Novel concrete load and freeze-thaw cycle coupling test device

Abstract

The utility model provides a novel concrete load and freeze-thaw cycle coupling test device which is characterized by comprising a freeze-thaw cycle testing machine, the freeze-thaw cycle box is located on the freeze-thaw cycle testing machine, and an anti-freezing solution is arranged between the freeze-thaw cycle box and the inner wall of the freeze-thaw cycle testing machine; the concrete load applying device is located in the freezing and thawing circulating box, freezing and thawing media are arranged between the concrete load applying device and the inner wall of the freezing and thawing circulating box, the concrete load applying device comprises a frame rod, the upper end of the frame rod is fixed to a shell of the hydraulic device, and the lower end penetrates through the top plate to be connected with the bottom plate; a concrete sample is mounted between the top plate and the bottom plate; a concrete sample is arranged on the bottom plate; a strain sensor is pre-embedded in the concrete sample; and the hydraulic device comprises a telescopic hydraulic rod, the lower end of the telescopic hydraulic rod is connected with a movable hinge, and the movable hinge is fixed on the bottom plate. The concrete freeze-thaw cycle coupling device solves the problems that in a concrete freeze-thaw cycle test, complex loads and freeze-thaw cycles cannot be coupled, and the load condition of concrete cannot be accurately regulated and controlled.

Description

Technical Field

[0001] The utility model belongs to the technical field of concrete load and freeze-thaw cycle coupling, and in particular relates to a novel concrete load and freeze-thaw cycle coupling test device. Background Art

[0002] Concrete freeze-thaw damage is an important problem faced by concrete structures under cold climate conditions. It usually occurs in high latitudes or high altitudes. The key conditions include periodic changes in temperature and the concrete being immersed, saturated or wet. The main cause of the damage is the internal stress caused by the freeze-thaw cycle, including freezing expansion pressure, penetration pressure and crystallization pressure, which causes cracks on the surface of the concrete and gradually erodes from the surface to the inside, affecting the strength and durability in the long term, and may even cause damage to the overall structure.

[0003] In actual engineering, freeze-thaw damage of concrete is usually caused by the coupling of load and other factors such as temperature. However, the current test device cannot couple complex loads with freeze-thaw cycles, and cannot accurately control the load on concrete during the freeze-thaw cycle, resulting in the test device being unable to obtain test data that is close to reality. Therefore, a new concrete load and freeze-thaw cycle coupling test device is needed to solve the above problems. Summary of the invention

[0004] The purpose of the utility model is to provide a novel concrete load and freeze-thaw cycle coupling test device, which solves the problems of being unable to couple complex loads with freeze-thaw cycles and being unable to accurately control the load conditions of concrete in concrete freeze-thaw cycle tests, and can better simulate the freeze-thaw damage of concrete in actual engineering.

[0005] A new concrete load and freeze-thaw cycle coupling test device, including:

[0006] Freeze-thaw cycle test machine 1;

[0007] The freeze-thaw cycle box 2 is located in the inner groove of the freeze-thaw cycle test machine 1, and antifreeze is provided between the freeze-thaw cycle box 2 and the inner wall of the freeze-thaw cycle test machine 1;

[0008] and a concrete load applying device, which is located in the freeze-thaw cycle box 2, and a freeze-thaw medium is provided between the freeze-thaw cycle box 2 and the inner wall of the freeze-thaw cycle box 2, including:

[0009] A frame rod 8, the upper end of which is fixed to the housing of the hydraulic device 4, and the lower end of which passes through the top plate 6 and is connected to the bottom plate 9;

[0010] A concrete sample 11 is installed between the top plate 6 and the bottom plate 9; the concrete sample 11 is placed on the bottom plate 9; a strain sensor is embedded in the concrete sample 11;

[0011] And a hydraulic device 4, including a telescopic hydraulic rod 5, the lower end of the telescopic hydraulic rod 5 is connected to a movable hinge 7, and the movable hinge 7 is fixed to a bottom plate 9.

[0012] Preferably, the movable hinge 7 comprises:

[0013] Bolts, fixed to the hydraulic rod 5 and passing through the connecting seat;

[0014] The spring washer is sleeved on the bolt and located between the connecting seat and the nut. The nut is screwed on the end of the bolt.

[0015] Preferably, the hydraulic device 4 includes four independent hydraulic machines, and the output end of each hydraulic machine is a telescopic hydraulic rod 5.

[0016] Preferably, the strain sensor is located at the axial center of the hydraulic rod 5 .

[0017] Preferably, it also includes: a hydraulic control system and a strain testing system 10;

[0018] The hydraulic control system is signal-connected to the hydraulic device 4;

[0019] The strain testing system 10 is connected to the output end of the strain sensor.

[0020] Preferably, it also includes a wiring harness 3 , which includes a hydraulic control system wiring harness and a strain test system wiring harness, and is connected to the control system of the freeze-thaw cycle tester 1 .

[0021] Compared with the prior art, the advantages of the utility model are:

[0022] 1. By regulating the hydraulic device, four small hydraulic presses can be independently controlled to apply loads of different working conditions to the concrete specimen, such as axial load, eccentric load, etc., and the stress distribution of the concrete can be accurately obtained. Among them, it can be known from the existing technology that in the linear elastic stage, the stress and strain of concrete are linearly related, and the product of the strain and elastic modulus of the concrete specimen is the internal stress.

[0023] 2. By integrating the freeze-thaw cycle machine control system and the hydraulic control system, the load condition of the concrete sample can be changed during the freeze-thaw cycle, the dynamic coupling of the concrete load and the freeze-thaw cycle can be achieved, and the freeze-thaw damage of concrete in actual engineering can be simulated more accurately.

[0024] 3. By integrating the hydraulic control system and the strain testing system, the stress distribution of the concrete can be directly obtained, saving the steps of manual calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a new concrete load and freeze-thaw cycle coupling test device;

[0026] Figure 2 for Figure 1 A schematic diagram of the combination of a freeze-thaw cycle box and a concrete load applying device is shown;

[0027] Figure 3 for Figure 2 An overall enlarged view of the concrete load applying device shown;

[0028] Figure 4 for Figure 3 An enlarged view of the living hinge is shown.

[0029] Among them, 1. freeze-thaw cycle testing machine, 2. freeze-thaw cycle box, 3. wiring harness, 4. hydraulic device, 5. hydraulic rod, 6. top plate, 7. movable hinge, 8. frame rod, 9. bottom plate, 10. strain testing system, 11. concrete specimen. DETAILED DESCRIPTION

[0030] The novel concrete load and freeze-thaw cycle coupling test device of the utility model will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the utility model is shown, and it should be understood that the technical personnel in the field can modify the utility model described herein, and still achieve the beneficial effects of the utility model. Therefore, the following description should be understood as being widely known to the technical personnel in the field, and not as a limitation to the utility model.

[0031] like Figures 1 to 4 A new concrete load and freeze-thaw cycle coupling test device includes a concrete load applying device, a freeze-thaw cycle box 2 and a freeze-thaw cycle testing machine 1.

[0032] The concrete sample 11 is placed in a concrete load applying device and is integrally mounted in a freeze-thaw cycle box 2, and a freeze-thaw cycle test is performed by a freeze-thaw cycle test machine 1. The working principle of the freeze-thaw cycle test machine 1 is the prior art.

[0033] The concrete load applying device includes:

[0034] The frame rod 8 has an upper portion fixed to the housing of the hydraulic device 4 and a lower end passing through the top plate 6 and connected to the bottom plate 9.

[0035] A concrete sample 11 is installed between the top plate 6 and the bottom plate 9 ; the concrete sample 11 is placed on the bottom plate 9 .

[0036] The hydraulic device 4 comprises a telescopic hydraulic rod 5 , the lower end of which is connected to a movable hinge 7 .

[0037] That is, the hydraulic device 4 is connected to the bottom plate 9 through the frame rod 8 to form a frame, and the concrete sample 11 is placed inside.

[0038] Furthermore, the hydraulic device 4 includes four independent small hydraulic machines, and the output end of each hydraulic machine is a telescopic hydraulic rod 5. The hydraulic machine applies loads of different working conditions to the concrete sample 11 through the telescopic hydraulic rod 5.

[0039] The movable hinge 7 is used to connect the hydraulic rod 5 and the top plate 6 so that the top plate 6 is closely attached to the upper surface of the concrete sample, and is fixed to the top plate 6.

[0040] Furthermore, the movable hinge 7 is connected to the hydraulic rod 5 by nuts, bolts and spring washers, and the tightness of the movable hinge 7 and the hydraulic rod 5 can be adjusted. By tightening the nut, the top plate is prevented from slipping due to the different forces on the hydraulic rod and the smooth surface of the concrete sample during the load application process.

[0041] Specifically: the movable hinge 7 includes: a connecting seat, a bolt, a nut, and a spring washer.

[0042] The bolt is fixed to the hydraulic rod 5 and passes through the connecting seat.

[0043] The spring washer is sleeved on the bolt and is located between the connecting seat and the nut, that is, it is limited by the nut, and the nut is screwed on the end of the bolt.

[0044] The strain testing system 10 is used to test the internal stress of concrete. A plurality of strain sensors are embedded in the concrete sample 11. The strain testing system 10 is connected to the output end of each strain sensor.

[0045] The concrete sample 11 is pre-embedded with strain sensors at the axis positions of the four hydraulic rods 5 .

[0046] Hydraulic control system, connected to each hydraulic press signal.

[0047] The freeze-thaw cycle machine control system integrates a hydraulic control system and a strain testing system 10, including freeze-thaw cycle control, hydraulic control, and strain data acquisition.

[0048] The wiring harness 3 includes a hydraulic control system wiring harness and a strain test system wiring harness, and is used to connect the hydraulic control system, the strain test system and the control system of the freeze-thaw cycle testing machine 1 .

[0049] Working principle of the new concrete load and freeze-thaw cycle coupling test device:

[0050] 1. Before conducting the freeze-thaw cycle test of concrete samples, first prepare the concrete according to the test requirements, and embed strain sensors at the axis positions of the four hydraulic rods 5. After the concrete sample 11 is cured and formed, place the concrete sample 11 on the bottom plate to ensure that the axis positions of the two are aligned.

[0051] 2. Connect the strain sensor and the strain testing system 10.

[0052] 3. Adjust the hydraulic control system and extend the four hydraulic rods 5 synchronously. At the same time, pay attention to the reading of the strain test system to make the top plate 6 just contact with the upper surface of the concrete sample.

[0053] That is, when the strain test system just starts to show readings, the top plate 6 just contacts the upper surface of the concrete sample.

[0054] 4. Tighten the nuts of the movable hinges 7 to lock the four movable hinges 7.

[0055] 5. Adjust the hydraulic control system so that the readings of each strain sensor meet the requirements of the test conditions.

[0056] 6. Place the concrete load applying device as a whole into the freeze-thaw cycle box 2, and pour the freeze-thaw medium until it just covers the concrete sample 11.

[0057] The freeze-thaw cycle box 2 is placed in the inner groove of the freeze-thaw cycle tester 1 , and antifreeze liquid is poured outside the freeze-thaw cycle box 2 .

[0058] 7. Cover the freeze-thaw cycle test machine 1, set the test type, test cycle and load cycle, and conduct the freeze-thaw cycle test.

[0059] The hydraulic control system will automatically adjust the pressure of four small hydraulic presses during the freeze-thaw cycle, and the strain testing system will measure and record the internal stress of the concrete.

[0060] In summary, the new concrete load and freeze-thaw cycle coupling test device provided by the utility model can independently control four small hydraulic presses by regulating the hydraulic device, apply loads of different working conditions to the concrete specimens, such as axial load, eccentric load, etc., and can accurately obtain the stress distribution of the concrete.

[0061] By integrating the freeze-thaw cycle machine control system and the hydraulic control system, the load condition of the concrete sample can be changed during the freeze-thaw cycle, the dynamic coupling of the concrete load and the freeze-thaw cycle can be achieved, and the freeze-thaw damage of concrete in actual engineering can be simulated more accurately.

[0062] By integrating the hydraulic control system and the strain testing system, the stress distribution of the concrete can be directly obtained, saving the steps of manual calculation.

[0063] The above are only preferred embodiments of the present invention and do not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, may make any equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which shall be deemed as the content of the technical solution of the present invention and still fall within the protection scope of the present invention.

Claims

1. A new concrete load and freeze-thaw cycle coupling test device, characterized in that: include: Freeze-thaw cycle test machine (1); A freeze-thaw cycle box (2) is located in a groove inside the freeze-thaw cycle test machine (1), and antifreeze liquid is provided between the freeze-thaw cycle box and the inner wall of the freeze-thaw cycle test machine (1); and a concrete load applying device, which is located in the freeze-thaw cycle box (2), and a freeze-thaw medium is provided between the freeze-thaw cycle box and the inner wall of the freeze-thaw cycle box (2), comprising: A frame rod (8), the upper end of which is fixed to the housing of the hydraulic device (4), and the lower end of which passes through the top plate (6) and is connected to the bottom plate (9); A concrete sample (11) is installed between the top plate (6) and the bottom plate (9); the concrete sample (11) is placed on the bottom plate (9); a strain sensor is embedded in the concrete sample (11); and a hydraulic device (4), comprising a telescopic hydraulic rod (5), the lower end of the telescopic hydraulic rod (5) being connected to a movable hinge (7), and the movable hinge (7) being fixed to a bottom plate (9).

2. The novel concrete load and freeze-thaw cycle coupling test device according to claim 1 is characterized in that: The movable hinge (7) comprises: A bolt fixed to the hydraulic rod (5) and passing through the connecting seat; The spring washer is sleeved on the bolt and located between the connecting seat and the nut. The nut is screwed on the end of the bolt.

3. The novel concrete load and freeze-thaw cycle coupling test device according to claim 1 is characterized in that: The hydraulic device (4) comprises four independent hydraulic machines, and the output end of each hydraulic machine is a telescopic hydraulic rod (5).

4. The novel concrete load and freeze-thaw cycle coupling test device according to claim 1 is characterized in that: The strain sensor is located at the axis center of the hydraulic rod (5).

5. The novel concrete load and freeze-thaw cycle coupling test device according to claim 1 is characterized in that: Also includes: Hydraulic control systems and strain testing systems (10); The hydraulic control system is signal-connected to the hydraulic device (4); The strain testing system (10) is connected to the output end of the strain sensor.

6. The novel concrete load and freeze-thaw cycle coupling test device according to claim 5 is characterized in that: It also includes a wiring harness (3), which includes a hydraulic control system wiring harness and a strain test system wiring harness, and is connected to the control system of the freeze-thaw cycle test machine (1).

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