A crack-resistant roller-compacted concrete structure and its construction method

Abstract

This invention discloses a crack-resistant roller-compacted concrete (RCC) structure. Several slow-release mechanisms are embedded between adjacent compacted layers within the RCC structure. These slow-release mechanisms are steel fibers with expanded clay aggregate connected to both ends. The invention also discloses a construction method for the crack-resistant RCC structure, comprising the following steps: 1. Fixing template A and then spreading the RCC; 2. Laying template B with the slow-release mechanisms and compacting it multiple times using a compaction machine; 3. Covering with mortar and then spreading the RCC; 4. Repeating steps 2 to 3 until the target thickness of the RCC structure is achieved. The RCC structure of this invention, by embedding slow-release mechanisms between adjacent compacted layers and connecting them with steel fibers, improves the bonding strength between the compacted layers. Combined with saturated expanded clay aggregate, it reduces drying shrinkage by slowly releasing moisture within the RCC, making it applicable to the field of RCC technology.

Description

Technical Field

[0001] This invention belongs to the field of roller-compacted concrete technology, and in particular relates to a crack-resistant roller-compacted concrete structure and construction method. Background Technology

[0002] Roller-compacted concrete (RCC), a dam-building material that combines earth-rock dam construction compaction technology with concrete pouring technology, has advantages such as low cement consumption, low heat of hydration, fast construction speed, and low cost, and is widely used in the field of water conservancy engineering.

[0003] Because dams in hydraulic engineering projects have large volumes, the hydration reaction causes heat to accumulate inside the dam, making it difficult to dissipate. This creates a significant temperature difference between the concrete's interior and surface, generating thermal stress. When this thermal stress exceeds the tensile strength of the concrete, cracks will form. Simultaneously, roller-compacted concrete has a lower internal water content, resulting in relatively faster water loss during hardening and more pronounced drying shrinkage. The tensile stress generated by drying shrinkage can lead to micro-cracks within the concrete. Over time, these micro-cracks may gradually expand, forming macro-cracks and reducing the concrete's impermeability and durability. Furthermore, roller-compacted concrete is constructed using layered compaction, which can create weak interfaces between layers. Under subsequent temperature changes, wet-dry cycles, and loads, these weak points are prone to cracking, which can propagate upwards or downwards, affecting the overall structural integrity. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a crack-resistant roller-compacted concrete structure. This roller-compacted concrete structure solves the problem of cracking in roller-compacted concrete structures by embedding a slow-release mechanism between adjacent roller-compacted layers, connecting the layers with steel fibers to improve the bonding strength, and by incorporating saturated expanded clay aggregates to slowly release moisture within the roller-compacted concrete, reducing drying shrinkage.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a crack-resistant roller-compacted concrete structure, wherein a plurality of slow-release mechanisms are embedded between adjacent roller-compacted layers in the roller-compacted concrete structure, wherein the slow-release mechanism is a steel fiber with ceramsite connected to both ends, and the ceramsite is treated with water saturation.

[0006] The aforementioned crack-resistant roller-compacted concrete structure contains thermosensitive hydrogel within the ceramsite.

[0007] The method for preparing the slow-release mechanism in the aforementioned crack-resistant roller-compacted concrete structure includes the following steps:

[0008] Step 1: Granulate the raw material powder and then sinter it to obtain ceramsite;

[0009] Step 2: Drill holes in the surface of the ceramsite obtained in Step 1, then press the ends of the steel fibers into the holes, inject epoxy resin at the connection between the ceramsite and the steel fibers, and then cure it to obtain the slow-release mechanism.

[0010] The above-mentioned crack-resistant roller-compacted concrete structure, the granulation process in step one is as follows: the raw material powder is placed in a disc granulator, and water or temperature-sensitive hydrogel is sprayed to roll the raw material powder into particles with a particle size of 10mm~20mm.

[0011] This invention controls the particle size of the expanded clay aggregate to 10mm~20mm, which is within the range of aggregate size for roller-compacted concrete, and thus enables better bonding with roller-compacted concrete.

[0012] In the aforementioned crack-resistant roller-compacted concrete structure, the steel fiber in step two has a length of not less than 60 mm and a diameter of 0.25 mm to 0.60 mm.

[0013] This invention controls the length and diameter of steel fibers to control their tensile strength, thereby improving the bonding force between the compacted surfaces. At the same time, the presence of expanded clay aggregates at both ends of the steel fibers increases the contact area between the steel fibers and the roller-compacted concrete, further enhancing the bonding force between the compacted surfaces.

[0014] The present invention also discloses a construction method for the above-mentioned crack-resistant roller-compacted concrete structure, the construction method comprising the following steps:

[0015] Step 1: Fix template A, and then spread the roller-compacted concrete mixture.

[0016] Step 2: Lay a template B with a slow-release mechanism on the roller-compacted concrete surface that was laid in Step 1, and then use a roller compactor to compact it multiple times. After removing the template, a compacted surface is obtained. The slow-release mechanism is soaked in water before being laid.

[0017] Step 3: Cover the compacted surface obtained in Step 2 with mortar, and then spread and compact concrete again;

[0018] Step 4: Repeat steps 2 to 3 until the target thickness of the roller-compacted concrete structure is achieved. Water curing is carried out after 6 to 12 hours.

[0019] In the above-mentioned construction method for a crack-resistant roller-compacted concrete structure, in step two, the template B is provided with several through holes, and a silicone groove is fixedly connected in the through holes. The silicone groove is used to wrap the end of the slow-release mechanism, and the silicone groove has a cavity inside. A piston is provided in the through hole. The piston consists of a piston head and a push rod. The front end of the piston head is embedded in the cavity of the silicone groove, and the end of the piston push rod away from the piston head extends out of the through hole.

[0020] The above-mentioned construction method for a crack-resistant roller-compacted concrete structure includes a through hole comprising a vertical section and a protective section, a silicone groove fixedly connected at the junction of the vertical section and the protective section, and a positioning key provided at the end of the vertical section away from the protective section.

[0021] In the above-mentioned construction method for a crack-resistant roller-compacted concrete structure, the piston head is made of rubber or silicone, and the rear end of the piston head is embedded in the vertical section and closely fits the inner wall of the vertical section.

[0022] In the above-mentioned construction method for a crack-resistant roller-compacted concrete structure, the end of the push rod away from the piston head is connected to a roller plate.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The roller-compacted concrete structure of the present invention improves the bonding force between adjacent roller-compacted layers by embedding a slow-release mechanism between adjacent roller-compacted layers and connecting steel fibers between them. In addition, it combines water-saturated ceramsite to reduce the degree of drying shrinkage and reduce the generation of internal cracks by slowly releasing water inside the roller-compacted concrete.

[0025] 2. This invention utilizes expanded clay aggregate containing thermosensitive hydrogel to increase the water content of the slow-release mechanism, extending the water release time and continuously providing moisture for the concrete hydration process. Simultaneously, due to the permeability of the expanded clay aggregate and the temperature-sensitive hydrogel's ability to absorb and release water with temperature changes, in humid weather such as rain or snow, where the external environment has extremely high moisture content, water seepage may occur inside the roller-compacted concrete structure. In this case, the pores of the expanded clay aggregate provide a path for water to penetrate, allowing water to contact the internal thermosensitive hydrogel, causing the hydrogel to absorb water and reduce the internal moisture content of the roller-compacted concrete structure. In hot weather, the thermosensitive hydrogel releases water, increasing the internal moisture content of the roller-compacted concrete structure, which is beneficial for long-term hydration. This ensures that the internal moisture content of the roller-compacted concrete remains within a small fluctuation range throughout its service life, extending its service life.

[0026] 3. The present invention, through the design of template B, enables the slow-release mechanism to be smoothly inserted into the compacted layer of roller-compacted concrete, and exposes the end of the slow-release mechanism on the surface of the compacted layer. After the roller-compacted concrete is laid, the end of the slow-release mechanism can extend into the adjacent compacted layer, thereby realizing the preparation of the roller-compacted concrete structure.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the roller-compacted concrete structure of the present invention.

[0029] Figure 2 This is a schematic diagram of the structure of template B of the present invention.

[0030] Figure 3 for Figure 2 A magnified structural diagram of point A.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1—Sustained-release mechanism; 2—Through hole; 201—Vertical section; 202—Protective section; 203—Positioning key; 3—Silicone groove; 4—Piston; 401—Piston head; 402—Push rod; 5—Rolling plate. Detailed Implementation

[0033] Example 1

[0034] like Figure 1 As shown, in this embodiment, several slow-release mechanisms 1 are embedded between adjacent roller-compacted concrete layers. Each slow-release mechanism 1 is a steel fiber with expanded clay aggregate connected to both ends. The expanded clay aggregate has been treated with water saturation. The preparation method of the slow-release mechanism 1 includes the following steps:

[0035] Step 1: Place the raw material powder in a disc granulator, spray water to roll the raw material powder into particles with a particle size of 10mm~20mm, and then sinter to obtain ceramsite.

[0036] Step 2: Drill holes in the surface of the ceramsite obtained in Step 1, then press the ends of steel fibers with a length of 60mm~80mm and a diameter of 0.25mm~0.60mm into the holes, inject epoxy resin at the connection between the ceramsite and the steel fiber and cure it to obtain the slow-release mechanism 1.

[0037] The method for constructing roller-compacted concrete structures using the slow-release mechanism 1 prepared in this embodiment includes the following steps:

[0038] Step 1: Fix template A, and then spread the roller-compacted concrete mixture.

[0039] Step 2: Lay a template B with a slow-release mechanism 1 on the roller-compacted concrete surface that was laid in Step 1, and then use a roller compactor to compact it multiple times. After removing the template, a compacted surface is obtained. The slow-release mechanism 1 is soaked in water before being laid.

[0040] Step 3: Cover the compacted surface obtained in Step 2 with mortar, and then spread and compact concrete again;

[0041] Step 4: Repeat steps 2 to 3 until the target thickness of the roller-compacted concrete structure is achieved. Water curing is carried out after 6 to 12 hours.

[0042] like Figure 2 and Figure 3As shown, template B in this embodiment has several through holes 2. A silicone groove 3 is fixedly connected in the through hole 2. The silicone groove 3 is used to wrap the end of the slow-release mechanism 1, and the silicone groove 3 has a cavity inside. A piston 4 is provided in the through hole 2. The piston 4 consists of a piston head 401 and a push rod 402. The front end of the piston head 401 is embedded in the cavity of the silicone groove 3, and the end of the piston 4 push rod 402 away from the piston head 401 extends out of the through hole 2.

[0043] In actual use, in this embodiment, several through holes 2 are opened on the template B, and a silicone groove 3 is fixedly connected in the through holes 2, so that the end of the slow-release mechanism 1 can be embedded in the silicone groove 3 and can move with the template B; by setting a cavity in the silicone groove 3 and setting a piston 4 in the through hole 2, and embedding the front end of the piston head 401 of the piston 4 into the cavity, and making the end of the push rod 402 away from the piston head 401 extend out of the through hole 2, the push rod 402 moves downward when subjected to the pressure of the rolling machinery, and drives the piston head 401 to open the cavity of the silicone groove 3, while pushing the slow-release mechanism 1 away from the silicone groove 3, and the lower end of the ceramsite is embedded in the roller-compacted concrete mixture.

[0044] In addition, it can prevent a large amount of water inside the roller-compacted concrete from freezing in winter, which would lead to crack formation and improve the freeze-thaw resistance of the roller-compacted concrete.

[0045] Furthermore, such as Figure 3 As shown, in this embodiment, the through hole 2 includes a vertical section 201 and a protective section 202. The silicone groove 3 is fixedly connected at the junction of the vertical section 201 and the protective section 202. A positioning key 203 is provided at the end of the vertical section 201 away from the protective section 202.

[0046] In actual use, in this embodiment, the through hole 2 is set as a vertical section 201 and a protective section 202, and the silicone groove 3 is fixedly connected at the junction of the vertical section 201 and the protective section 202, so that the slow-release mechanism 1 retains the top ceramic particles and a part of the steel fiber exposed on the rolling surface after multiple rolling under the action of the protective section 202; a positioning key 203 is provided at the end of the vertical section 201 away from the protective section 202 to control the push rod 402 to move downward smoothly.

[0047] Furthermore, such as Figure 3 As shown, in this embodiment, the piston head 401 is made of rubber or silicone, and the rear end of the piston head 401 is embedded in the vertical section 201 and is tightly fitted to the inner wall of the vertical section 201.

[0048] In actual use, in this embodiment, by setting the piston head 401 to be made of rubber or silicone and having its rear end tightly fitted to the inner wall of the vertical section 201, the friction between the piston head 401 and the inner wall of the vertical section 201 can be increased. After the compaction machine passes over the template B and inserts the slow-release mechanism 1 into the compacted concrete mixture, the greater friction makes the piston head 401 maintain its current position and not move upward, so that the end of the push rod 402 is basically flush with the upper surface of the template B, which facilitates subsequent compaction.

[0049] Furthermore, such as Figure 2 As shown, in this embodiment, the end of the push rod 402 away from the piston head 401 is connected to a rolling plate 5.

[0050] In actual use, by setting the rolling plate 5 in this embodiment, the force on each row of push rods 402 can be uniform, and the contact surface of the rolling mechanism during rolling is a large flat surface, which reduces the pressure on the rolling mechanism and reduces the wear of the rolling mechanism.

[0051] Example 2

[0052] The difference between this embodiment and Embodiment 1 is that the preparation method of the sustained-release mechanism 1 is different. Specifically, in step one, the sprayed water is replaced with the sprayed thermosensitive hydrogel, which is poly(N-isopropylacrylamide) or polymethyl vinyl ether.

[0053] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A crack-resistant roller-compacted concrete structure, characterized in that, Several slow-release mechanisms (1) are embedded between adjacent roller compaction layers in the roller compaction structure. The slow-release mechanism (1) is a steel fiber with ceramsite connected to both ends. The ceramsite is treated with water saturation. A template B with the slow-release mechanism (1) is laid on the surface of the roller compaction concrete of the adjacent roller compaction layers. The template B has several through holes (2), and a silicone groove (3) is fixedly connected in the through hole (2). The silicone groove (3) is used to wrap the end of the slow-release mechanism (1), and the silicone groove (3) has a cavity inside. The through hole (2) has a piston (4), which is composed of a piston head (401) and a push rod (402). The front end of the piston head (401) is embedded in the cavity of the silicone groove (3), and the end of the piston (4) push rod (402) away from the piston head (401) extends out of the through hole (2).

2. The crack-resistant roller-compacted concrete structure according to claim 1, characterized in that, The ceramsite contains a thermosensitive hydrogel.

3. A crack-resistant roller-compacted concrete structure according to claim 1 or 2, characterized in that, The preparation method of the sustained-release mechanism (1) includes the following steps: Step 1: Granulate the raw material powder and then sinter it to obtain ceramsite; Step 2: Drill holes in the surface of the ceramsite obtained in Step 1, then press the ends of the steel fibers into the holes, inject epoxy resin at the connection between the ceramsite and the steel fibers and then cure it to obtain the slow-release mechanism (1).

4. The crack-resistant roller-compacted concrete structure according to claim 3, characterized in that, The granulation process in step one is as follows: the raw material powder is placed in a disc granulator, and water or temperature-sensitive hydrogel is sprayed to roll the raw material powder into particles with a particle size of 10mm~20mm.

5. A crack-resistant roller-compacted concrete structure according to claim 3, characterized in that, In step two, the length of the steel fiber is not less than 60 mm, and the diameter of the steel fiber is 0.25 mm to 0.60 mm.

6. The crack-resistant roller-compacted concrete structure according to claim 1, characterized in that, The through hole (2) includes a vertical section (201) and a protective section (202). The silicone groove (3) is fixedly connected at the junction of the vertical section (201) and the protective section (202). A positioning key (203) is provided at the end of the vertical section (201) away from the protective section (202).

7. A crack-resistant roller-compacted concrete structure according to claim 6, characterized in that, The piston head (401) is made of rubber or silicone. The rear end of the piston head (401) is embedded in the vertical section (201) and is tightly fitted to the inner wall of the vertical section (201).

8. The crack-resistant roller-compacted concrete structure according to claim 1, characterized in that, The end of the push rod (402) away from the piston head (401) is connected to a rolling plate (5).

9. A construction method for a crack-resistant roller-compacted concrete structure as described in claim 1, characterized in that, The construction method includes the following steps: Step 1: Fix template A, and then spread the roller-compacted concrete mixture. Step 2: Lay a template B with a slow-release mechanism (1) on the roller-compacted concrete surface that was laid in Step 1, and then use a roller compactor to compact it multiple times. After removing the template, a compacted surface is obtained. The slow-release mechanism (1) is soaked in water before being laid. Step 3: Cover the compacted surface obtained in Step 2 with mortar, and then spread and compact concrete again; Step 4: Repeat steps 2 to 3 until the target thickness of the roller-compacted concrete structure is achieved. Water curing is carried out after 6 to 12 hours.

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