A flexible duct for preventing segregation during concrete pouring

Abstract

This invention relates to a flexible tremie pipe for preventing segregation in concrete pouring, comprising at least two vertically connected tremie pipe units. Each tremie pipe unit includes a pipe body and a flange. The pipe body is a funnel-shaped structure made of flexible rubber material, with a circular upper cross-section and a flattened lower section. The inner walls on opposite sides are fitted together. The top opening has an outwardly folded annular flange of a certain width. The flange includes an upper flange and a lower flange. The upper flange presses against the top surface of the flange on the pipe body, and the lower flange fits onto the pipe body and is close to the bottom surface of the flange. The upper and lower flanges are connected by bolts, clamping and fixing the flange. The flanges of the upper and lower tremie pipe units are connected by rigging or a lifting rod. This invention allows concrete to flow in a constrained state, preventing segregation.

Description

Technical Field

[0001] This invention belongs to the field of building construction and relates to concrete pouring construction, specifically to a flexible tremie pipe for preventing concrete segregation during the pouring process. Background Art

[0002] Concrete segregation refers to the phenomenon of concrete mixture components separating into one another, resulting in uneven internal composition and structure. Segregation occurs during the pouring of large concrete structural members when the free fall height exceeds two meters. Segregation significantly reduces the strength and load-bearing capacity of concrete structural members, affecting their safety. It also leads to poor appearance, such as sand veins, exposed aggregate, and exposed rebar, impacting the durability of the concrete structure. Therefore, when the pouring height of concrete structural members exceeds two meters, vertical pouring typically utilizes tremies, ducts, or chutes for transport. These chutes serve to gather and solidify the concrete, prevent dispersion, and buffer the flow, thus mitigating segregation to some extent.

[0003] In existing anti-segregation technologies, the guide pipes and ducts are all cylindrical structures made of thin steel plates, with segment lengths of 1.0 to 2.0 meters. The segments are connected by bolt threads or steel bar lifting rings. As the concrete pouring surface rises, the guide pipes or ducts are removed section by section to keep the bottom of the guide pipe or duct less than 2 meters from the concrete surface.

[0004] Concrete chutes are effective in preventing segregation, but because the chute needs to be at a certain angle to ensure that the concrete flows by its own weight, it is often necessary to build a stable and reliable chute support in order to adjust the chute angle, which increases the pouring cost and the risk of high-altitude operation for support construction. In addition, the opening position of the chute is fixed, and the distribution of concrete in the formwork is also limited. Therefore, its applicable places are very limited, mainly used for plain concrete pouring in shallow foundation pits with small areas.

[0005] When the concrete pouring drop is small, both the tremie pipe and the guide pipe can provide a certain degree of anti-segregation effect. However, when the pouring drop is large, due to the different unit densities of the aggregate, mortar, and cement paste in the concrete mixture, as well as the different frictional resistance with the tremie pipe wall, the free-fall velocity will differ after a certain distance, making segregation inevitable. In some engineering constructions, such as large deep foundation pits and other underground structures, the vertical drop height of concrete can reach over 10m, and in some cases even 40m, making segregation even more pronounced. If anti-segregation measures are not taken or are inappropriate, the impact on the concrete pouring quality will be even greater.

[0006] Currently, there are two main solutions in China for the segregation problem in large-drop concrete pouring. One is to install elbows at the bottom of the tremie pipe or conduit to slow down the concrete pouring speed. However, this method often results in segregation at the elbow, thus failing to effectively prevent segregation and frequently causing pipe blockage at the elbow. The other method is to install a gate valve structure at one or more locations in the middle of the conduit or tremie pipe to restrict the free fall height of the concrete in sections. However, this method has problems with the gate valve not opening and closing freely due to the adhesion of cement slurry, affecting subsequent pouring. Furthermore, since the gate valve is a machined part, it is generally heavy, making it difficult for workers to install and dismantle, and cleaning is time-consuming and labor-intensive. Therefore, its widespread application has not been very effective. Summary of the Invention

[0007] The purpose of this invention is to address the above-mentioned problems by providing a flexible cassette structure that is simple in structure, easy to use, and can effectively prevent segregation during the pouring of concrete with large drop.

[0008] The technical solution of the present invention is as follows:

[0009] A flexible tremie pipe for preventing segregation in concrete pouring includes at least two vertically connected tremie pipe units. Each tremie pipe unit comprises a cylinder and a flange. The cylinder is a funnel-shaped structure made of flexible rubber material, with a circular upper section and a flat lower section. The upper half has a circular cross-section, and the lower half has a flattened opening. The inner walls on opposite sides are fitted together. The top opening has an outwardly folded annular flange of a certain width. The flange includes an upper flange and a lower flange. The upper flange presses against the top surface of the flange on the cylinder, and the lower flange is fitted onto the cylinder and close to the bottom surface of the flange. The upper and lower flanges are connected by bolts, clamping and fixing the flange. The flanges of the upper and lower tremie pipe units are connected by rigging or a lifting rod.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] 1. The cylinder of the present invention is a flat-nosed funnel structure made of rubber. When a certain amount of concrete enters the upper part of the cylinder, the lower flat-nosed part automatically and gradually expands under the pressure of the concrete's own weight. The concrete flows slowly down from the expanded flat-nosed part by its own weight. After the concrete has flowed, the flat cylinder returns to its original shape. The entire flow process of the concrete is in a constrained state, without divergence or free fall, and segregation will not occur.

[0012] 2. Replace the hangers with different diameters that can support the weight of the tremie pipe and the concrete inside, and extend them to any length. Suitable for concrete pouring with any drop.

[0013] 3. The flexible rubber material is lightweight and low in cost, and is easy to install, disassemble and clean. Its smooth inner wall does not easily stick to concrete, and there will be no pipe jamming or blockage during the concrete pouring process. Attached Figure Description

[0014] Figure 1 This is a side view of the structure of the present invention;

[0015] Figure 2 This is a schematic diagram of the exploded structure of a tubular unit;

[0016] Figure 3 This is a front view structural diagram of a tubular unit;

[0017] Figure 4 This is a side view of a cylindrical unit.

[0018] Figure 5 This is a schematic diagram of the initial state of concrete pouring according to the present invention;

[0019] Figure 6 This is a schematic diagram showing the state of concrete falling from the upper cylinder to the lower cylinder;

[0020] Figure 7 This is a schematic diagram showing the state of the concrete after it has completely flowed out of the upper tremie pipe.

[0021] Figure 8 This is a schematic diagram of the state during continuous concrete pouring according to the present invention. Detailed Implementation

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the present invention includes at least two interconnected cylindrical units. Each cylindrical unit includes a cylinder 1 and a flange 2. The cylinder 1 is a funnel-shaped structure with a round upper part and a flat lower part, made of flexible rubber material. Its upper half has a circular cross-section, and its lower half has a flat mouth. The inner walls on the two opposite sides are fitted together. Its top opening is provided with an annular flange 11 that is folded outward to a certain width. The flange 2 includes an upper flange 21 and a lower flange 22. The upper flange 21 is pressed on the top surface of the flange 11 of the cylinder, and the lower flange 22 is fitted on the cylinder and close to the bottom surface of the flange 11. The upper flange and the lower flange are connected by bolts 3 and the flange is clamped and fixed. The flanges of the upper and lower cylindrical units are connected by rigging or lifting rods 4.

[0023] In a specific implementation of the present invention, the cylinder can be integrally formed using 3-5 mm thick flexible rubber.

[0024] In a specific implementation of this invention, the flange width at the top opening of the cylinder can be set to 5-8 cm to facilitate fixing with the flange.

[0025] In a specific implementation of this invention, the length of each cylinder can be set to 1-2m, and the top diameter of the cylinder is 25-35cm.

[0026] In a specific implementation of the present invention, both the upper flange and the lower flange can be processed from steel plates with a thickness of 3 to 5 mm, and their dimensions are consistent with the flange dimensions of the cylinder.

[0027] In a specific implementation of this invention, to facilitate the connection between the upper and lower tremie cylinder units, six circumferentially spaced through holes 5 for lifting rods can be provided on the upper flange, lower flange, and flange of the cylinder body of each tremie cylinder unit. Two adjacent tremie cylinder units are connected by three circumferentially spaced lifting rods 4. The lifting rods can be made of precision-rolled threaded steel. The upper and lower ends of the three lifting rods pass through the three circumferentially spaced through holes on the upper and lower tremie cylinder units, respectively. A nut 6 is screwed onto the top surface of the upper flange and the bottom surface of the lower flange of each tremie cylinder unit. The lifting rods and nuts also serve as the connection between the upper and lower flanges, increasing the connection strength. The lifting rods maintain the vertical posture and stability of the tremie cylinder, ensuring smooth concrete flow and descent.

[0028] In practice, bolts or threaded steel bars with hooks can be inserted into the through holes of the lifting rods, and the upper and lower duct units can be connected by rigging through the hooks.

[0029] This invention is used for pouring concrete by connecting an appropriate number of tremie pipe units to each other according to the pouring height difference. A lifting rope can be wound around the bottom of the flange of the uppermost tremie pipe unit and connected to the concrete hopper. The pouring process is as follows:

[0030] like Figure 5 , Figure 6 As shown, during the initial pouring, after the concrete 7 enters the cylinder 1 of the uppermost duct unit, it first accumulates in the circular part of the cylinder. When it reaches a certain amount, it slides down under the action of gravity and gradually opens the flat nozzle part of the cylinder, falling into the lower cylinder. The flat nozzle part can restrain and slow down the falling speed of the concrete to prevent segregation.

[0031] After the concrete in the upper cylinder enters the lower cylinder 1, its falling process in the lower cylinder is the same as that in the upper cylinder. It falls step by step in this way until it finally reaches the pouring position.

[0032] like Figure 7 As shown, after all the concrete in the upper cylinder 1 has flowed out, the cylinder recovers its original shape through elasticity; when subsequent concrete enters the cylinder, the concrete falling process is the same as during the initial pouring.

[0033] like Figure 8 As shown, when large volumes of concrete are poured continuously, the flat nozzle of each stage of the cylinder has a converging and retarding effect on the concrete. The entire flow process of the concrete is in a constrained state, without divergence or free fall, which can achieve an ideal anti-segregation effect.

[0034] As the pouring surface rises, the lowest tremie pipe unit can be removed step by step to accommodate the pouring height of the concrete.

Claims

1. A flexible tremie pipe for preventing segregation in concrete pouring, comprising at least two vertically connected tremie pipe units, characterized in that: Each cassette unit includes a cylinder and a flange. The cylinder is a funnel-shaped structure made of flexible rubber material, with a round upper part and a flat lower part. The upper half of the cross-section is circular, and the lower half is flat. The inner walls on opposite sides fit together. The top opening has an outwardly folded annular flange of a certain width. The flange includes an upper flange and a lower flange. The upper flange presses against the top surface of the flange on the cylinder, and the lower flange is fitted onto the cylinder and close to the bottom surface of the flange. The upper flange and the lower flange are connected by bolts, which clamp and fix the flange. The flanges of the upper and lower cassette units are connected by rigging or a lifting rod. The cylinder is integrally formed from 3-5 mm thick flexible rubber. The length of each cylinder is 1-2 m, and the top opening diameter of the cylinder is 25-35 cm.

2. The flexible concrete pouring anti-segregation tremie pipe according to claim 1, characterized in that: The flange width of the cylinder is 5-8cm.

3. The flexible concrete pouring anti-segregation tremie pipe according to claim 1, characterized in that: Both the upper and lower flanges are made of 3-5 mm thick steel plates, and their dimensions are consistent with the flange dimensions of the cylinder.

4. The flexible concrete pouring anti-segregation tremie pipe according to claim 1, characterized in that: Each tandem cylinder unit has six circumferentially spaced through holes for lifting rods on its upper flange, lower flange, and the flange of the cylinder body. Two adjacent tandem cylinder units are connected by three circumferentially spaced lifting rods. The upper and lower ends of the three lifting rods pass through the three circumferentially spaced through holes on the upper and lower tandem cylinder units, respectively, and a nut is screwed onto the top surface of the upper flange and the bottom surface of the lower flange of the upper and lower tandem cylinder units, respectively.

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