CN112412027A - Method for manufacturing large-section special-shaped load-bearing concrete bare concrete member - Google Patents

Abstract

A method for manufacturing a large-section special-shaped load-bearing concrete bare concrete member is characterized by comprising the following steps: a. the method comprises the following steps of template construction, b, template supporting system, c, template processing, d, wood back ridge processing, e, template inner member installation, f, template installation and reinforcement, g, positioning and supporting of an arc beam bottom, h, positioning measurement, i, steel bar engineering, j, fair-faced concrete pouring, k, fair-faced concrete curing, and l, finished product protection. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member has the advantages of scientific and reasonable design of construction steps, strong operability and safe and reliable engineering quality, solves the problem of the manufacturing method of the large-section special-shaped bare concrete member, particularly provides reference and help for the design and construction of domestic bare concrete as the load-bearing member for the construction technology of the load-bearing member, and achieves the construction of the special-shaped bare concrete member in a more detailed and simpler mode.

Description

Method for manufacturing large-section special-shaped load-bearing concrete bare concrete member

Technical Field

The invention relates to a method for manufacturing a concrete member, in particular to a method for manufacturing a large-section special-shaped load-bearing concrete bare concrete member.

Background

The fair-faced concrete is concrete which directly utilizes natural texture after the concrete forming effect as a decorative surface effect, is a representative of advanced technology in modern construction technology, and is more the embodiment of mature construction management. With the increasing design requirements of designers on building shapes, the role born by the fair-faced concrete is gradually developed from decoration to bearable stress, the main forms of a plurality of domestic fair-faced concrete structure bearing stress members are concentrated on a column or a square column, the manufacturing method of the special-shaped fair-faced concrete bearing stress member is greatly different from the manufacturing method of a conventional structure, and a standard, complete, detailed and operable large-section special-shaped bearing concrete fair-faced concrete member manufacturing method is needed in the industry.

Disclosure of Invention

The invention aims to provide a safe and reliable manufacturing method of a large-section special-shaped load-bearing concrete bare concrete member.

In order to achieve the purpose, the technical solution of the invention is as follows:

a method for manufacturing a large-section special-shaped load-bearing concrete bare concrete member is characterized by comprising the following steps:

a. formwork construction

Selecting a special clear water template for the clear water concrete template, selecting a covering template for a smooth surface clear water surface template of the clear water template, wherein the covering template comprises a wood grain clear water surface template and a wood grain surface lining plate; the clear water template is coated with films without connecting stubbles, the surface is smooth and flat, the rigidity is moderate, and the water absorption rate is low; trimming the periphery of the template by using special equipment, ensuring tight and flat seams without wrong platforms and preventing slurry leakage at the seams of the template; the template is compact in material, does not absorb water to expand and is not warped by temperature change;

b. formwork support system

The vertical section secondary keel of the template support is selected from a U-shaped beam, the main keel is selected from a square column buckle, the special-shaped surface secondary keel is selected from a U-shaped beam and a wood back ridge, the main keel is selected from special electroplating C-shaped steel, a special clamp is used, and a high-strength counter-pull screw rod is used for reinforcing the template;

c. the template processing comprises the following steps:

1) splicing the templates: processing a drawing on a CAD deepened template, determining the size, numbering and cutting, wherein a precise sliding table saw is adopted for blanking four straight surfaces of the template, a full-automatic numerical control plate cutting machine is adopted for a special-shaped template, and the template is assembled in advance in a woodworking processing field after blanking;

2) selecting materials: selecting each template, and checking the sizes of the surface layer, the frame and the templates one by one;

3) blanking: processing the panels with uniform specifications according to the deepened processing drawing by using a precision sliding table saw for the flat template, drawing the processing drawing by using a CAD (computer aided design) for the special-shaped template, then guiding the special-shaped template into a full-automatic numerical control plate cutting machine for processing, and numbering each template after blanking of the template is finished;

d. processing wood back arris

The keel of the arc part needs to be processed into a wood back edge according to modeling, the shape of the wood back edge is drawn on CAD, then the keel is guided into a numerical control plate cutting machine for processing by a 2440 x 1220 x 18mm template, and 3 back edges with the thickness of 18mm are spliced into a back edge with the thickness of 54mm after the processing is finished; the arc-shaped part of the outer arc curved surface of the arc-shaped wooden shaping back edge is not provided with arc line shapes, and is changed into a flat trapezoidal opening which is vertical to the inner arc surface of the back edge and the ground, so that enough contact surface is ensured for the reinforcement stress of the double-C-shaped steel section of the transverse main keel, and the integral horizontal reinforcement section steel of the whole sheet wall integrally surrounds the wall body;

e. formwork inner member installation

Installing the open seam strip and the arc external corner strip: the joint of the smooth clear water and the wood grain clear water is provided with a concave seam, the joint of the panel of the smooth clear water and the wood grain board needs to be arranged in the middle of the open seam strip, and the open seam strip is nailed on the joint of the panel of the smooth clear water and the wood grain board by a nail gun; the external corners are all arc external corners, and the customized arc external corner strips are arranged on the side faces of the templates; and (3) storing the template: after the template is processed, the template is numbered according to the sheet columns and is orderly stacked according to the specification;

f. template installation reinforcement

Before the template is installed, a plate buckle scaffold needs to be erected, the distance between the plate buckle scaffold and the edge of the sheet column needs to be reduced, the thickness of a horizontal and vertical reinforcing system of the panel needs to be increased, paying-off is carried out according to construction drawings to determine the structural sideline of the sheet column, a template positioning pile is formed underground by reinforcing steel bars according to the structural sideline, and then the processed template is installed according to a template layout; installing a secondary joist of the inverted V-shaped beam after the template is installed, fixing the beam on the template by using self-tapping screws, and reinforcing the main joist after the vertical section of the sheet column is installed; after the arched surface is provided with the U-shaped beam, double C-shaped steel is arranged to serve as a main keel, and a layer of steel pipe is added to form a three-layer reinforcing system; processing a wood back ridge at the arc surface radian to serve as a secondary keel, then using channel steel as a main keel, and finally reinforcing by using a high-strength screw;

g. positioning and supporting of arc beam bottom

Marking the distance and the height from the lower opening and the upper opening of each back edge to the axis on a drawing, and putting the line on the ground according to the size marked on the drawing to position the arc-shaped beam bottom; the arc-shaped beam bottom support is positioned by using a frame of a high formwork and a channel steel of 14#, an arc-shaped back edge and an arc-shaped beam bottom plate are installed, and finally the channel steel is obliquely supported by using a steel pipe jackscrew;

h. positioning measurement, comprising the following steps:

1) checking according to a reference coordinate point provided by an owner, after the checking is correct, carrying out the measurement and the setting of a main construction axis according to a construction drawing and a control point, and after the main construction axis control network meets the requirement through the accuracy index of the checking, encrypting the main construction axis control network according to the division of a construction flowing water section in the construction organization design so as to meet the construction requirement;

2) the sheet wall column is positioned by adopting a three-point positioning method, namely a total station is adopted to project a central point of the column and each point on two sides of the central point, and then the position is determined according to the positioning size of the sheet wall column;

i. the steel bar engineering comprises the following steps:

1) binding the reinforcing mesh, wherein two rows of reinforcing steel bar cross points around the unidirectional stressed reinforcing steel bar are firmly tied at each point, the cross points at the middle part can be firmly tied in a staggered way, and all the reinforcing steel bars need to be firmly tied at the cross points of the reinforcing mesh of the bidirectional main bar;

2) the bottom plate steel bars adopt double-layer steel bar meshes;

3) when the positions of all the building curved surfaces and the protective layers are larger than 50mm, reinforcing mesh sheets are additionally arranged;

4) when the section of the wall column changes, the bending part of the steel bar of the wall column must be within the height of the beam column wall node;

5) the stressed steel bars of the components are connected in a way that the steel bars d in the reinforced concrete column are larger than or equal to 22mm and are connected by adopting a straight thread sleeve, the steel bars d in the reinforced concrete slab component are larger than or equal to 18mm and are connected by adopting a straight thread sleeve, and the joints of the stressed steel bars are arranged at the positions with smaller stress;

6) mounting a stiff column in the sheet wall, drawing a BIM model of a section wall inserted section steel column according to a construction drawing and a rhinoceros model, and optimizing section steel processing according to the stiff column drawing;

7) when the length of the horizontal section of the beam main steel bar extending into the wall column is less than the anchoring length, the beam main steel bar is bent to meet the anchoring length; at the joint of the main beam and the secondary beam, when the length of the horizontal section of the secondary beam main rib extending into the main beam is less than 0.4La, the secondary beam main rib is bent downwards and upwards respectively; if the support satisfies roof beam owner reinforcing bar anchor length, then roof beam bottom reinforcing bar should stretch through the axis for at least 5 d. When two rows of main beam steel bars are arranged, a cushion block (which can be a short steel bar with the thickness of phi 25) with the thickness not less than 25mm is arranged between the two rows of steel bars; three binding points are needed to be arranged on the overlapped binding joints, and any joint needs to be arranged in a staggered mode; binding the cross points of the stirrups and the main reinforcements at each point, and folding the end parts of the binding wires into the framework;

8) the thickness of the bare concrete reinforcement protective layer is not less than the nominal diameter of the reinforcement;

9) the vertical component adopts a plastic gasket to replace the traditional concrete cushion block, and the plate bottom and the beam bottom adopt high-strength concrete cushion blocks;

j. the method comprises the following steps:

1) slump/spread requirements: the concrete pouring is performed in a mode of mainly using an automobile pump and secondarily using a tower crane, and in order to ensure that the pumping can be smoothly performed, the slump is required to be controlled when the concrete is pumped into the pump;

2) workability requirements: the concrete is required to have enough cohesiveness, and does not bleed and separate in the pumping process;

3) and (3) as-cast finish concrete entering inspection: the method comprises the following steps that a commercial concrete mixing station worker assigns workers to a field concrete worker to check vehicles one by one, the checked contents comprise visual concrete appearance color and whether bleeding segregation exists or not, a sampler carries out sampling experiments on slump of each vehicle, whether technical requirements specified by commercial concrete tickets are met or not is judged, and records are made;

4) pouring clear water concrete: before pouring, the interior of the template is kept clean and free of accumulated water, and a blower is used for cleaning dust; when the vertical component is poured, the interval time of layered pouring is strictly controlled, the layered thickness is not more than 500mm, loose stones or floating slurry layers at construction joints are removed before the clear water concrete is poured subsequently, and the loose stones or floating slurry layers are cleaned after the loose stones or floating slurry layers are removed; when concrete is poured, the concrete is prevented from being separated in layers, the height of the concrete when the concrete is unloaded from the distributing pipe orifice is not more than 2 meters, when the height of the concrete exceeds 2 meters, a string cylinder or an inclined eave is adopted to fall, when the concrete is poured, the concrete cannot directly impact the template, and the damage to the surface layer of the fair-faced template is avoided; pouring the beam and the plate simultaneously, and pushing forwards from one end; the thickness of the concrete bottom of the floor slab should be slightly larger than the slab thickness, after vibrating, a long-bottom wooden trowel is used for trowelling, then a plastic film is paved, and a protective layer is paved on the plastic film in time; the method comprises the following steps that a material distribution point of the clear water concrete pouring is close to a pouring position, measures for reducing concrete blanking impact are adopted, a vertical structural member is poured firstly, and then a horizontal structural member is poured;

5) the vibration requirement is as follows: the bare concrete is vibrated compactly and uniformly, and leakage vibration, over vibration and under vibration are strictly prohibited;

6) post-cast strip and construction joint operation: the post-cast strip is a contracted post-cast strip, the concrete mold-entering temperature of the post-cast strip is 5 +/-DEG, and the post-cast strip is required to penetrate through the foundation, each layer of wall body and the beam slab; the position of the construction joint is preferably reserved at a position where the structure shearing force is small and the construction is convenient;

7) curing the bare concrete: strictly controlling the form removal time of the concrete, wherein the form removal time can ensure that the wall does not drop corners or peel after the form removal, and the test block experiment under the same conditions is required to be taken as a standard; the method comprises the following steps that as for the formwork stripping of the bare concrete, on the basis that the strength of a test block under the same condition reaches 3MPa, the concrete is fully sprayed with water for maintenance before the formwork stripping, so that water permeates into the concrete through gaps between the concrete and a formwork; after the form is removed, spraying water on the surface of the concrete, and then wrapping the concrete by using a plastic film;

8) repairing concrete surface defects and plugging bolt holes: removing surface laitance and loose sand immediately after removing the mould, preparing cement paste by adopting cement with the same variety and the same strength grade, repairing and embedding the defect part, after the cement paste is hardened, uniformly polishing the whole component surface by using fine abrasive paper, and washing the component surface by using water to ensure that the surface has no color difference;

9) construction in winter

According to the stipulations of JGJ/T104-2011 of construction engineering winter construction regulations: according to local multi-year meteorological data statistics, when the average outdoor daily temperature is continuously 5d and is stably lower than 5 ℃, winter construction is carried out; when the average outdoor daily temperature is continuously higher than 5d and is higher than 5 ℃, the winter construction is removed;

k. curing of bare concrete

In order to prevent the micro-cracks of the wall body of the fair-faced concrete, after the wall body template is removed, wet curing is required to be immediately carried out, a polymer curing film is adopted, the inner layer is a polymer capable of adsorbing 200 times of the self weight of the wall body, the outer layer takes a plastic film as a carrier, the material absorbs water and expands to become transparent crystals, liquid water is changed into solid water, then the solid water continuously permeates to a curing surface through the capillary action, and simultaneously, water vapor generated by the self hydration heat reaction of the concrete is absorbed and retained, so that the concrete is always in a moisture-preserving curing state for a long time; bare concrete protective agent: according to the confirmation of the former stage and a designer, a 1:1 proportion sample plate is manufactured on site and is used as one of the acceptance standards of the construction of the cast-in-place fair-faced concrete protective agent after being accepted by architects, owners and supervision parties; the fair-faced concrete repairing principle is as follows: the repairing can be carried out as far as possible without repairing, the minimum range repairing is realized, the putty is repaired as little as possible, and the polishing is carried out properly; after the mould is removed, the clear concrete is directly coated with a protective agent except for repairing the defects;

protecting a finished product, comprising the following steps:

1) when the fair-faced concrete is poured, the finished product fair-faced concrete is not polluted or damaged, and after the formwork is removed, the external corner part which is easy to collide is protected by adopting a multilayer board and a plastic hard material;

2) before final setting, the concrete is not required to be piled with any material on the surface, and people can get on the concrete after the concrete reaches 1.2 Mpa; the concrete stair is cast in situ, the concrete is temporarily sealed after being formed, and an external hanging frame can be installed behind the concrete strength of the external wall which is up to 7.5 MPa;

3) when pumping concrete, the concrete polluted on the wall surface, the cylindrical surface and the floor surface is cleaned in time before being coagulated and cleaned by a mop;

4) the finished product of the fair-faced concrete surface is strictly forbidden to be randomly chiseled, and the ground is covered by color strip cloth when walls, columns, beams and slab bottoms are constructed during concrete coating construction, so that the trimmed ground is prevented from being polluted by the beams; the guardrails are erected by the scaffold tubes for coating the columns, the wall openings and the external corners to prevent damage.

The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member can be further realized by adopting the following technical measures.

The method, wherein the thickness of the cover plate is 2440 × 1220 × 17 mm.

In the above method, the thickness of the wood grain clean water surface template is more than or equal to 4000 × 120 × 12 mm.

The method, wherein the wood grain surface lining plate has a thickness of 2440 × 1220 × 12 mm.

The method, wherein the concrete slump is controlled within 200 +/-20 mm when the automobile pump is pumped.

In the aforementioned method, the fair-faced concrete protective agent is an organic silicon resin fair-faced concrete protective agent.

By adopting the technical scheme, the method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member has the following advantages:

1. the construction steps are scientific and reasonable in design and strong in operability;

2. the construction quality is safe and reliable, the problem of the manufacturing method of the large-section special-shaped fair-faced concrete member is solved, and particularly for the construction technology of the bearing member, reference and help are provided for the design and construction of domestic fair-faced concrete as the bearing member;

3. the construction of the special-shaped bare concrete member is achieved in a more detailed and simpler mode.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

The invention discloses a process flow for manufacturing and constructing a large-section special-shaped load-bearing concrete bare concrete member, which comprises the following steps: positioning measurement → template processing → field measurement and line laying → working surface leveling (chiseling) → erecting support and shaping frame → arc beam bottom surface secondary keel and liner plate panel installation → reinforcement → template installation → sheet wall reinforcement → inspection template correction → debris cleaning → concrete pouring → template dismantling → protective agent construction → finished product protection.

The invention discloses a method for manufacturing a large-section special-shaped load-bearing concrete bare concrete member, which comprises the following steps:

step 1: formwork construction

The bare concrete formwork is usually selected from high-grade special-purpose bare concrete formwork, the smooth bare concrete formwork is selected from 2440 × 1220 × 17mm thick covering formwork, the wood grain clean surface is selected from 4000 × 120 × 12, and the wood grain surface lining plate is selected from 2440 × 1220 × 12mm high-quality bare concrete lining plate. The template film has no joint, smooth and flat surface, moderate rigidity and low water absorption. The used template is clean and tidy so as to ensure the flatness and smoothness of the poured concrete surface; trimming the periphery of the template by using special equipment, ensuring tight and flat seams without wrong platforms and preventing slurry leakage at the seams of the template; the used template is compact in material, does not absorb water to expand and is not warped by temperature change;

step 2: formwork support system

The vertical section secondary keel selects a beam in a shape like a Chinese character 'ji', and the main keel selects a square column buckle. The special-shaped surface secondary keel is a n-shaped beam and a wood back ridge with the width of 54mm, the main keel is a special electroplating C-shaped steel, a special fixture is used, and a high-strength counter-pulling screw rod with the diameter of 16mm is used for reinforcing the template.

And step 3: template processing

The method comprises the steps of deepening a template processing drawing in CAD (computer aided design), determining the size, numbering and cutting, ensuring the maximum utilization rate of the template, adopting a precise sliding table saw for the four straight surfaces of the blanking of the template, using a full-automatic numerical control plate cutting machine for the special-shaped template, so as to ensure the accurate size and the smooth cut of the template, assembling the template in advance in a woodworking processing field after the blanking of the template is finished, and judging whether the template can be assembled or not so as to avoid the condition that the template cannot be assembled during field installation.

Selecting materials: because the clear water covers the template and probably has the defect, therefore must select each template before the unloading, from the size of surface course, frame and template all must inspect one by one.

Blanking: the flat template is processed by a precision sliding table saw according to a deepened processing drawing on a panel with uniform specification, the special-shaped template is processed by guiding a CAD drawing into a full-automatic numerical control plate cutting machine after the processing drawing is drawn by the CAD, and each template is numbered after the blanking of the template, so that the template can be conveniently used.

And 4, step 4: processing wood back arris

The keels of the arc-shaped part cannot be reinforced by the n-shaped beams, the wooden back edges need to be processed according to modeling, the shape of the wooden back edges needs to be drawn on CAD, then the wooden back edges are guided into a 2440 x 1220 x 18mm template for processing, and 3 back edges with the thickness of 18mm are spliced into a back edge with the thickness of 54mm after processing.

The arc line molding is cancelled to the wooden design back of the body stupefied outer arc curved surface of arc beginning at the great position of arc, changes into the level and smooth trapezoidal mouth of the stupefied inner arc face of perpendicular to back of the body and ground, guarantees that the two C shaped steel section bars of horizontal main joist consolidate the atress and have sufficient contact surface, and the whole level of wall reinforcement shaped steel encircles the wall body.

And 5: formwork inner member installation

Installing the open seam strip and the arc external corner strip: the method is characterized in that the smooth surface clean water with the thickness of 100mm is arranged on two sides of a column according to the deepening design, a concave joint with the thickness of 25mm x 15mm x 10mm is arranged at the joint of the smooth surface clean water and the wood grain clean water, the joint of a panel of the smooth surface clean water and a wood grain plate needs to be arranged in the middle of a bright seam strip during processing, and the bright seam strip is nailed on the joint of the panel of the smooth surface clean water and the wood grain plate by a nail gun, so that the joint of the smooth surface panel and the wood grain plate is. The external corners are all arc external corners, and the customized arc external corner strips are arranged on the side faces of the templates.

And (3) storage: after the template processing is finished, numbering is carried out according to the sheet columns, the sheet columns are stacked orderly in different specifications, the bottom of the template is overhead waterproof and moistureproof, and the top of the template is covered with color strip cloth to prevent rain and pollution.

Step 6: and (3) installing and reinforcing the template:

before the template is installed, a plate buckle scaffold needs to be erected, and the distance between the plate buckle scaffold and the edge of the sheet column needs to be reduced by the thickness of the horizontal and vertical reinforcing systems of the panel. The dimensional accuracy of the wall structure is ensured. The spacing between the bottom of the set-up plate buckle beams is 300mm 1500mm, the end parts of the columns are 600mm 900mm 1500mm, and the connecting racks between the sheet columns are 900mm 1500 mm.

And transporting the template processed by the processing field to a construction position. And paying off according to a construction drawing to determine a structure side line of the sheet column, and driving a template positioning pile with a steel bar underground according to the structure side line. And then installing the processed templates according to the template layout, wherein the edges of the joints of the templates are sealed by using double-sided adhesive tapes with the thickness of 1.5mm, and the double-sided adhesive tapes are used for controlling and adjusting the elevation of the templates, preventing slurry leakage and connecting the templates by using connecting sheets. After the template is installed, the secondary joist of the beam in the shape of Chinese character 'ji' is installed, the E-shaped beam is fixed on the template by self-tapping screws, and the vertical section of the sheet column is reinforced by using square and round buckles as the main joist after the beam in the shape of Chinese character 'ji' is installed.

The arc-shaped surface is formed by installing 100mm wide double-C-shaped steel serving as a main keel after the beam is installed, and then adding a layer of steel pipe to form a three-layer reinforcing system. And the arc-shaped surface is processed into a wood back ridge according to the arc-shaped radian to be used as a secondary keel, then a 14# channel steel is used as a main keel, and finally a phi 16 high-strength screw is used for reinforcement. The arc-shaped surface is required to be obliquely propped against the double-C-shaped steel main keel by using a steel pipe.

The end cap needs to be installed in the position of the bolt hole before the template is installed, the end cap needs to be screwed down to avoid wet water and slurry leakage, then the sleeve pipe is installed, the double-sided adhesive tape with the thickness of 1.5mm is tightly attached between the templates, the double-sided adhesive tape is 1mm away from the inner side of the template and is vertically connected by adopting a connecting sheet, a connecting sheet is additionally arranged at the crossing position of the vertical joint and the transverse joint independently to be connected, and the distance between the connecting sheets is not more than 300 mm. The main keel is installed by using 100# double C-shaped steel, and is vertically reinforced by using phi 48mm x 3mm thick steel pipes, so that a three-layer reinforcing system is formed, the integrity of the main keel is better, the main keel is not easy to deform, and the tension bolts are locked by using 16 mm-diameter high-strength national standard bolts, mountain-shaped clamps and gaskets through double nuts. And after finishing, checking whether the verticality flatness and reinforcement are qualified.

And 7: positioning and supporting the arc beam bottom:

the distance and the height of the lower opening and the upper opening of each back ridge from the axis are marked on a drawing, and the line is placed on the ground according to the size marked on the drawing on site, so that the position of the arc-shaped beam bottom is positioned.

The arc-shaped beam bottom support is positioned by a frame of a high formwork through a jackscrew and a 14# channel steel, then an arc-shaped back edge and an arc-shaped beam bottom plate are installed, and finally the channel steel is obliquely jacked through a steel pipe jackscrew.

And 8: positioning measurement

1) And checking according to a reference coordinate point provided by an owner, measuring and setting a main construction axis according to a construction drawing and a control point after the check is correct, and encrypting the main axis control network according to the division of a construction flowing water section in the construction organization design after the main axis control network of the building meets the requirement through the checking precision index so as to meet the construction requirement.

2) The sheet wall column is positioned by adopting a three-point positioning method, namely, a total station is adopted to project a central point of the column and each point (along the radial axis direction) on two sides of the central point, and then the position is determined according to the positioning size of the sheet wall column.

And step 9: steel bar engineering

1) And (3) binding the reinforcing mesh, wherein two rows of reinforcing steel bar cross points around the unidirectional stressed reinforcing steel bar are firmly bound at each point, the cross points at the middle part can be firmly bound in a staggered way, and all the reinforcing steel bars need to be firmly bound at the cross points of the reinforcing mesh of the bidirectional main reinforcing steel bar.

2) The bottom plate reinforcing steel bars adopt double-layer reinforcing steel bar meshes, and reinforcing steel bar split heads, reinforcing steel bar supports or angle steel supports are arranged between the upper reinforcing steel bar mesh and the lower reinforcing steel bar mesh so as to ensure that the reinforcing steel bars are correctly positioned. The hook of lower floor's reinforcing bar is up, and upper reinforcing bar hook is down.

3) When the positions of all building curved surfaces and protective layers are larger than 50mm, reinforcing mesh sheets (three-level steel 6@ 200) are additionally arranged.

4) When the section of the wall column changes, the bending part of the steel bar of the wall column must be within the height of the beam column wall node.

5) The connection mode of the stressed steel bars of each component in the project is shown in the following table 1 (the mode of beating the square root is adopted), the joints of the stressed steel bars are arranged at the positions with smaller stress and are not suitable to be arranged in the hoop reinforcement encryption area range of the node beam end and the column end.

TABLE 1 stress steel bar connection mode

Note: the axle center or small eccentric tension members such as suspension posts, frame struts, arch pull rods and the like can not be bound and overlapped. The connection and the structure of the non-stressed steel bars of each component are shown in the drawing.

6) And (3) mounting a stiff column in the sheet wall, drawing a BIM (building information modeling) model of the inserted section steel column in the sheet wall according to a construction drawing and a rhinoceros model, and optimizing section steel processing according to the stiff column drawing.

7) When the length of the horizontal section of the beam main steel bar extending into the wall column is less than the anchoring length, the beam main steel bar is bent to meet the anchoring length; at the joint of the main beam and the secondary beam, when the length of the horizontal section of the secondary beam main rib extending into the main beam is less than 0.4La, the secondary beam main rib is bent downwards and upwards respectively; if the support satisfies roof beam owner reinforcing bar anchor length, then roof beam bottom reinforcing bar should stretch through the axis for at least 5 d. When two rows of main beam steel bars are arranged, a cushion block (which can be a short steel bar with the thickness of phi 25) with the thickness not less than 25mm is arranged between the two rows of steel bars; three binding points are needed to be arranged on the overlapped binding joints, and any joint needs to be arranged in a staggered mode; the cross points of the stirrups and the main reinforcements must be bound at each point, and the ends of the binding wires must be folded into the framework.

8) The thickness of the bare concrete reinforcement protective layer is shown in table 2.

TABLE 2 protective layer thickness of reinforcing bar

Note: when the concrete protection layer of the longitudinal stress steel bar is larger than 50mm, in order to prevent the concrete from cracking, an additional steel bar mesh 4@200 x 200 is arranged in the protection layer, the thickness of the additional steel bar mesh protection layer is 15mm, and the anchoring length of the end part is 250 mm.

9) The vertical component of this engineering adopts the plastics packing ring to replace traditional concrete cushion, and the board is low and the beam bottom etc. adopts high strength concrete cushion.

Step 10: pouring of fair-faced concrete

1) Slump/spread requirements. The concrete pouring is performed by taking an automobile pump as a main mode and a tower crane as an auxiliary mode, and in order to ensure that the pumping can be smoothly performed, the slump is strictly controlled within 200 +/-20 mm and 500 +/-50 when the concrete is pumped. The concrete mixing plant can timely and properly finely adjust the original matching ratio (water-cement ratio) according to the conditions of air temperature conditions, transportation time (day or night), distance of transportation roads, change of water content of gravels, loss of concrete slump and the like so as to ensure that the slump during concrete pouring can meet the requirements of construction production, the concrete does not bleed or separate, the color and luster are kept consistent, and the supply quality of the concrete is ensured.

2) And the workability is required. In order to ensure that the concrete is not isolated in the pouring process, the concrete is required to have enough cohesiveness, and the concrete is not weeping and isolated in the pumping process. The JGJ/T10-2011 stipulates that the relative pressure bleeding rate when concrete is pumped for 10s is not more than 40%, so that the bleeding speed of the concrete supplied by a mixing plant is required to be low, and the stability and the pumpability of the concrete are ensured. When the climate changes, the concrete mixing plant is required to provide slump loss values at different temperatures and in unit time so as to be convenient for the site to master the standing time of the concrete tank truck on the site, and when the concrete is poured, the mixing plant needs to dispatch a dispatching site to allocate vehicles so as to adjust the frequency of the concrete tank truck at any time according to the concrete pouring condition.

3) And (5) inspecting the bare concrete in the field. The method is characterized in that a concrete delivery inspection system is strictly executed, a commercial concrete mixing plant worker assigns workers to a field concrete worker to check vehicles one by one, the checking contents comprise visual inspection of the appearance color and luster of the concrete and whether bleeding segregation exists, a sampler performs sampling experiments on the slump of each vehicle, whether the slump meets the technical requirements specified by commercial concrete tickets or not is judged, and the technical requirements are recorded. If the concrete does not meet the mold-entering requirement, the concrete must be returned to the mixing plant and is forbidden to use.

4) And pouring clear water concrete.

Before pouring the fair-faced concrete, keeping the interior of the template clean and free of accumulated water, and cleaning dust by adopting an air blower; when the vertical component is poured, the interval time of layered pouring is strictly controlled, the layered thickness is not more than 500mm, loose stones or floating slurry layers at construction joints are removed before the clear water concrete is poured subsequently, and the loose stones or floating slurry layers are cleaned after the loose stones or floating slurry layers are removed; when concrete is poured, the concrete is prevented from being separated in layers, the height of the concrete when the concrete is unloaded from the distributing pipe opening cannot exceed 2 meters, a string cylinder or an inclined eave falls off when the height of the concrete exceeds 2 meters, the concrete cannot directly impact the formwork when being poured, and damage to the surface layer of the bare formwork is avoided. The door and window opening is suitable for pouring the fair-faced concrete from two sides simultaneously.

The beams and slabs are typically poured simultaneously, advancing from one end. Only when the height of the beam is more than 1m, the beam is allowed to be poured independently, the construction joint is required to be left 20-30 mm below the floor surface, tamping needs to be carried out on the bottom and the side faces of the beam, and the vibrator does not directly contact with a steel bar or an embedded part. The thickness of the concrete bottom of the floor slab should be slightly larger than the slab thickness, the concrete bottom is trowelled by long-bottom wood after being vibrated, then a plastic film is paved, and a protective layer is paved on the plastic film in time.

The distribution point of the cast fair-faced concrete is close to the casting position, measures for reducing the impact of concrete blanking are adopted, and the following regulations are met: preferably, the vertical structural member is cast first, and then the horizontal structural member is cast; when the structural plane of the casting area has height difference, the low area part is preferably cast first, and the high area part is cast; when the main reinforcements of the concrete with different grades are bound at the node of the beam column, the distance between the concrete with different grades and the column edge is more than or equal to 500mm and more than or equal to 1/2 beam height, the concrete with different grades and different grade is separated from the top of the beam to the bottom surface of the beam along a 45-degree inclined plane by a 2mm mesh dense steel wire mesh (as a grade boundary of high-grade and low-grade concrete), and the clear water concrete is extended and poured to the common concrete for more than 500mm at the node of the clear water concrete and the common concrete.

5) And (5) vibrating. The bare concrete is vibrated compactly and uniformly, and leakage vibration, over vibration and under vibration are strictly prohibited; using either a 30-stick or a 50-stick insertion tamper requires: the quick insertion and the slow drawing are performed, insertion points are arranged in a plum blossom shape and are sequentially performed, omission is avoided, and the distance between the vibrating rod and the template is not more than 50% of the action radius of the vibrating rod; the moving distance is not more than 1.4 times of the action radius of the vibrating rod, and the depth of the vibrating rod inserted into the surface of the lower layer concrete is more than 50 mm. Before the subsequent pouring of the clear water concrete, loose stones or floating slurry layers at construction joints are removed, and the loose stones or floating slurry layers are cleaned after the removal. The post-cast strip and the construction joint corners need to be encrypted with vibrating points and are suitable for prolonging the vibrating time. And after the concrete pouring is finished, determining the secondary vibration plastering time according to the state of the concrete after the concrete is poured into the mold.

6) Post-cast strip and construction joint. The engineering post-cast strip is a shrinkage post-cast strip, the concrete can be folded at the rear of the layer of concrete casting 60, the concrete mold-entering temperature of the post-cast strip is required to be 5 +/-DEG, the post-cast strip penetrates through the foundation, each layer of wall body and the beam plate, and the non-shrinkage concrete sealing with the strength improved by one step (when the concrete strength grades of the two side members are different, the concrete strength grade is improved by one step higher than that of the two side members) is adopted. The post-cast strip inner beam steel bars are not broken, and the wall plate steel bars are all broken and are overlapped by 100 percent (the overlapping length is 1.6 times of the anchoring length); the position of the construction joint is preferably reserved at a position where the structure shearing force is small and the construction is convenient; horizontal seams should be reserved for the columns, and vertical seams should be reserved for the beams, the plates and the walls; the pillars should be left on the top surface of the foundation, and the high beams should be left 20-30 mm below the bottom surface of the slab; the slab floor should be left in any position parallel to the short sides of the slab; the stairway should remain within the middle 1/3 of the length of the stairway.

7) And (5) maintaining the bare concrete. The method is characterized in that the form removal time of the concrete is strictly controlled, the form removal time can ensure that the wall body does not drop corners and peel after the form removal, the test block experiment under the same conditions is used as a standard, and the concrete form removal of the dry concrete part of the project is based on the fact that the strength of the test block under the same conditions reaches 3 MPa. Before the form is removed, the concrete is fully watered for maintenance, so that water permeates into the concrete through the gap between the concrete and the form; after the form is removed, spraying water on the surface of the concrete, wrapping the concrete by using a plastic film, and tightly compacting the corner joint parts, wherein the curing time is not less than 14 days. The fair-faced concrete should be cured immediately after the form removal, and the same curing measures should be adopted for the fair-faced concrete in the same visual range.

8) Repairing the concrete surface defects and plugging bolt holes. Although various measures are taken, the defects of small bubbles, holes, sand belts and the like can be generated on the local surface of the demolded concrete due to the bleeding property of the concrete, the slurry leakage of a template and the high air content of the concrete. After the mould is removed, the surface laitance and loose sand are immediately removed, cement paste made of the same kind of cement with the same strength grade is used for repairing and embedding the defect part, after the cement paste is hardened, the whole component surface is evenly polished by fine sand paper and washed clean by water, and the surface is ensured to have no color difference. The plugging requirement of the bolt hole is the same as the defect repairing, but the plugging is finished before the frame body is dismantled.

9) Construction in winter

The regulation of construction engineering winter construction regulation JGJ/T104-2011: according to local multi-year meteorological data statistics, when the average outdoor daily temperature is continuously 5d and is stably lower than 5 ℃, winter construction is carried out; and when the average daily temperature of the outdoor is continuously 5 days higher than 5 ℃, the winter construction is removed.

Step 11: curing of bare concrete

In order to prevent the micro-cracks of the wall body of the fair-faced concrete, after the wall body formwork is completely dismantled, wet curing is required immediately, the project adopts a polymer curing film, the inner layer is a polymer capable of adsorbing 200 times of self weight, the outer layer takes a plastic film as a carrier, the material is changed into transparent crystals after water absorption and expansion, liquid water is changed into solid water, then the solid water continuously permeates into a curing surface through capillary action, and simultaneously, water vapor generated by the self hydration heat reaction of the concrete is absorbed and retained, so that the concrete is always in a moisturizing curing state for a long time. And the risk of cracking of concrete is reduced. Fair-faced concrete protective agent

According to the confirmation of the former stage and a designer, a 1:1 proportion sample plate is made on site and is used as one of the acceptance standards for the construction of the cast-in-place fair-faced concrete protective agent after being accepted by architects, owners, supervisors and the like. Repairing principle: the method can repair the materials as far as possible without repairing, can repair the materials in a minimum range, can repair putty as little as possible, and can polish the materials properly.

1) The engineering is designed to adopt the organic silicon resin fair-faced concrete protective agent for construction, the chromatic aberration cannot be generated in the same visual range, and the construction process is consistent. (the organic silicon resin has good air permeability and freeze-thaw resistance and is not easy to bulge and peel.)

2) After the form is removed, except for defect repair, the clear concrete is directly coated with a protective agent, if the problems of serious chromatic aberration and the like caused by the segregation defect of the large-area construction concrete occur, the whole large-area color matching work is required, and the serious chromatic aberration is reduced.

Step 12: finished product protection

1) When the fair-faced concrete is poured, the finished product fair-faced concrete is not polluted or damaged, and after the formwork is removed, the external corner part which is easy to collide is protected by adopting hard materials such as multilayer plates, plastics and the like below 1.8 m.

2) Any material can not be stacked on the surface of the concrete before final setting, and the concrete can be loaded after reaching 1.2Mpa, so that constructors can be controlled to walk freely. The concrete stair is cast in situ, the concrete is temporarily sealed after being formed, and the outer hanging frame can be installed behind the outer wall concrete with the strength reaching 7.5 MPa. When hangers, scaffolding, baskets, etc. come into contact with the finished bare concrete surface, a liner should be used for protection.

3) When pumping concrete, the concrete polluted on the wall surface, the column surface and the floor surface is cleaned in time before being condensed and cleaned by a mop. Manually smearing a splayed slope with the height of 3cm on the periphery of the top of the column, storing water in the middle for maintenance, and simultaneously preventing the rust of the reinforcing steel bars from flowing to the side surface of the column along with water; immediately scrubbing and cleaning flowing mortar appearing in the coupling during pouring

4) The finished product of the fair-faced concrete surface is strictly forbidden to be randomly chiseled. When the concrete paint is used for construction, the ground is covered by the color strip cloth when walls, columns, beams and plate bottoms are constructed, so that the trimmed ground is prevented from being polluted by the beams. The guardrails are erected by scaffold tubes for coating columns, wall openings, external corners and the like to prevent damage.

The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member solves the problem of the manufacturing method of the large-section special-shaped bare concrete member, especially provides reference and help for the design and construction of domestic bare concrete as the load-bearing member for the construction technology of the load-bearing member, and achieves the construction of the special-shaped bare concrete member in a more detailed and simpler mode.

The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Accordingly, all equivalents are intended to fall within the scope of the invention, which is defined in the claims.

Claims (6)

1. A method for manufacturing a large-section special-shaped load-bearing concrete bare concrete member is characterized by comprising the following steps:

a. formwork construction

Selecting a special clear water template for the clear water concrete template, selecting a covering template for a smooth surface clear water surface template of the clear water template, wherein the covering template comprises a wood grain clear water surface template and a wood grain surface lining plate; the clear water template is coated with films without connecting stubbles, the surface is smooth and flat, the rigidity is moderate, and the water absorption rate is low; trimming the periphery of the template by using special equipment, ensuring tight and flat seams without wrong platforms and preventing slurry leakage at the seams of the template; the template is compact in material, does not absorb water to expand and is not warped by temperature change;

b. formwork support system

The vertical section secondary keel of the template support is selected from a U-shaped beam, the main keel is selected from a square column buckle, the special-shaped surface secondary keel is selected from a U-shaped beam and a wood back ridge, the main keel is selected from special electroplating C-shaped steel, a special clamp is used, and a high-strength counter-pull screw rod is used for reinforcing the template;

c. the template processing comprises the following steps:

1) splicing the templates: processing a drawing on a CAD deepened template, determining the size, numbering and cutting, wherein a precise sliding table saw is adopted for blanking four straight surfaces of the template, a full-automatic numerical control plate cutting machine is adopted for a special-shaped template, and the template is assembled in advance in a woodworking processing field after blanking;

2) selecting materials: selecting each template, and checking the sizes of the surface layer, the frame and the templates one by one;

3) blanking: processing the panels with uniform specifications according to the deepened processing drawing by using a precision sliding table saw for the flat template, drawing the processing drawing by using a CAD (computer aided design) for the special-shaped template, then guiding the special-shaped template into a full-automatic numerical control plate cutting machine for processing, and numbering each template after blanking of the template is finished;

d. processing wood back arris

The keel of the arc part needs to be processed into a wood back edge according to modeling, the shape of the wood back edge is drawn on CAD, then the keel is guided into a numerical control plate cutting machine for processing by a 2440 x 1220 x 18mm template, and 3 back edges with the thickness of 18mm are spliced into a back edge with the thickness of 54mm after the processing is finished; the arc-shaped part of the outer arc curved surface of the arc-shaped wooden shaping back edge is not provided with arc line shapes, and is changed into a flat trapezoidal opening which is vertical to the inner arc surface of the back edge and the ground, so that enough contact surface is ensured for the reinforcement stress of the double-C-shaped steel section of the transverse main keel, and the integral horizontal reinforcement section steel of the whole sheet wall integrally surrounds the wall body;

e. formwork inner member installation

Installing the open seam strip and the arc external corner strip: the joint of the smooth clear water and the wood grain clear water is provided with a concave seam, the joint of the panel of the smooth clear water and the wood grain board needs to be arranged in the middle of the open seam strip, and the open seam strip is nailed on the joint of the panel of the smooth clear water and the wood grain board by a nail gun; the external corners are all arc external corners, and the customized arc external corner strips are arranged on the side faces of the templates; and (3) storing the template: after the template is processed, the template is numbered according to the sheet columns and is orderly stacked according to the specification;

f. template installation reinforcement

Before the template is installed, a plate buckle scaffold needs to be erected, the distance between the plate buckle scaffold and the edge of the sheet column needs to be reduced, the thickness of a horizontal and vertical reinforcing system of the panel needs to be increased, paying-off is carried out according to construction drawings to determine the structural sideline of the sheet column, a template positioning pile is formed underground by reinforcing steel bars according to the structural sideline, and then the processed template is installed according to a template layout; installing a secondary joist of the inverted V-shaped beam after the template is installed, fixing the beam on the template by using self-tapping screws, and reinforcing the main joist after the vertical section of the sheet column is installed; after the arched surface is provided with the U-shaped beam, double C-shaped steel is arranged to serve as a main keel, and a layer of steel pipe is added to form a three-layer reinforcing system; processing a wood back ridge at the arc surface radian to serve as a secondary keel, then using channel steel as a main keel, and finally reinforcing by using a high-strength screw;

g. positioning and supporting of arc beam bottom

Marking the distance and the height from the lower opening and the upper opening of each back edge to the axis on a drawing, and putting the line on the ground according to the size marked on the drawing to position the arc-shaped beam bottom; the arc-shaped beam bottom support is positioned by using a frame of a high formwork and a channel steel of 14#, an arc-shaped back edge and an arc-shaped beam bottom plate are installed, and finally the channel steel is obliquely supported by using a steel pipe jackscrew;

h. positioning measurement, comprising the following steps:

1) checking according to a reference coordinate point provided by an owner, after the checking is correct, carrying out the measurement and the setting of a main construction axis according to a construction drawing and a control point, and after the main construction axis control network meets the requirement through the accuracy index of the checking, encrypting the main construction axis control network according to the division of a construction flowing water section in the construction organization design so as to meet the construction requirement;

2) the sheet wall column is positioned by adopting a three-point positioning method, namely a total station is adopted to project a central point of the column and each point on two sides of the central point, and then the position is determined according to the positioning size of the sheet wall column;

i. the steel bar engineering comprises the following steps:

1) binding the reinforcing mesh, wherein two rows of reinforcing steel bar cross points around the unidirectional stressed reinforcing steel bar are firmly tied at each point, the cross points at the middle part can be firmly tied in a staggered way, and all the reinforcing steel bars need to be firmly tied at the cross points of the reinforcing mesh of the bidirectional main bar;

2) the bottom plate steel bars adopt double-layer steel bar meshes;

3) when the positions of all the building curved surfaces and the protective layers are larger than 50mm, reinforcing mesh sheets are additionally arranged;

4) when the section of the wall column changes, the bending part of the steel bar of the wall column must be within the height of the beam column wall node;

5) the stressed steel bars of the components are connected in a way that the steel bars d in the reinforced concrete column are larger than or equal to 22mm and are connected by adopting a straight thread sleeve, the steel bars d in the reinforced concrete slab component are larger than or equal to 18mm and are connected by adopting a straight thread sleeve, and the joints of the stressed steel bars are arranged at the positions with smaller stress;

6) mounting a stiff column in the sheet wall, drawing a BIM model of a section wall inserted section steel column according to a construction drawing and a rhinoceros model, and optimizing section steel processing according to the stiff column drawing;

7) when the length of the horizontal section of the beam main steel bar extending into the wall column is less than the anchoring length, the beam main steel bar is bent to meet the anchoring length; at the joint of the main beam and the secondary beam, when the length of the horizontal section of the secondary beam main rib extending into the main beam is less than 0.4La, the secondary beam main rib is bent downwards and upwards respectively; if the support meets the anchoring length of the main beam steel bar, the steel bar at the bottom of the beam should extend through the axis for at least 5 d;

when two rows of main beam steel bars are arranged, a cushion block (which can be a short steel bar with the thickness of phi 25) with the thickness not less than 25mm is arranged between the two rows of steel bars; three binding points are needed to be arranged on the overlapped binding joints, and any joint needs to be arranged in a staggered mode; binding the cross points of the stirrups and the main reinforcements at each point, and folding the end parts of the binding wires into the framework;

8) the thickness of the bare concrete reinforcement protective layer is not less than the nominal diameter of the reinforcement;

the vertical component adopts a plastic gasket to replace the traditional concrete cushion block, and the plate bottom and the beam bottom adopt high-strength concrete cushion blocks;

j. the method comprises the following steps:

1) slump/spread requirements: the concrete pouring is performed in a mode of mainly using an automobile pump and secondarily using a tower crane, and in order to ensure that the pumping can be smoothly performed, the slump is required to be controlled when the concrete is pumped into the pump;

2) workability requirements: the concrete is required to have enough cohesiveness, and does not bleed and separate in the pumping process;

3) and (3) as-cast finish concrete entering inspection: the method comprises the following steps that a commercial concrete mixing station worker assigns workers to a field concrete worker to check vehicles one by one, the checked contents comprise visual concrete appearance color and whether bleeding segregation exists or not, a sampler carries out sampling experiments on slump of each vehicle, whether technical requirements specified by commercial concrete tickets are met or not is judged, and records are made;

4) pouring clear water concrete: before pouring, the interior of the template is kept clean and free of accumulated water, and a blower is used for cleaning dust; when the vertical component is poured, the interval time of layered pouring is strictly controlled, the layered thickness is not more than 500mm, loose stones or floating slurry layers at construction joints are removed before the clear water concrete is poured subsequently, and the loose stones or floating slurry layers are cleaned after the loose stones or floating slurry layers are removed; when concrete is poured, the concrete is prevented from being separated in layers, the height of the concrete when the concrete is unloaded from the distributing pipe orifice is not more than 2 meters, when the height of the concrete exceeds 2 meters, a string cylinder or an inclined eave is adopted to fall, when the concrete is poured, the concrete cannot directly impact the template, and the damage to the surface layer of the fair-faced template is avoided; pouring the beam and the plate simultaneously, and pushing forwards from one end; the thickness of the concrete bottom of the floor slab should be slightly larger than the slab thickness, after vibrating, a long-bottom wooden trowel is used for trowelling, then a plastic film is paved, and a protective layer is paved on the plastic film in time; the method comprises the following steps that a material distribution point of the clear water concrete pouring is close to a pouring position, measures for reducing concrete blanking impact are adopted, a vertical structural member is poured firstly, and then a horizontal structural member is poured;

5) the vibration requirement is as follows: the bare concrete is vibrated compactly and uniformly, and leakage vibration, over vibration and under vibration are strictly prohibited;

6) post-cast strip and construction joint operation: the post-cast strip is a contracted post-cast strip, the concrete mold-entering temperature of the post-cast strip is 5 +/-DEG, and the post-cast strip is required to penetrate through the foundation, each layer of wall body and the beam slab; the position of the construction joint is preferably reserved at a position where the structure shearing force is small and the construction is convenient;

7) curing the bare concrete: strictly controlling the form removal time of the concrete, wherein the form removal time can ensure that the wall does not drop corners or peel after the form removal, and the test block experiment under the same conditions is required to be taken as a standard; the method comprises the following steps that as for the formwork stripping of the bare concrete, on the basis that the strength of a test block under the same condition reaches 3MPa, the concrete is fully sprayed with water for maintenance before the formwork stripping, so that water permeates into the concrete through gaps between the concrete and a formwork; after the form is removed, spraying water on the surface of the concrete, and then wrapping the concrete by using a plastic film;

8) repairing concrete surface defects and plugging bolt holes: removing surface laitance and loose sand immediately after removing the mould, preparing cement paste by adopting cement with the same variety and the same strength grade, repairing and embedding the defect part, after the cement paste is hardened, uniformly polishing the whole component surface by using fine abrasive paper, and washing the component surface by using water to ensure that the surface has no color difference;

9) construction in winter

According to the stipulations of JGJ/T104-2011 of construction engineering winter construction regulations: according to local multi-year meteorological data statistics, when the average outdoor daily temperature is continuously 5d and is stably lower than 5 ℃, winter construction is carried out; when the average outdoor daily temperature is continuously higher than 5d and is higher than 5 ℃, the winter construction is removed;

k. curing of bare concrete

In order to prevent the micro-cracks of the wall body of the fair-faced concrete, after the wall body template is removed, wet curing is required to be immediately carried out, a polymer curing film is adopted, the inner layer is a polymer capable of adsorbing 200 times of the self weight of the wall body, the outer layer takes a plastic film as a carrier, the material absorbs water and expands to become transparent crystals, liquid water is changed into solid water, then the solid water continuously permeates to a curing surface through the capillary action, and simultaneously, water vapor generated by the self hydration heat reaction of the concrete is absorbed and retained, so that the concrete is always in a moisture-preserving curing state for a long time; bare concrete protective agent: according to the confirmation of the former stage and a designer, a 1:1 proportion sample plate is manufactured on site and is used as one of the acceptance standards of the construction of the cast-in-place fair-faced concrete protective agent after being accepted by architects, owners and supervision parties; the fair-faced concrete repairing principle is as follows: the repairing can be carried out as far as possible without repairing, the minimum range repairing is realized, the putty is repaired as little as possible, and the polishing is carried out properly; after the mould is removed, the clear concrete is directly coated with a protective agent except for repairing the defects;

protecting a finished product, comprising the following steps:

1) when the fair-faced concrete is poured, the finished product fair-faced concrete is not polluted or damaged, and after the formwork is removed, the external corner part which is easy to collide is protected by adopting a multilayer board and a plastic hard material;

2) before final setting, the concrete is not required to be piled with any material on the surface, and people can get on the concrete after the concrete reaches 1.2 Mpa; the concrete stair is cast in situ, the concrete is temporarily sealed after being formed, and an external hanging frame can be installed behind the concrete strength of the external wall which is up to 7.5 MPa;

3) when pumping concrete, the concrete polluted on the wall surface, the cylindrical surface and the floor surface is cleaned in time before being coagulated and cleaned by a mop;

4) the finished product of the fair-faced concrete surface is strictly forbidden to be randomly chiseled, and the ground is covered by color strip cloth when walls, columns, beams and slab bottoms are constructed during concrete coating construction, so that the trimmed ground is prevented from being polluted by the beams; the guardrails are erected by the scaffold tubes for coating the columns, the wall openings and the external corners to prevent damage.

2. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member according to claim 1, wherein the thickness of the cover plate is more than or equal to 2440 x 1220 x 17 mm.

3. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member according to claim 1, wherein the thickness of the wood grain bare concrete formwork is more than or equal to 4000 x 120 x 12 mm.

4. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member according to claim 1, wherein the thickness of the wood grain surface lining plate is more than or equal to 2440 x 1220 x 12 mm.

5. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member according to claim 1, wherein the concrete slump is controlled to be 200 +/-20 mm when the automobile pump is pumped.

6. The method for manufacturing the large-section special-shaped load-bearing concrete bare concrete member according to claim 1, wherein the bare concrete protective agent is an organic silicon resin bare concrete protective agent.