A screen-type fiber orientation device

Abstract

The present application relates to a kind of production methods of factory production prefabricated fiber concrete component, mainly a kind of filter screen type control fiber direction pouring tool and pouring method and pouring device, including mixing discrete device, fiber orientation device, filter screen, conical stirring blade etc..By filter screen selection and fiber orientation device angle and height control, change the fiber distribution inside slurry, so as to realize the different fiber direction demand inside component.At the same time, the existence of conical stirring blade makes the possible fiber cluster separate.The device is simple, widely applicable, and the operation method is easy to operate, and reusable, especially suitable for factory mass prefabricated component, only a few sets of different types and filter leaf spacing filter screen, the component poured by this way can improve the utilization rate of fiber.

Description

TECHNICAL FIELD

[0001] TECHNICAL FIELD: The present application relates to the technical field of fiber ultra-high performance concrete preparation, and particularly relates to a filter screen type fiber orientation pouring device for factory production of ultra-high performance concrete prefabricated components. BACKGROUND

[0002] Ultra-high performance concrete (UHPC) is a new type of building material that has been widely concerned and used in recent years, and has the advantages of high strength, high ductility, high durability, etc. The incorporation of fibers can improve the ductility, tensile resistance, and crack resistance of concrete. When micro cracks appear in the interior under the action of force, the presence of fibers between the cracks prevents the expansion of micro cracks, minimizes crack development, and the tensile resistance of fibers improves the tensile and bending performance of ultra-high performance concrete. Based on the mechanism of action of fibers, fiber-matrix bridging can only be achieved when the fibers between the cracks play a role in tensile resistance, which also means that the optimal choice of fiber direction is consistent with the main tensile stress direction of the component, and the bridging effect of the fibers is exerted at the first time of micro cracking of the component. Studies have shown that the distribution direction of internal fibers can greatly improve the performance of the finished product under the same fiber content. Therefore, regular orientation of the internal fibers of ultra-high performance concrete can improve the utilization rate of fibers as much as possible and reduce the cost of fibers.

[0003] Ultra-high performance concrete has high requirements for curing performance, and is generally prefabricated in a factory, which is difficult to meet the curing requirements on site. Factory prefabrication requires versatility for different forms of components and different size specifications of components.

[0004] At present, the fiber mixing method in construction is to directly add the slurry and stir, and then pour into a mold for forming. The fibers in the obtained component are in disorder. The existing methods for fiber orientation pouring are less studied, and the fiber orientation treatment is mostly concentrated in the stirring stage. This method cannot make the fibers flexibly distributed according to the actual stress direction of the component, and cannot achieve the best effect of fiber orientation. A few methods for fiber orientation pouring in the curing stage face the problem of collision with steel bars. The control methods for fiber orientation are basically divided into three categories: electromagnetic action, slurry flow direction and flow rate, and physical disturbance of stirring blades. The electromagnetic action requires that the fibers can be magnetized, and the electromagnetic force needs to be adjusted according to the fibers, which is complex to operate. The control effect of slurry flow on fibers is not good, and the stirring blades are mostly used in the stirring machine to avoid collision with steel bars. In general, there is no fiber orientation device that is widely used and easy to operate. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the present application aims to provide a simple and easy-to-use fiber orientation device and method suitable for different types and lengths of fibers and different structural components, which realizes fiber orientation during the pouring stage and avoids the collision problem of fiber orientation adjustment during the curing stage, so that the fiber distribution is along the main tensile stress direction of the component, and the fiber utilization rate and the performance indicators of UHPC are improved.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is: a new type of factory-produced reusable fiber dispersion and orientation device, which comprises a stirring dispersion device, a conveying pipe and a curing mold. The stirring dispersion device is mainly used to avoid fiber agglomeration. After the slurry is dispersed through the stirring dispersion device, it is preliminarily oriented in the conveying pipe, and finally oriented when entering the curing mold. After the slurry is oriented, it flows into the mold. According to the required stress direction of the component, the fiber direction is controlled by controlling the flow rate and the mold inlet, so as to avoid the collision problem when adjusting the fiber direction during the curing stage. The device and the pouring method are suitable for all types of fibers, and can be applied to different fiber lengths and types. After pouring is completed, the position of the conveying pipe can be moved to continue pouring other molds, realizing the efficiency of factory prefabrication. After the curing is completed, the mold can be repeatedly used, which is economical and reasonable. The fiber orientation method provided by the present application provides a new idea for controlling the direction of fibers, which has great significance for further popularizing the application of UHPC.

[0007] The stirring dispersion device is installed on the lifting platform and the movable chassis, which facilitates the movement of the equipment position. The stirring dispersion device can be lifted and lowered up and down through the lifting platform. It is divided into a cavity and a stirring blade. The cavity is provided with conical protrusions at a certain interval at the bottom. The stirring blade moves with the concrete slurry and fibers in the cavity under the action of power. When passing through the conical protrusions, if the fibers have serious "agglomeration" phenomenon, the two together will exert shear force on the agglomerated fibers to separate them. The fiber clusters that cannot be separated will be directly cut off, avoiding the problem of fiber agglomeration causing blockage in the subsequent device.

[0008] The part of the device that plays a role in fiber orientation is in the pouring stage. After the concrete slurry enters the fiber orientation device, it passes through multiple filter screens. The filter screens have the following two types according to the different requirements for the direction of the fibers: the filter leaves are parallel to the bottom of the device (a); the filter leaves are perpendicular to the bottom of the device (b). The former changes the vertical fibers into horizontal fibers under the combing of the filter leaves after the fibers pass through the filter screen, and the latter combs the fibers perpendicular to the flow direction into the same direction as the flow direction. After orientation through the filter screen, the slurry is smoothly guided into the mold through the connection of the stirring dispersion device and the mold, so as to realize the fiber guiding effect. The following will briefly describe the use process of the device with several typical components as examples.

[0009] For the unidirectional plate, the unidirectional plate load is transmitted along the short span direction, and the plate is mainly in bending, and the fiber distribution is suitable to be arranged along the short span direction. Since the thickness of the unidirectional plate is not high, the slurry can be directly poured into the mold from top to bottom, which has little effect on the fiber direction. For the fiber orientation filter screen of the unidirectional plate, the filter screen (a) and (b) combination orientation is selected, and the spacing between the filter leaves of the front and rear multiple layers of filter screens is sequentially reduced. The filter screen leaf spacing is related to the fiber length of the slurry, and the orientation filter leaf spacing is preferably 1.2 times the fiber length.

[0010] Further, for the complex stress and multi-directional stress component, the filter leaf spacing can be increased to improve the multi-directional performance of the concrete. After the fiber is oriented by the filter screen, the fiber is mainly distributed along the fiber flow direction, and then poured into the mold from the long span direction of the unidirectional plate, so that the required fiber direction requirement is basically achieved.

[0011] For the bidirectional plate, the plate is mainly in bending, and the fiber reduces the proportion of vertical fiber distribution. For the transverse fiber distribution, the filter screen (a) is selected to reduce the proportion of vertical fiber.

[0012] Further, it is noted that the fiber of the plate component is not suitable for vertical distribution, and the inclination angle of the fiber orientation device should be small or even horizontal.

[0013] For the beam component, the beam component is in bending and the web is in shear. According to the direction of the tensile stress distribution inside the beam, the fiber distribution is suitable for the beam bottom and the beam top to be distributed along the beam length, and the web is perpendicular to the tensile stress direction and is distributed obliquely, which plays a role similar to the web reinforcement. Therefore, a layered pouring method is required, and due to the high height of the beam, unlike the plate, directly pouring the oriented slurry will cause the fiber orientation to change during pouring. Therefore, for the pouring mold of the beam, several notches are arranged at the lower part of the beam end mold, which can be connected to the pouring orientation device, and the pouring is divided into three layers. After the beam reinforcement cage is bound and installed, the fiber orientation device is first adjusted to be horizontal, aligned with the beam end mold notch, the oriented filter screen (a) and (b) combination is selected, and the oriented slurry is introduced into the mold, and the fiber distributed along the beam length fills the bottom layer of the mold. Then the fiber orientation device is pulled out, the inclination angle is adjusted to 30°-45°, the slurry outlet is placed on the upper end of the beam end mold, and the slurry is poured from top to bottom until the upper end of the steel layer is reached. The fiber orientation device is adjusted to be horizontal again, and the pouring is completed. For the column component, according to the stress characteristics, the fiber distribution of the column component is vertical, and the proportion of horizontal distribution fiber is reduced. Therefore, the inclination angle of the fiber orientation device is adjusted to 70-80°, the filter screen (a) is used, and the slurry is poured from top to bottom.

[0014] Further, for special stress components (such as UHPC shell, etc.), based on the above principles, the form and inclination angle of the filter screen can be adjusted to achieve the orientation control of the fiber.

[0015] Preferably, the filter page spacing of the filter screen is preferably 2 times the fiber length.

[0016] Optionally, the distance between the stirring blades at the bottom of the stirring dispersion device can be 3 times the length of the fibers.

[0017] Through the above technical solutions, the beneficial effects of the present application are: according to the actual stress distribution of different components required, the filter screen form, the filter screen size, and the conveying pipe angle are changed, and good fiber orientation effect can be achieved for different types and lengths of fibers. The device structure is simple and does not need to add electric field and magnetic field. Only the filter screen needs to be replaced and the angle needs to be adjusted, which almost does not affect the pouring efficiency and improves the fiber utilization rate. The device can be recycled, which can improve the efficiency of pouring a large number of prefabricated ultra-high performance concrete components in the same batch and is suitable for factory prefabrication needs. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Overall schematic diagram of the filter screen type fiber orientation device

[0019] Figure 2 Schematic diagram of the stirring dispersion device

[0020] Figure 3 Schematic diagram of the fiber orientation device

[0021] Figure 4 Schematic diagram of two types of filter screens (a) and (b)

[0022] Figure 5 Schematic diagram of the orientation principle

[0023] Figure 6 Beam component as an example to illustrate the fiber direction distribution diagram

[0024] Figure 7 Schematic diagram of the beam formwork

[0025] BRIEF DESCRIPTION OF DRAWINGS: 1. Stirring dispersion device, 11. Gate, 12. Roller, 13. Conical stirring blade, 14. Conical protrusion, 15. Exit gate, 2. Lifting device, 21. Side notch, 3. Fiber orientation device, 31. a and b type filter screen, 32. Discharge gate, 33. Leakage-proof bottom plate, 34. Arc-shaped hole of fixed plate, 35. Fixed bolt, 4. Movable base, 41. Roller, 5. Arc-shaped hole, 6. Fixed plate, 7. Hinge, 8. Slurry outlet, 9. Filter sheet, 10. Fiber, 101. Beam formwork, 111. Bottom notch, 112. Baffle. DETAILED DESCRIPTION

[0026] Example 1 (beam component)

[0027] This embodiment is a prefabricated UHPC beam-like component fiber directional pouring. According to the stress characteristics of the beam-like component, the beam bottom and top are subjected to horizontal tensile stress, and the middle web is subjected to oblique tensile stress. The fiber direction should be consistent with the distribution direction of the tensile stress. The fiber direction distribution of the beam-like component is shown in Figure 6 .

[0028] As for the overall manufacturing of the fiber directional device, refer to Figures 1-4 . It can be simply divided into three parts, the stirring dispersion device 1, the fiber directional device 3 and the pouring mold. The roller 12 is connected with the conical stirring blade 13 in the stirring dispersion device 1, and the conical protrusion 14 is connected at the bottom of the stirring device. This design is mainly to solve the problem of fiber agglomeration in a large area. When the fiber clusters pass through the conical stirring blade, if the agglomeration is not serious, the fibers will be separated under the action of slight shear force. If the agglomeration is too serious, the fiber clusters will be directly sheared and separated under the action of shear force.

[0029] On one side of the stirring dispersion device 1, the side notch 21 is connected with the lifting device 2, and the lifting device 2 and the movable base 4 are used to move the whole device, thereby improving the work efficiency. The other side uses the gate plate 11 to control the opening and closing of the discharge gate 15. Arc-shaped holes 5 are opened on the wall of the device, and bolts 35 can be used to fix the fiber directional device 3.

[0030] The outer side of the fiber directional device 3 is connected with the stirring dispersion device 1. The fixed plate 6 is provided outside the connection position, and is rotated through the hinge 7. The fixed plate 6 also has a fixed plate arc-shaped hole 34 corresponding to the stirring dispersion device 1. In order to prevent the slurry from leaking from the joint position during rotation, a leakage prevention bottom plate 33 is provided. There are several bottom notches in the fiber directional device, which can insert the a and b type filter screens 31. By selecting and arranging the (a) and (b) type filter screens, the fiber directional control is realized. Between the fiber directional device 3 and the pouring mold, the discharge gate plate 32 is provided to control the opening and closing of the slurry outlet. For the beam mold 101, the bottom notch is needed to realize the horizontal pouring of the bottom fiber, and the baffle plate 112 is provided to control the opening and closing of the bottom notch 111.

[0031] The specific construction steps of the manufacturing method are as follows: according to the stress of the poured component, the required fiber arrangement angle and position are determined, the height of the stirring dispersion device 1 is adjusted through the side notch 21, the position of the arc-shaped hole 5 and the fixed bolt 35 is adjusted, and the angle of the fiber directional device is controlled.

[0032] For beam-like members, first raise the baffle 112 to control the opening of the bottom slot 111, and align the fiber orientation device outlet with the bottom slot. Pour the raw or mixed fiber concrete slurry into the mixing and dispersing device 1, and turn on the power. The conical mixing blade 13 starts to rotate and disperses the fiber clusters. Adjust the fiber orientation device to horizontal, align the beam end formwork bottom slot, and select the appropriate filter leaf spacing a, b filter screen combination according to the fiber length used. Introduce the oriented slurry into the formwork, and distribute the fibers along the beam length to cover the formwork bottom layer. Then lower the baffle 112, adjust the arc-shaped hole 5 and the fixing bolt 35 and the side slot 21, so that the fiber orientation device 3 has an inclination angle of 30-45°. Keep the a, b filter screen 31 form and combination unchanged, and pass the slurry through the a, b filter screen 31 again and flow into the formwork at an angle, so that the fiber in the newly poured middle part of the web is at an angle of 30-40°. When pouring to the top of the formwork, adjust the fiber orientation device 3 to be horizontal, keep the filter screen form and combination unchanged, and pass the slurry through the filter screen again and flow into the formwork horizontally, so that the fibers at the top of the beam are distributed horizontally.

[0033] For factory batch pouring, after pouring a test piece, directly move the device to the next formwork position. After all pouring is completed, wash the mixing and dispersing device 1 and the fiber orientation device 3 for next use.

[0034] Example 2 (plate-like members)

[0035] The difference from Example 1 is that the member stress form is different, and the filter screen form and pouring method are different. For one-way plates, the one-way plate load is transmitted along the short span direction, and the plate is mainly in bending. The fibers should be distributed along the short span direction. The first step of pouring method for beam members is used, and the appropriate filter screen (a) (b) combination is used. The oriented slurry is introduced into the formwork, and the fibers distributed along the short span cover the formwork bottom layer. The plate formwork does not need to be slotted, because the plate height is very low, the free falling process is short, and the fiber direction change is small. The two-way plate is mainly in bending, and the fibers are uniformly distributed along the long span and the short span. Compared with one-way plates, the filter screen only uses (a) type to control the horizontal distribution of fibers.

Claims

1. A screen-type fiber orientation device characterized by: The device comprises a plurality of layers of filter screen modules and pulp flow channels in series, the filter screen modules comprising at least two types of filter screens with different forms: filter screen a with filter leaves parallel to the bottom of the device and filter screen b with filter leaves vertical to the bottom of the device, which can be arranged in combination as needed; when the fibers pass through the plurality of layers of filter screens in sequence with the pulp, the fibers contact the filter leaves and rotate to complete the functional step-by-step carding: filter screen a is used to convert vertical fibers to horizontal fibers, and filter screen b is used to further convert fibers perpendicular to the flow direction to be consistent with the flow direction; the filter leaves of the plurality of layers of filter screens gradually decrease in spacing along the flow direction of the pulp, and the spacing of the filter leaves is 1.2 times or 2 times the length of the fibers; the overall height and inclination angle of the device are adjustable, and the filter screen combination and posture can be adjusted to meet the needs of different prefabricated components for fiber direction distribution, which is suitable for various fibers including non-steel fibers, and avoids clogging by sequential filtering from large spacing to small spacing, which is suitable for UHPC systems to maintain pouring efficiency.

2. The screen-type fiber orientation device of claim 1, wherein: The orientation and alignment process of the fibers is completed during the fiber pouring stage, and the device completes the step-by-step carding and orientation of the fibers upstream of the formwork and steel bar area, thereby avoiding the problem of steel bar collision caused by readjustment during the maintenance stage.

3. The screen-type fiber orientation device of claim 1, wherein: When the fibers pass through filter screen a and filter screen b in sequence with the pulp, the fibers contact the filter leaves and rotate, filter screen a converts vertical fibers to horizontal fibers, and filter screen b further converts fibers perpendicular to the flow direction to be consistent with the flow direction, completing the step-by-step carding and orientation from three-dimensional to two-dimensional to one-dimensional.

4. The screen-type fiber orientation device of claim 1, wherein, The inclination angle of the device is adjustable and is realized by a pair of arc-shaped holes and bolts on the wall of the stirring dispersion device and the fixed plate of the fiber orientation device, the fixed plate is connected to the device through a hinge, and a leak-proof bottom plate is provided at the joint to prevent high rheological UHPC pulp from leaking; the overall height of the device is adjustable through the side notches on the device, so that the angle and height are linked to match the pouring path of different components.

5. The screen-type fiber orientation device of claim 1, wherein, The conical protrusions are arranged at the bottom of the cavity, and the conical stirring leaves are located above the conical protrusions for dispersing agglomerated fibers, and then filtered in sequence through filter screens with large spacing to small spacing, realizing the process connection of dispersion, orientation and flow; since UHPC does not contain coarse aggregate, the filter screen does not clog with aggregate.

6. The screen-type fiber orientation device of claim 1, wherein, When used for pouring beam components, the beam formwork is provided with a baffle and cooperates with the bottom notch to control opening and closing, so as to realize horizontal pouring of the bottom layer of the beam after orientation is completed, and ensure that the oriented fibers are preferentially deposited along the tension bottom surface of the beam.

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