Pressurized compact recycled concrete precast block preparation device and method

Abstract

The invention provides a pressurized compact recycled concrete precast block preparation device and method.The pressurized compact recycled concrete precast block preparation device comprises a variable-frequency vibration machine body, the variable-frequency vibration machine body comprises a variable-frequency vibration table located at the bottom, a special mold used for forming is fixedly installed at the top end of the variable-frequency vibration table, and the variable-frequency vibration table is connected with a variable-frequency controller through a signal line; a top plate is fixed to the top of the variable-frequency vibration table through multiple stand columns, a telescopic rod is installed at the bottom end of the top plate, and a variable-frequency balancing weight is installed at the bottom end of the telescopic rod. And by adopting the pressurizing compacting device, through variable-frequency vibration and pressurizing forming, the use amount of a cementing material is reduced, the compactness of the recycled concrete precast block is improved, and the mechanical property and durability of the recycled concrete precast block are improved.

Description

Technical Field

[0001] The invention relates to the technical field of recycled concrete, and in particular to a device and method for preparing pressurized dense recycled concrete prefabricated blocks. Background Art

[0002] The durability problem of concrete structures has brought serious economic burdens to countries around the world. Prefabricated concrete structures in my country are in the stage of large-scale promotion and application. Using recycled aggregates to replace natural aggregates to prepare recycled concrete prefabricated blocks as a green building material can not only promote the sustainable development of prefabricated concrete structures, reduce and alleviate the problem of natural resource scarcity to a certain extent, but also help solve the worsening environmental problems. However, compared with natural aggregates, recycled aggregates have obvious differences in parameters such as apparent density, porosity, water absorption, water absorption rate and crushing index. The mechanical properties, durability and deformation properties of recycled concrete are significantly lower than those of ordinary concrete.

[0003] At present, the performance of recycled concrete is mainly improved by increasing density and optimizing pore structure. Common methods include mechanical treatment or soaking of recycled aggregates, adding admixtures to recycled concrete, or adjusting the mixing process. However, the above methods will increase the cost of concrete to a certain extent, are time-consuming and labor-intensive, and are not conducive to improving the working performance of concrete. Summary of the invention

[0004] Based on the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a device and method for preparing pressurized and compacted recycled concrete prefabricated blocks suitable for assembled concrete structures. The pressurized and compacted device is used to reduce the amount of cementitious materials, increase the density of recycled concrete prefabricated blocks, and improve their mechanical properties and durability through variable frequency vibration and pressurized molding. At the same time, the preparation method is simple.

[0005] In order to achieve the above-mentioned technical features, the purpose of the present invention is achieved as follows: a pressurized dense recycled concrete prefabricated block preparation device includes a variable frequency vibration body, the variable frequency vibration body includes a variable frequency vibration table located at the bottom, a special mold for forming is fixedly installed on the top of the variable frequency vibration table, the variable frequency vibration table is connected to the frequency conversion controller through a signal line, a top plate is fixed to the top of the variable frequency vibration table through a plurality of columns, a telescopic rod is installed at the bottom end of the top plate, and a variable frequency counterweight is installed at the bottom end of the telescopic rod.

[0006] Preferably, the variable frequency vibration body is a vertically arranged rectangular body, and support feet are fixedly connected to the four corners of the bottom end.

[0007] Preferably, the special mold adopts a rectangular box structure, and a raised grid texture is arranged inside the rectangular box structure.

[0008] Preferably, the special mold is positioned and installed on the top of the variable frequency vibration table through a plurality of slots.

[0009] Preferably, the frequency conversion controller is capable of performing timed frequency conversion.

[0010] Preferably, the variable frequency counterweight block is connected to a variable frequency controller; and a raised grid texture is provided on the lower end surface of the variable frequency counterweight block.

[0011] Preferably, the size of the variable frequency counterweight block matches the size of the special mold, and can increase the variable frequency vibration of the recycled concrete inside the special mold.

[0012] Preferably, during operation, the pressure of the variable frequency counterweight block is controlled at 2.0-6.0 kPa, and the vibration frequency is controlled at: low frequency 25-50 HZ, medium frequency 83-133 HZ, and high frequency 167 HZ.

[0013] Preferably, during the operation, the vibration frequency of the variable frequency vibration table is controlled within the range of: low frequency 25~50 HZ, medium frequency 83~133 HZ, and high frequency 167 HZ.

[0014] On the other hand, the present invention provides a method for preparing a pressurized dense recycled concrete prefabricated block, the preparation method being implemented by the preparation device, comprising the following steps: Step 1: Preparation of recycled concrete mixture: Pour cement, sand, gravel, recycled aggregate, solid waste, admixture and water required for preparing prefabricated blocks into a mixing barrel and stir to obtain a recycled concrete mixture; Step 2: Transportation of recycled concrete mixture: The recycled concrete mixture prepared in step 1 is transported into a special mold through a transport pipeline, and the special mold is then positioned and fixed on the top of the variable frequency vibration table; Step 3: Add vibration molding of recycled concrete mixture: Control the telescopic rod to press down, extend the variable frequency counterweight block into the interior of the special mold, and control the pressure within a certain range, then start the variable frequency controller, and control the vibration frequency of the variable frequency counterweight block within a certain range through the variable frequency controller; At the same time, the variable frequency vibration table is controlled by the variable frequency controller to vibrate, thereby vibrating the special mold as a whole, and the vibration frequency of the variable frequency vibration table is controlled within a certain range; This ensures that pressure-boosted variable-frequency vibration is performed during the preparation process; Step 4: Pressure maintenance of precast concrete blocks: After the supercharged variable frequency vibration is finished, the vibration of the variable frequency vibration table and the variable frequency counterweight is suspended by the variable frequency controller, and the variable frequency vibration machine is allowed to stand for at least 2 hours to obtain a supercharged dense recycled concrete prefabricated block; Step 5: Removal of precast concrete blocks: After preparation is completed, the recycled concrete precast blocks are taken out from the special mold.

[0015] The present invention has the following beneficial effects: 1. The present invention uses a mode combining a variable frequency vibration machine and a special mold, etc., so that the entire control process is automated and easy to operate, and an integrated operation process of real-time observation and self-adjustment is realized, which reduces the intensity of manpower work, reduces the influence of human factors, and is scale-controllable.

[0016] 2. The preparation device and method of the present invention realize the resource utilization of solid waste, can save the consumption of natural resources such as cement and sand and gravel mining, reduce carbon emissions in the production process, promote environmental protection, and can be widely used in green buildings.

[0017] 3. The present invention ensures the density of the final prepared precast concrete blocks by adopting a preparation process combining pressurization and vibration, thereby ensuring the quality and reliability of the precast concrete blocks.

[0018] 4. The present invention ensures the best quality of the prepared concrete test block by coordinating the above-mentioned boost pressure and vibration frequency.

[0019] 5. The present invention adopts timed frequency conversion control to achieve control of vibration rate and pressure during the preparation process, thereby ensuring the quality of the prepared precast concrete blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is the overall structure diagram of the present invention.

[0022] In the figure: variable frequency vibration body 1, special mold 2, variable frequency counterweight block 3, variable frequency vibration table 4, variable frequency controller 5, telescopic rod 6, card slot 7, signal line 8, support foot 9, column 10, top plate 11. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1: like Figure 1As shown, a pressurized compact recycled concrete prefabricated block preparation device, a pressurized compact recycled concrete prefabricated block preparation device, includes a variable frequency vibration body 1, the variable frequency vibration body 1 includes a variable frequency vibration table 4 located at the bottom, the top of the variable frequency vibration table 4 is fixedly installed with a special mold 2 for molding, the variable frequency vibration table 4 is connected to the frequency conversion controller 5 through a signal line 8, the top of the variable frequency vibration table 4 is fixed with a top plate 11 through a plurality of columns 10, the bottom end of the top plate 11 is installed with a telescopic rod 6, and the bottom end of the telescopic rod 6 is installed with a variable frequency counterweight 3. The pressurized compacting device is adopted, and the amount of cementitious materials is reduced, the density of the recycled concrete prefabricated block is increased, and its mechanical properties and durability are improved through variable frequency vibration and pressurized molding. At the same time, the preparation method is simple. In the specific preparation process, the recycled concrete is pressurized by the variable frequency counterweight 3, and the concrete is vibrated while pressurizing. Through the pressurized variable frequency vibration process, the pressurized compacted recycled concrete prefabricated block can be finally obtained.

[0025] Furthermore, the variable frequency vibration body 1 is a vertically arranged rectangular body, and the four corners of the bottom are fixedly connected with support feet 9. The variable frequency vibration body 1 can be used to provide vibration power during the preparation process, thereby vibrating the prepared concrete to ensure the density of the concrete.

[0026] Furthermore, the special mold 2 adopts a rectangular box structure, and a raised grid texture is arranged inside the rectangular box structure. The raised grid texture is used to facilitate subsequent demoulding.

[0027] Furthermore, the special mold 2 is positioned and installed on the top of the variable frequency vibration table 4 through a plurality of slots 7. The slots 7 ensure the reliability of the installation and fixation of the special mold 2, and prevent the problem of falling off during the preparation process.

[0028] Furthermore, the frequency conversion controller 5 can perform timed frequency conversion. The timed frequency conversion control ensures the control of pressure and vibration frequency in the subsequent preparation process of the concrete prefabricated blocks, thereby ensuring the best preparation effect.

[0029] Furthermore, the variable frequency counterweight block 3 is connected to the variable frequency controller 5; the lower end surface of the variable frequency counterweight block 3 is provided with a raised grid texture. The above-mentioned grid texture facilitates demoulding and also facilitates molding of the outer surface of the concrete.

[0030] Furthermore, the size of the variable frequency counterweight block 3 matches the size of the special mold 2 , and can increase the variable frequency vibration of the recycled concrete inside the special mold 2 .

[0031] In the specific preparation process: when preparing the recycled concrete prefabricated blocks, a certain amount of cement, sand, gravel, recycled aggregate, solid waste, admixture and water are poured into a mixing barrel and stirred to obtain a recycled concrete mixture for standby use; The preparation process of the pressurized dense recycled concrete prefabricated block preparation device is specifically as follows: transporting the recycled concrete mixture into the special mold 2 through the transport pipeline; starting the frequency conversion controller 5, controlling the pressure of the frequency conversion counterweight block 3 to be 2.0 kPa, the frequency to be low frequency 25~50 HZ, 20 s, medium frequency 83~133 HZ, 20 s, high frequency 167 HZ, 20 s, controlling the frequency of the frequency conversion vibration table 4 to be consistent with the frequency of the frequency conversion counterweight block, and performing pressurized variable frequency vibration; After the supercharged variable frequency vibration is finished, the variable frequency controller 5 is suspended, and the variable frequency vibration body 1 is allowed to stand for 2 hours to obtain a supercharged compact recycled concrete prefabricated block. The supercharged compact recycled concrete prefabricated block formed in this embodiment is tested for compressive strength, splitting strength, axial tensile performance and impermeability performance with reference to DL / T 5150-2017 "Testing Procedures for Hydraulic Concrete", and the test results are shown in Tables 1 to 4.

[0032] Embodiment 2: The requirements for raw materials and the preparation device of recycled concrete prefabricated blocks in this embodiment are the same as those in Embodiment 1. The difference is that the pressure of the variable frequency counterweight block 3 is 3.5 kPa.

[0033] The test method of the pressurized compact recycled concrete prefabricated blocks formed in this embodiment is the same as that in Embodiment 1, and the test results are shown in Tables 1-2.

[0034] Embodiment 3: The requirements for raw materials and the preparation device of recycled concrete prefabricated blocks in this embodiment are the same as those in Embodiment 1. The difference is that the pressure of the variable frequency counterweight block 3 is 4.5 kPa.

[0035] The test method of the pressurized compact recycled concrete prefabricated blocks formed in this embodiment is the same as that in Embodiment 1, and the test results are shown in Tables 1-2.

[0036] Embodiment 4: The requirements for raw materials and the preparation device of recycled concrete prefabricated blocks in this embodiment are the same as those in Embodiment 1. The difference is that the pressure of the variable frequency counterweight block 3 is 5.5 kPa.

[0037] The test method of the pressurized compact recycled concrete prefabricated blocks formed in this embodiment is the same as that in Embodiment 1, and the test results are shown in Tables 1-2.

[0038] Comparative Example 1: The requirements for raw materials and the preparation device of recycled concrete prefabricated blocks in this comparative example are the same as those in Example 1. The difference is that the variable frequency counterweight block 3 is not used.

[0039] The test method of the recycled concrete prefabricated blocks formed in this comparative example is the same as that in Example 1, and the test results are shown in Tables 1-2.

[0040] Effect analysis: Table 1 Compressive strength test results

[0041] Table 1 shows that the compressive strength of the pressurized compacted recycled concrete precast blocks formed by different pressure frequency conversion counterweights in Examples 1 to 4 at different ages is greater than that of the recycled concrete precast blocks formed by frequency conversion counterweights in Comparative Example 1. At the same time, the compressive strength of the pressurized compacted recycled aggregate precast blocks increases with the increase of the pressure value of the frequency conversion counterweight. Compared with Comparative Example 1, the compressive strength increase of the pressurized compacted recycled concrete precast blocks in Examples 1 to 4 is between 0.84% ​​and 8.67%. This shows that the use of a pressurized compacting device to form recycled concrete precast blocks is beneficial to increasing their density, thereby improving the compressive strength of the recycled concrete precast blocks. The compressive strength improvement effect of Example 4 is the best.

[0042] Table 2 Splitting strength test results

[0043] Table 2 shows that the splitting tensile strength at different ages of the pressurized compacted recycled concrete precast blocks formed by different pressure frequency conversion counterweights in Examples 1 to 4 is greater than that of the recycled concrete precast blocks formed by frequency conversion counterweights in Comparative Example 1. At the same time, the splitting tensile strength of the pressurized compacted recycled concrete precast blocks increases with the increase of the pressure value of the frequency conversion counterweight. Compared with Comparative Example 1, the increase in the compressive strength of the pressurized compacted recycled concrete precast blocks in Examples 1 to 4 is between 2.27% and 26.95%. The splitting tensile strength improvement effect of Example 4 is the best. Consistent with the law of compressive strength change, it is once again shown that the use of a pressurized compacting device to form recycled concrete precast blocks is beneficial to increase their density, thereby improving the splitting tensile strength of the recycled concrete precast blocks.

[0044] Table 3 Axial tensile properties test results

[0045] Table 3 shows that the axial tensile strength and ultimate tensile value of the pressurized compacted recycled concrete prefabricated blocks formed by different pressure frequency conversion counterweights in Examples 1 to 4 at different ages are greater than those of the recycled concrete prefabricated blocks formed by frequency conversion counterweights in Comparative Example 1. At the same time, the axial tensile strength and ultimate tensile value of the pressurized compacted recycled concrete prefabricated blocks increase with the increase of the pressure value of the frequency conversion counterweight. Among them, the axial tensile performance of Example 4 is the best. This is consistent with the variation law of the above test results, indicating that the use of a pressurized compacting device to form recycled concrete prefabricated blocks is beneficial to improving the axial tensile strength and ultimate tensile value of recycled concrete prefabricated blocks.

[0046] Table 4 Anti-seepage performance test results

[0047] Table 3 shows that the water seepage height of the pressurized compact recycled concrete prefabricated blocks formed by different pressure frequency conversion counterweight blocks in Examples 1 to 4 is lower than that of the recycled concrete prefabricated blocks formed by frequency conversion counterweight blocks in Comparative Example 1. At the same time, the anti-seepage grade of the pressurized compact recycled concrete prefabricated blocks in Examples 1 to 4 is higher than that of Comparative Example 1. In addition, the water seepage height of the pressurized compact recycled concrete prefabricated blocks decreases with the increase of the pressure value of the frequency conversion counterweight block, and the anti-seepage grade of the pressurized compact recycled concrete prefabricated blocks increases with the increase of the pressure value of the frequency conversion counterweight block. Compared with Comparative Example 1, the water seepage height of the pressurized compact recycled concrete prefabricated blocks in Examples 1 to 4 decreases by more than 28.5%, and can reach up to 86.13%. Among them, the anti-seepage performance of Example 4 is the best. This shows that the pressurized compacting device is beneficial to improving the anti-seepage performance of the recycled concrete prefabricated blocks.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pressurized compact recycled concrete prefabricated block preparation device, characterized in that: The invention comprises a variable frequency vibration machine body (1), wherein the variable frequency vibration machine body (1) comprises a variable frequency vibration table (4) located at the bottom, a special mold (2) for forming is fixedly installed on the top of the variable frequency vibration table (4), the variable frequency vibration table (4) is connected to a variable frequency controller (5) via a signal line (8), a top plate (11) is fixed on the top of the variable frequency vibration table (4) via a plurality of columns (10), a telescopic rod (6) is installed at the bottom end of the top plate (11), and a variable frequency counterweight (3) is installed at the bottom end of the telescopic rod (6).

2. According to claim 1, a pressurized dense recycled concrete prefabricated block preparation device is characterized in that: The variable frequency vibration body (1) is a vertically arranged rectangular body, and support feet (9) are fixedly connected to the four corners of the bottom end.

3. The device for preparing pressurized compact recycled concrete prefabricated blocks according to claim 1, characterized in that: The special mold (2) adopts a rectangular box structure, and a raised grid texture is arranged inside the rectangular box structure.

4. The device for preparing pressurized compact recycled concrete prefabricated blocks according to claim 1, characterized in that: The special mold (2) is positioned and installed on the top of the variable frequency vibration table (4) through a plurality of slots (7).

5. The device for preparing pressurized dense recycled concrete prefabricated blocks according to claim 1, characterized in that: The frequency conversion controller (5) is capable of performing timed frequency conversion.

6. The device for preparing pressurized dense recycled concrete prefabricated blocks according to claim 5, characterized in that: The variable frequency counterweight block (3) is connected to the variable frequency controller (5); and a raised grid texture is provided on the lower end surface of the variable frequency counterweight block (3).

7. The device for preparing pressurized dense recycled concrete prefabricated blocks according to claim 5, characterized in that: The size of the variable frequency counterweight block (3) matches the size of the special mould (2), and can increase variable frequency vibration on the recycled concrete inside the special mould (2).

8. The device for preparing pressurized compact recycled concrete prefabricated blocks according to claim 1, characterized in that: During the operation, the pressure of the variable frequency counterweight (3) is controlled at 2.0-6.0 kPa, and the vibration frequency is controlled at: low frequency 25-50 Hz, medium frequency 83-133 Hz, and high frequency 167 Hz.

9. The device for preparing pressurized dense recycled concrete prefabricated blocks according to claim 1, characterized in that: During the operation, the vibration frequency of the variable frequency vibration table (4) is controlled within the range of: low frequency 25-50 Hz, medium frequency 83-133 Hz, and high frequency 167 Hz.

10. A method for preparing pressurized dense recycled concrete prefabricated blocks, characterized in that: The preparation method is implemented by using the preparation device according to any one of claims 1 to 9, comprising the following steps: Step 1: Preparation of recycled concrete mixture: Pour cement, sand, gravel, recycled aggregate, solid waste, admixture and water required for preparing prefabricated blocks into a mixing barrel and stir to obtain a recycled concrete mixture; Step 2: Transportation of recycled concrete mixture: The recycled concrete mixture prepared in step 1 is transported into a special mold (2) through a transport pipeline, and the special mold (2) is then positioned and fixed on the top of a variable frequency vibration table (4); Step 3: Add vibration molding of recycled concrete mixture: The telescopic rod (6) is controlled to be pressed downward, so that the variable frequency counterweight (3) is extended into the interior of the special mold (2), and the pressure is controlled within a certain range, and then the variable frequency controller (5) is started, and the vibration frequency of the variable frequency counterweight (3) is controlled within a certain range through the variable frequency controller (5); At the same time, the variable frequency vibration table (4) is controlled to vibrate by the variable frequency controller (5), thereby vibrating the special mold (2) as a whole, and controlling the vibration frequency of the variable frequency vibration table (4) within a certain range; This ensures that pressure-boosted variable-frequency vibration is performed during the preparation process; Step 4: Pressure maintenance of precast concrete blocks: After the pressurized variable frequency vibration is finished, the vibration of the variable frequency vibration table (4) and the variable frequency counterweight (3) is suspended by the variable frequency controller (5), and the variable frequency vibration machine body (1) is allowed to stand for at least 2 hours, thereby obtaining a pressurized compact recycled concrete prefabricated block; Step 5: Removal of precast concrete blocks: After the preparation is completed, the recycled concrete prefabricated block is taken out from the special mold (2).

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