Clamp for small-size concrete splitting damage test

Abstract

The utility model discloses a clamp for a small-size concrete splitting damage test, and belongs to the field of concrete test tools. The clamp comprises a base composed of a bottom plate and four side plates, a clamping assembly arranged on the first set of side plates and a sliding groove formed in the top of the upper side plate of the second set of side plates. The clamping assembly is composed of threaded rods and flexible rubber sheets, small-size concrete can be effectively fixed and clamped by screwing the two threaded rods, and due to the fact that the inhibition effect of the flexible rubber sheets on cracking of the concrete towards the left side and the right side is small, a more accurate test result is guaranteed; the sliding grooves provide precise guidance for the splitting rods, in the test process, the splitting rods are located in the sliding grooves and move up and down along the sliding grooves, the sliding grooves are designed to be matched with the two clamping assemblies, in the splitting process, the slipping phenomenon can be effectively prevented, the flatness of the small-size concrete splitting face is guaranteed, and then the accuracy of the test result is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of concrete testing tools, in particular to a fixture for small-sized concrete splitting damage testing. Background Art

[0002] In recent years, the use of precision instruments such as low-field nuclear magnetic resonance and electronic computed tomography (CT) to explore the internal pore structure of concrete and establish the coupling relationship between the micro- and macro-scales has become one of the hot topics in structural engineering durability research. In the current standard GBT50081-2019 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", a cubic specimen with a side length of 150mm is used as the standard specimen for splitting tensile strength test, but no regulations are made for small-sized concrete specimens (side length 40mm). As the precision requirements for splitting damage tests increase, more and more researchers are choosing small-sized concrete specimens as test subjects.

[0003] At present, for the splitting damage test of standard specimens, the upper and lower ends of the standard specimens are usually clamped between plain round steel bars, and then pressurized by a press until the concrete splits and fails. However, for non-standard small-sized concrete specimens, the above-mentioned clamping method has certain limitations, which are specifically reflected in: First, since the contact area between the small-sized specimen and the splitting rod is small, it is easy to slip and the small-sized concrete specimen cannot be fixed, resulting in an uneven splitting surface of the specimen, affecting the accuracy of the test results; Second, the use of the above-mentioned clamp usually requires two people to operate, one person to apply pressure and the other person to fix, resulting in low work efficiency; Third, the concrete is fixed with the help of conventional clamps, usually using iron rods or other rigid material fixtures, which may inhibit the development of the crack tip at the end of concrete cracking and affect the stress mode of splitting of small-sized specimens, and thus cannot guarantee the accuracy of the test results; Fourth, due to structural reasons, conventional clamps are not convenient for test personnel to observe and record the crack expansion process during splitting loading, and when performing strain cloud map analysis in conjunction with digital imaging technology, the edges of the specimen may be shadowed by the influence of laboratory environmental lighting conditions, affecting the analysis effect.

[0004] It can be seen that for the splitting damage test of small-sized concrete specimens, it is difficult to use the existing fixture to effectively clamp the small-sized concrete specimens during the splitting process, resulting in an uneven splitting surface and affecting the accuracy of the test results. Utility Model Content

[0005] The utility model provides a fixture for a small-sized concrete splitting damage test, which solves the technical problem that existing fixtures are difficult to effectively clamp small-sized concrete specimens during the splitting process, resulting in uneven splitting surfaces and affecting the accuracy of test results.

[0006] In order to achieve the above purpose, the present invention adopts the following technical contents:

[0007] A fixture for a small-sized concrete splitting damage test comprises a base;

[0008] The base includes a bottom plate and four side plates connected thereto; the four side plates and the bottom plate together form a cubic structure with a top opening; wherein two symmetrical side plates form a group;

[0009] The bottom plate is provided with a pad for abutting against small-sized concrete;

[0010] The first set of side plates are respectively provided with clamping assemblies for clamping small-sized concrete, and the two clamping assemblies are arranged opposite to each other;

[0011] The top of the second set of side plates is respectively provided with a slide groove; the slide groove cooperates with the splitting rod of the press, and when in use, the splitting rod is located in the slide groove and can move up and down along the slide groove;

[0012] The clamping assembly includes a threaded rod, and the threaded rod is screwed into the threaded hole of the first set of side plates;

[0013] A flexible rubber sheet is provided at the end of the threaded rod.

[0014] Furthermore, one end of the threaded rod is connected to a steel column, and the steel column is glued to the flexible rubber sheet; the other end of the threaded rod is connected to a knob.

[0015] Furthermore, a spring is sleeved on the threaded rod; one end of the spring abuts against the inner wall of the side plate, and the other end abuts against the flexible rubber sheet.

[0016] Further, the second set of side panels includes a third side panel and a fourth side panel;

[0017] An observation port is provided below the second chute provided on the fourth side plate, for observing and recording the surface damage evolution and mechanical properties of small-sized concrete during splitting loading.

[0018] Furthermore, the observation port is arranged in a square shape, and a lighting component is arranged around the observation port, and the lighting component is arranged on the inner wall of the fourth side plate.

[0019] Furthermore, the lighting assembly includes LED lights arranged on the top and two side edges of the observation port; the LED lights are embedded in the inner wall of the fourth side panel; the bottom of the second slide groove is higher than the LED lights arranged on the top edge of the observation port.

[0020] Furthermore, the lighting assembly also includes a power supply; the LED lights are all connected to the power supply; the power supply is arranged inside the fourth side panel or embedded on the inner wall of the fourth side panel.

[0021] Furthermore, the pad is a steel arc-shaped pad fixed to the base plate by bolts.

[0022] Furthermore, the four side plates are all made of steel and are welded to the bottom plate.

[0023] Furthermore, the bottom of the chute adopts an arc-shaped structure.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The utility model provides a fixture for testing small-sized concrete splitting damage, the fixture comprises a base consisting of a bottom plate and four side plates, a clamping assembly arranged on a first group of side plates and a slide groove opened on the top of the side plates of a second group of side plates; the clamping assembly consists of a threaded rod and a flexible rubber sheet, and small-sized concrete can be effectively fixed and clamped by screwing the two threaded rods, because the flexible rubber sheet has a smaller inhibitory effect on the concrete cracking to the left and right sides, more accurate test results are guaranteed; the slide groove provides precise guidance for the splitting rod, and during the test, the splitting rod is located in the slide groove and moves up and down along the slide groove. The design of the slide groove cooperates with the two groups of clamping assemblies, which can effectively prevent slipping during the splitting process, ensure the flatness of the splitting surface of the small-sized concrete, and thus ensure the accuracy of the test results; the structure and principle of the fixture are simple, easy to use and maintain, with high work efficiency, and good promotion and application value.

[0026] Preferably, in the present invention, the bonding of the steel column and the flexible rubber sheet enhances the stability of the clamping assembly, and the design of the knob makes the adjustment of the clamping force more convenient, thereby improving the flexibility and efficiency of the test operation.

[0027] Preferably, in the present invention, the addition of the spring provides an adaptive clamping force for the clamping assembly, which can automatically adjust the clamping force according to the actual situation of the test piece, avoiding test errors caused by over-tightening or over-loosening, and further improving the accuracy of the test results.

[0028] Preferably, in the present invention, the provision of the observation port enables the test personnel to directly observe and record the damage evolution and mechanical properties of the specimen surface during splitting loading, which greatly facilitates the collection and analysis of test data.

[0029] Preferably, in the present invention, the square observation port is combined with the lighting components arranged around it to ensure sufficient lighting of the observation area, reduce observation errors caused by insufficient lighting, and improve the reliability of test data; in this way, it can effectively avoid being affected by the lighting conditions of the laboratory environment during image analysis, and avoid the influence of shadows generated by the edges of the specimen on the analysis effect.

[0030] Furthermore, in the present invention, the provision of LED lights further enhances the lighting effect of the observation area, and the position design thereof avoids obstruction during the movement of the chopping rod, thereby ensuring the continuity and accuracy of the observation.

[0031] Further preferably, in the present invention, the setting of the power supply ensures stable power supply to the lighting component, so that the lighting needs during the test are met, and the reliability and repeatability of the test are improved; and the power supply is located inside the fourth side panel or embedded in the inner wall of the fourth side panel, which improves the compactness of the entire clamping device structure.

[0032] Preferably, in the present invention, the design of the steel arc-shaped pad ensures a stable support of the test piece, making the splitting surface more regular, the test data less discrete, and improving the accuracy of the test results.

[0033] Preferably, in the present invention, the welding connection between the steel side plates and the bottom plate enhances the overall strength and stability of the fixture, ensuring safety during the test.

[0034] Preferably, in the present invention, the bottom of the slide groove adopts an arc-shaped structure, which can effectively prevent the pressure head of the splitting rod from escaping from the slide groove and can effectively control the distance between the lowest point of the pressure head and the base; in addition, it also reduces the friction and resistance of the splitting rod during movement, making the splitting process smoother and improving the efficiency and accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A top view of the structure of a small-sized concrete splitting damage test fixture provided by an embodiment of the present utility model;

[0036] Figure 2 A side sectional view of a small-sized concrete splitting damage test fixture provided in an embodiment of the present utility model;

[0037] Figure 3 A side view of a small-sized concrete splitting damage test fixture provided by an embodiment of the present utility model;

[0038] Figure 4 A schematic structural diagram of a chopping rod provided in an embodiment of the utility model.

[0039] Reference numerals:

[0040] Bottom plate 1, first side plate 2, second side plate 3, first threaded rod 4, second threaded rod 5, first rubber sheet 6, second rubber sheet 7, first LED lamp 8, second LED lamp 9, third LED lamp 10, power supply 11, first chute 12, cushion strip 13, pressure head 14, connecting rod 15, observation port 16, second chute 17, third side plate 18, fourth side plate 19. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0045] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear to indicate an orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the product of the present invention is typically placed when in use. These terms are used solely to facilitate the description of the present invention and to simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0048] The present invention is described in further detail below with reference to the accompanying drawings:

[0049] Example

[0050] As mentioned in the background technology, there are certain limitations to the conventional clamping method for non-standard small-sized concrete specimens, which are specifically reflected in: First, since the contact area between the small-sized specimen and the splitting rod is small, it is easy to slip and the small-sized concrete specimen cannot be fixed, resulting in an uneven splitting surface of the specimen, affecting the accuracy of the test results; Second, the use of the above-mentioned clamp usually requires two people to operate, one person to apply pressure and the other person to fix, resulting in low work efficiency; Third, with the help of conventional clamps, iron rods or other rigid materials are usually used to fix the concrete, which may inhibit the development of the crack tip at the end of concrete cracking and affect the force mode of splitting of small-sized specimens, and thus cannot guarantee the accuracy of the test results; Fourth, due to structural reasons, conventional clamps are not convenient for test personnel to observe and record the crack expansion process during splitting loading, and when performing strain cloud map analysis in conjunction with digital imaging technology, the edge of the specimen may be shadowed by the influence of laboratory environmental lighting conditions, affecting the analysis effect.

[0051] It can be seen that the existing clamping measures and fixtures are not suitable for splitting damage tests on small-sized concrete specimens.

[0052] In order to solve the above problems, this embodiment provides a fixture for small-sized concrete splitting damage testing. The use of this fixture facilitates the effective clamping of small-sized concrete specimens during the test, and is conducive to observing and recording the evolution of surface damage and mechanical properties, which not only improves the test efficiency but also ensures the accuracy of the test results.

[0053] Combine Figure 1 and Figure 2As shown, this embodiment provides a fixture for a small-scale concrete splitting damage test, comprising: a base; the base comprises a bottom plate 1 and a pad 13 located in the middle of the bottom plate, the pad 13 is a steel arc pad, and is connected to the bottom plate 1 through a nut, and the length covers the bottom plate 1. After disassembly, it can be replaced with a rectangular steel block of the same height, which is used to carry out unilateral splitting research on the upper part of small-scale concrete under stress.

[0054] In this embodiment, the vertical cross-section of the cushion strip 13 is in the shape of a 25 mm circular arc. Such a specification setting can make the cleavage surface more regular and the test data less discrete.

[0055] The four side panels are connected around the bottom plate 1 to form a cubic structure with an open top. The first side panel 2, the second side panel 3, the third side panel 18 and the fourth side panel 19 are all made of steel, arranged perpendicular to the edge of the bottom plate 1 and connected by welding.

[0056] The two ends of the steel arc-shaped gasket 13 are respectively fitted to the third side plate 18 and the fourth side plate 19 .

[0057] like Figure 2 and Figure 3 As shown, in this embodiment, in order to facilitate observation and recording, a square observation port 16 with a side length of 50 mm is opened on the fourth side plate 19, and LED lights are provided on the upper, left and right sides of the inner side of the observation port 16, namely the second LED light 9, the first LED light 8 and the third LED light 10, which are connected to the inner side of the observation port 16, that is, the inner wall of the fourth side plate 19 using nuts, and the connected circuits and power supply 11 are buried in the space at the upper end of the fourth side plate 19, ensuring the compactness of the overall fixture device structure.

[0058] In this embodiment, the first side plate 2 and the second side plate 3 each include a clamping assembly, which is connected to the two side plates respectively through threads.

[0059] like Figure 1 As shown, one end of the clamping assembly extends through the side panel, and the position of the clamping assembly can be adjusted by controlling the threaded rod with a plastic knob on the outside. Flexible rubber sheets, namely first and second rubber sheets 6 and 7, are provided near the backing strip. These flexible rubber gaskets are positioned above the backing strip 13 and are bonded to the flexible rubber gasket on the threaded rod near the backing strip 13 using epoxy resin adhesive. The backing strip 13 and the two clamping assemblies interact to center a small concrete specimen placed on the backing strip 13 and secure it at the observation port 16 before the splitting test begins.

[0060] Specifically, the clamping components include threaded rods, namely, a first threaded rod 4 and a second threaded rod 5. The first threaded rod 4 and the second threaded rod 5 are both arranged parallel to the bottom plate 1 and inserted into the screw holes on the corresponding side plates. The other ends of the threaded rods are connected to the cylindrical steel block through the screw holes, and the cylindrical steel block is bonded to the flexible rubber gasket through epoxy resin. Figure 3 As shown, one end of the threaded rod is connected to the inner wall of the side panel, and the other end is connected to the cylindrical steel block. By twisting the plastic knob on the outside of the threaded rod, the distance between the flexible rubber gasket and the small-sized concrete specimen to be tested can be adjusted.

[0061] In this embodiment, a spring is sleeved on the first threaded rod 4 and the second threaded rod 5, one end of the spring abuts against the inner wall of the corresponding side plate, and the other end abuts against the corresponding flexible rubber sheet; the addition of the spring provides an adaptive clamping force for the clamping assembly, which can automatically adjust the clamping force according to the actual situation of the test piece, avoiding test errors caused by overtightening or overloosening, and further improving the accuracy of the test results.

[0062] Another example Figure 3 As shown, in this embodiment, the first threaded rod 4 and the second threaded rod 5 are threaded rods with plastic knobs, and the knobs can be designed to be handle-shaped to facilitate holding and twisting the clamp.

[0063] Combine Figure 1 and Figure 2 As shown, in this embodiment, the tops of the third side plate 18 and the fourth side plate 19 are both provided with sliding grooves, namely the first sliding groove 12 and the second sliding groove 17; Figure 4 As shown, the splitting rod of the press includes a connecting rod 15 and a pressure head 14 located at the end of the connecting rod 15; during the test, the two splitting rods are respectively located in the first slide groove 12 and the second slide groove 17, driving the two pressure heads 14 located at the end to apply pressure to the small-sized concrete specimen. In the process of moving up and down, the first slide groove 12 and the second slide groove 17 provide a good guiding effect for the pressure head 14, so that the connecting rod 15 together with the pressure head 14 moves up and down along the slide groove. With the cooperation of the clamping assembly, slipping is prevented, thereby ensuring the accuracy of the test results.

[0064] In this embodiment, the bottoms of the first chute 12 and the second chute 17 are both configured to be arc-shaped, which can effectively prevent the pressure head from escaping from the chute and control the distance between the lowest point of the pressure head and the base.

[0065] The splitting rod cooperates closely with the hydraulic servo of the press to split the small-sized concrete specimen placed on the pad 13.

[0066] During the splitting test, the flexible rubber gasket near the gasket end of the clamp assembly minimized the effect of concrete cracking to the left or right, ensuring more accurate test results. Furthermore, any falling concrete specimens were caught by the fixture base, preventing debris from flying. During concurrent digital imaging monitoring, activating the LED light on the inside of the fourth side panel effectively avoided shadows at the concrete edges caused by the angle of the laboratory light source, thereby minimizing the adverse effects on subsequent speckle analysis.

[0067] In this embodiment, during the test, the fixture base is placed on the press workbench, and the top of the pad 13 is aligned with the pressure head 14 of the press, thereby achieving the cooperation between the press and the fixture and ensuring the smooth progress of the concrete splitting damage test.

[0068] In this embodiment, the surfaces of the fixture, i.e., the surfaces of the base 1, the first side plate 2, the second side plate 3, the third side plate 18 and the fourth side plate 19 can be galvanized or blackened to prevent the fixture from rusting, which would affect the accuracy of the test results of the concrete splitting test.

[0069] When conducting a splitting damage test, the fixture base is placed on the press workbench, with the press's ram 14 positioned directly above the pad 13. The small-sized concrete specimen to be tested is clamped and fixed by screwing the threaded rods at both ends. The power supply 11 is turned on to illuminate the LED light. The connecting rod 15 and the ram 14 are then lowered along the first chute 12 and the second chute 17. The connecting rod 15 is connected to the press, and the ram 14 rests against the top of the concrete specimen. The press is started, and the ram 14 and pad 13 work together to fracture the small-sized concrete specimen. After the test, the fixture base is removed from the workbench, and the concrete specimen is taken out to measure its water-resistance height. The fallen debris will be collected by the fixture base. Simply pick up the fixture base and pour out the debris to complete the cleaning work.

[0070] In summary, the present invention provides a small-sized fixture for concrete splitting damage testing, which has the following advantages over existing clamping measures:

[0071] First, this fixture uses steel arc pads and flexible rubber sheets to effectively fix small-sized concrete specimens, ensure a smooth splitting surface, and effectively improve splitting efficiency and quality.

[0072] Second, the cube observation port of this fixture design is equipped with an LED strip light, which effectively avoids the shadow of the concrete edge caused by the angle of the laboratory light source, is conducive to digital image technology monitoring and subsequent speckle analysis, and improves the accuracy of observing and recording the evolution of surface damage.

[0073] Third, by optimizing the clamping components, this fixture can center the small-sized concrete specimen at the observation port before the splitting test begins, simplifying the test operation process, increasing work efficiency, and improving the test accuracy of the concrete splitting tensile test.

[0074] Fourth, this fixture can adjust the spacing between the flexible rubber sheets by rotating the threaded rod, thereby effectively clamping small-sized concrete specimens; only one person is needed to complete the test operation, which simplifies the operation steps and improves work efficiency.

[0075] Fifth, the fixture can store fallen concrete fragments through the arrangement of the fixture bottom plate and the left and right side plates, thereby improving safety and making it easier to clean and move.

[0076] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes within the technical scope disclosed by the present invention, any changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field.

Claims

1. A small-sized concrete splitting damage test fixture, characterized in that: Including base; The base comprises a bottom plate (1) and four side plates connected thereto; the four side plates and the bottom plate (1) together form a cubic structure with a top opening; wherein two symmetrical side plates form a group; The bottom plate (1) is provided with a pad (13) for contacting small-sized concrete; The first set of side plates are respectively provided with clamping assemblies for clamping small-sized concrete, and the two clamping assemblies are arranged opposite to each other; The top of the second set of side plates is respectively provided with a slide groove; the slide groove cooperates with the splitting rod of the press, and when in use, the splitting rod is located in the slide groove and can move up and down along the slide groove; The clamping assembly includes a threaded rod, and the threaded rod is screwed into the threaded hole of the first set of side plates; A flexible rubber sheet is provided at the end of the threaded rod.

2. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: One end of the threaded rod is connected to a steel column, and the steel column is glued to the flexible rubber sheet; the other end of the threaded rod is connected to a knob.

3. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: A spring is sleeved on the threaded rod; one end of the spring abuts against the inner wall of the side plate, and the other end abuts against the flexible rubber sheet.

4. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: The second set of side panels includes a third side panel (18) and a fourth side panel (19); An observation port (6) is provided below the second chute (17) provided on the fourth side plate (19) for observing and recording the surface damage evolution and mechanical properties of small-sized concrete during splitting loading.

5. The small-scale concrete splitting damage test fixture according to claim 4, characterized in that: The observation port (6) is arranged in a square shape, and a lighting component is arranged around the observation port (6), and the lighting component is arranged on the inner wall of the fourth side plate (19).

6. The small-scale concrete splitting damage test fixture according to claim 5, characterized in that: The lighting assembly includes LED lights arranged on the top and two side edges of the observation port (6); the LED lights are embedded in the inner wall of the fourth side panel (19); and the bottom of the second chute (17) is higher than the LED lights arranged on the top edge of the observation port (6).

7. The small-scale concrete splitting damage test fixture according to claim 6, characterized in that: The lighting assembly further comprises a power supply (11); the LED lights are all connected to the power supply (11); the power supply (11) is arranged inside the fourth side plate (19) or embedded on the inner wall of the fourth side plate (19).

8. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: The pad (13) is a steel arc-shaped pad and is fixed to the base plate (1) by bolts.

9. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: The four side plates are all made of steel and are welded to the bottom plate (1).

10. The small-scale concrete splitting damage test fixture according to claim 1, characterized in that: The bottom of the chute adopts an arc-shaped structure.

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