A device for testing the crack resistance of concrete specimens

Abstract

This invention discloses a device for testing the crack resistance of concrete specimens, comprising a box, an outer cylinder, an inner cylinder, a force-applying mechanism, an external pressure mechanism, and an internal expansion mechanism. Three outer cylinders are evenly arranged laterally. The inner cylinder is fixed to the center of the bottom plate of the outer cylinder. The force-applying mechanism includes a motor, a sleeve, and a lifting seat. The leftmost force-applying mechanism drives both the external pressure mechanism and the internal expansion mechanism; the middle force-applying mechanism drives the external pressure mechanism; and the last force-applying mechanism drives the internal expansion mechanism. The beneficial effect of this invention is that it provides three outer cylinders and an inner cylinder, with the space between the inner and outer cylinders used for pouring concrete specimens. By driving the external pressure mechanism and the internal expansion mechanism through the force-applying mechanism, the three concrete specimens respectively bear external pressure and internal expansion force, or external pressure and internal expansion force, thereby observing the crack formation of the concrete specimens under different forms of force, and further analyzing the crack resistance of the concrete specimens under different forms of force.

Description

Technical Field

[0001] This invention relates to the field of concrete performance testing devices, specifically to a device for testing the crack resistance of concrete specimens. Background Technology

[0002] Concrete is a heterogeneous brittle material formed by mixing sand and gravel aggregates, cement, water and other additives. It has the characteristics of high compressive strength and good durability. Moreover, it is inexpensive and easy to obtain, making it the most widely used structural engineering material in the world today.

[0003] The performance of concrete directly affects the strength of the structures it forms. Therefore, concrete needs to undergo performance testing before use. The crack resistance of concrete is an important indicator of its performance. The crack resistance test of concrete is generally completed by observing and measuring the cracks in its cast test blocks.

[0004] However, existing testing devices for the crack resistance of concrete test blocks have some problems.

[0005] For example, Chinese patent application number 202022329684.3 discloses a concrete crack resistance testing device; Chinese patent application number 202122169039.4 discloses a concrete crack resistance testing device; and Chinese patent application number 202121466507.8 discloses a concrete crack resistance testing device.

[0006] All three patents involve applying external pressure to concrete test blocks to induce cracks, and then observing the cracks to determine the crack resistance of the concrete test blocks. However, they cannot detect the crack resistance of concrete test blocks when subjected to internal expansion forces.

[0007] Furthermore, the three patents mentioned above cannot be used to determine the crack resistance of concrete test blocks under different conditions based on the controlled variable method. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an apparatus for testing the crack resistance of concrete specimens, which is achieved through the following technical solution.

[0009] An apparatus for testing the crack resistance of concrete specimens, comprising:

[0010] Box;

[0011] The outer cylinder is fixed inside the top plate of the box body, and three are evenly arranged along the length of the box body;

[0012] The inner cylinder is fixed to the center of the bottom plate of the outer cylinder, the axes of the inner cylinder and the outer cylinder coincide, and a casting cavity for the concrete test block is formed between the inner cylinder and the outer cylinder.

[0013] The force-applying mechanism includes a motor, a sleeve, and a lifting seat. A shaft is rotatably connected between the left and right side plates of the housing. A drive bevel gear is fixedly connected to the shaft at the position corresponding to each outer cylinder. A cover is fixedly connected to the right side of the housing. The motor is fixedly connected inside the cover, and the output shaft of the motor is connected to the right end of the shaft via a coupling. The sleeve is rotatably connected to the center of the bottom plate of the outer cylinder. A threaded cavity is opened inside the sleeve. A driven bevel gear that meshes with the drive bevel gear is fixedly connected to the bottom of the sleeve. The lifting seat is located directly above the inner cylinder. Insert rods are evenly fixedly connected to the lower surface of the lifting seat. Insert holes corresponding to the insert rods are opened in the side plates of the inner cylinder. A pull rod is fixedly connected to the center of the lower surface of the lifting seat. A screw is fixedly connected to the bottom of the pull rod, and the screw meshes in the threaded cavity.

[0014] The external pressure mechanism and the internal expansion mechanism are driven by the leftmost force-applying mechanism, the middle force-applying mechanism, and the last force-applying mechanism.

[0015] Furthermore, the external pressure mechanism includes a support rod and a pressure head. The support rod is uniformly fixed to the outer circumference of the lifting seat. The support rod is L-shaped, and a conical pressure head is fixed to the bottom of the vertical rod.

[0016] Furthermore, the internal expansion mechanism includes a top rod and a top seat; the side plate of the inner cylinder is provided with uniformly spaced clearance holes around its circumference, the top rod is slidably connected in the clearance holes, the end of the top rod away from the pull rod is tapered, the end of the top rod near the pull rod is fixed with a triangular block, a return spring is sleeved on the top rod between the triangular block and the inner wall of the inner cylinder, the top seat is a frustum shape with a larger top and a smaller bottom, the top seat is coaxially fixed with the pull rod, and the inclined surface of the top seat cooperates with the inclined surface of the triangular block.

[0017] Furthermore, an annular mounting cavity is provided inside the side plate of the outer cylinder, and a spiral heating wire is fixedly connected inside the mounting cavity.

[0018] Furthermore, the outer cylinder is made of a transparent material.

[0019] Furthermore, the inner wall of the outer cylinder is densely covered with conical induced protrusions.

[0020] Furthermore, the number of teeth of the driving bevel gear is less than the number of teeth of the driven bevel gear.

[0021] Furthermore, self-locking casters are fixed at the four corners of the bottom of the box.

[0022] The beneficial effects of this invention are that it is provided with three outer cylinders and an inner cylinder, and the space between the inner and outer cylinders is used for pouring concrete test blocks. The external pressure mechanism and the internal expansion mechanism are driven by the force application mechanism. The three concrete test blocks are respectively subjected to external pressure and internal expansion force, and external pressure and internal expansion force, so as to observe the crack generation of the concrete test blocks when subjected to different forms of force, and then analyze the crack resistance of the concrete test blocks when subjected to different forms of force. Attached Figure Description

[0023] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 : A schematic diagram of the structure of the device for testing the crack resistance of concrete specimens according to the present invention;

[0025] Figure 2 : A schematic diagram of the installation of the pressure head and the top seat described in this invention;

[0026] Figure 3 : Figure 1 Enlarged view of the local area at points I, II, III, and IV shown;

[0027] Figure 4 : Figure 1 A magnified view of section II shown;

[0028] Figure 5 : Figure 1 A magnified view of section III shown;

[0029] Figure 6 : Figure 1 A magnified view of a portion of point IV shown.

[0030] The attached figures are labeled as follows:

[0031] A-Concrete test block, 1-Box body, 11-Self-locking caster wheel, 2-Outer cylinder, 21-Mounting cavity, 22-Heating wire, 23-Inducing protrusion, 3-Inner cylinder, 41-Motor, 42-Sleeve, 43-Lifting seat, 44-Shaft, 45-Driving bevel gear, 46-Machine cover, 47-Coupling, 48-Threaded cavity, 49-Driven bevel gear, 410-Insertion rod, 411-Insertion hole, 412-Pull rod, 413-Screw rod, 51-Support rod, 52-Pressure head, 61-Top rod, 62-Top seat, 63-Allowing hole, 64-Triangular block, 65-Reset spring. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1-6 As shown, an apparatus for testing the crack resistance of concrete specimens includes:

[0034] Box 1;

[0035] The outer cylinder 2 is fixed inside the top plate of the box 1, and three are evenly arranged along the length of the box 1.

[0036] The inner cylinder 3 is fixed to the center of the bottom plate of the outer cylinder 2. The axes of the inner cylinder 3 and the outer cylinder 2 coincide, and a casting cavity for the concrete test block is formed between the inner cylinder 3 and the outer cylinder 2.

[0037] The force-applying mechanism includes a motor 41, a sleeve 42, and a lifting seat 43. A shaft 44 is rotatably connected between the left and right side plates of the housing 1. A drive bevel gear 45 is fixedly connected to the shaft 44 at the corresponding position of each outer cylinder 2. A cover 46 is fixedly connected to the right side of the housing 1. The motor 41 is fixedly connected inside the cover 46. The output shaft of the motor 41 is connected to the right end of the shaft 44 via a coupling 47. The sleeve 42 is rotatably connected to the center of the bottom plate of the outer cylinder 2. An opening is formed inside the sleeve 42. The sleeve 42 has a threaded cavity 48, and a driven bevel gear 49 that meshes with the driving bevel gear 45 is fixedly connected to the bottom of the sleeve 42. The lifting seat 43 is located directly above the inner cylinder 3. Insert rods 410 are evenly fixedly connected to the lower surface of the lifting seat 43. Insert holes 411 corresponding to the insert rods 410 are opened in the side plate of the inner cylinder 3. A pull rod 412 is fixedly connected to the center of the lower surface of the lifting seat 43. A screw 413 is fixedly connected to the bottom of the pull rod 412 and meshes in the threaded cavity 48.

[0038] The external pressure mechanism and the internal expansion mechanism are driven by the leftmost force-applying mechanism, the middle force-applying mechanism, and the last force-applying mechanism.

[0039] like Figure 1 As shown, concrete test block A is poured between the inner cylinder 3 and the outer cylinder 2. Three concrete test blocks A can be poured from left to right.

[0040] When the motor 41 is working, it drives the shaft 44 and the driving bevel gear 45 fixed thereon to rotate through the coupling 47. When the driving bevel gear 45 rotates, it drives the driven bevel gear 49 that meshes with it to rotate, thereby rotating the sleeve 42. Since the screw 413 meshes with the threaded cavity 48 in the sleeve 42, when the sleeve 42 rotates, the screw 413 moves up and down. The integrated structure of the screw 413, the pull rod 412 and the lifting seat 43 moves up and down. The cooperation between the insertion rod 410 and the insertion hole 411 can limit the movement of the lifting seat 43.

[0041] When the force-applying mechanism is working, it drives the external pressure mechanism and the internal expansion mechanism to work. The external pressure mechanism and the internal expansion mechanism apply external pressure and internal expansion force to the concrete specimen A, respectively.

[0042] The leftmost concrete test block A is subjected to both external pressure and internal expansion force.

[0043] The middle concrete test block A was subjected to only external pressure;

[0044] The rightmost concrete test block A is only subjected to internal expansion force.

[0045] This allows us to observe the crack formation of concrete specimen A under different types of forces, and further analyze the crack resistance of concrete specimen A under different types of forces.

[0046] Preferably, the external pressure mechanism includes a support rod 51 and a pressure head 52. The support rod 51 is uniformly fixed to the outer circumference of the lifting seat 43. The support rod 51 is L-shaped, and a conical pressure head 52 is fixed to the bottom of the vertical rod of the support rod 51.

[0047] like Figure 1 and 4 As shown, when the lifting seat 43 is working, it drives the support rod 51 and the pressure head 52 to move. That is, when the test is being conducted, the pressure head 52 moves downward to apply pressure to the concrete test block A.

[0048] Preferably, the internal expansion mechanism includes a top rod 61 and a top seat 62; the side plate of the inner cylinder 3 is provided with uniformly spaced clearance holes 63, the top rod 61 is slidably connected in the clearance holes 63, the end of the top rod 61 away from the pull rod 412 is tapered, the end of the top rod 61 near the pull rod 412 is fixedly connected to a triangular block 64, a return spring 65 is sleeved on the top rod 61 between the triangular block 64 and the inner wall of the inner cylinder 3, the top seat 62 is a frustum shape with a larger top and a smaller bottom, the top seat 62 is coaxially fixed with the pull rod 412, and the inclined surface of the top seat 62 cooperates with the inclined surface of the triangular block 64.

[0049] like Figure 5 As shown, under the action of the return spring 65, the triangular block 64 and the top seat 62 abut against each other. When the top seat 62 moves downward, it can push the integrated structure of the triangular block 64 and the top rod 61 away from the top seat 62. The top rod 61 applies an internal expansion force to the concrete test block A.

[0050] Preferably, an annular mounting cavity 21 is provided in the side plate of the outer cylinder 2, and a spiral heating wire 22 is fixedly connected in the mounting cavity 21.

[0051] During the test, heating wire 22 can be activated to heat concrete specimen A and analyze the crack formation of concrete specimen A when it expands due to heat.

[0052] Preferably, the outer cylinder 2 is made of a transparent material.

[0053] Because the outer cylinder 2 is made of transparent material, it is easy to observe the occurrence of cracks.

[0054] Preferably, the inner wall of the outer cylinder 2 is densely covered with conical induced protrusions 23.

[0055] By inducing the protrusions 23, cracks can be easily generated, making the test more efficient and faster.

[0056] Preferably, the number of teeth of the driving bevel gear 45 is less than the number of teeth of the driven bevel gear 49.

[0057] Since the number of teeth of the driving bevel gear 45 is less than the number of teeth of the driven bevel gear 49, the speed of the driven gear can be reduced, thereby increasing the power of the external pressure mechanism and the internal expansion mechanism.

[0058] Preferably, self-locking casters 11 are fixed at the four corners of the bottom of the housing 1.

[0059] The device can be easily moved using the self-locking casters 11.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A device for testing the crack resistance of concrete specimens, characterized in that, include: Box (1); The outer cylinder (2) is fixed inside the top plate of the box (1) and three are evenly arranged along the length of the box (1); Inner cylinder (3), the inner cylinder (3) is fixed to the center of the bottom plate of the outer cylinder (2), the axes of the inner cylinder (3) and the outer cylinder (2) coincide, and a casting cavity for concrete test blocks is formed between the inner cylinder (3) and the outer cylinder (2); The force-applying mechanism includes a motor (41), a sleeve (42), and a lifting seat (43); a shaft (44) is rotatably connected between the left and right side plates of the housing (1), and a drive bevel gear (45) is fixedly connected to the shaft (44) at the position corresponding to each outer cylinder (2). A cover (46) is fixedly connected to the right side of the housing (1), and the motor (41) is fixedly connected inside the cover (46). The output shaft of the motor (41) is connected to the right end of the shaft (44) through a coupling (47); the sleeve (42) is rotatably connected to the center of the bottom plate of the outer cylinder (2), and the sleeve (42) contains... A threaded cavity (48) is provided. The bottom of the sleeve (42) is fixedly connected to a driven bevel gear (49) that meshes with the driving bevel gear (45). The lifting seat (43) is located directly above the inner cylinder (3). Insert rods (410) are uniformly fixedly connected to the lower surface of the lifting seat (43). Insert holes (411) corresponding to the insert rods (410) are provided in the side plate of the inner cylinder (3). A pull rod (412) is fixedly connected to the center of the lower surface of the lifting seat (43). A screw (413) is fixedly connected to the bottom of the pull rod (412). The screw (413) meshes in the threaded cavity (48). The external pressure mechanism and the internal expansion mechanism are driven by the leftmost force application mechanism, the middle force application mechanism, and the last force application mechanism. The external pressure mechanism includes a support rod (51) and a pressure head (52). The support rod (51) is uniformly fixed to the outer circumference of the lifting seat (43). The support rod (51) is L-shaped, and a conical pressure head (52) is fixed to the bottom of the vertical rod of the support rod (51). The internal expansion mechanism includes a top rod (61) and a top seat (62); the side plate of the inner cylinder (3) is provided with uniformly spaced clearance holes (63) around its circumference. The top rod (61) is slidably connected in the clearance holes (63). The end of the top rod (61) away from the pull rod (412) is tapered. The end of the top rod (61) near the pull rod (412) is fixed with a triangular block (64). A return spring (65) is sleeved on the top rod (61) between the triangular block (64) and the inner wall of the inner cylinder (3). The top seat (62) is a frustum shape with a larger top and a smaller bottom. The top seat (62) is coaxially fixed with the pull rod (412). The inclined surface of the top seat (62) and the inclined surface of the triangular block (64) cooperate with each other.

2. The device for testing the crack resistance of concrete specimens according to claim 1, characterized in that, The outer cylinder (2) has an annular mounting cavity (21) inside its side plate, and a spiral heating wire (22) is fixedly connected inside the mounting cavity (21).

3. The device for testing the crack resistance of concrete specimens according to claim 1, characterized in that, The outer cylinder (2) is made of transparent material.

4. The device for testing the crack resistance of concrete specimens according to claim 1, characterized in that, The inner wall of the outer cylinder (2) is densely covered with conical induced protrusions (23).

5. The apparatus for testing the crack resistance of concrete specimens according to claim 1, characterized in that, The number of teeth of the driving bevel gear (45) is less than the number of teeth of the driven bevel gear (49).

6. The apparatus for testing the crack resistance of concrete specimens according to claim 1, characterized in that, Self-locking casters (11) are fixed at the four corners of the bottom of the box (1).

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