Anti-crack roller compacted concrete structure and construction method thereof

Abstract

The invention discloses an anti-crack roller compacted concrete structure, a plurality of slow release mechanisms are embedded between adjacent rolling layers in the roller compacted concrete structure, and the slow release mechanisms are steel fibers with two ends connected with ceramsite; the invention further discloses a construction method of the anti-crack roller compacted concrete structure, and the construction method comprises the following steps that firstly, the formwork A is fixed, and then roller compacted concrete is paved; 2, a template B with a slow release mechanism is laid, and a rolling machine is adopted for multiple times of rolling; 3, covering mortar, and then paving roller compacted concrete; and fourthly, the process from the second step to the third step is repeated till the target thickness of the roller compacted concrete structure is achieved. According to the roller compacted concrete structure, the slow release mechanism is embedded between the adjacent roller compacted layers, so that the steel fibers are connected between the adjacent roller compacted layers, the binding force between the roller compacted layers is improved, water-saturated ceramsite is combined, moisture is slowly released in the roller compacted concrete, the drying shrinkage degree is reduced, and the roller compacted concrete structure is suitable for the technical field of roller compacted concrete.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of roller compacted concrete, and particularly relates to an anti-crack roller compacted concrete structure and a construction method. BACKGROUND

[0002] As a dam construction material combining the roller compacting technology and the concrete pouring technology, the roller compacted concrete has the advantages of less cement consumption, low hydration heat, fast construction speed and low cost, and is widely applied in the field of water conservancy projects.

[0003] Due to the large volume of the dam body in the water conservancy project, the hydration reaction causes the heat accumulation in the dam body to be difficult to dissipate, a large temperature difference is formed between the inside and the surface of the concrete, and temperature stress is generated. When the temperature stress exceeds the tensile strength of the concrete, cracks are caused. Meanwhile, the water content in the roller compacted concrete is relatively low, the water loss speed is relatively fast during the hardening process, and the dry shrinkage phenomenon is more obvious; the tensile stress generated by the dry shrinkage causes the micro-cracks in the concrete, and with the time elapsing, the micro-cracks may gradually expand to form macro-cracks, thereby reducing the impermeability and durability of the concrete. Meanwhile, the roller compacted concrete is constructed by layering and rolling, and the weak bonding surface is more likely to exist between the layers, and under the subsequent temperature change, dry-wet cycle and load action, the weak parts are prone to cracks, and the cracks are expanded upward or downward, thereby affecting the integrity of the structure. SUMMARY

[0004] The application aims to overcome the defects in the prior art, and provides an anti-crack roller compacted concrete structure. The roller compacted concrete structure is provided with the slow-release mechanism embedded between the adjacent roller compacted layers, so that the steel fibers are connected between the adjacent roller compacted layers, the bonding force between the roller compacted layers is improved, the saturated ceramsite is combined, the water in the roller compacted concrete is slowly released, and the dry shrinkage degree is reduced, thereby solving the problem that the roller compacted concrete structure is prone to cracks.

[0005] To achieve the above-mentioned purpose, the application adopts the technical scheme of an anti-crack roller compacted concrete structure, and the slow-release mechanism is embedded between the adjacent roller compacted layers in the roller compacted concrete structure, the slow-release mechanism is the steel fiber with the ceramsite connected at both ends, and the ceramsite is subjected to saturated water treatment.

[0006] The anti-crack roller compacted concrete structure is provided with the temperature-sensitive hydrogel in the ceramsite.

[0007] The preparation method of the slow-release mechanism of the anti-crack roller compacted concrete structure includes the following steps: Step one, the raw material powder is granulated and sintered to obtain the ceramsite; Step two, the surface of the ceramsite obtained in step one is perforated, then the end of the steel fiber is pressed into the hole, and the epoxy resin is injected and solidified at the connection between the ceramsite and the steel fiber to obtain the slow-release mechanism.

[0008] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0009] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0010] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0011] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0012] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm. Step one, fixing a formwork A, and then paving a mixture of roller compacted concrete; Step two, paving a formwork B with a slow-release mechanism on the surface of the roller compacted concrete paved in step one, and then rolling multiple times by using a roller compacting machine, and obtaining a primary roller compacted surface after removing the formwork; the slow-release mechanism is soaked in water before paving; Step three, covering mortar on the primary roller compacted surface obtained in step two, and then paving roller compacted concrete again; Step four, repeating the process of steps two to three until the target thickness of the roller compacted concrete structure is reached, and then performing water spraying maintenance after 6h-12h.

[0013] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0014] The anti-cracking roller compacted concrete structure has the granulation process in step one, i.e., placing raw material powder in a disc granulator, and spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10mm-20mm.

[0015] The piston head is made of rubber or silica gel material, and the rear end of the piston head is embedded in the vertical section and tightly adheres to the inner wall of the vertical section.

[0016] The end of the push rod away from the piston head is connected with a rolling plate.

[0017] Compared with the prior art, the present application has the following advantages: 1. The rolling concrete structure of the present application connects steel fibers between adjacent rolling layers by embedding a slow-release mechanism between the adjacent rolling layers, thereby improving the bonding force between the rolling layers, and combines with saturated ceramsite to release water inside the rolling concrete, thereby reducing the degree of dry shrinkage and reducing the generation of internal cracks.

[0018] 2. The present application uses ceramsite containing temperature-sensitive hydrogel to increase the water content of the slow-release mechanism and prolong the duration of water release, thereby continuously providing water for the hydration process of the concrete. At the same time, due to the water permeability of the ceramsite and the characteristics of the temperature-sensitive hydrogel in absorbing and releasing water with temperature, in humid weather such as rain and snow, water will seep into the interior of the rolling concrete structure due to the high water content of the external environment. At this time, the pores of the ceramsite can provide a permeation path for water, allowing the water to contact the temperature-sensitive hydrogel inside, causing the temperature-sensitive hydrogel to absorb water and reduce the water content inside the rolling concrete structure. In hot weather, the temperature-sensitive hydrogel releases water, increasing the water content inside the rolling concrete structure, which is beneficial to the long-term hydration of the rolling concrete. The water content inside the rolling concrete remains in a small fluctuation range during the service process, thereby prolonging the service life of the rolling concrete.

[0019] 3. The present application designs template B to enable the slow-release mechanism to be smoothly inserted into the rolling layer of the rolling concrete, with the end of the slow-release mechanism exposed on the surface of the rolling layer. After further laying of the rolling concrete, the end of the slow-release mechanism can be inserted into the adjacent rolling layer, thereby realizing the preparation of the rolling concrete structure.

[0020] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the rolling concrete structure of the present application.

[0022] Figure 2 The figure is a schematic diagram of the structure of template B of the present application.

[0023] Figure 3 The figure is Figure 2 The figure is an enlarged schematic diagram of A.

[0024] MARKING OF THE DRAWINGS: 1—slow-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 DESCRIPTION

[0025] Example 1 like Figure 1 As shown, a plurality of slow-release mechanisms 1 are embedded between adjacent rolling layers in the roller-compacted concrete structure of this embodiment. The slow-release mechanism 1 is a steel fiber with ceramsite connected at both ends. The ceramsite is saturated with water. The preparation method of the slow-release mechanism 1 includes the following steps: 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; Step 2: Punch holes on the surface of the ceramsite obtained in step 1, then press the end of a steel fiber with a length of 60mm~80mm and a diameter of 0.25mm~0.60mm into the hole, pour epoxy resin at the connection between the ceramsite and the steel fiber and solidify it to obtain a slow-release mechanism 1.

[0026] The method for constructing a roller-compacted concrete structure using the slow-release mechanism 1 prepared in this embodiment includes the following steps: Step 1: Fix the formwork A and then spread the RCC mixture; Step 2: A template B with a slow-release mechanism 1 is laid on the surface of the roller-compacted concrete paved in step 1, and then a rolling machine is used to perform multiple rolling. After the template is removed, a primary rolling surface is obtained; the slow-release mechanism 1 is soaked in water before laying; Step 3: Cover the first rolled surface obtained in step 2 with mortar, and then spread the rolled concrete again; Step 4: Repeat the process from step 2 to step 3 until the target thickness of the RCC structure is reached. After 6h~12h, water curing is carried out.

[0027] like Figure 2 and Figure 3 As shown, the template B of this embodiment is provided with a plurality of through holes 2, and a silicone groove 3 is fixedly connected inside the through hole 2. The silicone groove 3 is used to wrap the end of the sustained-release mechanism 1, and the silicone groove 3 has a cavity inside. A piston 4 is provided in the through hole 2, and 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. In actual use, in this embodiment, a number of through holes 2 are opened on the template B, and a silicone groove 3 is fixedly connected in the through hole 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; a cavity is set inside the silicone groove 3 and a piston 4 is set in the through hole 2, and the front end of the piston head 401 of the piston 4 is embedded in the cavity, and the end of the push rod 402 away from the piston head 401 is extended out of the through hole 2, so that the push rod 402 moves downward when it is subjected to the pressure of the rolling machine, and drives the piston head 401 to expand the cavity of the silicone groove 3, and at the same time pushes the slow-release mechanism 1 to leave the silicone groove 3, and the expanded clay at the lower end is embedded in the roller-compacted concrete mixture.

[0028] In addition, in winter, it can prevent a large amount of water inside the roller-compacted concrete from freezing, causing cracks to form, and improve the frost resistance of the roller-compacted concrete.

[0029] Furthermore, if 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, and a positioning key 203 is provided at one end of the vertical section 201 away from the protective section 202.

[0030] In actual use, in this embodiment, by setting the through hole 2 as a vertical section 201 and a protective section 202, and fixing the silicone groove 3 at the junction of the vertical section 201 and the protective section 202, the sustained-release mechanism 1 is able to retain the top expanded clay and a portion 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, which is used to control the smooth downward movement of the push rod 402.

[0031] Furthermore, if 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 fits tightly with the inner wall of the vertical section 201 .

[0032] In actual use, in this embodiment, by setting the piston head 401 to be made of rubber or silicone material, and the rear end is in close contact with 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 rolling machine presses over the template B and inserts the slow-release mechanism 1 into the rolled concrete mixture, the greater friction force causes the piston head 401 to 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 is convenient for subsequent rolling.

[0033] Furthermore, if Figure 2 As shown, in this embodiment, the end of the push rod 402 away from the piston head 401 is connected to the rolling plate 5.

[0034] In actual use, the roller plate 5 is arranged in the embodiment, so that each row of push rods 402 is uniformly stressed, the contact surface during rolling of the rolling mechanism is a large plane, the pressure intensity borne by the rolling mechanism is reduced, and the loss of the rolling mechanism is reduced.

[0035] Embodiment 2 The difference between the embodiment and the embodiment 1 is that the preparation method of the slow-release mechanism 1 is different, specifically, the spraying water in step one is replaced by spraying a temperature-sensitive hydrogel, and the temperature-sensitive hydrogel is poly-N-isopropyl acrylamide or polymethyl vinyl ether.

[0036] The above is only a preferred embodiment of the present application, not any limitation on the present application, any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A crack-resistant roller-compacted concrete structure, characterized in that: A plurality of slow-release mechanisms (1) are embedded between adjacent rolling layers in the roller-compacted concrete structure. The slow-release mechanisms (1) are steel fibers with ceramsite connected at both ends. The ceramsite is saturated with water.

2. The crack-resistant roller-compacted concrete structure according to claim 1, characterized in that: The ceramsite contains temperature-sensitive 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) comprises the following steps: Step 1: granulating the raw material powder and then sintering it to obtain ceramsite; Step 2: punch holes on the surface of the ceramsite obtained in step 1, then press the end of the steel fiber into the hole, and pour epoxy resin into the connection between the ceramsite and the steel fiber and solidify it to obtain a slow-release mechanism (1).

4. The crack-resistant roller-compacted concrete structure according to claim 3, characterized in that: The granulation process in step 1 is as follows: placing the raw material powder in a disc granulator, spraying water or temperature-sensitive hydrogel to roll the raw material powder into particles with a particle size of 10 mm to 20 mm.

5. The crack-resistant roller-compacted concrete structure according to claim 3, characterized in that: The length of the steel fiber in step 2 is not less than 60 mm, and the diameter of the steel fiber is 0.25 mm to 0.60 mm.

6. A construction method for a crack-resistant roller-compacted concrete structure according to claim 1, characterized in that: The construction method comprises the following steps: Step 1: Fix the formwork A and then spread the RCC mixture; Step 2: a template B with a slow-release mechanism (1) is laid on the surface of the roller-compacted concrete paved in step 1, and then a rolling machine is used to perform multiple rolling, and a single-rolled surface is obtained after the template is removed; the slow-release mechanism (1) is soaked in water before laying; Step 3: Cover the first rolled surface obtained in step 2 with mortar, and then spread the rolled concrete again; Step 4: Repeat the process from step 2 to step 3 until the target thickness of the RCC structure is reached. After 6h~12h, water curing is carried out.

7. The construction method of a crack-resistant roller-compacted concrete structure according to claim 6, characterized in that: In step 2, the template B is provided with a plurality of through holes (2), wherein a silicone groove (3) is fixedly connected in the through hole (2), wherein the silicone groove (3) is used to wrap the end of the slow-release mechanism (1), and the silicone groove (3) has a cavity therein; wherein a piston (4) is provided in the through hole (2), wherein the piston (4) is composed of a piston head (401) and a push rod (402), wherein the front end of the piston head (401) is embedded in the cavity of the silicone groove (3), and the end of the push rod (402) of the piston (4) away from the piston head (401) extends out of the through hole (2).

8. The construction method of a crack-resistant roller-compacted concrete structure according to claim 7, characterized in that: The through hole (2) comprises 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), and a positioning key (203) is provided at one end of the vertical section (201) away from the protective section (202).

9. The construction method of a crack-resistant roller-compacted concrete structure according to claim 8, 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 fits tightly against the inner wall of the vertical section (201).

10. The construction method of a crack-resistant roller-compacted concrete structure according to claim 7, characterized in that: The end of the push rod (402) away from the piston head (401) is connected to a rolling plate (5).

Images