Concrete tension and compression loading device and method under environment-load coupling

Abstract

The application discloses a kind of environment and load under the joint action concrete load split test device and method, device includes: environmental simulation device, for providing outdoor simulation environment;Load device, including base, top seat, spring, stopper and extensometer;The top is equipped with multiple guide columns, and top seat can slide up and down along guide column;Spring is sleeved on guide column;Guide column is equipped with stopper, for the spring in compression state is positioned;Bottom and top seat are equipped with extensometer;Base includes two bottom plates, two connecting plates and a force plate, with the sequence of bottom plate-connecting plate-force plate-connecting plate-bottom plate and using the way of mutual lap joint is connected;Top seat includes two top plates, two connecting plates and a force plate, with the sequence of top plate-connecting plate-force plate-connecting plate-top plate and using the way of mutual lap joint is connected;The method based on above experimental device can conveniently carry out compression / splitting test.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of civil engineering and concrete structure performance testing, and particularly relates to a concrete tension and compression loading device and method under environment-load coupling. BACKGROUND

[0002] In the forefront fields of transportation, civil construction and material science and engineering, the durability of concrete materials has always played a vital role and is regarded as a scientific issue that needs to be further explored. During the actual service period of concrete materials, they often face the dual challenges of complex and variable environmental factors and long-term external loads. These external effects accumulate over time, gradually leading to the gradual degradation of the performance of concrete materials, and even eventually losing their basic functions, which has a serious impact on the integrity and safety of the structure. Therefore, in-depth research and improvement of the durability of concrete not only has important significance for prolonging the service life of engineering structures, but also has a profound impact on improving the overall level of the field of material science

[0003] In the current field of concrete research, the traditional test method for the strength characteristics of concrete under long-term load often adopts the method of loading and unloading, and then testing the stress and strain. However, this method ignores the strain recovery phenomenon exhibited by concrete after unloading, which is one of the inherent time-varying characteristics of concrete under load. In fact, in engineering practice, concrete members will continue to be in a loaded state, and often will be loaded again on the basis of the original load until they are destroyed. This continuous loading condition is much more complex and realistic than the traditional test method can simulate. Therefore, in-depth research on the strength characteristics of concrete under long-term load must more accurately simulate the stress state in actual engineering in order to provide more accurate and reliable basis for engineering design and application.

[0004] Under the current technical background, the existing load and simulation environment instruments generally have the problems of large size and low operation efficiency. Such large instruments can only load one sample at a time, resulting in a long testing process and greatly restricting the progress of scientific research and engineering projects. SUMMARY

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

[0006] The technical solution for achieving the purpose of the present application is as follows:

[0007] A kind of concrete load split test device under the action of environment and load, comprising:

[0008] Environment simulation device, for providing including temperature, humidity, salt concentration, UV intensity environmental parameters, and can accommodate load retention device outdoor simulation environment;

[0009] Load retention device, including base, top seat, spring, stopper and extensometer;The base is equipped with multiple guide columns, and the top seat can slide up and down along the guide column, and the top seat is used to place the sample between the base;The spring is sleeved on the guide column and located on the top side of the top seat;The guide column is equipped with a stopper for limiting the spring in a compressed state, so that the load retention device maintains a pressurized load retention state;The extensometer is arranged between the base and the top seat for monitoring the deformation of the sample;

[0010] The base includes two bottom plates, two connecting plates and a stress plate, which are connected in the order of bottom plate-connection plate-stress plate-connection plate-bottom plate and are connected in a mutually overlapping manner;Wherein, after the connecting plate is removed, the stress plate can be overlapped on the bottom plate;

[0011] The top seat includes two top plates, two connecting plates and a stress plate, which are connected in the order of top plate-connection plate-stress plate-connection plate-top plate and are connected in a mutually overlapping manner;Wherein, after the connecting plate is removed, the stress plate can be overlapped on the top plate;

[0012] When the connecting plates of the base and the top seat are overlapped, it is used for uniaxial compression test and triaxial compression test;When the connecting plates of the base and the top seat are removed, it is used for uniaxial tensile test and triaxial tensile test.

[0013] A test method of a concrete load split test device under the action of environment and load, comprising:

[0014] The base is assembled, and the sample is placed in the middle of the base;The top seat is assembled, the top seat is passed through the guide column, and the top seat is in contact with the sample;The spring is inserted into the guide column, and a load is applied, and after reaching the required load, the spring deformation is limited by the stopper, so that the load on the top seat is maintained;

[0015] The assembled load retention device is placed in the environment simulation system, and the outdoor environment is simulated by controlling temperature, humidity, salt concentration and UV intensity, and the load retention device is taken out after the simulation time;

[0016] When uniaxial compression test is carried out, the load retention 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 application has the following advantages:

[0018] The present invention relates to an improved testing device and testing method, which realizes long-term and stable load application to samples through a unique loading device. Subsequently, the loaded samples are precisely placed in an environment simulation box for comprehensive performance testing. The core of the present invention is the detachable loading device, which makes it convenient to carry out compression / splitting tests while stress application is being carried out. This design greatly improves the flexibility of the test, making the test process closer to the actual working conditions, thereby ensuring the high accuracy and reliability of the test data. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is an environmental and load interaction device.

[0020] Figure 2 It is an environmental simulation device.

[0021] Figure 3 It is a load maintaining device.

[0022] Figure 4 It is a first load maintaining device.

[0023] Figure 5 It is a first load maintaining device base.

[0024] Figure 6 It is a first load maintaining device top base.

[0025] Figure 7 It is a second load maintaining device.

[0026] Figure 8 It is a second load maintaining device base.

[0027] Figure 9 It is a second load maintaining device base connection method.

[0028] Figure 10 It is a second load maintaining device top base.

[0029] Figure 11 It is a uniaxial compression test.

[0030] Figure 12 It is a uniaxial tension test.

[0031] Figure 13 It is a triaxial loading device.

[0032] Figure 14 It is a triaxial loading device top view.

[0033] Figure 15 It is a triaxial loading device cross-sectional view.

[0034] Figure 16 This is a schematic diagram of a triaxial compression test.

[0035] Figure 17 This is a schematic diagram of a triaxial tensile test. Detailed Implementation

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

[0037] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] This invention provides a test apparatus and method for concrete splitting crack under the combined action of environment and load, such as... Figure 1 As shown, it includes an environmental simulation system 1 and a load-carrying device 2; as Figure 2 As shown, the environmental simulation system 1 includes a control room 11, a heater 12, a humidifier 13, a salting device 14, and an ultraviolet irradiation device 15, all housed within the control room 11. The heater 12 heats the test environment via an electric heating element or heat exchanger; the humidifier 13 humidifies the test environment via a spray or steam generator; the salting 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 using ultraviolet lamps.

[0040] The load-carrying device 2 is as follows Figure 3As shown, including base 21, top seat 22, spring 23, stop 24 and extensometer 25, 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, 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 through from top to bottom on the side away from the connecting plate 27, and is distributed in front and back positions; the top seat 22 includes a top plate 29, a connecting plate 27 and a force plate 28, wherein the force plate 28 and the connecting plate 27 of the base 21 and the top seat 22 overlap consistently, the top plate 29 has two guide columns on the side away from the connecting plate 27, and is distributed in front and back positions, corresponding to the hole position of the bottom plate 26, the lower end of the guide column is fixed with the bottom plate 26 and passes through the top plate 29, and the top plate 29 can slide up and down along the guide column. According to the specific requirements and working conditions of the test, different load maintaining devices are selected, and the main difference lies in the base 21 and the top seat 22.

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

[0042] The second type of load maintaining device is shown in Figure 7 , which is different from the first type of load maintaining device in that the connecting plate 27-2 is similar to a right-angled trapezoidal body, the long inclined surface of the right-angled trapezoidal body is arranged as a concave arc surface, and the concave arc surface overlaps the arc surface of the force plate 28; the base is shown in Figure 8 , the bottom plate 26-2 has a slot on the side close to the connecting plate, which is rectangular in shape, the force plate 28 is clamped into the slot of the bottom plate 26-2, the hemisphere plane of the force plate 28 overlaps the lower surface in the slot, the lower side surface of the slot overlaps the rectangular surface of the force plate, and the upper side surface of the slot overlaps the right-angled surface of the connecting plate 27-2, as shown in Figure 9 . The top seat 22 is spliced by the top plate 29-2, the connecting plate 27-2 and the force plate 28 to form the top seat 22, as shown in Figure 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, the spring 23 is installed on the guide column at the upper end of the top seat 21, force is applied to the spring 23, and after the designed value is reached, the stopper 24 is installed above the spring 23 (for example, by screwing into the guide column), the spring 23 is no longer deformed, the 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 preservation device is assembled, it is placed in the environmental simulation system 1. According to the designed time, the preservation device 2 is taken out for mechanical test. The implementation steps are as follows:

[0045] Step 1. Select the appropriate form of base and top seat combination; assemble the base, place the sample in the middle of the base; assemble the top seat, pass the hole of the top seat through the guide column, so that the top seat contacts the sample; pass the spring into the guide column, and apply the required load, and after reaching the required load, limit the deformation of the spring with the stopper, so that it maintains the load applied to the top seat, thereby applying load to the sample.

[0046] Step 2. Place the assembled preservation device in the environmental simulation system, simulate the outdoor environment by controlling temperature, humidity, salt concentration, and ultraviolet intensity, and take out the preservation device after the simulation time.

[0047] Step 3. When performing uniaxial compression test, place the preservation 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 preservation device on the mechanical testing machine, apply uniform load to the base 21 and the top seat 22 of the preservation device 2, and realize uniaxial compression test under the preservation effect, as shown in Figure 11 .

[0049] Uniaxial tensile test: remove the connecting plate 27 of the base 21 and the top seat 22 of the preservation device, place the preservation device on the mechanical testing machine, and apply load to the stress plate 28 of the base 21 and the top seat 22, to realize uniaxial tensile test under the preservation effect, as shown in Figure 12 .

[0050] Triaxial compression test: the triaxial loading device 4 is composed of a support surface 41 and a force applying rod 42, as shown in Figure 13 The support surface 41 is a hollow cube with an open top and bottom, and a hole in the middle of the four sides, through which the force applying rod passes. The preservation device can be placed in the hole. The force applying rod 42 is composed of a cylinder and a cuboid, and the contact surface of the cuboid with the sample is consistent with the area of the sample. Figure 14 Figure 15The load is applied to the force applying rod 42 according to the design, the sample is distributed with the uniform load, the base 21 and the top base 22 of the load preserving device 2 are applied with the uniform load by the mechanical testing machine, the triaxial compression test under the load preserving is realized, and the triaxial compression test under the load preserving is realized. Figure 16 .

[0051] The triaxial tensile test: the load preserving device 2 is placed in the triaxial loading device 4 and then placed on the mechanical testing machine. According to the design, the load is applied to the force applying rod 42, the sample is distributed with the uniform load, the connecting plate 27 of the base 21 and the top base 22 of the load preserving device is removed, the stress plate 28 of the base 21 and the top base 22 is applied with the load, and the triaxial tensile test under the load preserving is realized. As shown in Figure 17 .

Claims

1. A device for a concrete load-restrained splitting test under combined action of environment and load, characterized in that, include: An environmental simulation device is used to provide an outdoor simulated environment including environmental parameters such as temperature, humidity, salt concentration, and ultraviolet intensity, and can accommodate a load-bearing device. The load-holding device includes a base, a top seat, a spring, a limiter, and an extensometer. The base has multiple guide posts, and the top seat can slide up and down along the guide posts. A sample is placed between the top seat and the base. The spring is sleeved on the guide posts and located on the upper side of the top seat. A limiter is provided on the guide posts to limit the spring in its compressed state, ensuring the load-holding device maintains a pressurized load-holding state. An extensometer is located between the base and the top seat to monitor sample deformation. The base includes two base plates, two connecting plates, and one load-bearing plate, which are connected in the order of base plate-connecting plate-load-bearing plate-connecting plate-base plate and by overlapping each other; wherein, after the connecting plates are removed, the load-bearing plate can overlap on the base plate; The top support includes two top plates, two connecting plates, and one load-bearing plate, which are connected in the order of top plate-connecting plate-load-bearing plate-connecting plate-top plate and by overlapping each other; wherein, after the connecting plates are removed, the load-bearing plate can overlap on the top plate; When the connecting plates of the base and the top are in the overlapping state, they are used for uniaxial compressive strength tests and triaxial compressive strength tests; when the connecting plates of the base and the top are in the removed state, they are used for uniaxial tensile strength tests and triaxial tensile strength tests.

2. The device for the concrete load and environment interaction test according to claim 1, wherein, The bottom plate and top plate each have a convex arc surface that overlaps with the connecting plate and a rectangular surface that supports the bottom of the arc surface of the load-bearing plate on the side near the connecting plate. The longitudinal section of the load-bearing plate is an arc surface and a rectangle in the middle of the arc surface. The arc surface overlaps with the concave arc surfaces of the connecting plates on the left and right sides. The rectangle is located between the two bottom plates. The connecting plates have concave arc surfaces on both sides. One concave arc surface overlaps with the bottom plate or top plate, and the other concave arc surface overlaps with the load-bearing plate.

3. The device for the concrete load-restrained splitting test under combined action of environment according to claim 1, characterized in that, The bottom plate and top plate have a rectangular groove near the connecting plate. The connecting plate is a right trapezoid with a concave arc surface on its inclined surface, which overlaps with the arc surface of the load-bearing plate. The longitudinal section of the load-bearing plate consists of an arc surface and a rectangle in the middle of the arc surface. The load-bearing plate is inserted into the groove, and the load-bearing plate overlaps with the bottom of the groove. The lower side of the groove overlaps with the rectangular surface of the load-bearing plate, and the upper side of the groove overlaps with the right-angled surface of the connecting plate.

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

5. The device for the concrete load-restrained splitting test under combined action of environment according to claim 4, characterized in that, The heater heats the test environment through an electric heating element or a heat exchanger.

6. The device for the concrete load-restrained splitting test under combined action of environment according to claim 4, characterized in that, The humidifier humidifies the test environment through a spray or steam generator.

7. The device for the concrete load-restrained splitting test under combined action of environment according to claim 4, characterized in that, The ultraviolet irradiation device simulates strong solar radiation in the test environment through ultraviolet lamps.

8. The apparatus for concrete load-restrained split testing under combined environmental and load action according to claim 1, characterized in that, It is also equipped with a triaxial loading device, which consists of a support surface and a force-applying rod. The force-applying rod passes through the support surface, and the contact surface between the force-applying rod and the specimen is consistent with the specimen area.

9. The test method of the environmental and load interaction concrete load- retaining splitting test device according to any one of claims 1-8, characterized in that, include: Once the base is assembled, place the sample in the center of the base. After the top seat is assembled, the top seat is passed through the guide column to make the top seat contact with the sample; The spring is passed into the guide column, and a load is applied. After the required load is reached, the spring deformation is limited by the limiter to keep it applying load to the top seat; The assembled load-retaining device is placed in the environmental simulation system to simulate outdoor environment by controlling temperature, humidity, salt concentration, and ultraviolet intensity. After the simulation time is reached, the load-retaining device is taken out; When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test.

10. The test method of the concrete load-retaining splitting test device under the combined action of environment and load according to claim 9, characterized in that, When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test. When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test. When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test. When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test. When uniaxial compression test is performed, the load-retaining device is placed on the compression plate of the mechanical testing machine, and the mechanical testing machine applies pressure to the top seat to perform the test.

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