Concrete construction method for large-gradient sloping roof

Abstract

The invention discloses a concrete construction method for a large-gradient sloping roof. Relates to the technical field of roof construction. The method comprises the following steps that firstly, an inclined roof formwork is constructed, (1) a full space supporting frame is erected, (2) an anti-sliding structure is installed, and (3) the formwork is installed and reinforced; (2) concrete pouring: (1) dividing pouring sections; (2) conveying concrete; (3) pouring and paving in a layered manner; step 3, vibrating and compacting: (1) vibrating and checking; (2) compacting the surface; and 4, concrete curing: (1) covering and moisturizing curing, and (2) mold removal control. According to the concrete construction method for the large-gradient sloping roof, concrete is optimized, and the situation that under the action of gravity, aggregate sinks, slurry floats upwards, and consequently the structure is not uniform is avoided; through vibration compaction, the fluidity is reduced, and supporting is stable; anti-sliding and formwork system strengthening are achieved by installing an anti-sliding structure and installing and strengthening the formwork.

Description

Technical Field

[0001] This invention relates to the field of roof construction technology, and more specifically to a method for constructing a steeply sloping concrete roof. Background Technology

[0002] A pitched roof is a roof form characterized by a large slope (usually exceeding 10%), which has excellent drainage performance and can reduce the cost of waterproofing construction through self-drainage. This type of roof is widely used in construction, and common structural types include single-slope, double-slope, four-slope, and zigzag roofs. It can prevent snow accumulation through steep slope design and expand usable area by utilizing attic space.

[0003] Currently, the main challenges in constructing steeply pitched roofs lie in controlling the fluidity of concrete, ensuring compaction during vibration, implementing anti-slip measures, and addressing curing issues. Under gravity, freshly mixed concrete is prone to downward flow, causing aggregates to sink and slurry to float, resulting in structural heterogeneity. The concrete exerts a tremendous downward force on the formwork, requiring the formwork system to possess extremely high strength, rigidity, and resistance to deformation, especially ensuring the stability of the support system.

[0004] Therefore, how to provide an optimized concrete construction method for steeply sloping roofs that reduces flowability, provides stable support, resists slippage, and strengthens the formwork system is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for constructing a steeply sloping roof concrete structure, which aims to solve one of the problems in the background art mentioned above, optimize concrete, reduce fluidity, improve support stability, resist slippage, and strengthen the formwork system.

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

[0007] A method for constructing a steeply sloping roof using concrete, comprising:

[0008] Step 1: Construction of Sloping Roof Formwork

[0009] (1) Erect a full-span support frame with a pole spacing of no more than 0.8m and a step distance of no more than 1.2m. Set up bidirectional horizontal bars and scissor bracing, and harden the bottom and pave with steel plates;

[0010] (2) Install anti-slip structure by using the template opening and rebar insertion method. Set quincunx-shaped openings on the template at intervals of 300mm-500mm, insert Φ12mm-14mm short rebars, and let both ends extend out of the template.

[0011] The template surface is welded with reinforcing bars. Short reinforcing bar ends are spot welded to the template surface. The spacing of the short reinforcing bar ends is also set to 300mm-500mm to match the spacing of the quincunx-shaped openings.

[0012] (3) Template installation and reinforcement, template joints are sealed with glue, slope and flatness are checked after installation, the spacing of back ribs is not greater than 200mm, and the tie rods are densified;

[0013] Step 2: Concrete Pouring

[0014] (1) Divide the pouring section and set multiple anti-slip strips along the direction perpendicular to the ridge. The width of the anti-slip strips is set to 1.5m-2m, and they extend from the eaves to the ridge.

[0015] (2) Concrete delivery: The pump truck delivers the concrete to the area below the roof and guides it to the pouring point through a mobile chute. The discharge port is no more than 1m above the pouring surface.

[0016] (3) Layered pouring and paving, with a single layer thickness not exceeding 300mm, paving upwards, and covering the upper layer before the lower layer initially sets (time interval not exceeding 1.5 hours);

[0017] Step 3: Vibrate and compact.

[0018] (1) Vibration and inspection: Use a Φ30mm vibrator to vibrate, with an insertion point spacing of no more than 250mm. Vibrate around the anti-slip steel bars and the edge of the formwork, avoiding over-vibration. Use auxiliary tapping on the outside of the formwork to check the compactness.

[0019] (2) Surface compaction: Before initial setting, use a wooden trowel to pat and compact the surface to reduce laitance;

[0020] Step 4: Concrete Curing

[0021] (1) Cover and moisturize the roof. Within 12 hours after pouring, cover with wet burlap sacks and fix with several steel nails. The spacing between the steel nails should not be greater than 1m. Install a sprinkler pipe on the ridge to automatically sprinkle water and keep the surface continuously moist for no less than 14 days.

[0022] (2) Formwork removal control: the formwork removal time shall not be less than 14 days and the concrete strength shall not be less than 75% of the design strength. The anti-slip steel bars shall be removed first, and the formwork shall be removed according to the principle of removing the last support first.

[0023] Furthermore, in step one, the plum blossom-shaped opening is sealed with expanding foam and tape to prevent grout leakage.

[0024] Furthermore, in step two, pouring should be avoided during the midday high-temperature period to prevent the concrete from setting too quickly.

[0025] Furthermore, in step four, the concrete mix proportion is optimized as follows: the maximum particle size of coarse aggregate is within 15mm, the proportion of coarse aggregate is 40%-43%, continuous gradation is adopted, crushed stone with a continuous particle size of 5-15mm is used, fine aggregate is increased, the fineness modulus of fine aggregate is 2.4-2.8, the sand ratio of fine aggregate is 43%-46%, and the mud content of fine aggregate is not greater than 2%.

[0026] Furthermore, in step one, the anti-slip steel bars are spot-welded to the main reinforcement bars to prevent displacement during casting.

[0027] Furthermore, in step one, construction joints are provided: construction joints are set at the boundary of the strip, near the ridge or eaves, and the direction is set to be perpendicular to the ridge;

[0028] Treatment of construction joints: chisel into a sawtooth shape, remove laitance → apply interface agent → lay 10cm of mortar with the same mix ratio before pouring;

[0029] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for constructing a large-slope sloping roof concrete. By optimizing the concrete, it avoids aggregate sinking and slurry floating under gravity, which would cause structural heterogeneity. By vibrating and compacting the surface, it ensures that the concrete is fully compacted, reducing fluidity and providing stable support. By installing anti-slip structures and installing and reinforcing the formwork, it achieves anti-slip and strengthens the formwork system, making the support system stable. Attached Figure Description

[0030] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 The construction flowchart of the method for constructing a steeply sloping roof concrete structure provided by this invention is shown. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] See Figure 1 This invention discloses a method for constructing a steeply sloping roof concrete structure, comprising:

[0034] Step 1: Construction of Sloping Roof Formwork

[0035] (1) Erect a full-span support frame with a pole spacing of no more than 0.8m and a step distance of no more than 1.2m. Set up bidirectional horizontal bars and scissor braces, and harden the bottom and pave with steel plates to resist the lateral thrust of concrete and prevent the formwork from deforming and collapsing.

[0036] (2) Install anti-slip structure by using the template opening and rebar insertion method. Set quincunx-shaped openings on the template at intervals of 300mm-500mm. The diameter of the openings is slightly larger than that of the rebar. Insert Φ12mm-14mm short rebars and let them protrude from the template at both ends. Pre-embed the short rebars to form anti-slip keys, anchor the concrete to the template, and suppress slippage.

[0037] The template surface is welded with reinforcing bars. Short reinforcing bar ends are spot-welded to the template surface. The spacing of the short reinforcing bar ends is also set to 300mm-500mm to match the spacing of the quincunx-shaped openings. This increases the roughness of the template surface and improves the concrete bond strength.

[0038] (3) Template installation and reinforcement, template joints are sealed with glue, slope and flatness are checked after installation, the spacing of back ribs is not greater than 200mm, and the tie rods are densified;

[0039] Step 2: Concrete Pouring

[0040] (1) Divide the pouring section and set multiple anti-slip strips along the direction perpendicular to the ridge. The width of the anti-slip strips is set to 1.5m-2m, and they are pushed from the eaves to the ridge; reduce the load of a single pouring and reduce the side pressure of the formwork; push from bottom to top to avoid concrete accumulation and slippage;

[0041] (2) Concrete delivery: The pump truck delivers the concrete to the area below the roof and guides it to the pouring point through a mobile chute to avoid high-throwing. The discharge port is no more than 1m above the pouring surface. The drop height of the material is controlled to be ≤1m in the chute to reduce segregation. Thin-layer pouring shortens the initial setting time and enhances the interlayer bonding.

[0042] (3) Layered pouring and paving, with a single layer thickness not exceeding 300mm, paving upwards, and covering the upper layer before the lower layer initially sets (time interval not exceeding 1.5 hours);

[0043] Step 3: Vibrate and compact.

[0044] (1) Vibration and inspection: Use a Φ30mm vibrator to vibrate. Insert the vibrator quickly and pull it out slowly. The spacing between insertion points should not exceed 250mm. Vibrate around the anti-slip reinforcement and the edge of the formwork for 10-20 seconds at each point. Use auxiliary tapping on the outside of the formwork to check the compactness. Avoid over-vibration that could cause aggregate separation. Focus on vibrating around the anti-slip key to eliminate voids. Use tapping on the outside or attaching a vibrator to compensate for the vibration blind spots caused by the slope.

[0045] (2) Surface compaction: Before initial setting, use a wooden trowel to pat and compact the surface to reduce laitance;

[0046] Step 4: Concrete Curing

[0047] (1) Cover and moisturize the roof. Within 12 hours after pouring, cover with wet burlap sacks or U-shaped clips and fix with several steel nails. The spacing between the steel nails should not be greater than 1m. Sprinkler pipes are installed on the ridge to automatically spray water and keep the surface continuously moist for no less than 14 days. Wet burlap sacks + steel nails and U-shaped clips are used to resist the evaporation of water from the slope and reduce shrinkage cracks.

[0048] (2) Formwork removal control: the formwork removal time shall not be less than 14 days and the concrete strength shall not be less than 75% of the design strength. The anti-slip steel bars shall be removed first, and the formwork shall be removed according to the principle of removing the last support first. Spray pipes shall be installed on the ridge to keep it moist and ensure a 14-day curing period to improve impermeability.

[0049] In this embodiment, in step one, the plum blossom-shaped opening is sealed with expanding foam and tape to prevent grout leakage.

[0050] In this embodiment, in step two, pouring is avoided during the midday high-temperature period to prevent the concrete from setting too quickly.

[0051] In this embodiment, in step four, the concrete mix proportion is optimized as follows: the maximum particle size of coarse aggregate is within 15mm to reduce the weight of a single aggregate and reduce the tendency to slide; the proportion of coarse aggregate is 40%-43% to reduce coarse aggregate and increase the thickness of the mortar coating layer; continuous gradation is adopted, using crushed stone with a continuous particle size of 5-15mm to fill voids and reduce mortar loss; fine aggregate is increased, with a fineness modulus of 2.4-2.8, increasing particles smaller than 0.3mm to improve viscosity; the sand ratio of fine aggregate is 43%-46% to compensate for the reduction of coarse aggregate and enhance coating properties; the mud content of fine aggregate is not greater than 2% to reduce the damage of mud content to the mortar bonding force;

[0052] Low-slump or semi-dry hard concrete is used, with the slump controlled within 50-80mm. Admixtures such as thickeners, water-retaining agents, or silica fume are added according to the actual situation.

[0053] In this embodiment, in step one, the anti-slip steel bars are spot-welded to the main steel bars to prevent displacement during casting.

[0054] In this embodiment, in step one, a construction joint is left: the construction joint is set at the boundary of the strip, near the ridge or eaves, and the direction is set to be perpendicular to the ridge; the template surface is inserted into the movable insert plate to separate the pouring area, and pulled out before initial setting to form a construction joint, so as to accurately control the thickness and density;

[0055] Treatment of construction joints: chisel into a sawtooth shape, remove laitance → apply interface agent → lay 10cm of mortar with the same mix ratio before pouring;

[0056] A concrete retaining wall was added at the ridge to prevent water from flowing out; the formwork at the gutter was reinforced separately and drainage pipes were pre-embedded.

[0057] In addition, in this embodiment, a working platform is set up: double-row scaffolding is fully covered with scaffold boards, and a 1.2m high guardrail + safety net is set on the outside; the operators wear double-hook safety belts, and the wire ropes are anchored to the beams; anti-slip strips are nailed to the scaffold boards, and the workers wear anti-slip shoes.

[0058] During construction, a double-layer steel wire mesh is installed, and the fine mesh enhances the overall resistance of the concrete to sliding.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for constructing a steeply sloping roof concrete structure, characterized in that, Specifically, the following steps are included: Step 1: Construction of Sloping Roof Formwork (1) Erect a full-span support frame with a pole spacing of no more than 0.8m and a step distance of no more than 1.2m. Set up bidirectional horizontal bars and scissor bracing, and harden the bottom and pave with steel plates; (2) Install anti-slip structure by using the template opening and rebar insertion method. Set quincunx-shaped openings on the template at intervals of 300mm-500mm, insert Φ12mm-14mm short rebars, and let both ends extend out of the template. The template surface is welded with reinforcing bars. Short reinforcing bar ends are spot welded to the template surface. The spacing of the short reinforcing bar ends is also set to 300mm-500mm to match the spacing of the quincunx-shaped openings. (3) Template installation and reinforcement, template joints are sealed with glue, slope and flatness are checked after installation, the spacing of back ribs is not greater than 200mm, and the tie rods are densified; Step 2: Concrete Pouring (1) Divide the pouring section and set multiple anti-slip strips along the direction perpendicular to the ridge. The width of the anti-slip strips is set to 1.5m-2m, and they extend from the eaves to the ridge. (2) Concrete delivery: The pump truck delivers the concrete to the area below the roof and guides it to the pouring point through a mobile chute. The discharge port is no more than 1m above the pouring surface. (3) Layered pouring and paving, with a single layer thickness not exceeding 300mm, paving upwards, and covering the upper layer before the lower layer initially sets (time interval not exceeding 1.5 hours); Step 3: Vibrate and compact. (1) Vibration and inspection: Use a Φ30mm vibrator to vibrate, with an insertion point spacing of no more than 250mm. Vibrate around the anti-slip steel bars and the edge of the formwork, avoiding over-vibration. Use auxiliary tapping on the outside of the formwork to check the compactness. (2) Surface compaction: Before initial setting, use a wooden trowel to pat and compact the surface to reduce laitance; Step 4: Concrete Curing (1) Cover and moisturize the roof. Within 12 hours after pouring, cover with wet burlap sacks and fix with several steel nails. The spacing between the steel nails should not be greater than 1m. Install a sprinkler pipe on the ridge to automatically sprinkle water and keep the surface continuously moist for no less than 14 days. (2) Formwork removal control: the formwork removal time shall not be less than 14 days and the concrete strength shall not be less than 75% of the design strength. The anti-slip steel bars shall be removed first, and the formwork shall be removed according to the principle of removing the last support first.

2. The method for constructing a steeply sloping roof concrete structure according to claim 1, characterized in that, In step one, the plum blossom-shaped opening is sealed with expanding foam and tape to prevent grout leakage.

3. The method for constructing a steeply sloping roof concrete structure according to claim 1, characterized in that, In step two, avoid pouring concrete during the midday high-temperature period to prevent the concrete from setting too quickly.

4. The method for constructing a steeply sloping roof concrete structure according to claim 1, characterized in that, In step four, the concrete mix proportion is optimized as follows: the maximum particle size of coarse aggregate is within 15mm, the proportion of coarse aggregate is 40%-43%, continuous gradation is adopted, crushed stone with a continuous particle size of 5-15mm is used, fine aggregate is increased, the fineness modulus of fine aggregate is 2.4-2.8, the sand ratio of fine aggregate is 43%-46%, and the mud content of fine aggregate is not greater than 2%.

5. The method for constructing a steeply sloping roof concrete structure according to claim 1, characterized in that, In step one, the anti-slip steel bars are spot-welded to the main reinforcement bars to prevent displacement during pouring.

6. The method for constructing a steeply sloping roof concrete structure according to claim 1, characterized in that, Step one also includes leaving construction joints: construction joints are set at the boundary of the strip, near the ridge or eaves, and the direction is set to be perpendicular to the ridge; Treatment of construction joints: chisel into a sawtooth shape, remove laitance → apply interface agent → lay 10cm of mortar with the same mix ratio before pouring.

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