leakage; the steam supply pipeline is inspected, and any problems found are promptly addressed and recorded.

[0119] In one embodiment, the preset parameter is the cooling rate. Setting preset parameters for steam curing to adapt to different stages of steam curing includes the following steps:

[0120] Step G130: When the steam curing is in the cooling stage, adjust the cooling rate V2;

[0121] Where V2≤5℃ / h.

[0122] Specifically, steam should be stopped slowly, the temperature should be lowered evenly, and humidity should be maintained. Special attention should be paid to controlling the cooling rate during the first 2 hours and ensuring that the temperature difference between the structure surface and the ambient temperature does not exceed the standard (20℃) at the end of cooling. Temperature should be measured every hour, and the cooling rate should be controlled within 5℃ / h; excessively rapid cooling is prohibited. Steam curing can only be stopped when the temperature difference between the concrete surface and the ambient temperature is ≤20℃, the concrete temperature is <10℃, and the temperature has stabilized.

[0123] In one embodiment, the step of installing the external insulation body 300 of the formwork on the side of the climbing formwork device away from the construction segment includes:

[0124] Step S210: Install wire mesh 330 on the side of the climbing formwork away from the construction segment;

[0125] Step S220: Lay the electric heating tape on the wire mesh 330;

[0126] Step S230: Install glass wool insulation boards on the climbing formwork;

[0127] Among them, the glass wool insulation board covers the side of the electric heating tape away from the steel wire mesh 330 to form a closed-structure template outer insulation body 300.

[0128] Specifically, the external insulation body 300 has a 5cm*5cm steel wire mesh 330 fixed on the outside of the template. An electric heating cable 320 is then laid out in an S-shape on the steel wire mesh 330, and then the glass wool insulation board 310 is fixed to form a closed insulation body. The external insulation body 300 of the main tower is crucial to the success or failure of the main tower construction quality. After the external insulation body 300 is installed, it is inspected step by step according to the procedures. The main inspection items are: whether the steel wire mesh 330 is firmly fixed, whether the spacing of the electric heating cable 320 meets the requirements, the electric heating cable 320, the insulation performance of the electric heating cable 320, the absence of joints in the electric heating cable 320 within the insulation body, the sealing performance of the glass insulation board, and the fire resistance performance of the glass insulation board.

[0129] It should be noted that the electric heating cable 320 in this embodiment and other embodiments is model DXW-8Z; self-limiting temperature: 70±5℃; power: 25w / m; starting current: ≤0.55A / m; maximum service length: 50m; and the glass insulation board in this embodiment and other embodiments has a fire rating of Class A and a density of 10~32kg / m³. 3 Glass insulation board with a thermal conductivity of 0.038 W / (m2.K).

[0130] In one embodiment, to further ensure the stability of the electric heating cable, the step of installing an external insulation body 300 on the side of the climbing formwork device away from the construction segment includes:

[0131] Step S201: Install the wooden I-beam on the side of the climbing formwork away from the construction segment;

[0132] Step S202: Install electric heating tape on the wooden I-beam;

[0133] Step S203: Install glass wool insulation boards on the climbing formwork;

[0134] Among them, the glass wool insulation board covers the side of the electric heating cable away from the wooden I-beam to form a closed-structure template external insulation body 300. The wooden I-beam is connected to the climbing frame through shell-type steel, and the climbing frame is made of steel.

[0135] As one option in this embodiment, after the wooden beam is connected to the climbing frame via shellfish, a wire mesh 330 is hung on the wooden beam, and then an electric heating cable 320 is laid out in an S-shape on the wire mesh 330. Finally, the glass wool insulation board 310 is fixed to form a closed insulation body.

[0136] Understandably, the biggest challenge in winter construction of the main tower is the thermal insulation and curing of the concrete. To ensure the quality of the concrete, everything from heating and insulating the raw materials to curing after pouring is extremely important.

[0137] (1) Before mixing concrete, the raw materials should be heated to prevent frozen lumps from forming in the aggregate. The mixing plant uses electric heaters to heat the mixing water, and the mixing water storage tank is covered with insulation material for hot water storage and backup. When the temperature of the electric heater is insufficient to reach the required temperature, heating rods are added to the water tank to increase the temperature and ensure that the water temperature reaches 40℃-60℃. The mixing plant main unit is enclosed with insulated sandwich panels. Before concrete pouring, electric heaters are installed to ensure that the indoor temperature of the operating room is not lower than 10℃. At the same time, the mixer drum is rinsed with hot water before mixing concrete and after mixing is stopped. The mixer should be rinsed with hot water before feeding materials. The concrete mixing time is extended by 50% compared to normal temperature and complies with relevant regulations. The mixing time is set to 180 seconds to ensure that the outlet temperature is above 10℃. After the concrete mix leaves the mixer, it should be transported to the pouring site in a timely manner.

[0138] (2) After the concrete is mixed, it should be transported to the pouring site in a timely manner using concrete mixer trucks. In winter, the concrete mixer trucks should be covered with specially made tarpaulins to enhance insulation during transportation and ensure that the concrete temperature upon entering the formwork is greater than 5°C. At the same time, the process should be organized reasonably, with a tight schedule, unloading immediately upon arrival of the truck to reduce the waiting time for concrete to enter the formwork. Before pouring concrete, the on-site insulation shed should be preheated. Preheating inside the shed should be done using a hot air blower; steam is prohibited to prevent water droplets from forming and freezing inside after the top layer of insulation is opened during concrete pouring. Proper sealing should be ensured during preheating. After the concrete mixer truck arrives at the site, the top of the shed should be opened in sections for pouring the concrete. After the concrete is poured, the shed should be covered. When pouring concrete in winter, the joint surfaces should be heated before pouring new concrete to ensure a temperature above 5°C. After pouring, measures should be taken to maintain the concrete joint surfaces at a positive temperature until the specified frost resistance is achieved.

[0139] (3) When welding steel bars in sub-zero temperatures during winter, all welding should be carried out indoors as much as possible. If welding must be done outdoors, the ambient temperature should not be lower than -20℃, and windbreaks should be provided when the wind force exceeds level 3. Joints that have not cooled after welding must not come into contact with ice and snow, and all vertical main bars 700mm in diameter should be mechanically connected.

[0140] (4) The main tower is heated by a miniature intelligent electric boiler. The steam generators are installed on the hydraulic climbing frame operating platform and extend into the curing section through their own pipes. The upper and lower parts of the chamber are sealed with aluminum silicate plates to ensure that there are always two sections being cured.

[0141] (5) The external insulation of the main tower is mainly implemented by the external insulation body 300mm of the formwork. The external insulation body is fixed to the outside of the climbing formwork device and rises synchronously with the climbing formwork device. The top insulation body needs to be erected and dismantled for each section according to the construction progress. The external insulation body is fixed with an S-shaped electric heating cable on the outside of the formwork, and then the rock wool insulation board is fixed to form a closed insulation body. The external insulation body is at least 20cm higher than the top surface of the concrete. The top surface of the box is sealed with aluminum silicate board, which is at least 20cm higher than the top surface of the concrete to ensure steam circulation on the top surface of the concrete. The gaps between the vertical main reinforcement bars 700mm are sealed with aluminum silicate board and perlite to reduce heat loss.

[0142] (6) After the inner formwork of each tower column segment is reinforced, a scaffold is erected on the top of the tower column box chamber using φ48*3mm steel pipes, and φ20 steel mesh is installed with a mesh size of 20cm*20cm. Before pouring concrete, the top is encased with aluminum silicate board, and the spaces between the double rows of steel bars are also encased in sections with aluminum silicate board. The gaps between the 700mm vertical main bars can be filled with perlite to create a closed space inside the box chamber. When erecting the insulation scaffold, it must be 20cm higher than the top surface of the concrete to allow steam circulation inside the box chamber, prevent the top concrete from freezing, and ensure the quality of the concrete. The top insulation material is fixed with φ12 steel mesh to prevent the insulation material from being lost due to wind.

[0143] Using this solution for winter construction can meet the temperature requirements of concrete and ensure the quality of the structure. The external insulation uses electric heating tape and rock wool boards, significantly reducing the weight on the climbing formwork. The steam generator in the inner chamber not only ensures the required temperature of the concrete but also maintains the surface humidity. This solution is characterized by its ease of operation, high safety, environmental friendliness, and cost-effectiveness. All insulation materials are fire-resistant, preventing high-altitude fires. The main tower concrete insulation forms a closed loop with significant insulation effect. Furthermore, the external concrete insulation is fixed to the formwork and can be adjusted as the formwork is raised, avoiding waste caused by removing the insulation.

[0144] It should be noted that the sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above embodiments are only optional embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made under the inventive concept of the present invention using the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are all included within the patent protection scope of the present invention.

Claims

1. A method for winter curing of concrete in irregularly shaped main tower construction segments, characterized in that, A climbing formwork device is used, the climbing formwork device being circumferentially framed within the construction segment, the climbing formwork device including climbing formwork and climbing frame, the construction segment including an initial segment, a current segment, and a target segment, the current segment being the next construction segment after the initial segment, the target segment being the next construction segment after the current segment, the method including: A lower tower column is formed on the tower base; wherein, the lower tower column includes a bottom chamber; An external insulation body is installed on the side of the climbing formwork device away from the construction segment; wherein the external insulation body is hung on the climbing formwork. The climbing formwork device is used to construct the initial segment, and an insulated shed is erected on top of the initial segment; A partition layer is provided inside the bottom chamber; wherein, the partition layer, the insulated frame, and the outer insulation body of the template together enclose a first insulated chamber that seals the initial segment. Concrete is poured into the initial segment, and the first insulation chamber is heated to steam cure the concrete of the initial segment. After steam curing of the initial concrete segment is completed, the insulation frame and the partition layer are removed to obtain the initial shaped segment. Above the initially formed segment, the climbing formwork device is raised to construct the current segment, and the heat-insulating shed is erected on top of the current segment; The partition layer is provided within the initial forming segment; wherein, the partition layer, the heat-insulating frame, and the external heat-insulating body of the template together enclose a second heat-insulating chamber that seals the initial forming segment and the current segment. Concrete is poured into the current segment, and the second insulation chamber is heated to steam cure the concrete of the current segment and the initially formed segment. After steam curing of the concrete in the current segment and the concrete in the initial forming segment is completed, the insulation frame and the partition layer are removed to obtain the current forming segment. Above the currently formed segment, the climbing formwork device is raised to construct the target segment, and the heat-insulating shed is erected on top of the target segment; The partition layer is provided within the current forming segment; wherein, the partition layer, the heat-insulating frame, and the external heat-insulating body of the template together enclose a third heat-insulating chamber that seals the current forming segment and the target segment. Concrete is poured into the target segment, and the third insulation chamber is heated to steam-cur the concrete of the target segment and the currently formed segment. After steam curing of the concrete in the target segment and the concrete in the currently formed segment is completed, the insulation frame and the partition layer are removed to obtain the irregular-shaped main tower. The insulated frame covers the outer insulation body of the template; Before the step of constructing the initial segment using the climbing formwork device and erecting an insulated shed on top of the initial segment, the method further includes: A miniature intelligent electric boiler is installed on the climbing frame; Steam pipes are laid within the construction segment and connected to the miniature intelligent electric boiler to provide heat to the construction segment.

2. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 1, characterized in that, The distance between the insulated shed frame and the top of the climbing formwork device is 20cm.

3. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 2, characterized in that, The partition layer is made of aluminum silicate board.

4. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 1, characterized in that, Before the step of pouring concrete into the initial segment and heating the first insulated chamber to steam-cur the concrete of the initial segment, the method further includes: Set preset parameters for steam therapy to suit different stages of steam therapy; According to the preset parameters, the construction section is heated through the steam pipeline.

5. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 4, characterized in that, The preset parameter is the heating rate. The step of setting the preset parameters for steam conditioning to adapt to different stages of steam conditioning includes: When the steam curing is in the heating stage, adjust the heating rate V1; Among them, 6℃ / h≤V1≤10℃ / h.

6. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 4, characterized in that, The preset parameter is temperature. The steps of setting the preset parameters for steam therapy to adapt to different stages of steam therapy include: When the steam curing is in the constant temperature stage, adjust the temperature T; Among them, 15℃≤T≤30℃.

7. The method for winter curing of concrete in irregular-shaped main tower construction segments as described in claim 4, characterized in that, The preset parameter is the cooling rate. The step of setting the preset parameters for steam conditioning to adapt to different stages of steam conditioning includes: When the steam curing is in the cooling phase, adjust the cooling rate V2; Where V2≤5℃ / h.

8. The method for winter curing of concrete in the construction segment of an irregularly shaped main tower as described in any one of claims 1 to 7, characterized in that, The step of installing an external insulation body for the formwork on the side of the climbing formwork device away from the construction segment includes: A wire mesh is installed on the side of the climbing formwork that is away from the construction segment; An electric heating tape is laid on the wire mesh; Install glass wool insulation boards on the climbing template; The glass wool insulation board covers the side of the electric heating tape away from the wire mesh to form a closed-structure external insulation body for the template.

9. The method for winter curing of concrete in the construction segment of an irregularly shaped main tower as described in any one of claims 1 to 7, characterized in that, The step of installing an external insulation body for the formwork on the side of the climbing formwork device away from the construction segment includes: A wooden I-beam is installed on the side of the climbing formwork opposite to the construction segment; An electric heating cable is embedded in the wooden I-beam; Install glass wool insulation boards on the climbing template; The glass wool insulation board covers the side of the electric heating cable away from the wooden I-beam to form the outer insulation body of the template with a closed structure.

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