Concrete pulling and pressing loading device and method under environment-load coupling

Abstract

The invention discloses a concrete load-holding splitting test device and method under the combined action of an environment and a load, and the device comprises an environment simulation device which is used for providing an outdoor simulation environment; the load holding device comprises a base, a top seat, a spring, a limiter and an extensometer; a plurality of guide columns are arranged on the top seat, and the top seat can slide up and down along the guide columns; the spring is sleeved on the guide post; a limiter is arranged on the guide post and is used for limiting the spring in a compressed state; an extensometer is arranged between the base and the top seat; the base comprises two bottom plates, two connecting plates and a stress plate, and the bottom plates, the connecting plates, the stress plate, the connecting plates and the bottom plates are sequentially connected in a mutual lap joint mode. The top seat comprises two top plates, two connecting plates and a stress plate, and the top plates, the connecting plates, the stress plate, the connecting plates and the top plates are sequentially connected in a mutual lap joint mode. According to the method based on the experimental device, the compression / splitting test can be conveniently carried out.

Description

Technical Field

[0001] The invention belongs to the field of civil engineering and concrete structure performance testing, in particular to a concrete tension and compression loading device and method under environment-load coupling. Background Art

[0002] In the frontier fields of transportation, civil construction, and materials science and engineering, the durability of concrete materials has always occupied a pivotal position and is regarded as a scientific issue that urgently needs in-depth exploration. During its actual service life, concrete materials often face the dual challenges of complex and changeable environmental factors and long-term external loads. These external forces continue to accumulate, and over time, they gradually lead to the gradual decline in the performance of concrete materials, and even eventually lose their basic functions, causing serious impacts on the integrity and safety of the structure. Therefore, in-depth research and improvement on the durability of concrete is not only of great significance for extending the service life of engineering structures, but also has a far-reaching impact on improving the overall level of materials science.

[0003] In the current field of concrete research, the traditional test method for the strength characteristics of concrete under long-term loads often adopts the method of loading, unloading, and then performing stress-strain tests. However, this method ignores the strain recovery phenomenon of concrete after unloading, which is one of the inherent time-varying characteristics of concrete under load. In fact, in engineering practice, concrete components will continue to be loaded, and will often be loaded again on the basis of the original load until they are damaged. This continuous loading situation is far more complex and realistic than what traditional test methods can simulate. Therefore, in order to conduct in-depth research on the strength characteristics of concrete under long-term loads, it is necessary to more accurately simulate the stress state in actual engineering in order to provide a more accurate and reliable basis for engineering design and application.

[0004] Under the current technical background, existing load and environment simulation instruments generally have the problems of large size and low operating efficiency. Such large instruments can only load one sample at a time, which makes the entire test process time-consuming, greatly restricting the progress of scientific research and engineering projects. Summary of the invention

[0005] The purpose of the present invention is to provide a concrete tension and compression loading device and method under environment-load coupling, which loads the sample through the loading device, and then puts the sample into an environmental simulation system in a load-maintaining state to simulate environmental degradation, and performs a compression / tensile test in the load-maintaining state, thereby solving the above-mentioned problems.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A concrete load-keeping splitting test device under the combined action of environment and load, comprising:

[0008] An environmental simulation device, used to provide an outdoor simulated environment including environmental parameters such as temperature, humidity, salt concentration, and ultraviolet intensity, and capable of accommodating a carrier device;

[0009] The load-holding device comprises a base, a top seat, a spring, a stopper and an extensometer; the base is provided with a plurality of guide posts, the top seat can slide up and down along the guide posts, and the top seat and the base are used to place the sample; the spring is sleeved on the guide post and is located on the upper side of the top seat; the guide post is provided with a stopper, which is used to limit the spring in a compressed state, so that the load-holding device maintains a pressurized load-holding state; an extensometer is provided between the base and the top seat, which is used to monitor the deformation of the sample;

[0010] The base comprises two bottom plates, two connecting plates and a load-bearing plate, which are connected in the order of bottom plate-connecting plate-load-bearing plate-connecting plate-bottom plate and overlapped with each other; wherein after the connecting plates are removed, the load-bearing plates can overlap on the bottom plates;

[0011] The top seat comprises two top plates, two connecting plates and a bearing plate, which are connected in the order of top plate-connecting plate-bearing plate-connecting plate-top plate and overlapped with each other; wherein after the connecting plates are removed, the bearing plates can overlap on the top plates;

[0012] When the connecting plates of the base and the top seat are in an overlapped state, they are used for uniaxial compression test and triaxial compression test; when the connecting plates of the base and the top seat are removed, they are used for uniaxial tensile test and triaxial tensile test.

[0013] A test method for a concrete load-holding splitting test device under the combined effects of environment and load, comprising:

[0014] After the base is assembled, the sample is placed in the middle of the base; after the top seat is assembled, the top seat is passed through the guide column so that the top seat contacts the sample; the spring is inserted into the guide column and a load is applied. When the required load is reached, the spring deformation is limited by a limiter so that the load is applied to the top seat;

[0015] Place the assembled carrier into the environmental simulation system, and simulate the outdoor environment by controlling the temperature, humidity, salt concentration, and ultraviolet intensity. Take out the carrier after the simulation time is reached;

[0016] When conducting a uniaxial compression test, the load retaining device is placed on the pressure plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat for testing.

[0017] Compared with the prior art, the present invention has the following significant advantages:

[0018] The present invention relates to an improved test device and test method, which realizes long-term and stable load application to the specimens through a unique loading device. Subsequently, these loaded specimens are accurately placed in an environmental simulation box for comprehensive performance testing. The core of the present invention lies in its detachable loading device. This innovation enables compression / splitting tests to be conveniently performed while stress is applied. This design greatly improves the flexibility of the test, making the test process closer to actual working conditions, thereby ensuring the high accuracy and reliability of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the device where environment and load interact with each other.

[0020] Figure 2 Schematic diagram of the environmental simulation device.

[0021] Figure 3 Schematic diagram of the load-keeping device.

[0022] Figure 4 This is a schematic diagram of the first type of load-carrying device.

[0023] Figure 5 This is a schematic diagram of the first type of carrier base.

[0024] Figure 6 This is a schematic diagram of the top seat of the first type of loading protection device.

[0025] Figure 7 Schematic diagram of the second type of loading device.

[0026] Figure 8 Schematic diagram of the second type of carrier base.

[0027] Fig. 9 Schematic diagram of the second connection method of the carrier base.

[0028] Fig.10 Schematic diagram of the top seat of the second type of loading protection device.

[0029] Fig.11 Schematic diagram of uniaxial compression test.

[0030] Fig.12 Schematic diagram of uniaxial tensile test.

[0031] Fig.13 Schematic diagram of the triaxial loading device.

[0032] Fig.14 It is a top view schematic diagram of the triaxial loading device.

[0033] Fig.15 It is a cross-sectional schematic diagram of the triaxial loading device.

[0034] Fig.16 Schematic diagram of triaxial compression test.

[0035] Fig.17 Schematic diagram of triaxial tensile test. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The present invention provides a concrete load-keeping splitting test device and method under the combined action of environment and load, such as Figure 1 As shown, it includes an environment simulation system 1 and a carrier device 2; Figure 2 As shown, the environment simulation system 1 includes a control room 11, a heater 12, a humidifier 13, a salt adding device 14, and an ultraviolet irradiation device 15 arranged in the control room 11. The heater 12 heats the test environment through an electric heating element or a heat exchanger; the humidifier 13 humidifies the test environment through a spray or a steam generator; the salt adding device 14 simulates a high-salinity environment by spraying a salt solution into the test environment; and the ultraviolet irradiation device 15 simulates strong solar radiation in the test environment through an ultraviolet lamp.

[0040] The carrying device 2 is as follows Figure 3The test apparatus shown in the figure includes a base 21, a top seat 22, a spring 23, a stopper 24 and an extensometer 25, and the sample 3 is placed between the base 21 and the top seat 22. The base 21 includes two bottom plates 26, two connecting plates 27 and a force plate 28. The connecting plate 27 overlaps the bottom plate 26 on one side and overlaps the force plate 28 on the other side. The bottom plate 26 has two holes that pass through the bottom plate 26 on the side away from the connecting plate 27, which are distributed in the front and back positions; the top seat 22 includes a top plate 29, a connecting plate 27 and a force plate 28, wherein the overlap conditions of the force plates 28 and the connecting plates 27 of the base 21 and the top seat 22 are consistent, and the top plate 29 has two guide columns on the side away from the connecting plate 27, which are distributed in the front and back positions, corresponding to the positions of the holes of the bottom plate 26, and the lower ends of the guide columns are fixed to the bottom plate 26 and pass through the top plate 29, and the top plate 29 can slide up and down along the guide columns. Different load-carrying devices are selected according to the specific needs and working conditions of the test, and the main difference lies in the base 21 and the top seat 22.

[0041] The first type of load-carrying device is Figure 4 As shown, the bottom plate 26-1, the load-bearing plate 28 and the connecting plate 27-1 are spliced ​​to form the base 21. Figure 5 The bottom plate 26-1 is provided with a convex curved surface overlapped with the connecting plate 27-1 and a rectangular surface supporting the bottom of the curved surface of the force-bearing plate 28 on one side close to the connecting plate 27-1. The force-bearing plate 28 is composed of a hemispherical shape and a rectangular parallelepiped arranged in the middle of the hemispherical plane. The longitudinal section shape is an arc surface and a rectangle arranged in the middle of the arc surface. The arc surface overlaps with the concave curved surfaces of the connecting plates 27-1 on the left and right sides. The rectangle is arranged between the left and right bottom plates 26-1. The connecting plate 27-1 is shaped like a triangular prism with concave curved surfaces on both sides. The concave curved surface on one side overlaps with the bottom plate 26-1, and the concave curved surface on the other side overlaps with the force-bearing plate 28. Similarly, two top plates 29-1, the force-bearing plate 28 and the two connecting plates 27-1 are spliced ​​to form a top seat 22, such as Figure 6 .

[0042] The second type of load-carrying device is Figure 7 As shown, the difference from the first type of loading device is that the connecting plate 27-2 is shaped like a right-angled trapezoid, and the long inclined surface of the right-angled trapezoid is set as a concave arc surface, which overlaps the arc surface of the load-bearing plate 28; the base is as shown Figure 8 As shown, the bottom plate 26-2 has a groove near the connecting plate on one side, which is rectangular in shape. The force-bearing plate 28 is inserted into the groove of the bottom plate 26-2. The hemispherical plane of the force-bearing plate 28 overlaps with the bottom of the groove, the side surface below the groove overlaps with the rectangular surface of the force-bearing plate, and the side surface above the groove overlaps with the right-angle surface of the connecting plate 27-2. Fig. 9 The connection method of the top seat 22 is the same as that of the base, and the top seat 22 is composed of a top plate 29-2, a connecting plate 27-2 and a force plate 28. Fig.10 .

[0043] After the base 21 and the top seat 22 are assembled, the sample 3 is placed between the base 21 and the top seat 22, and the spring 23 is installed on the guide column at the upper end of the top seat 21. After a force is applied to the spring 23 and added to the design value, a limiter 24 is installed above the spring 23 (for example, by screwing a nut into the guide column), and the spring 23 no longer deforms. An extensometer 25 is installed on the same side of the base 21 and the top seat 22. One end of the extensometer 25 is connected to the base 21, and the other end is connected to the top seat 22, which is used to monitor the deformation of the sample.

[0044] After the loading device is assembled, it is placed in the environmental simulation system 1. According to the designed time, the loading device 2 is taken out and the mechanical test is carried out. The implementation steps are as follows:

[0045] Step 1. Select a suitable combination of base and top seat; assemble the base and place the sample in the middle of the base; after assembling the top seat, pass the hole of the top seat through the guide column to make the top seat contact with the sample; insert the spring into the guide column and apply the load as required. After reaching the required load, use the limiter to limit the deformation of the spring so that it keeps applying load to the top seat, thereby applying load to the sample.

[0046] Step 2. Place the assembled carrier into the environmental simulation system, and simulate the outdoor environment by controlling the temperature, humidity, salt concentration, and ultraviolet intensity. Take out the carrier after the simulation days are reached.

[0047] Step 3. When conducting a uniaxial compression test, place the load-holding device on the pressure plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat for testing.

[0048] Uniaxial compression test: Place the load-holding device on a mechanical testing machine, apply a uniform load to the base 21 and the top seat 22 of the load-holding device 2, and perform a uniaxial compression test under the load-holding effect. Fig.11 .

[0049] Uniaxial tensile test: Remove the connecting plate 27 between the base 21 and the top 22 of the load-holding device, place the load-holding device on a mechanical testing machine, apply load to the force-bearing plates 28 of the base 21 and the top 22, and perform a uniaxial tensile test under load holding. Fig.12 .

[0050] Triaxial compression test: Triaxial loading device 4 as Fig.13 As shown, it is composed of a support surface 41 and a force rod 42. The force rod 42 passes through the support surface 41. The support surface 41 is a hollow cube with an open top and bottom. There are holes in the middle of the four sides. The force rod passes through the holes and the loading device can be placed in it. The force rod 42 is composed of a cylinder and a cuboid. The contact surface between the cuboid and the sample is consistent with the sample area. Fig.14 Fig.15As shown; the load-holding device 2 is placed in the triaxial loading device 4, and then placed on the mechanical testing machine. According to the design, a load is applied to the force rod 42, and the load is evenly distributed around the sample. Then, the mechanical testing machine applies a uniform load to the base 21 and the top seat 22 of the load-holding device 2 to achieve a triaxial compression test under the load-holding action, as shown in FIG. Fig.16 .

[0051] Triaxial tensile test: Place the load-holding device 2 in the triaxial loading device 4 and then place it on the mechanical testing machine. According to the design, a load is applied to the force rod 42, and the load is evenly distributed around the specimen; the connecting plate 27 between the base 21 and the top seat 22 of the load-holding device is removed, and a load is applied to the force plate 28 of the base 21 and the top seat 22 to achieve a triaxial tensile test under the load-holding effect. Fig.17 .

Claims

1. A concrete load-keeping splitting test device under the combined action of environment and load, characterized in that: include: An environmental simulation device, used to provide an outdoor simulated environment including environmental parameters such as temperature, humidity, salt concentration, and ultraviolet intensity, and capable of accommodating a carrier device; The load-holding device comprises a base, a top seat, a spring, a stopper and an extensometer; the base is provided with a plurality of guide posts, the top seat can slide up and down along the guide posts, and the top seat and the base are used to place the sample; the spring is sleeved on the guide post and is located on the upper side of the top seat; the guide post is provided with a stopper, which is used to limit the spring in a compressed state, so that the load-holding device maintains a pressurized load-holding state; an extensometer is provided between the base and the top seat, which is used to monitor the deformation of the sample; The base comprises two bottom plates, two connecting plates and a load-bearing plate, which are connected in the order of bottom plate-connecting plate-load-bearing plate-connecting plate-bottom plate and overlapped with each other; wherein after the connecting plates are removed, the load-bearing plates can overlap on the bottom plates; The top seat comprises two top plates, two connecting plates and a bearing plate, which are connected in the order of top plate-connecting plate-bearing plate-connecting plate-top plate and overlapped with each other; wherein after the connecting plates are removed, the bearing plates can overlap on the top plates; When the connecting plates of the base and the top seat are in an overlapped state, they are used for uniaxial compression test and triaxial compression test; when the connecting plates of the base and the top seat are removed, they are used for uniaxial tensile test and triaxial tensile test.

2. The concrete load-keeping splitting test device under the combined action of environment and load according to claim 1 is characterized in that: The bottom plate and the top plate are each provided with a convex arc surface overlapping the connecting plate and a rectangular surface supporting the bottom of the arc surface of the load-bearing plate on one side close to the connecting plate; the longitudinal section of the load-bearing plate is a arc surface and a rectangle arranged in the middle of the arc surface, the arc surface overlaps the concave arc surfaces of the connecting plates on the left and right sides, the rectangle is arranged between the left and right bottom plates, and the two sides of the connecting plate are concave arc surfaces, one side of the concave arc surface overlaps the bottom plate or the top plate, and the other side of the concave arc surface overlaps the load-bearing plate.

3. The concrete load-keeping splitting test device under the combined action of environment and load according to claim 1 is characterized in that: The bottom plate and the top plate have a groove on one side close to the connecting plate, which is in the shape of a rectangle; the connecting plate is in the shape of a right-angled trapezoid with the inclined surface set as a concave arc surface, and the concave arc surface overlaps the arc surface of the force-bearing plate; the longitudinal section of the force-bearing plate is in the shape of an arc surface and a rectangle set in the middle of the arc surface, the force-bearing plate is inserted into the groove, the force-bearing plate overlaps the bottom of the groove, the side surface below the groove overlaps the rectangular surface of the force-bearing plate, and the side surface above the groove overlaps the right-angle surface of the connecting plate.

4. The concrete load-keeping splitting test device under the combined action of environment and load according to claim 1 is characterized in that: The environmental simulation system includes a control room, a heater, a humidifier, a salt adding device and an ultraviolet irradiation device arranged in the control room; the heater is used to heat the test environment; the humidifier 1 is used to humidify the test environment; the salt adding device is used to simulate the salinity environment; the ultraviolet irradiation device is used to simulate the strong solar radiation of the test environment.

5. The concrete load-keeping splitting test device under the combined effect of environment and load according to claim 4 is characterized in that: The heater heats the test environment through an electric heating element or a heat exchanger.

6. The concrete load-keeping splitting test device under the combined effect of environment and load according to claim 4 is characterized in that: The humidifier 13 humidifies the test environment through spray or steam generator.

7. The concrete load-keeping splitting test device under the combined effects of environment and load according to claim 4 is characterized in that: The ultraviolet irradiation device realizes the simulation of strong solar radiation of the test environment through the ultraviolet lamp tube.

8. The concrete load-keeping splitting test device under the combined action of environment and load according to claim 1 is characterized in that: A triaxial loading device is also provided, which consists of a supporting surface and a force-applying rod. The force-applying rod passes through the supporting surface, and the contact surface between the force-applying rod and the sample is consistent with the sample area.

9. The test method of the concrete load-keeping splitting test device under the combined effect of environment and load according to any one of claims 1 to 8, characterized in that: include: After the base is assembled, the sample is placed in the middle of the base; After the top seat is assembled, pass the top seat through the guide column so that the top seat contacts the specimen; Insert the spring into the guide column and apply the load. When the required load is reached, use the limiter to limit the deformation of the spring so that the load is applied to the top seat. Place the assembled carrier into the environmental simulation system, and simulate the outdoor environment by controlling the temperature, humidity, salt concentration, and ultraviolet intensity. Take out the carrier after the simulation time is reached; When conducting a uniaxial compression test, the load retaining device is placed on the pressure plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat for testing.

10. The test method of the concrete load-keeping splitting test device under the combined action of environment and load according to claim 9 is characterized in that: During the uniaxial compression test, the load-holding device is placed on the mechanical testing machine, and a uniform load is applied to the base and top seat of the load-holding device to achieve the uniaxial compression test under the load-holding action; During the uniaxial tensile test, the connecting plate between the base and the top seat of the load-holding device is removed, the load-holding device is placed on the mechanical testing machine, and loads are applied to the load-bearing plates of the base and the top seat to achieve the uniaxial tensile test under the load-holding action; During the triaxial compression test, the load-holding device is placed in the triaxial loading device and then placed on the mechanical testing machine; The load is evenly distributed around the specimen, and then the uniform load is applied to the base and top seat of the load-holding device by a mechanical testing machine to achieve a triaxial compression test under load-holding action; During the triaxial tensile test, the load holding device is placed in the triaxial loading device and then placed on the mechanical testing machine, with the load evenly distributed around the specimen; the connecting plate between the base and the top seat of the load holding device is removed, and load is applied to the force plates of the base and the top seat to realize the triaxial tensile test under the action of the load holding device.

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