Multifunctional comprehensive testing machine for mechanical property and durability of fiber concrete

Abstract

The invention discloses a multifunctional comprehensive testing machine for mechanical property and durability of fiber concrete, which comprises a testing machine base with a test box assembled on the upper end face; the stand columns are vertically and symmetrically fixed in the test box; the loading units are installed on the stand columns and located on the opposite end faces of the two stand columns; the salt mist spraying unit is arranged in the test box, and the salt mist spraying unit is located between the two loading units; the supporting top shaft is vertically fixed at the central position in the test box; according to the invention, mechanical loading functions of axial tension and compression, bending, torsion, dynamic fatigue and the like and environmental simulation functions of salt spray erosion, temperature and humidity control and the like are highly integrated in a closed test box, so that one-stop test is realized, movement damage and state change of a test piece are avoided, and the test efficiency, data coherence and result comparability are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of fiber-reinforced concrete performance testing technology, specifically a multi-functional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete. Background Technology

[0002] Fiber-reinforced concrete, as a high-performance composite material, possesses high crack resistance, toughness, impact resistance, and durability, and is widely used in major engineering projects such as civil engineering, transportation, water conservancy, and national defense. Traditional universal testing machines mainly perform uniaxial tension, compression, or simple bending tests, with a single loading method (mainly uniaxial tension / compression), and cannot realize multiaxial stress states. However, actual engineering structures made of fiber-reinforced concrete (such as bridge piers and building joints) are under complex multiaxial stress states caused by compression, bending, shear, and torsion, and traditional equipment cannot reproduce this complex stress state in the laboratory. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides the following technical solution: a multi-functional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete, comprising:

[0004] The testing machine base has a testing chamber mounted on its upper surface;

[0005] The columns are vertically and symmetrically fixed inside the test chamber;

[0006] The loading unit is installed on each of the columns and located on the opposite end faces of the two columns;

[0007] A salt spray unit is installed inside the test chamber, and the salt spray unit is located between two loading units;

[0008] The top support shaft is vertically fixed in the center of the test chamber.

[0009] Furthermore, as a preferred embodiment, multiple sets of heating wires are symmetrically distributed on the upper interior of the test chamber; and multiple air vents are provided on the side wall of the test chamber, with cold air delivery pipes connected to the outside of the air vents.

[0010] Furthermore, preferably, the salt spray unit includes:

[0011] The brackets are arranged in a plurality, and each bracket is configured as an inverted J-shaped structure;

[0012] A spray pipe is fixed to the lower end face of the bracket, and one end of the spray pipe is connected to a water pipe;

[0013] The spray holes are multiple and evenly distributed, with each spray hole arranged along the length of the spray pipe;

[0014] Capillary tubes are installed inside the spray pipe;

[0015] Capillary nozzles are equidistantly distributed along the length of the capillary tube, and each capillary nozzle is connected through the tube wall of the spray tube. The other end of the capillary tube is connected to a solution tube.

[0016] Furthermore, preferably, the loading unit includes:

[0017] The machine plate is vertically installed on one end face of the column;

[0018] The fixing columns are two parallel columns, which are vertically fixed to the machine plate.

[0019] The loading frame is fixed on the two fixed columns, and shaft cylinders are symmetrically fixed at the upper and lower ends of the loading frame;

[0020] A loading plate is coaxially arranged with each of the aforementioned cylinders, and the loading plate is slidably connected to the cylinders.

[0021] Furthermore, as a preferred embodiment, a threaded rod is vertically rotatably connected inside the shaft cylinder, and a threaded sleeve is fixed on the loading plate, with the threaded rod and the threaded sleeve being threadedly slidably connected.

[0022] A drive motor is fixed on the loading frame, and the output end of the drive motor engages with the threaded rod through gear meshing.

[0023] Furthermore, as a preferred embodiment, a movable plate is arranged parallel to the machine plate and the column, a guide rail is provided on the side wall of the column, the movable plate is slidably mounted on the guide rail, and a lead screw is vertically rotatably connected inside the column, the movable plate and the lead screw are threadedly slidably connected.

[0024] A turntable is rotatably connected to the movable plate, and the machine plate is fixed to the turntable;

[0025] An electric telescopic rod is hinged to one side of the movable plate at an angle, and one end of the electric telescopic rod is connected to the turntable.

[0026] Furthermore, as a preferred embodiment, the upper end of the supporting top shaft is coaxially slidably connected to a guide shaft, and a support spring is connected between the guide shaft and the supporting top shaft; the inner circumference of the supporting top shaft is provided with multiple sliding cavities, and a top rod is vertically slidably connected in each of the sliding cavities;

[0027] An inner tube is coaxially fixed inside the supporting top shaft. A ball shaft is provided on the inner tube, and a slip ring is rotatably sleeved on the outside of the ball shaft. A guide plate is provided below the supporting top shaft. Multiple ball grooves are opened on the guide plate. A universal shaft is connected to the outside of the ball grooves. The upper end of the universal shaft is connected to each of the top rods.

[0028] Furthermore, as a preferred embodiment, the lower end face of the guide shaft is provided with a guide groove corresponding to the top rod, and the upper end of the top rod slides through the support top shaft and extends into the guide groove;

[0029] A return spring is fitted onto the top rod.

[0030] Furthermore, as a preferred embodiment, a swashplate is rotatably connected to the base of the testing machine, and the upper end face of the swashplate abuts against the guide plate;

[0031] The lower end of the top rod is fixed with a connecting shaft. Multiple claws are distributed around the inner circumference of the connecting shaft. Each claw is rotatably mounted inside the connecting shaft by a torsion spring. The universal joint slides into and connects to the connecting shaft. A retaining ring is fixed at the end of the universal joint. One end of each claw engages with the retaining ring.

[0032] The inner wall of the sliding cavity is provided with a reset groove, and the other end of the chuck is slidably disposed in the reset groove.

[0033] Furthermore, as a preferred embodiment, a central shaft is rotatably connected inside the supporting top shaft, the central shaft is fixed to the swashplate, and an active gear is sleeved on the central shaft. Each of the sliding cavities is rotatably connected to a bushing, and the top rod is slidably connected inside the bushing and rotates synchronously with the bushing.

[0034] The bushing is fitted with a driven tooth, and the driving tooth meshes with the driven tooth; a centrifugal column is eccentrically fixed on the push rod.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] In this invention, loading units are installed on two columns inside the test chamber. Each loading unit clamps and loads the two ends of the concrete specimen using two loading plates distributed vertically. On one hand, the loading units can compress the concrete specimen using the loading plates, thereby measuring its compressive strength. On the other hand, the two loading units can work together, with one loading frame moving upwards and the other downwards to test the flexural properties of the concrete specimen and its internal fiber-reinforced toughening effect. Furthermore, the turntables on the two moving plates can apply torque to the concrete specimen during their opposite rotational motion, thereby testing the torsional strength, torsional stiffness, torsional toughness, and failure mode of the fiber-reinforced concrete. The salt spray unit enables salt spray corrosion of the concrete specimen during testing, allowing for further precise analysis of changes in the load-bearing capacity of the concrete specimen under corrosive conditions, in conjunction with stress loading tests.

[0037] In addition, the supporting top shaft set in this invention can provide dynamic loading from the bottom of the concrete specimen, accurately simulating the destructive effect of uneven settlement of the foundation and elastic or elastoplastic reaction force of the foundation on the concrete specimen in real structures, and further studying the long-term deformation and bearing effect of concrete under the combined action of environment and load. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0039] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the salt spray unit in this invention;

[0041] Figure 4 This is a schematic diagram of the loading unit in this invention;

[0042] Figure 5 This is a schematic diagram of the internal structure of the shaft cylinder in this invention;

[0043] Figure 6 This is a schematic diagram of the supporting top shaft structure in this invention;

[0044] Figure 7 This is a schematic diagram of the connecting shaft in this invention;

[0045] In the diagram: 1. Testing machine base; 11. Test chamber; 12. Column; 13. Air vent; 2. Loading unit; 21. Machine plate; 22. Fixed column; 23. Loading frame; 24. Shaft cylinder; 25. Loading plate; 26. Threaded rod; 27. Drive motor; 3. Salt spray unit; 31. Bracket; 32. Spray pipe; 33. Spray hole; 34. Capillary tube; 35. Capillary nozzle; 4. Support top shaft; 41. Vibration guide shaft; 42. Top rod; 43. Inner tube body; 44. Ball shaft; 45. Guide plate; 46. Universal shaft; 47. Guide groove; 48. Swashplate; 49. Central shaft; 410. Bushing; 411. Centrifugal column; 5. Moving plate; 51. Lead screw; 52. Turntable; 53. Electric telescopic rod; 6. Connecting shaft; 61. Claw; 62. Snap ring; 63. Reset groove. Detailed Implementation

[0046] Please see Figures 1-7 In this embodiment of the invention, a multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete includes:

[0047] The testing machine base 1 has a test chamber 11 mounted on its upper end face. The test chamber 11 is an integral sealed box structure with a door installed on one side for taking out and putting in the concrete test block to be tested.

[0048] The columns 12 are vertically and symmetrically fixed inside the test chamber 11;

[0049] Loading unit 2 is installed on each of the columns 12 and located on the opposite end faces of the two columns 12. The concrete test block is clamped and placed between the two loading units.

[0050] Salt spray unit 3 is installed inside the test chamber 11. The salt spray unit 3 is located between the two loading units 2. It can spray salt spray onto the surface of the concrete test block to achieve corrosion testing of the concrete test block.

[0051] The top support shaft 4 is vertically fixed at the center of the test chamber 11, and is located below the concrete test block.

[0052] In this embodiment, multiple sets of heating wires (not shown in the figure) are symmetrically distributed on the upper part of the interior of the test chamber 11. These heating wires are used to rapidly and precisely heat the test chamber 11, thereby adjusting the internal test temperature to simulate the changes in the load-bearing capacity of concrete specimens under high-temperature conditions. Furthermore, multiple air vents 13 are provided on the side wall of the test chamber 11, and these vents 13 are connected to cold air delivery pipes, which can rapidly force cooling to achieve a low-temperature effect inside the test chamber 11. Therefore, during testing, the heating wires and cold air delivery pipes can directly perform freeze-thaw cycles within the test chamber. The heating wires melt, and the cold air delivery pipes freeze, simulating the process of water freezing, expanding, melting, and contracting in the pores of concrete.

[0053] In a preferred embodiment, the salt spray unit 3 includes:

[0054] The brackets 31 are arranged in a plurality of ways, and each bracket 31 is configured as an inverted J-shaped structure;

[0055] A spray pipe 32 is fixed to the lower end face of the bracket 31. One end of the spray pipe 32 is connected to a water pipe, which is used to transport high-pressure water.

[0056] The spray holes 33 are multiple equidistantly distributed, and each spray hole 33 is arranged along the length of the spray pipe 32. In this way, high-pressure water can be sprayed vertically onto the surface of the concrete test block through each spray hole 33, thereby simulating the processes of rainstorm erosion, wave splashing, and high-speed water flow abrasion in nature.

[0057] Capillary tube 34 is disposed inside the spray pipe 32;

[0058] Capillary nozzles 35 are equidistantly distributed along the length of capillary tube 34. Each capillary nozzle 35 is connected through the wall of spray pipe 32. The other end of capillary tube 34 is connected to a solution tube for conveying salt-containing liquid. In this way, through the capillary nozzles, the salt-containing liquid slowly and continuously contacts the concrete surface in the form of extremely fine droplets or in a near-evaporated state, simulating the long-term adsorption and capillary absorption process in the salt mist of the marine atmosphere and the humid and salty environment.

[0059] In this embodiment, the loading unit 2 includes:

[0060] The machine plate 21 is vertically installed on one end face of the column 12;

[0061] The two fixing columns 22 are arranged in parallel and are vertically fixed on the machine plate 21.

[0062] The loading frame 23 is fixed on the two fixed columns 22, and the upper and lower ends of the loading frame 23 are symmetrically fixed with shaft cylinders 24;

[0063] The loading plate 25 is coaxially arranged with each of the shaft cylinders 24, and the loading plate 25 is slidably connected to the shaft cylinders 24. In the loading test, the two loading plates 25 distributed vertically can slide against each other to gradually compress the concrete specimen, thereby obtaining the uniaxial compressive strength data of the concrete specimen and simulating the boundary conditions of the concrete specimen being constrained at both ends in the actual environment.

[0064] In this embodiment, a threaded rod 26 is vertically rotatably connected inside the shaft cylinder 24, and a threaded sleeve is fixed on the loading plate 25. The threaded rod 26 and the threaded sleeve are threadedly slidably connected.

[0065] A drive motor 27 is fixed on the loading frame 23. The output end of the drive motor 27 is engaged with the threaded rod 26 through gear meshing. When the drive motor 27 rotates in both directions, it can drive the threaded rod 26 to rotate synchronously through gear meshing, thereby realizing the axial loading and unloading of the loading plate 25.

[0066] In this embodiment, a movable plate 5 is arranged parallel to the machine plate 21 and the column 12. A guide rail is provided on the side wall of the column 12, and the movable plate 5 is slidably assembled on the guide rail. A lead screw 51 is vertically rotatably connected inside the column 12, and the movable plate 5 and the lead screw 51 are threadedly slidably connected. In this way, during the test, on the one hand, the lead screws 51 in the two columns 12 rotate in opposite directions, so that the two movable plates 5 slide upward and downward respectively, thereby testing the bending performance and fiber toughening effect of the concrete specimen. On the other hand, when the two lead screws 51 rotate in the same direction, the two movable plates 5 slide downward synchronously. At this time, the lower end face of the concrete specimen contacts the supporting top shaft 4. The supporting top shaft 4 supports the concrete specimen from the bottom. As the loading force increases, the contact pressure between the supporting top shaft 4 and the concrete specimen increases, thereby simulating the local crushing of the concrete specimen.

[0067] A turntable 52 is rotatably connected to the movable plate 5, and the machine plate 21 is fixed to the turntable 52;

[0068] An electric telescopic rod 53 is inclinedly hinged to one side of the movable plate 5. One end of the electric telescopic rod 53 is connected to the turntable 52. The electric telescopic rod 53 can realize the forward and reverse rotation of the turntable 52 during telescopic adjustment. Therefore, during the test, the two electric telescopic rods 53 work in opposite directions to realize the forward and reverse rotation of the turntable 52, thereby testing the torsional strength, torsional stiffness, torsional toughness and failure mode of fiber-reinforced concrete.

[0069] In a preferred embodiment, a guide shaft 41 is slidably connected to the upper end of the support top shaft 4, and a support spring is connected between the guide shaft 41 and the support top shaft 4. The support spring causes the guide shaft 41 to partially retract downward into the support top shaft 4 through the elastic force. Multiple sliding cavities are opened in the inner circumference of the support top shaft 4, and a top rod 42 is vertically slidably connected in each of the sliding cavities.

[0070] An inner tube 43 is coaxially fixed inside the supporting top shaft 4. A ball shaft 44 is provided on the inner tube 43, and a slip ring is rotatably sleeved on the outside of the ball shaft. A guide plate 45 is provided below the supporting top shaft 4. Multiple ball grooves are opened on the guide plate 45. A universal shaft 46 is connected to the outside of the ball grooves. The upper end of the universal shaft is connected to each of the top rods 42. In the test, each top rod 42 provides a dynamic lifting force to the guide shaft 41 as it slides axially upward. Each top rod 42 can use the guide shaft 41 to dynamically stress load the concrete specimen from the bottom, thereby simulating the uneven settlement of the foundation and the destructive effect of the elastic or elastoplastic reaction force of the foundation on the concrete specimen in the real structure. In the static stress loading combined with the loading unit 2, it can simulate the multi-point excitation of the foundation input during the propagation of seismic waves, or the continuous dynamic reaction force of the roadbed under the vehicle moving load, thus improving the realism of the test.

[0071] In this embodiment, the lower end face of the guide shaft 41 is provided with a guide groove 47 corresponding to the top rod 42. The upper end of the top rod 42 slides through the support top shaft 4 and extends into the guide groove 47, partially lifting the guide shaft 41 and compressing the support spring.

[0072] A return spring is fitted on the top rod 42. The return spring causes the top rod 42 to slide upward and push out of the support top shaft 4 through the elastic force. When the top rod 42 slides downward, the return spring is gradually compressed.

[0073] In this embodiment, a swashplate 48 is rotatably connected to the base 1 of the testing machine, and the upper end face of the swashplate 48 abuts against the guide plate 45.

[0074] The lower end of the top rod 42 is fixed with a connecting shaft 6. Multiple claws 61 are distributed around the inner circumference of the connecting shaft 6. Each claw 61 is rotatably disposed in the connecting shaft 6 by a torsion spring. The universal shaft 46 slides into and connects to the connecting shaft 6. A retaining ring 62 is fixed at the end of the universal shaft 46. One end of each claw 61 is engaged with the retaining ring 62.

[0075] The inner wall of the sliding cavity is provided with a reset groove 63, and the other end of the pawl 61 is slidably disposed in the reset groove 63. When the universal joint 46 is at its lowest position, the upper end of the universal joint 46 is disengaged from the connecting shaft 6. As the swashplate 48 rotates, the universal joint 46 is gradually lifted and penetrates into the connecting shaft 6. When the universal joint 46 reaches its highest lifting height, the retaining ring 62 on the universal joint 46 engages with the pawl 61, temporarily fixing the universal joint 46 and the push rod 42. As the swashplate 48 continues to rotate, the universal joint 46 drives the push rod 42 to begin to descend. The reset spring on the push rod 42 is gradually compressed, and the pawl 61 on the connecting shaft 6 slides along the reset groove 63. When the connecting shaft 6 is lower than the reset groove 63, the pawl 61 is deflected by the squeezing action of the inner wall of the sliding cavity, and the retaining ring 62 disengages from the pawl 61. The reset spring causes the push rod 42 to slide upward and impact (energy release) through its elastic force, thereby creating an impact lifting effect on the guide shaft 41.

[0076] The push rods 42 in each sliding cavity can be pushed upward sequentially as the swashplate 48 rotates continuously. This can apply a huge upward impact acceleration to the push rods in a very short time (milliseconds), thereby generating a high-energy, high-strain-rate transient impact force on the bottom of the concrete specimen. This can simulate, for example, the propagation process of seismic waves in the soil, or intermittently trigger bottom impacts during the long process of salt spray corrosion and multiaxial (tension-compression-torsion) fatigue loading of the concrete specimen, so as to study whether fatigue damage and corrosion damage will significantly reduce the impact toughness of the structure.

[0077] A central shaft 49 is rotatably connected inside the supporting top shaft 4. The central shaft 49 is fixed to the swashplate 48, and an active gear is sleeved on the central shaft 49. Each of the sliding cavities is rotatably connected to a bushing 410. The top rod 42 is slidably connected inside the bushing 410 and rotates synchronously with the bushing 410.

[0078] The bushing 410 is fitted with a driven tooth, and the driving tooth meshes with the driven tooth; the push rod 42 is eccentrically fixed with a centrifugal column 411, wherein the swashplate 48 can drive the central shaft 49 to rotate synchronously, so that each push rod 42 generates centrifugal vibration by using the centrifugal column 411, further enhancing the dynamic stress simulation loading effect. As the rotation speed of the swashplate 48 increases, the centrifugal force generated by each push rod 42 is greater, and the dynamic stress loading effect is more significant.

[0079] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multi-functional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete, characterized in that, It includes: The testing machine base (1) has a testing chamber (11) mounted on its upper end face. The column (12) is vertically and symmetrically fixed inside the test chamber (11); The loading unit (2) is installed on each of the columns (12) and located on the opposite end faces of the two columns (12); A salt spray unit (3) is installed inside the test chamber (11), and the salt spray unit (3) is located between two loading units (2); The top support shaft (4) is vertically fixed at the center of the test chamber (11).

2. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 1, characterized in that: Multiple sets of heating wires are symmetrically distributed inside the test chamber (11); and multiple air ducts (13) are provided on the side wall of the test chamber (11), with cold air delivery pipes connected to the outside of the air ducts (13).

3. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 1, characterized in that, The salt spray unit (3) includes: The brackets (31) are arranged in multiple ways, and each bracket (31) is configured as an inverted J-shaped structure; A spray pipe (32) is fixed to the lower end face of the bracket (31), and one end of the spray pipe (32) is connected to a water pipe; The spray holes (33) are a plurality of equidistantly distributed, and each spray hole (33) is arranged along the length direction of the spray pipe (32); A capillary tube (34) is disposed inside the spray pipe (32); Capillary nozzles (35) are equidistantly distributed along the length of the capillary tube (34), and each capillary nozzle (35) is connected through the wall of the spray pipe 32. The other end of the capillary tube 34 is connected to a solution tube.

4. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 1, characterized in that, The loading unit (2) includes: The machine plate (21) is vertically installed on one end face of the column (12); The two fixed columns (22) are arranged in parallel and are vertically fixed on the machine plate (21); The loading frame (23) is fixed on the two fixed columns (22), and the upper and lower ends of the loading frame (23) are symmetrically fixed with shaft cylinders (24). The loading plate (25) is coaxially arranged with each of the shaft cylinders (24), and the loading plate (25) is slidably connected to the shaft cylinders (24).

5. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 4, characterized in that: A threaded rod (26) is vertically rotatably connected inside the shaft cylinder (24), and a threaded sleeve is fixed on the loading plate (25). The threaded rod (26) and the threaded sleeve are threadedly slidably connected. A drive motor (27) is fixed on the loading frame (23), and the output end of the drive motor (27) is engaged with the threaded rod (26) through gear meshing.

6. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 4, characterized in that: A movable plate (5) is arranged parallel between the machine plate (21) and the column (12). A guide rail is provided on the side wall of the column (12). The movable plate (5) is slidably mounted on the guide rail. A lead screw (51) is vertically rotatably connected inside the column (12). The movable plate (5) and the lead screw (51) are threadedly slidably connected. A turntable (52) is rotatably connected to the movable plate (5), and the machine plate (21) is fixed to the turntable (52); An electric telescopic rod (53) is inclinedly hinged to one side of the movable plate (5), and one end of the electric telescopic rod (53) is connected to the turntable (52).

7. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 1, characterized in that: The upper end of the support top shaft (4) is coaxially slidably connected to a guide shaft (41), and a support spring is connected between the guide shaft (41) and the support top shaft (4); the inner circumference of the support top shaft (4) is provided with multiple sliding cavities, and a top rod (42) is vertically slidably connected in each of the sliding cavities. An inner tube (43) is coaxially fixed inside the supporting top shaft (4). A ball shaft (44) is provided on the inner tube (43). A slip ring is rotatably sleeved on the outside of the ball shaft. A guide plate (45) is provided below the supporting top shaft (4). Multiple ball grooves are opened on the guide plate (45). A universal shaft (46) is connected to the outside of the ball groove. The upper end of the universal shaft is connected to each of the top rods (42).

8. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 7, characterized in that: The lower end face of the guide shaft (41) is provided with a guide groove (47) corresponding to the top rod (42), and the upper end of the top rod (42) slides through the support top shaft (4) and extends into the guide groove (47). A reset spring is fitted onto the top rod (42).

9. The multifunctional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 7, characterized in that: A swash plate (48) is rotatably connected to the base (1) of the testing machine, and the upper end face of the swash plate (48) abuts against the guide plate (45); The lower end of the top rod (42) is fixed with a connecting shaft (6). Multiple claws (61) are distributed around the inner circumference of the connecting shaft (6). Each claw (61) is rotatably disposed inside the connecting shaft (6) by a torsion spring. The universal shaft (46) slides into and is connected to the connecting shaft (6). A retaining ring (62) is fixed at the end of the universal shaft (46). One end of each claw (61) is engaged with the retaining ring (62). The inner wall of the sliding cavity is provided with a reset groove (63), and the other end of the claw (61) is slidably disposed in the reset groove (63).

10. A multi-functional comprehensive testing machine for the mechanical properties and durability of fiber-reinforced concrete according to claim 9, characterized in that: The supporting top shaft (4) is rotatably connected to a central shaft (49), which is fixed to the swashplate (48). The central shaft (49) is fitted with an active gear. Each of the sliding cavities is rotatably connected to a bushing (410). The top rod (42) is slidably connected to the bushing (410) and rotates synchronously with the bushing (410). The bushing (410) is fitted with a driven tooth, and the driving tooth meshes with the driven tooth; the push rod (42) is eccentrically fixed with a centrifugal column (411).

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