A processing device and preparation method for preparing UHPC based on manufactured sand

Abstract

This invention relates to the field of concrete preparation equipment, and in particular to a preparation method and processing equipment for UHPC based on manufactured sand, comprising the following steps: S1, raw material selection; S2, raw material proportioning; S3, raw material mixing; S4, casting and molding; S5, finished product curing; solving the technical problem that the finished product has many internal pores and microcracks that affect the quality of the finished product in the existing process of preparing UHPC using manufactured sand.

Description

Technical Field

[0001] This invention relates to the field of concrete preparation equipment, and more particularly to a processing equipment and preparation method for preparing UHPC based on manufactured sand. Background Technology

[0002] UHPC, or Ultra-High Performance Concrete, is a new type of cement-based composite material with ultra-high strength, high toughness, and ultra-high durability. It achieves superior mechanical properties and durability by optimizing particle size distribution and using efficient admixtures and mineral additives to minimize internal porosity and microcracks.

[0003] Using manufactured sand to prepare UHPC can improve the excellent properties of UHPC while reducing production costs. This is because manufactured sand refers to rock, mine tailings, or industrial waste particles with a particle size of less than 4.75 mm, which are produced by mechanical crushing and screening after soil removal. The raw materials are widely available, including various natural rocks such as granite, limestone, river pebbles, and basalt. Mine tailings, industrial waste, construction waste, waste bricks, and concrete blocks can also be used.

[0004] The preparation process of UHPC requires the selection of raw materials, followed by mixing and stirring according to the required proportions. After stirring, the materials are cast and molded, and then cured.

[0005] Chinese patent application number 202210319212.0 discloses a reinforced concrete pipe with ultra-high performance concrete (UHPC) spigot and socket joints and its preparation method. The reinforced concrete pipe includes: a pipe body, a spigot body, a socket body, and a reinforcing cage; the pipe body is mainly made of concrete; the spigot body is located at one end of the pipe body, coaxial with the pipe body, and is mainly made of UHPC; the socket body is located at the other end of the pipe body, coaxial with the pipe body, and is also mainly made of UHPC; the reinforcing cage is located inside the pipe body, protruding from both ends of the pipe body and extending into the spigot and socket bodies. The reinforced concrete pipe disclosed in this invention has an integrated structure of spigot and socket joints with the pipe body, making it less prone to deformation during production and use. It eliminates the need for separate processing of the spigot and socket steel rings, saving steel and improving production efficiency and product quality. Simultaneously, the pipe joints exhibit good impermeability, corrosion resistance, and high waterproofing. In the process of preparing UHPC, the casting and molding process is particularly important, as it directly affects the quality of the finished UHPC. How to minimize the porosity and microcracks inside the UHPC during the casting and molding process has become a research direction and topic of in-depth discussion in the industry. Summary of the Invention

[0006] Therefore, in view of the above problems, the present invention proposes a processing equipment and preparation method for preparing UHPC based on manufactured sand, which solves the technical problem that the finished product has a lot of internal pores and microcracks, which affects the quality of the finished product in the existing process of preparing UHPC using manufactured sand.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a processing equipment for preparing UHPC based on manufactured sand, comprising a mixer and an integrated casting and molding equipment, wherein the integrated casting and molding equipment comprises a storage reactor, a connecting pipe, and a molding die, the connecting pipe connecting the storage reactor and the molding die, a first defoaming mechanism being provided inside the storage reactor, and a second defoaming mechanism being provided inside the connecting pipe, both the first and second defoaming mechanisms being used to eliminate air bubbles in the mixture, the first defoaming mechanism being located on the inner circumferential side of the storage reactor, and the second defoaming mechanism being located on the inner wall of the connecting pipe; the storage reactor has a structure of a cylinder and a frustum joined together, the storage reactor comprising a first storage section and a second storage section from top to bottom, the first defoaming mechanism... Located at the boundary between the first and second storage sections, the first defoaming mechanism includes an annular drive track surrounding the inner circumferential side of the storage reactor, an annular rotating ring locked within the annular drive track, and a lever surrounding the annular rotating ring. The annular drive track has a first meshing tooth, and the annular rotating ring has a second meshing tooth. The first meshing tooth and the second meshing tooth mesh with each other. The first meshing tooth is driven to rotate by a drive motor, which in turn drives the annular rotating ring to rotate through the second meshing tooth. The annular drive track has a first electric push rod, and the annular rotating ring has a push block that cooperates with the first electric push rod. The lever is fixedly connected to the push block, and the first electric push rod is magnetically connected to the push block.

[0008] Furthermore, the actuating rod has a thin plate-like structure, and the speed at which the first electric push rod pushes outward is 3-5 times the speed at which it retracts inward.

[0009] Furthermore, the second defoaming mechanism includes a first convex ring, a second convex ring, and a third convex ring that are arranged around the inner wall of the connecting pipe. The convex height of the first convex ring, the second convex ring, and the third convex ring increases sequentially. The difference in convex height between two adjacent convex rings is 3mm-5mm, and the vertical spacing between two adjacent convex rings is the same.

[0010] A preparation method for preparing UHPC based on manufactured sand using processing equipment includes the following steps:

[0011] S1. Raw material selection; Raw material selection includes cementitious materials, fine aggregates, fiber materials, and additives;

[0012] S2. Raw material ratio: Based on the design requirements and performance indicators, accurately calculate the amount of each raw material to ensure the optimal material gradation.

[0013] S3. Raw material mixing; The raw material mixing method is mixed mixing, which includes dry mixing and wet mixing. Dry mixing is performed first, followed by wet mixing.

[0014] S4. Casting and molding: The mixed material is cast and molded using an integrated casting and molding equipment.

[0015] S5. Finished Product Curing: UHPC is cured under specific temperature and humidity conditions to ensure the full performance of the material.

[0016] In step S1, the cementitious materials include silicate cement, silica fume, and fly ash; the fine aggregates include quartz sand and manufactured sand; the fiber material is steel fiber; and the admixtures include high-efficiency water-reducing agent and defoamer. In step S2, the raw material ratio is 80-120 parts silicate cement, 50-60 parts silica fume, 50-60 parts fly ash, 120-150 parts water, 5-8 parts high-efficiency water-reducing agent, 4-5 parts defoamer, 48-54 parts steel fiber, 100-120 parts quartz sand, and 100-120 parts manufactured sand. In step S4, the integrated casting and molding equipment simultaneously performs vibration refining treatment during operation and uses a plasma generator to perform plasma treatment on the mixture.

[0017] Furthermore, the mixing and stirring in step S3 is further divided into the following steps:

[0018] S3.1 Dry mixing; First, add the cementitious materials and fine aggregates to the mixer for dry mixing. The dry mixing time is 30 minutes to ensure that all materials are fully mixed and uniform.

[0019] S3.2 Wet mixing: Add purified water, additives and fiber materials to the uniformly mixed dry materials, and stir thoroughly until the mixture is uniform and has good workability. The stirring time is 15 minutes.

[0020] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0021] 1. This invention uses manufactured sand as the main raw material to prepare UHPC. The advantage lies in improving the inherent properties of UHPC while reducing production costs. This is because manufactured sand refers to rock, mine tailings, or industrial waste particles with a particle size less than 4.75 mm, produced by mechanical crushing and screening after soil removal. Its raw material sources are wide-ranging, commonly including various natural rocks such as granite, limestone, river pebbles, and basalt. Mine tailings, industrial waste, construction waste, waste bricks, and concrete blocks can also be used. By subdividing the steps and improving key processes during preparation, the finished UHPC can overcome the technical problem of excessive internal pores and micro-cracks affecting the quality of the finished product when using manufactured sand in existing UHPC preparation processes. Specifically, vibration during the casting process eliminates internal pores and cracks in the UHPC, ensuring that the finished UHPC does not exhibit micro-cracks. To address cracking, this invention selects silica fume as the cementitious material. The addition of silica fume can significantly improve the strength and durability of UHPC, while fly ash helps improve the workability of concrete. Increasing steel fibers can improve the toughness and tensile strength of UHPC. The diameter of the steel fibers is 0.15-0.2 mm and the length is 8-14 mm. The purpose of adding a high-efficiency water-reducing agent is to reduce the water-cement ratio of the concrete and increase its strength. At the same time, in the preparation of UHPC in this invention, the mud content and mud lump content will be minimized as much as possible to ensure the quality of the concrete. During the mixing process, it should be ensured that the steel fibers are evenly dispersed in the concrete to improve the toughness and tensile strength of the concrete.

[0022] 2. In this invention, the mixing process is divided into dry mixing and wet mixing. Dry mixing allows various materials to be mixed evenly in a dry state. Then, pure water, additives and steel fibers are gradually added. The mixing is carried out using a vertical shaft planetary mixer to overcome the problem of uneven mixing due to excessive viscosity of the mixture.

[0023] 3. The processing equipment used in this invention includes a mixer and an integrated casting and molding equipment. The main improvement to the integrated casting and molding equipment is the addition of a first defoaming mechanism and a second defoaming mechanism. The purpose of adding the first and second defoaming mechanisms is that the UHPC in this invention has already reduced the porosity and microcracks inside the material to a minimum through optimizing the particle size distribution, using high-efficiency additives and mineral admixtures. However, despite the improvement of the raw materials, porosity and microcracks may still exist in the mixture. Therefore, a vibration sweeping method is used to remove any possible porosity and microcracks.

[0024] 4. The first defoaming mechanism in this invention provides a first defoaming process for the mixture. It is located at the boundary between the first and second storage sections. The first and second storage sections are cylindrical and frustum-shaped, respectively. When the mixture moves from the first storage section to the second storage section, its diameter shrinks, undergoing a pre-contraction process. During this process, any pores that may exist inside the mixture are initially eliminated by compression or its volume is reduced. The defoaming principle of the first defoaming mechanism is that the first meshing tooth on the annular drive track rotates, driving the second meshing tooth on the annular rotating ring to rotate. Consequently, the annular rotating ring follows the rotation. During the rotation, a lever on the annular rotating ring moves the mixture, meaning that the mixture flowing down from top to bottom passes through the lever. The actuation of the lever eliminates any possible internal pores. The lever does not rotate laterally; instead, when the connecting push block is magnetically connected to the first electric push rod, it drives the lever to perform a reciprocating motion near or away from the center of the annular rotating ring. This motion, combined with the horizontal rotation of the lever, improves defoaming efficiency. Simultaneously, during defoaming, the lever's simultaneous horizontal rotation and horizontal extension / retraction motion defoams more effectively in the more central area of ​​the mixture. Furthermore, in this invention, the outward pushing speed of the first electric push rod is 3-5 times its inward retraction speed. This ensures that the lever pushes out quickly, and after contacting the pores, the retraction process is slow, minimizing the creation of new pores during retraction.

[0025] 5. In this invention, the first electric push rod and the push block are connected by magnetic attraction. The reason for using magnetic attraction is specifically electromagnetic attraction. The reason for using electromagnetic attraction is that it ensures the flexibility of the connection between the two. On the other hand, the electromagnetic attraction ensures that the first electric push rod and the push block will vibrate due to instantaneous contact at the moment of magnetic attraction. This vibration will be transmitted from the first electric push rod to the push block and then to the actuating rod, so that the actuating rod will defoam at this moment by vibration.

[0026] 6. The second defoaming mechanism in this invention works in conjunction with the first defoaming mechanism. After the mixture passes through the first defoaming mechanism, there are almost no pores inside. However, in order to improve the quality of the finished product, the second defoaming mechanism uses overlapping convex rings, and the height of each convex ring is different, presenting a stepped shape. This ensures that the mixture flowing down from top to bottom has an inward contraction process. Its principle is similar to the first and second storage sections in the internal structure of the storage reactor. However, because the first, second, and third convex rings are spaced apart, the mixture undergoes a vibration process when passing through the second defoaming mechanism. Thus, any pores that may exist in the mixture can be completely eliminated through multiple defoaming processes and the characteristics of the raw materials themselves. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0028] Figure 1 This is a schematic diagram of the integrated casting and molding equipment in this invention;

[0029] Figure 2 This is a schematic diagram of the first defoaming mechanism in this invention;

[0030] Figure 3 This is a top view schematic diagram of the annular drive track structure in this invention;

[0031] Figure 4 This is a top view of the annular rotating ring structure in this invention;

[0032] Figure 5 This is a sectional view of the vertical cross-section of the lever in this invention;

[0033] Figure 6 This is a schematic diagram of the second defoaming mechanism in this invention;

[0034] Figure 7 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0035] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0036] Please see Figures 1-7 This invention provides a method for preparing UHPC based on manufactured sand, comprising the following steps:

[0037] S1. Raw material selection; Raw material selection includes cementitious materials, fine aggregates, fiber materials, and additives;

[0038] S2. Raw material ratio: Based on the design requirements and performance indicators, accurately calculate the amount of each raw material to ensure the optimal material gradation.

[0039] S3. Raw material mixing; The raw material mixing method is mixed mixing, which includes dry mixing and wet mixing. Dry mixing is performed first, followed by wet mixing.

[0040] S4. Casting and molding: The mixed material is cast and molded using an integrated casting and molding equipment.

[0041] S5. Finished Product Curing: UHPC is cured under specific temperature and humidity conditions to ensure the full performance of the material.

[0042] In step S1, the cementitious materials include silicate cement, silica fume, and fly ash; the fine aggregates include quartz sand and manufactured sand; the fiber material is steel fiber; and the admixtures include high-efficiency water-reducing agents and defoamers.

[0043] In step S2, the raw material ratio is 80 parts silicate cement, 50 parts silica fume, 50 parts fly ash, 120 parts water, 5 parts high-efficiency water-reducing agent, 4 parts defoamer, 48 parts steel fiber, 100 parts quartz sand, and 100 parts manufactured sand.

[0044] Step S3, mixing and stirring, is further divided into the following steps:

[0045] S3.1 Dry mixing; First, add the cementitious materials and fine aggregates to the mixer for dry mixing. The dry mixing time is 30 minutes to ensure that all materials are fully mixed and uniform.

[0046] S3.2 Wet mixing: Add purified water, additives and fiber materials to the evenly mixed dry materials, and stir thoroughly until the mixture is uniform and has good workability. The stirring time is 15 minutes.

[0047] In step S4, the integrated casting and molding equipment simultaneously performs vibration refining during operation, and uses a plasma generator to perform plasma treatment on the mixture.

[0048] This embodiment also proposes a processing device for the preparation method described above, used in the preparation method of UHPC based on manufactured sand. The device includes a mixer and an integrated casting and molding equipment. The mixer is an industrial mixer, which is a well-known device with a wide range of options, and will not be described in detail here. The integrated casting and molding equipment includes a storage reactor 1, a connecting pipe 2, and a molding die 3. The connecting pipe 2 connects the storage reactor 1 and the molding die 3. A first defoaming mechanism 4 is installed inside the storage reactor 1, and a second defoaming mechanism 5 is installed inside the connecting pipe 2. Both the first defoaming mechanism 4 and the second defoaming mechanism 5 are used to eliminate air bubbles in the mixture. The first defoaming mechanism 4 is located on the inner circumferential side of the storage reactor 1, and the second defoaming mechanism 5 is located on the inner wall of the connecting pipe 2.

[0049] The storage reactor 1 has a structure consisting of a cylinder and a frustum joined together. From top to bottom, the storage reactor 1 includes a first storage section 11 and a second storage section 12. A first defoaming mechanism 4 is located at the boundary between the first storage section 11 and the second storage section 12. The first defoaming mechanism 4 includes an annular drive track 41 surrounding the inner circumferential side of the storage reactor 1, an annular rotating ring 42 engaged within the annular drive track 41, and a lever 43 surrounding the annular rotating ring 42. The annular drive track 41 has a first meshing tooth 411, and the annular rotating ring 42 has a second meshing tooth 421. The first meshing tooth 411 meshes with the second meshing tooth 421. The first meshing tooth 411 is driven to rotate by a drive motor, thereby driving the annular rotating ring through the second meshing tooth 421. The ring rotates. A first electric push rod 44 is provided on the annular drive track 41. A push block 45 that cooperates with the first electric push rod 44 is provided on the annular rotating ring 42. A deflector 43 is fixedly connected to the push block 45. The first electric push rod 44 is magnetically connected to the push block 45. The first electric push rod 44 is fixedly set and does not rotate with the first meshing tooth. When the annular rotating ring 42 rotates to the point where the first electric push rod 44 is magnetically connected to the push block 45, the deflector 43 is extended and retracted by the traction force of the first electric push rod 44. When the first electric push rod 44 and the push block 45 are separated, the deflector 43 rotates horizontally. When the deflector 43 is extended and retracted, the annular rotating ring 42 remains stationary and does not rotate.

[0050] The actuating rod 43 is a thin plate-shaped structure. The speed at which the first electric push rod 44 pushes outward is 5 times the speed at which it retracts inward, ensuring a fast outward and slow retraction process. The purpose of the slow retraction is to avoid the actuating rod 43 regenerating a gap during the retraction process.

[0051] refer to Figure 6 The second defoaming mechanism 5 includes a first protruding ring 51, a second protruding ring 52, and a third protruding ring 53 arranged around the inner wall of the connecting pipe. The protrusion height of the first protruding ring 51, the second protruding ring 52, and the third protruding ring 53 increases sequentially. The difference in protrusion height between two adjacent protruding rings is 5mm, and the vertical spacing between two adjacent protruding rings is the same.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0053] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A processing device for preparing UHPC based on manufactured sand, comprising a mixer and an integrated casting and molding device, characterized in that: The integrated casting and molding equipment includes a storage reactor, a connecting pipe, and a molding die. The connecting pipe connects the storage reactor and the molding die. A first defoaming mechanism is installed inside the storage reactor, and a second defoaming mechanism is installed inside the connecting pipe. Both the first and second defoaming mechanisms are used to eliminate air bubbles in the mixture. The first defoaming mechanism is located on the inner circumferential side of the storage reactor, and the second defoaming mechanism is located on the inner wall of the connecting pipe. The storage reactor has a structure consisting of a cylinder and a frustum joined together. From top to bottom, the storage reactor includes a first storage section and a second storage section. The first defoaming mechanism is located at the boundary between the first and second storage sections. The foaming mechanism includes an annular drive track surrounding the inner circumferential side of the storage reactor, an annular rotating ring locked within the annular drive track, and a lever surrounding the annular rotating ring. The annular drive track has a first meshing tooth, and the annular rotating ring has a second meshing tooth. The first meshing tooth and the second meshing tooth mesh with each other. The first meshing tooth is driven to rotate by a drive motor, which in turn drives the annular rotating ring to rotate through the second meshing tooth. The annular drive track has a first electric push rod, and the annular rotating ring has a push block that cooperates with the first electric push rod. The lever is fixedly connected to the push block, and the first electric push rod is magnetically connected to the push block.

2. The processing equipment for preparing UHPC based on manufactured sand according to claim 1, characterized in that: The actuating lever has a thin plate-like structure, and the speed at which the first electric push rod pushes outward is 3-5 times the speed at which it retracts inward.

3. The processing equipment for preparing UHPC based on manufactured sand according to claim 2, characterized in that: The second defoaming mechanism includes a first convex ring, a second convex ring, and a third convex ring that are arranged around the inner wall of the connecting pipe. The convex height of the first convex ring, the second convex ring, and the third convex ring increases sequentially. The difference in convex height between two adjacent convex rings is 3mm-5mm, and the vertical spacing between two adjacent convex rings is the same.

4. A preparation method, wherein the processing equipment as described in claim 3 is used to prepare UHPC based on manufactured sand, characterized in that: Includes the following steps: S1. Raw material selection; Raw material selection includes cementitious materials, fine aggregates, fiber materials, and additives; S2, Raw material ratio; Based on the design requirements and performance indicators, the amount of each selected raw material is precisely calculated to ensure the optimal material gradation. S3. Raw material mixing; The raw material mixing method is mixed mixing, which includes dry mixing and wet mixing. Dry mixing is performed first, followed by wet mixing. S4. Casting and molding: The mixed material is cast and molded using an integrated casting and molding equipment. S5. Finished Product Curing: UHPC is cured under specific temperature and humidity conditions to ensure the full performance of the material. In step S1, the cementitious materials include silicate cement, silica fume, and fly ash; the fine aggregates include quartz sand and manufactured sand; the fiber material is steel fiber; and the admixtures include high-efficiency water-reducing agent and defoamer. In step S2, the raw material ratio is 80-120 parts silicate cement, 50-60 parts silica fume, 50-60 parts fly ash, 120-150 parts water, 5-8 parts high-efficiency water-reducing agent, 4-5 parts defoamer, 48-54 parts steel fiber, 100-120 parts quartz sand, and 100-120 parts manufactured sand. In step S4, the integrated casting and molding equipment simultaneously performs vibration refining treatment during operation and uses a plasma generator to perform plasma treatment on the mixture.

5. The preparation method according to claim 4, characterized in that: Step S3, mixing and stirring, is further divided into the following steps: S3.1 Dry mixing; First, add the cementitious materials and fine aggregates to the mixer for dry mixing. The dry mixing time is 30 minutes to ensure that all materials are fully mixed and uniform. S3.2 Wet mixing: Add purified water, additives and fiber materials to the uniformly mixed dry materials, and stir thoroughly until the mixture is uniform and has good workability. The stirring time is 15 minutes.

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