Pull-out test device for testing bonding performance of rib material and concrete under different prestress levels

Abstract

The utility model discloses a pull-out test device for testing the bonding performance of a rib material and concrete under different prestress levels. The pull-out test device comprises a data acquisition and analysis system, a clamping device, a load sensor, a fixed pulley, a pedestal and an anchorage device, according to the device, the two ends of the steel bar are fixed, and the bonding performance is measured by moving the concrete test block; the method comprises the following steps: firstly, manufacturing a concrete test block by using a pre-tensioning method, fixing one end of a basalt fiber composite rib, fixing the other end of the basalt fiber composite rib when the basalt fiber composite rib is tensioned to a certain pre-stress level, then erecting a mold, pouring the concrete test block, and horizontally putting the manufactured test block into a pedestal for fixing; then the concrete test block is sleeved with a clamp, and vertical force is converted into horizontal force through the two sets of fixed pulleys, so that the concrete test block can move horizontally. The device can simulate a stress state in a real project, evaluates the bonding performance between the prestressed reinforcement and the concrete by measuring parameters such as bonding strength, and has the advantages of simple structure, easiness in operation, reusability and the like.

Description

Technical Field

[0001] The utility model relates to a pull-out test device for testing the bonding performance between reinforcement materials and concrete under different prestress levels, and belongs to the field of pull-out test research. Background Art

[0002] The strength of reinforced concrete building materials generally depends on the bonding performance between concrete and its internal reinforcement. Therefore, in order to ensure construction safety and building quality, the bonding performance between the two needs to be tested before the corresponding reinforced concrete building materials are put into use. The reinforcement-concrete tensile test is the main means. In order to avoid the premature appearance of cracks in the reinforcement-concrete structure and make full use of high-strength materials, people have created prestressed concrete structures in long-term production practice. That is, before the structural member is subjected to external loads, it is artificially pressed. The resulting prestressed state is used to reduce or offset the tensile stress caused by the external load, that is, the higher compressive strength of concrete is used to make up for its lack of tensile strength, so as to delay the cracking of concrete in the tensile zone. However, the influence of different levels of prestress on the bonding performance between reinforcement and concrete is not clear. In order to explore its law, it is necessary to carry out tests on the bonding performance of reinforcement and concrete under different prestress levels. However, the existing test devices are generally aimed at ordinary reinforcement concrete components, lacking tests on prestressed reinforcement-concrete components, which limits the development of related research and engineering applications. Utility Model Content

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the utility model provides a pull-out test device for testing the bonding performance of reinforcement and concrete under different prestress levels, which has a more reasonable structural design, more convenient operation and higher pulling efficiency.

[0004] Technical solution: In order to solve the above technical problems, the utility model provides a pull-out test device for testing the bonding performance of reinforcement and concrete under different prestress levels, including a pedestal, a concrete test block is placed on the pedestal, reinforcement is arranged in the test block, both ends of the reinforcement are anchored by anchors fixed on the pedestal, the concrete test block is wrapped with a clamp, a connecting rope is installed on the clamp, the connecting rope passes through a fixed pulley and is connected to an upper clamping device, a load sensor is installed on the connecting rope, a displacement meter is installed on one side of the clamp, and the displacement meter is connected to a data acquisition and analysis device.

[0005] Preferably, the portion of the reinforcement located in the concrete test block is reinforcement A, and reinforcement A is sleeved with a plastic sleeve.

[0006] Preferably, there are two plastic sleeves, which are symmetrically distributed on both sides of the reinforcement material A.

[0007] Preferably, the reinforcement material A is divided into three equal parts in length, with plastic sleeves sleeved on both sides, and the middle part directly contacts the concrete test block.

[0008] Preferably, a lower clamping device is provided below the base.

[0009] Preferably, the fixture comprises two parts, and the concrete test block is wrapped by two fixture units with U-shaped cross-sections.

[0010] Preferably, each clamp is connected to a connecting rope, and each connecting rope passes through a fixed pulley.

[0011] Preferably, the connecting rope is a steel wire rope or a steel strand.

[0012] Preferably, the axes of the upper clamping device and the lower clamping device coincide with each other.

[0013] In the utility model, the position of the fixed pulley is determined so that the axes of the two steel wire ropes or steel strands are on the same horizontal plane as the axis of the prestressed reinforcement. The upper and lower upper clamping devices are perpendicular to the horizontal plane and cannot be tilted, and the axes must coincide. The upper clamping device is T-shaped to ensure that the steel wire ropes or steel strands remain vertical.

[0014] Beneficial effects: The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestress levels of the utility model has the following advantages:

[0015] 1. The traditional pull-out test device is aimed at ordinary reinforced concrete components, but for prestressed reinforced concrete components, the measured results are inaccurate. The present invention is more suitable for the actual engineering application of prestressed reinforced concrete and can provide reliable test data for engineering practice and material research.

[0016] 2. The traditional pull-out test device is to fix the concrete, with the two ends of the steel bar as the loading end and the free end. By applying load to the steel bar, the steel bar and concrete will slide relative to each other, so as to measure the bonding performance between the steel bar and concrete. However, this device fixes both ends of the steel bar and measures the bonding performance by moving the concrete test block, which is novel and cutting-edge.

[0017] 3. The present invention adopts two sets of fixed pulleys to convert vertical force into horizontal force, which is convenient to operate, high in efficiency, simple to manufacture and highly reproducible. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the interior of the concrete test block;

[0019] Figure 2 It is a structural schematic diagram of the utility model.

[0020] In the figure: 1-data acquisition and analysis device; 2-upper clamping device; 3-load sensor; 4-fixed pulley; 5-wire rope or steel strand; 6-concrete test block; 7-clamp; 8-reinforcement; 9-displacement meter; 10-base; 11-lower clamping device; 12-anchor; 13-plastic sleeve. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with the accompanying drawings.

[0022] like Figure 2 As shown, the utility model is a pull-out test device for testing the bonding performance of reinforcement 8 and concrete under different prestress levels, including a pedestal 10, a concrete test block 6 is placed on the pedestal 10, reinforcement 8 is arranged in the test block, both ends of the reinforcement 8 are anchored by anchors 12 fixed on the pedestal 10, the concrete test block 6 is wrapped with a clamp 7, a connecting rope 5 is installed on the clamp 7, the connecting rope 5 passes through a fixed pulley 4 and is connected to the upper clamping device 2, a load sensor is installed on the connecting rope 5, a displacement meter 9 is installed on one side of the clamp 7, and the displacement meter 9 is connected to the data acquisition and analysis device 1.

[0023] like Figure 1 As shown, in the present invention, the part of the reinforcement 8 located in the concrete test block 6 is reinforcement A, and a plastic sleeve 13 is sleeved on the reinforcement A. There are two plastic sleeves 13, which are symmetrically distributed on both sides of the reinforcement A. The reinforcement A is divided into three equal parts in length, and plastic sleeves are sleeved on both sides, and the middle part directly contacts the concrete test block 6.

[0024] In the utility model, a lower clamping device 11 is provided below the pedestal 10. The clamp 7 comprises two parts, and the concrete test block 6 is wrapped by two clamp 7 units with U-shaped cross-sections. Each clamp 7 is connected to a connecting rope 5, and each connecting rope 5 passes through a fixed pulley 4. The connecting rope 5 is a steel wire rope or a steel strand. The axis of the upper clamping device 2 coincides with the axis of the lower clamping device 11.

[0025] The test process of this utility model is as follows:

[0026] The first step is to prepare a basalt fiber composite bar, put a plastic sleeve on the steel bar in advance, and use the pre-tensioning method to tension the steel bar;

[0027] The second step is to cast the concrete test block 6 after the tensioning is completed. The size of the test block is 150mm×150mm×150mm, and the steel bar is located in the center of the test block. Then the formwork is removed for curing.

[0028] The third step is to place the prepared prestressed reinforced concrete test block 6 into the pedestal 10 and fix it with anchors 12 on both sides, and at the same time start the clamping device below to fix the pedestal 10 as a whole;

[0029] Step 4: Put the fixture 7 on the concrete test block 6 and install the displacement meter 9;

[0030] Step 5: Install two sets of fixed pulleys 4 and connect the clamp 7 to the T-shaped steel bar above with steel strands or wire ropes to convert the vertical force into horizontal force;

[0031] Step 6: Clamp the T-shaped steel bar with the upper clamping device and install the load sensor 3;

[0032] Step 7: Apply the load, start the data acquisition and analysis device 1, and record the data.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels, characterized in that: It includes a pedestal, on which a concrete test block is placed, in which reinforcement is arranged, and both ends of the reinforcement are anchored by anchors fixed on the pedestal, and the concrete test block is wrapped with a clamp, on which a connecting rope is installed, the connecting rope passes through a fixed pulley and is connected to an upper clamping device, a load sensor is installed on the connecting rope, and a displacement meter is installed on one side of the clamp, and the displacement meter is connected to a data acquisition and analysis device.

2. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 1, characterized in that: The portion of the reinforcement located in the concrete test block is reinforcement A, and reinforcement A is sleeved with a plastic sleeve.

3. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 2, characterized in that: There are two plastic sleeves, which are symmetrically distributed on both sides of the reinforcement material A.

4. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 3, characterized in that: The reinforcement material A is divided into three equal parts in length, with plastic sleeves on both sides, and the middle part directly contacts the concrete test block.

5. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 1, characterized in that: A lower clamping device is provided below the pedestal.

6. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 1, characterized in that: The fixture comprises two parts, and the concrete test block is wrapped by two fixture units with U-shaped cross sections.

7. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 6, characterized in that: Each clamp is connected to a connecting rope, and each connecting rope passes through a fixed pulley.

8. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 1, characterized in that: The connecting rope is a steel wire rope or a steel strand.

9. The pull-out test device for testing the bonding performance between reinforcement and concrete under different prestressing levels according to claim 5, characterized in that: The axes of the upper clamping device and the lower clamping device coincide with each other.

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