Device for testing adhesive property of rusted reinforced concrete

Abstract

The utility model discloses a rusted reinforced concrete bonding property testing device, which belongs to the technical field of reinforced concrete test block testing and comprises an initial stress applying device, a reinforced concrete test block is mounted in the initial stress applying device, a steel bar penetrating through the reinforced concrete test block is arranged on the reinforced concrete test block, and the initial stress applying device is provided with a plurality of steel bars penetrating through the reinforced concrete test block. The tensioning end of the steel bar is sleeved with a high-strength durable cylindrical compression spring, a force transmission steel plate, an anchoring drawing instrument and an anchorage device. Horizontal baffle plates are arranged at the end parts of the free end and the tensioning end of the reinforcing steel bar, and high-precision displacement sensors are arranged at the end parts of the free end and the tensioning end of the reinforcing steel bar through magnetic clamps. According to the corroded reinforced concrete bonding property testing device disclosed by the utility model, the time-varying slippage effect of the reinforcing steel bar is considered, the initial tensile stress and the initial stress can be respectively applied to the reinforcing steel bar and the concrete test block, and the real environment of the reinforced concrete test block under the action of the initial stress and corrosion can be simulated; and the adhesive property of the rusted steel bar and the concrete can be conveniently researched.

Description

Technical Field

[0001] The utility model relates to the technical field of reinforced concrete test block testing, in particular to a device for testing the bonding performance of corroded reinforced concrete. Background Art

[0002] Steel bar corrosion is one of the most critical factors affecting the durability of reinforced concrete structures. When the steel bars in concrete begin to corrode, the formation of a rust layer on the contact surface between the steel bars and concrete destroys the chemical adhesion between them and reduces the friction between the two. At the same time, the corrosion of the transverse ribs on the surface of the steel bars weakens their mechanical bite force. The volume expansion of the corrosion products leads to cracking and peeling of the concrete surface layer, further weakening the bonding performance between the steel bars and concrete.

[0003] During service, the reinforced concrete structure itself will produce cracks due to shrinkage creep, and the continuous stress will gradually increase the number of cracks and the width of the cracks. Oxygen, moisture and other corrosive substances in the surrounding environment will enter the concrete structure through the cracks, accelerate the corrosion of the steel bars, and further reduce the bonding performance between the steel bars and concrete.

[0004] The study of the bonding performance of reinforced concrete specimens considering both corrosion and initial stress is of great significance for the durability assessment and life prediction of reinforced concrete components. However, there are currently few related test devices, so it is urgent to design a test device for the bonding performance of corroded reinforced concrete that considers the time-varying slip effect under initial stress. Summary of the invention

[0005] The purpose of the utility model is to provide a testing device for the bonding performance of corroded steel bars and concrete, which can take into account the time-varying slip effect of the steel bars, apply initial tensile stress and initial stress to the steel bars and concrete test blocks respectively, and can simulate the real environment of the steel bar concrete test blocks under the initial stress and corrosion, so as to facilitate the study of the bonding performance of the corroded steel bars and concrete.

[0006] To achieve the above-mentioned purpose, the utility model provides a device for testing the bonding performance of corroded steel bars and concrete, including an initial stress applying device, in which a reinforced concrete test block is installed, the reinforced concrete test block is provided with steel bars passing through the reinforced concrete test block, the tensioning end of the steel bar is provided with a high-strength and durable cylindrical compression spring, a force transmission steel plate, an anchor puller and an anchor; horizontal baffles are provided at the end positions of the free end and the tensioning end of the steel bar, and high-precision displacement sensors are arranged through magnetic clamps.

[0007] Preferably, the initial stress applying device adopts electric hydraulic loading, the material used is corrosion-resistant material and the surface is painted with anti-rust paint.

[0008] Preferably, the reinforced concrete test block is a 150mm×150mm×150mm standard concrete tensile test block.

[0009] Preferably, two force transmission steel plates are provided and are respectively installed on both sides of the high-strength and durable cylindrical compression spring, and both ends of the two force transmission steel plates are arranged horizontally; the outer surface of the high-strength and durable cylindrical compression spring is sprayed with a pure aluminum coating and pre-oxidized.

[0010] Preferably, the force-transmitting steel plate is a hot-dip Al-Zn-Si-Mg-Sr steel plate; the length, width and thickness of the force-transmitting steel plate are 150 mm, 150 mm and 30 mm respectively.

[0011] Preferably, the anchor puller is connected to the DH3816 static strain collector by wire.

[0012] Preferably, the high-precision displacement sensors at the free end and the tensioning end of the steel bar are respectively connected to the DH3816 static strain collector, and the pointer probes of the two high-precision displacement sensors are respectively against the horizontal baffle on the same side.

[0013] Preferably, a cushion block is provided at the bottom of the initial stress applying device.

[0014] Therefore, the utility model adopts the above-mentioned corroded steel bar concrete bonding performance testing device to achieve the following beneficial effects:

[0015] (1) The initial stress applying device in the utility model can simultaneously apply initial stress (bidirectional compression-compression combined stress, bidirectional tension-tension combined stress, bidirectional tension-compression combined stress) and corrosion effect to the concrete test block, simulating the service state of the concrete structure in a real environment.

[0016] (2) The utility model adopts a high-strength and durable cylindrical compression spring. After the anchor puller applies the initial tensile stress, the spring is compressed and can continuously apply tensile stress to the steel bar, more realistically simulating the stress state of the steel bar when in service.

[0017] (3) The high-precision displacement meter and anchor puller of the utility model are respectively connected to the DH3816 static strain collector, which can monitor and record the slippage of the steel bars in the reinforced concrete test block and the tensile stress on the steel bars in real time, which is convenient for quantifying the bonding performance.

[0018] (4) Each unit of the utility model can be assembled and disassembled, which is convenient for use and transportation. The device is small in size and easy to install, and can be applied to a variety of test environments.

[0019] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a structural schematic diagram of an embodiment of a device for testing the bonding performance of corroded steel bars and concrete.

[0021] Reference numerals

[0022] 1. Anchor; 2. Anchor puller; 3. High-strength and durable cylindrical compression spring; 4. Force transmission steel plate; 5. Reinforced concrete test block; 6. Initial stress application device; 7. Spacer; 8. Horizontal baffle; 9. Magnetic clamp; 10. High-precision displacement sensor; 11. Rebar. DETAILED DESCRIPTION

[0023] The technical solution of the utility model is further described below through the accompanying drawings and embodiments.

[0024] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] Embodiment 1

[0026] like Figure 1 As shown, the utility model provides a device for testing the bonding performance of corroded steel bars and concrete, including an initial stress applying device 6, which is made of corrosion-resistant material and has an anti-rust paint on the surface, which is beneficial to improving the service life of the initial stress applying device 6. The initial stress applying device 6 can apply bidirectional compression-compression combined stress, bidirectional tension-tension combined stress, and bidirectional tension-compression combined stress to the concrete test block.

[0027] A reinforced concrete test block 5 is installed in the initial stress applying device 6 , and a cushion block 7 is provided at the bottom of the initial stress applying device 6 to ensure that the reinforced concrete test block 5 can be smoothly placed into the initial stress applying device 6 .

[0028] The reinforced concrete test block 5 is a 150mm×150mm×150mm standard concrete tensile test block. The reinforced concrete test block 5 is provided with a steel bar 11 that runs through the reinforced concrete test block 5 longitudinally. The upper end of the steel bar 11 is longer and is the tension end, and the lower end is shorter and is the free end.

[0029] The tensioning end of the steel bar 11 is sequentially sleeved with a force transmission steel plate 4, a high-strength and durable cylindrical compression spring 3, a force transmission steel plate 4, an anchor puller 2 and an anchor 1 from bottom to top. The upper and lower sides of the high-strength and durable cylindrical compression spring 3 are both provided with force transmission steel plates 4, which are hot-dip Al-Zn-Si-Mg-Sr steel plates with excellent corrosion resistance and force bearing performance. The length, width and thickness of the two force transmission steel plates 4 are 150mm, 150mm and 30mm respectively, and the two ends of the two force transmission steel plates 4 are arranged horizontally, which can ensure that the elastic force generated by the high-strength and durable cylindrical compression spring 3 is smoothly transmitted along the direction of the steel bar 11.

[0030] The outer surface of the high-strength and durable cylindrical compression spring 3 is sprayed with a pure aluminum coating and pre-oxidized, which can greatly enhance the corrosion resistance of the high-strength and durable cylindrical compression spring 3. The anchor puller 2 is wired to the DH3816 static strain collector, and the experimental data of the anchor puller 2 can be sent to the DH3816 static strain collector in real time.

[0031] Horizontal baffles 8 are provided at the end positions of the free end and the tensioned end of the steel bar 11, and high-precision displacement sensors 10 are arranged through magnetic clamps 9. The high-precision displacement sensors 10 at the free end and the tensioned end of the steel bar 11 are respectively connected to the DH3816 static strain collector, and the pointer probes of the two high-precision displacement sensors 10 are respectively against the horizontal baffles 8 on the same side, so that the slippage of the reinforced concrete test block 5 can be accurately collected in real time.

[0032] The initial stress applying device 6 adopts electric hydraulic loading, which can apply initial tensile stress to the steel bar 11. After the end, the anchor ring is driven to move quickly on the steel bar 11 through the recovery of the cylinder head, thereby realizing the rapid and automatic separation of the anchor ring and the anchor 1, which facilitates the rapid manual disassembly of the anchor ring and the anchor 1.

[0033] The specific operation of using the utility model to test the bonding performance of corroded steel bars and concrete on a steel bar and concrete test block comprises the following steps:

[0034] S1. Place the steel bar 11 in a concrete mold in advance, prepare a concrete cube test block 5 with a center-bonded steel bar, the size of which is 150 mm × 150 mm × 150 mm, perform standard curing for 28 days, and perform sampling test on the cube compressive strength according to the specification.

[0035] S2. The prepared reinforced concrete test block 5 is installed in the initial stress applying device 6. After applying continuous initial stress, the test block is placed in a corrosion tank and energized to accelerate corrosion. The calculation formula for accelerating corrosion by energization is as follows:

[0036]

[0037] Where: t is the power-on time; λ Fe is the number of valence electrons of iron; C Faraday is the Faraday constant; ΔM is the steel bar mass loss; I is the current intensity; M Fe is the molar mass of iron.

[0038] S3. Place the reinforced concrete test block 5 after corrosion together with the initial stress applying device 6 on the cushion block 7 as a whole, ensuring that the long end of the steel bar 11 faces upward and the short end faces downward.

[0039] S4, force transmission steel plate 4, high-strength and durable cylindrical compression spring 3, force transmission steel plate 4, anchor puller 2, anchor 1, horizontal baffle 8, magnetic clamp 9 and high-precision displacement sensor 10 are installed in sequence at the long end of the steel bar 11. The pointer of the high-precision displacement sensor 10 is against the horizontal baffle 8 through the magnetic clamp 9. The high-precision displacement sensor 10 is arranged at the tensioning end and the free end of the steel bar 11. Among them, the anchor puller 2 and the high-precision displacement sensor 10 are wired to the DH3816 static strain collector, and the DH3816 static strain collector is wired to the computer.

[0040] S5. Start the anchor puller 2, continuously apply pressure to the reinforced concrete test block 5 and the high-strength and durable cylindrical compression spring 3, stop applying pressure after loading to the specified stress, stabilize the anchor puller 2, and record the initial slippage of the reinforced concrete test block 5 and the initial tensile stress of the steel bar 11 on the computer.

[0041] S6. The real-time slippage of the reinforced concrete test block 5 and the tensile stress of the steel bars are continuously recorded by a DH3816 static strain collector and a computer.

[0042] S7. To ensure that the initial stress applied to the reinforced concrete test block 5 and the tensile stress applied to the steel bar 11 are continuous and stable, the pressure gauge should be checked every 12 hours, and the changes in the pressure readings should be noted. The stress and tensile stress should be supplemented in time to ensure the stability of the test.

[0043] Therefore, the utility model adopts the above-mentioned corroded steel bar concrete bonding performance testing device, takes into account the time-varying slip effect of the steel bar, can apply initial tensile stress and initial stress to the steel bar and concrete test block respectively, and can simulate the real environment of the steel bar concrete test block under the initial stress and corrosion, which is convenient for studying the bonding performance of the corroded steel bar and concrete.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that they can still modify or replace the technical solution of the utility model with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the utility model.

Claims

1. A device for testing the bonding performance of corroded steel bars and concrete, characterized in that: It comprises an initial stress applying device, in which a reinforced concrete test block is installed, on which a steel bar is provided which penetrates the reinforced concrete test block, and the tensioning end of the steel bar is provided with a high-strength and durable cylindrical compression spring, a force transmission steel plate, an anchoring puller and an anchor; horizontal baffles are provided at the end positions of the free end and the tensioning end of the steel bar, and high-precision displacement sensors are arranged through magnetic clamps.

2. A corroded steel bar concrete bonding performance testing device according to claim 1, characterized in that: The initial stress applying device adopts electric hydraulic loading, and the material used is corrosion-resistant material and the surface is painted with anti-rust paint.

3. A corroded steel bar concrete bonding performance testing device according to claim 1, characterized in that: The reinforced concrete test block is a 150mm×150mm×150mm standard concrete tensile test block.

4. A corroded steel bar concrete bonding performance testing device according to claim 1, characterized in that: The force transmission steel plates are provided with two pieces and are respectively installed on both sides of the high-strength and durable cylindrical compression spring, and the two ends of the two force transmission steel plates are arranged horizontally; the outer surface of the high-strength and durable cylindrical compression spring is sprayed with a pure aluminum coating and pre-oxidized.

5. The device for testing the bonding performance of corroded steel bars and concrete according to claim 1, characterized in that: The force transmission steel plate is a hot-dip Al-Zn-Si-Mg-Sr steel plate; the length, width and thickness of the force transmission steel plate are 150 mm, 150 mm and 30 mm respectively.

6. The device for testing the bonding performance of corroded steel bars and concrete according to claim 1, characterized in that: The anchor puller is connected to the DH3816 static strain collector by wire.

7. The device for testing the bonding performance of corroded steel bars and concrete according to claim 1, characterized in that: The high-precision displacement sensors at the free end and the tensioning end of the steel bar are respectively connected to the DH3816 static strain collector, and the pointer probes of the two high-precision displacement sensors are respectively against the horizontal baffle on the same side.

8. The device for testing the bonding performance of corroded steel bars and concrete according to claim 1, characterized in that: A cushion block is provided at the bottom of the initial stress applying device.

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