A device for testing the tensile strength of a concrete curing

Abstract

This invention relates to the field of concrete testing technology, specifically providing a device for testing the tensile strength of cured concrete. The invention includes a base, a cylinder, a square specimen clamping assembly, and a circular specimen clamping assembly. The square specimen clamping assembly is located on the upper and lower sides of the cylinder, while the circular specimen clamping assembly is located on the left and right sides. The base has a triangular structure with a semi-circular mounting groove on one of its inclined sides. The cylinder is fitted into and fixed within the semi-circular mounting groove. By flipping the base to change its bottom support surface, the working conditions of the square and circular specimen clamping assemblies can be quickly switched, enabling convenient conversion between testing modes for two different specimen sizes. This device utilizes another set of clamping assemblies that is not currently in use, forming a double lateral protection system with the cylinder wall, eliminating the need for additional thin protective bars.

Description

Technical Field

[0001] This invention relates to the field of concrete testing technology, specifically to a device for testing the tensile strength of cured concrete. Background Technology

[0002] Cement-based materials such as concrete are artificial stone materials made by mixing cement as the main binder with water, sand, and gravel, and, when necessary, chemical admixtures and mineral admixtures, in appropriate proportions, followed by uniform mixing, compaction, molding, and curing. According to the degree of setting, concrete mainly exhibits two stages and states: the plastic state before setting and hardening, i.e., fresh concrete or concrete mixture; and the hard state after hardening, i.e., hardened concrete or concrete.

[0003] The tensile strength of concrete is one of the most important basic mechanical properties for evaluating the crack resistance, impermeability, and durability of concrete structures. The main methods for testing the tensile strength of concrete in engineering and laboratories are the splitting tensile test and the axial tensile test. Among them, the splitting tensile test is the most widely used because it is simple to operate and easy to prepare specimens.

[0004] Standard specimens commonly used in concrete splitting tensile tests are divided into two categories: square cube specimens and cylindrical specimens. The test conditions, stress forms, and centerline calibration requirements of the two types of specimens are completely different, and the structures of the pressure fixtures used for them are significantly different: For square specimens, splitting tests require the use of an arc-shaped pressure plate, which relies on the concave arc structure to accurately align with the transverse centerline of the specimen to form a standard linear splitting stress line, ensuring that the stress is concentrated and centered; for cylindrical specimens, splitting tests require the use of a flat pressure plate, with the flat end face conforming to the tangent position of the outer wall of the cylinder, to accurately calibrate the axial splitting stress line, ensuring that the stress position is standardized and uniform, and avoiding distortion of test data caused by off-center loading.

[0005] The existing concrete tensile strength testing equipment has the following prominent defects: 1. Low integration of tooling and cumbersome switching: The pressure plates, sliders, positioning parts and other components used in the test are scattered and independent, and have not formed an integrated and compatible structure; when changing to different types of specimens such as square and cylindrical specimens, it is necessary to disassemble and remove the pressure parts one by one, and then re-select and reassemble the corresponding specifications of the parts. The disassembly and assembly steps are complicated, the matching and assembly of parts is difficult, the overall debugging takes a long time, and it is impossible to quickly complete the switching of specimen types. The equipment has extremely low adaptability and seriously reduces the efficiency of the test.

[0006] 2. Insufficient safety protection: After the specimen reaches its ultimate tensile strength under pressure, it will instantly split into two halves along the stress centerline. The fractured specimen is prone to high-speed ejection and splashing to both sides due to stress release. Existing equipment is only equipped with simple vertical protective bars, which are structurally weak and have a limited protective range, posing a significant safety hazard.

[0007] Therefore, there is an urgent need for a method that can quickly switch between arc-shaped and flat pressure plates to meet the test requirements of different test blocks for linear splitting, while optimizing and improving the lateral protection structure to enhance the overall protection capability, effectively avoid test safety risks, make up for many shortcomings of existing test equipment, and provide reliable protection for the basic performance tests of cement-based materials such as concrete. Summary of the Invention

[0008] To address the shortcomings of existing concrete tensile strength testing fixtures, such as cumbersome specimen type switching, scattered fixtures, and weak protective capabilities, this invention provides a concrete curing tensile strength testing device. It employs a cylindrical, orthogonally integrated square and circular specimen clamping components. By rotating the triangular base, one set of components faces the pressure loading for tensile testing, while the other set automatically retreats to a lateral position to provide shielding and avoidance. The workstations are mutually exclusive and do not interfere with each other, requiring no disassembly or assembly of parts. This device offers multiple advantages, including rapid switching and safe protection.

[0009] The technical solution adopted by this invention is as follows: This invention provides a concrete curing tensile strength testing device, comprising a base, a cylinder, a square specimen clamping assembly, and a circular specimen clamping assembly. The square specimen clamping assembly is located on the upper and lower sides of the cylinder, and the circular specimen clamping assembly is located on the left and right sides of the cylinder. The base has a triangular structure, with a semi-circular mounting groove on one of its inclined sides. The cylinder is adapted to and fixed in the semi-circular mounting groove. By flipping the base to change its bottom support surface, the working condition switching between the square specimen clamping assembly and the circular specimen clamping assembly can be quickly completed, realizing convenient conversion between the test modes of two different specimen specifications.

[0010] Furthermore, the square test block clamping assembly includes an upper pressure unit and a bottom pressure-bearing unit; the upper pressure unit includes a top pressure slider and a top pressure block, the top pressure slider slides radially through the top of the cylinder, and the top pressure block is fixed to the bottom end of the top pressure slider and located inside the cylinder; the bottom pressure-bearing unit includes a bottom support slider and a bottom support block, the bottom support slider slides radially through the bottom of the cylinder, and the bottom support block is fixed to the top end of the bottom support slider and located inside the cylinder.

[0011] Furthermore, the end faces of the top pressure block and the bottom support block that are opposite each other are arc-shaped.

[0012] Furthermore, the circular test block clamping assembly includes a side-pressure unit and a side-bearing unit; the side-pressure unit includes a side-pressure slider and a side-pressure block, the side-pressure slider slides radially through one side of the cylinder wall, and the side-pressure block is fixed to the inner end of the side-pressure slider and extends into the cylinder; the side-bearing unit includes a side-bearing slider and a side-bearing block, the side-bearing slider slides radially through the other side of the cylinder wall, and the side-bearing block is fixed to the inner end of the side-bearing slider and extends into the cylinder.

[0013] Furthermore, the end faces of the side pressure block and the side bearing block opposite each other are planes.

[0014] Furthermore, both the top-pressure slider and the side-pressure slider are fixedly connected to a fixed plate at one end outside the cylinder. Guide rods are slidably sleeved on the front and rear sides of the fixed plate. The guide rods are arranged radially along the cylinder and fixedly connected to the side wall of the cylinder. A limit block is fixedly connected to the end of the guide rod away from the cylinder, and a return spring is slidably sleeved on the guide rod. The two ends of the return spring are respectively fixed to the fixed plate and the cylinder.

[0015] Furthermore, the inner wall of the bottom side of the semi-circular mounting groove is provided with a guide groove one that slides and engages with the bottom bearing slider, and the inner wall of one side is provided with a guide groove two that slides and engages with the side bearing slider.

[0016] Furthermore, connecting plates are fixed to both the front and rear side walls of the base. The connecting plates are located on the front and rear sides of the guide groove one and the guide groove two. The connecting plates are provided with a first insertion hole. The bottom support slider and the side support slider are provided with a second insertion hole corresponding to the first insertion hole. After the first insertion hole and the second insertion hole are aligned, they are limited by a pin to fix the bottom support slider and the side support slider.

[0017] Furthermore, the front and rear side walls of the fixing plate are provided with insertion holes three, and the guide rod is provided with insertion holes four corresponding to insertion holes three. After the insertion holes three and four are aligned, they are limited by pins to realize the position locking of the top pressure slider and the side pressure slider.

[0018] Furthermore, the contact surfaces of the bottom support block and the side support block facing the cylinder are both arc-shaped surfaces with the same diameter as the inner wall of the cylinder; when the bottom support block is in contact with the inner wall of the cylinder, the bottom support slider abuts against the bottom wall of the guide groove; when the side support block is in contact with the inner wall of the cylinder, the side support slider abuts against the bottom wall of the guide groove.

[0019] The beneficial effects achieved by the present invention using the above structure are as follows: 1. This device integrates square and round specimen clamping components in a cross-shaped orthogonal manner on the upper, lower, left, and right sides of the cylinder, and is equipped with a triangular base with a semi-circular mounting groove. The test conditions of square and cylindrical concrete specimens can be interchanged simply by flipping the base. There is no need to disassemble, remove, select, or reassemble various pressure plates and positioning parts, eliminating tedious disassembly, alignment, and debugging steps. The equipment has high adaptability and flexibility, greatly shortens the changeover time, and significantly improves the efficiency of concrete tensile strength testing.

[0020] 2. This device utilizes another set of unused clamping components at the workstation to form a double lateral protection system in conjunction with the cylinder wall, eliminating the need for additional thin protective bars. When the concrete test block reaches its ultimate strength and splits, the unused clamping components and the cylinder can form a barrier to effectively prevent fragments from flying and splashing at high speed to both sides, expanding the protection range, strengthening the protection capability, avoiding safety risks during the test, and improving the problems of weak protective structure and limited protection range of traditional tooling. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural schematic diagram from another perspective of the present invention; Figure 3 This is a front view of the circular test block clamping assembly and the square test block clamping assembly in this invention; Figure 4 This is a three-dimensional structural diagram of the circular test block clamping assembly and the square test block clamping assembly in this invention; Figure 5 This is a front view of the base and the cylinder in this invention; Figure 6 This is a three-dimensional structural diagram of the base and the cylinder in this invention; Figure 7 This is a schematic diagram showing the placement of the base when testing a square test block according to the present invention; Figure 8 This is a schematic diagram showing the placement of the base when testing a circular test block according to the present invention.

[0022] The components are as follows: 1. Base; 2. Cylinder; 3. Circular test block clamping assembly; 4. Square test block clamping assembly; 5. Semi-circular mounting groove; 6. Top pressure slider; 7. Top pressure block; 8. Bottom support slider; 9. Bottom support block; 10. Side pressure slider; 11. Side pressure block; 12. Side support slider; 13. Side support block; 14. Fixing plate; 15. Guide rod; 16. Return spring; 17. Guide groove one; 18. Guide groove two; 19. Connecting plate; 20. Insertion hole one; 21. Insertion hole two; 22. Insertion hole three; 23. Insertion hole four. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0025] like Figures 1-8 As shown, the present invention discloses a concrete curing tensile strength testing device, comprising a base 1, a cylinder 2, a square specimen clamping assembly 4, and a circular specimen clamping assembly 3. The square specimen clamping assembly 4 is located on the upper and lower sides of the cylinder 2, and the circular specimen clamping assembly 3 is located on the left and right sides of the cylinder 2. The base 1 has a triangular structure, with a semi-circular mounting groove 5 on one side of its inclined surface. The cylinder 2 is fitted with and fixed in the semi-circular mounting groove 5. By flipping the base 1 to change its bottom support surface, the working condition switching between the square specimen clamping assembly 4 and the circular specimen clamping assembly 3 can be quickly completed, realizing convenient conversion between the test modes of two different specimen specifications.

[0026] This device arranges the square test block clamping assembly 4 and the round test block clamping assembly 3 in a cross shape on the upper and lower, left and right sides of the cylinder 2, respectively. It is fixedly assembled with the triangular base 1 with a semi-circular mounting groove 5. By utilizing the flip-out structure of the triangular base 1, the upper and lower working positions and the left and right shielding positions of the two sets of clamping assemblies can be quickly switched by simply flipping the base 1 to change the support posture. No disassembly or modification of any parts is required. It automatically realizes the interchangeability and convenient switching of the two test modes of square test blocks and round test blocks. It has a high degree of structural integration and simple working condition switching. At the same time, it uses the idle clamping assemblies to form lateral shielding protection, and takes into account multiple functions such as dual use, quick changeover and safety protection.

[0027] like Figures 1-8 As shown, the square test block clamping assembly 4 includes an upper pressing unit and a bottom bearing unit; the upper pressing unit includes a top pressing slider 6 and a top pressing block 7. The top pressing slider 6 slides radially through the top of the cylinder 2, and the top pressing block 7 is fixed to the bottom end of the top pressing slider 6 and located inside the cylinder 2; the bottom bearing unit includes a bottom bearing slider 8 and a bottom bearing block 9. The bottom bearing slider 8 slides radially through the bottom of the cylinder 2, and the bottom bearing block 9 is fixed to the top end of the bottom bearing slider 8 and located inside the cylinder 2. The end faces of the top pressing block 7 and the bottom bearing block 9 opposite each other are arc-shaped surfaces.

[0028] The square test block clamping assembly 4 consists of an upper pressure unit and a bottom pressure bearing unit. The top pressure slider 6 and the bottom pressure bearing slider 8 slide radially along the top and bottom of the cylinder 2, respectively, driving the fixed top pressure block 7 and bottom pressure block 9 to move synchronously in alignment within the cylinder 2. The opposite end faces of the top pressure block 7 and the bottom pressure block 9 are set as arc-shaped surfaces. When in the upper and lower working positions, the vertical clamping and alignment of the test block and the transmission of the pressure machine loading force can be achieved by the radial sliding of the slider. When switching to the left and right idle positions, the arc-shaped surface structure can fit against the side wall of the test block to form a shield and protection. One set of components can be flipped with the base 1 and has the dual functions of pressure testing and enclosure protection.

[0029] like Figures 1-8 As shown, the circular test block clamping assembly 3 includes a side-pressure unit and a side-bearing unit; the side-pressure unit includes a side-pressure slider 10 and a side-pressure block 11. The side-pressure slider 10 slides radially through one side of the cylinder wall of the cylinder 2, and the side-pressure block 11 is fixed to the inner end of the side-pressure slider 10 and extends into the cylinder 2; the side-bearing unit includes a side-bearing slider 12 and a side-bearing block 13. The side-bearing slider 12 slides radially through the other side of the cylinder wall of the cylinder 2, and the side-bearing block 13 is fixed to the inner end of the side-bearing slider 12 and extends into the cylinder 2. The end faces of the side-pressure block 11 and the side-bearing block 13 opposite to each other are planes.

[0030] The circular test block clamping assembly 3 consists of a side pressure unit and a side bearing unit. The side pressure slider 10 and the side bearing slider 12 are respectively arranged radially along the two sides of the cylinder wall of the cylinder 2, which can drive the side pressure block 11 and the side bearing block 13 to extend into the cylinder 2 for position adjustment. The opposite end faces of the side pressure block 11 and the side bearing block 13 are set as planar structures. The assembly can flexibly switch working states as the base 1 flips and changes direction. When it is in the upper and lower working positions, it can adapt the planar end face to the vertical bearing pressure clamping of the test block and transmit the test pressure. When it is switched to the left and right lateral working positions, it can block and shield the test block laterally.

[0031] like Figures 1-8 As shown, the top pressure slider 6 and the side pressure slider 10 are both fixed to a fixed plate 14 at one end outside the cylinder 2. Guide rods 15 are slidably sleeved on the front and rear sides of the fixed plate 14. The guide rods 15 are arranged radially along the cylinder 2 and fixed to the side wall of the cylinder 2. A limit block is fixed to the end of the guide rod 15 away from the cylinder 2, and a return spring 16 is slidably sleeved on the guide rod 15. The two ends of the return spring 16 are fixed to the fixed plate 14 and the cylinder 2 respectively.

[0032] The guide rod 15 is fitted with a return spring 16, which is fixed at both ends between the fixed plate 14 and the cylinder 2. Under normal conditions, it can drive the slider and the pressure block to automatically move towards the inside of the cylinder 2 to fit the test block through stretching energy storage and rebound traction. After the test, it can drive the slider to automatically reset. It has multiple functions of sliding guidance, elastic adaptation and automatic reset.

[0033] like Figures 1-8As shown, the inner wall of the bottom side of the semi-circular mounting groove 5 is provided with a guide groove 17 that slides with the bottom bearing slider 8, and the inner wall of one side is provided with a guide groove 18 that slides with the side bearing slider 12.

[0034] Guide groove 17 and guide groove 28, which are respectively adapted to the bottom bearing slider 8 and the side bearing slider 12, are opened on the inner wall of the semi-circular mounting groove 5 of the base 1. These grooves limit the radial sliding of the bottom bearing slider 8 and the side bearing slider 12 and constrain their trajectory to prevent the sliders from sliding off course. At the same time, when the test is under pressure, the bottom bearing slider 8 and the side bearing slider 12 can abut against the bottom wall of the guide groove 17 and the guide groove 28 to form rigid support points, effectively offsetting the force generated by the test loading and preventing the sliders from shifting or swaying under load.

[0035] like Figures 1-8 As shown, connecting plates 19 are fixed to both the front and rear side walls of the base 1. The connecting plates 19 are located on the front and rear sides of the guide groove 17 and the guide groove 18. The connecting plates 19 are provided with insertion holes 20. The bottom bearing slider 8 and the side bearing slider 12 are provided with insertion holes 21 corresponding to insertion holes 20. After the insertion holes 20 and insertion holes 21 are aligned, they are limited by pins to fix the bottom bearing slider 8 and the side bearing slider 12.

[0036] like Figures 1-8 As shown, the front and rear side walls of the fixed plate 14 are provided with insertion holes 22, and the guide rod 15 is provided with insertion holes 23 corresponding to insertion holes 22. After the insertion holes 22 and 23 are aligned, they are limited by pins to lock the positions of the top pressing slider 6 and the side pressing slider 10.

[0037] like Figures 1-8 As shown, the contact surfaces of the bottom support block 9 and the side support block 13 facing the cylinder 2 are both arc-shaped surfaces with the same diameter as the inner wall of the cylinder 2; when the bottom support block 9 is in contact with the inner wall of the cylinder 2, the bottom support slider 8 abuts against the bottom wall of the guide groove 17; when the side support block 13 is in contact with the inner wall of the cylinder 2, the side support slider 12 abuts against the bottom wall of the guide groove 18.

[0038] In specific use I. Testing Procedure for Square Specimen Blocks Place the triangular base 1 upright without flipping it, ensuring the square test block clamping assembly 4 is vertically distributed radially and the circular test block clamping assembly 3 is horizontally distributed radially. Maintain openness at the front and rear openings of the cylinder 2. Pull outwards the fixing plates 14 on the outer sides of the top-pressure slider 6 and side-pressure slider 10. The fixing plates 14 move outwards along the guide rod 15, stretching and storing energy in the return spring 16. Then, push the cured square test block from the front opening of the cylinder 2 into the internal cavity of the cylinder 2, placing it horizontally and centered on the upper surface of the bottom support block 9. Release the fixing plates 14 corresponding to the top-pressure slider 6 and side-pressure slider 10. Under the return force of the return spring 16, the top pressure block 7 and the bottom support block 9 clamp the square test block from the top and bottom directions, while the side pressure block 11 and the side support block 13 clamp the side wall of the square test block from the left and right directions. Then, a pin is used to lock the side pressure slider 10 and the side support slider 12, limiting the left and right swaying of the square test block and achieving lateral centering. At this time, the square test block clamping assembly 4, located in the upper and lower positions, has its top pressure block 7 and bottom support block 9 with their contact surfaces adapted to the upper and lower surfaces of the square test block, forming a vertically centered clamping structure, serving as the main pressure-bearing body of the press. The circular test blocks arranged horizontally to the left and right... Clamping component 3 only makes slight contact with the side wall of the square test block with its own block, does not bear vertical load, and only serves as a lateral enclosure to reduce the splatter gap after the test block splits; align the corresponding insertion holes 1 20 and 21, 3 22 and 4 23 of the circular test block clamping component 3 and insert the pins to lock the positions of the side pressure slider 10 and the side support slider 12; the corresponding insertion holes of the square test block clamping component 4 do not require pin limiters; after assembly, the outer arc surface of the bottom support block 9 naturally fits against the inner wall of the cylinder 2, and the bottom end of the bottom support slider 8 tightly abuts against the bottom wall of the guide groove 17. A rigid support and limiting structure is formed to ensure that there is no slippage or tilting at the bottom during the vertical pressure of the press, and the support is stable and reliable. The whole device is placed smoothly on the test workbench of the existing press, so that the vertical center of the device is aligned with the center of the press head. The press is started, the press head moves down to apply vertical pressure, and the fixed plate 14 drives the top pressure slider 6 to move down to load, completing the splitting tensile strength test of the square test block. During the test, the cylinder 2 and the circular test block clamping components 3 arranged on the left and right constitute a double protection system, which effectively prevents the fragments generated by the splitting of the square test block from flying and splashing to the side.

[0039] II. Circular Specimen Block Testing Procedure The triangular base 1 is rotated 90 degrees and repositioned, and the cylinder 2 rotates synchronously with the base 1 to adjust its orientation. At this time, the circular test block clamping components 3, which were originally distributed horizontally, are converted to vertically distributed radially, and the square test block clamping components 4, which were originally distributed vertically, are converted to horizontally distributed radially, thus realizing the interchange of the positions and functions of the two sets of clamping components. The operation of inserting, centering, spring-fitting clamping, pin locking, rigid support positioning, and machine testing of the circular test block is consistent with the operation steps of testing the square test block.

[0040] The core features of this device are as follows: the square specimen clamping assembly 4 and the round specimen clamping assembly 3 are fixedly installed in a cross-shaped orthogonal manner in the vertical and horizontal radial positions of the cylinder 2. The cylinder 2 adopts a front and rear open structure, and the specimen is inserted into the cavity through the front and rear openings. The vertical and horizontal arrangement and working functions of the two sets of clamping assemblies can be quickly interchanged by simply flipping the base 1 ninety degrees. Regardless of whether the specimen is square or round, the device always follows a unified working logic: the clamping assembly in the vertical position bears the vertical centering clamping and pressure loading of the specimen, and completes the concrete splitting tensile strength test; the other set of clamping assemblies in the horizontal position does not participate in pressure bearing, but only plays the role of lateral enclosure and shielding, and together with the cylinder wall of the cylinder 2 itself, forms a reinforced anti-bounce protection structure. The working condition switching is simple, the positioning is reliable, and the force is stable, which can effectively improve the test accuracy and operation safety.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for testing the tensile strength of concrete during curing, characterized in that: The device includes a base (1), a cylinder (2), a square test block clamping assembly (4), and a circular test block clamping assembly (3). The square test block clamping assembly (4) is located on the upper and lower sides of the cylinder (2), and the circular test block clamping assembly (3) is located on the left and right sides of the cylinder (2). The base (1) has a triangular structure, and a semi-circular mounting groove (5) is provided on one side of its inclined surface. The cylinder (2) is adapted to the semi-circular mounting groove (5) and fixed in the groove. By flipping the base (1) to change its bottom support surface, the working conditions of the square test block clamping assembly (4) and the circular test block clamping assembly (3) can be switched.

2. The concrete curing tensile strength testing device according to claim 1, characterized in that: The square test block clamping assembly (4) includes an upper pressure unit and a bottom pressure unit; the upper pressure unit includes a top pressure slider (6) and a top pressure block (7), the top pressure slider (6) slides radially through the top of the cylinder (2), and the top pressure block (7) is fixed to the bottom end of the top pressure slider (6) and located inside the cylinder (2); the bottom pressure unit includes a bottom support slider (8) and a bottom support block (9), the bottom support slider (8) slides radially through the bottom of the cylinder (2), and the bottom support block (9) is fixed to the top end of the bottom support slider (8) and located inside the cylinder (2).

3. The concrete curing tensile strength testing device according to claim 2, characterized in that: The end face of the top pressure block (7) opposite to the bottom support block (9) is an arc-shaped surface.

4. The concrete curing tensile strength testing device according to claim 2, characterized in that: The circular test block clamping assembly (3) includes a side pressure unit and a side bearing unit; the side pressure unit includes a side pressure slider (10) and a side pressure block (11). The side pressure slider (10) slides radially through one side of the cylinder wall of the cylinder (2), and the side pressure block (11) is fixed to the inner end of the side pressure slider (10) and extends into the cylinder (2); the side bearing unit includes a side bearing slider (12) and a side bearing block (13). The side bearing slider (12) slides radially through the other side of the cylinder wall of the cylinder (2), and the side bearing block (13) is fixed to the inner end of the side bearing slider (12) and extends into the cylinder (2).

5. The concrete curing tensile strength testing device according to claim 4, characterized in that: The end faces of the side pressure block (11) and the side bearing block (13) opposite each other are flat.

6. The concrete curing tensile strength testing device according to claim 4, characterized in that: The top-pressure slider (6) and the side-pressure slider (10) are both fixed to a fixed plate (14) at one end outside the cylinder (2). The fixed plate (14) is slidably sleeved with guide rods (15) on both the front and rear sides. The guide rods (15) are arranged radially along the cylinder (2) and fixed to the side wall of the cylinder (2). The end of the guide rod (15) away from the cylinder (2) is fixed to a limit block, and a return spring (16) is slidably sleeved on the guide rod (15). The two ends of the return spring (16) are fixed to the fixed plate (14) and the cylinder (2) respectively.

7. The concrete curing tensile strength testing device according to claim 6, characterized in that: The semi-circular mounting groove (5) has a guide groove 1 (17) on the bottom inner wall that slides with the bottom bearing slider (8), and a guide groove 2 (18) on one side inner wall that slides with the side bearing slider (12).

8. The concrete curing tensile strength testing device according to claim 7, characterized in that: The base (1) has connecting plates (19) fixed to both the front and rear side walls. The connecting plates (19) are located on the front and rear sides of the guide groove one (17) and the guide groove two (18). The connecting plates (19) have a first insertion hole (20). The bottom support slider (8) and the side support slider (12) have a second insertion hole (21) corresponding to the first insertion hole (20). After the first insertion hole (20) and the second insertion hole (21) are aligned, they are limited by a pin to fix the bottom support slider (8) and the side support slider (12).

9. The concrete curing tensile strength testing device according to claim 6, characterized in that: The fixing plate (14) has three insertion holes (22) on its front and rear side walls. The guide rod (15) has four insertion holes (23) corresponding to the three insertion holes (22). After the three insertion holes (22) and the four insertion holes (23) are aligned, they are limited by a pin to lock the position of the top pressure slider (6) and the side pressure slider (10).

10. The concrete curing tensile strength testing device according to claim 9, characterized in that: The contact surfaces of the bottom support block (9) and the side support block (13) facing the cylinder (2) are both arc-shaped surfaces with the same diameter as the inner wall of the cylinder (2); when the bottom support block (9) is in contact with the inner wall of the cylinder (2), the bottom support slider (8) abuts against the bottom wall of the first guide groove (17); when the side support block (13) is in contact with the inner wall of the cylinder (2), the side support slider (12) abuts against the bottom wall of the second guide groove (18).

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