Indoor concrete and rock bonding strength testing device

Abstract

The utility model discloses a device for testing the bonding strength of indoor concrete and rock, which comprises a bonding strength detector for detecting the tensile force and a limiting device for limiting the vertical displacement of the rock, and the limiting device is positioned below the bonding strength detector; a drawing rod of the bonding strength detector is fixedly connected with the concrete test block; the limiting device comprises two side plates and two or more evenly-arranged limiting rods, the two ends of each limiting rod are connected with the two side plates respectively, and the limiting rods are located above the rock and are in contact connection with the top surface of the rock. According to the utility model, the concrete test block is only subjected to tensile force, gravity and cohesive force, the eccentric phenomenon and shear force do not exist between the rock and the concrete test block, and the measurement is convenient and accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of bond strength testing devices, and particularly relates to a testing device for the bond strength between indoor concrete and rock. Background Art

[0002] In civil engineering, concrete is usually used for structural connection with rock, such as bridges, tunnels, dams, etc. The bond strength test between concrete and rock can be used to evaluate the construction quality, ensure the firm combination of concrete and rock, and reduce the risks of the structure.

[0003] The specifications have corresponding regulations on the test methods for the bond strength of shotcrete. Most of the indoor tests use the indoor splitting method of spraying large plates as the main detection means. During the test, it is easy to generate force eccentricity due to human factors, and it is very difficult to accurately process the rock into a test block with half rock and half concrete, that is, there is also eccentricity in the test block itself, resulting in inaccurate test data. Moreover, there is a shear force during the splitting test, resulting in a higher splitting bond strength obtained by the splitting method of spraying large plates, which is different from the actual bonding situation between shotcrete and surrounding rock.

[0004] In addition, due to the action of its own gravity, the bond strength between concrete and rock will slowly decrease to a stable value. Therefore, in indoor tests, it is more meaningful to measure the strength of rock and concrete bonded for 3h and 8h. However, the splitting test requires making test blocks by casting with molds, and it often takes one or two days to remove the molds, and it is difficult to remove the molds. When removing the molds forcefully, it is easy to damage the bonding structure between concrete and rock (the bonding force between the two is small). Therefore, it is impossible to remove the molds and measure at the best test time points of 3h and 8h. Content of the Utility Model

[0005] Aiming at the above deficiencies of the prior art, the utility model provides a testing device for the bond strength between indoor concrete and rock, which solves the problem that the splitting bond strength obtained by the indoor splitting test in the prior art is inaccurate.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] Provide a testing device for the bond strength between indoor concrete and rock, which includes a bond strength detector for detecting the magnitude of the pulling force and a limiting device for restricting the vertical displacement of the rock. The limiting device is located below the bond strength detector; the pulling rod of the bond strength detector is fixedly connected to the concrete test block; the limiting device includes two side plates and two or more uniformly arranged limiting rods. The two ends of the limiting rods are respectively connected to the two side plates. The limiting rods are located above the rock and are in contact connection with the top surface of the rock.

[0008] The beneficial effects of the present utility model are as follows: Rotate the handle of the continuous rotation bond strength detector and apply a tensile force to the concrete test block through the pulling rod until the bonding interface between the rock and the concrete test block is damaged. At this time, the reading shown on the bond strength detector is the magnitude of the tensile force, which is also the sum of the bonding force between the concrete test block and the rock and the gravity of the concrete test block. Subtract the self-weight of the concrete test block from the tensile force to obtain the magnitude of the bonding force. The present utility model enables the concrete test block to be only subjected to tensile force, gravity, and bonding force, and there is no eccentricity phenomenon and shear force between the rock and the concrete test block, making the measurement convenient and accurate.

[0009] Preferably, the limiting device further includes a bottom plate perpendicular to the side plate. The bottom plate and the side plate are of an integral structure, and the bottom plate is fixedly connected to the test bench by bolts. During use, the rock and the concrete test block are placed on the bottom plate. When an upward tensile force is applied, since the limiting device is fixed to the test bench through the bottom plate, the limiting device will not be lifted. Therefore, the limiting device does not need to be manually pressed, saving manpower and being convenient to use.

[0010] Preferably, a plurality of mounting holes are uniformly formed in the two side plates in an array arrangement. The number of vertical columns of the mounting holes is an even number, and the vertical columns are symmetrically distributed along the center line of the side plate; both ends of the limiting rod extend into the mounting holes and are movably connected to the mounting holes.

[0011] The beneficial effects of the above technical solution are as follows: According to the different heights and surface areas of the rock, two or more limiting rods can be correspondingly installed in different mounting holes. In order to ensure uniform limitation of the rock, two or more limiting rods need to be centrosymmetric. The pre-opened centrosymmetric mounting holes can ensure the centrosymmetry of the limiting rods.

[0012] Preferably, a cushion block for increasing the mounting height of the rock is placed on the bottom plate. The cushion block is used to raise the rock. When the height of the rock is less than the distance between the limiting rod and the bottom plate, the cushion block can ensure that the limiting rod is in contact with the top surface of the rock.

[0013] Preferably, a test block joint is threadedly connected to one end of the pulling rod close to the limiting device. The bottom surface of the test block joint is a flat structure, and the concrete test block is fixedly connected to the bottom surface of the test block joint.

[0014] Preferably, the cross-sectional area of the test block joint is larger than that of the pulling rod. It can increase the contact area with the concrete test block, increase the stress area, and make the fixation between the two more firm. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of a test device for the bond strength between indoor concrete and rock.

[0016] Among them, 1 is a bond strength detector; 11 is a handle; 12 is a pulling rod; 13 is a test block joint; 2 is a limiting device; 21 is a limiting rod; 22 is a mounting hole; 23 is a bolt; 24 is a bottom plate, and 25 is a side plate; 3 is a rock; 4 is a concrete test block. Specific embodiments

[0017] The following describes the specific embodiments of the present invention to facilitate those skilled in the art of this technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of this technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all utility models created using the concept of the present invention are within the scope of protection.

[0018] As Figure 1 shown, the indoor concrete and rock bond strength testing device of this solution includes a bond strength detector 1 for detecting the magnitude of the pulling force and a limiting device 2 for restricting the vertical displacement of the rock 3. The limiting device 2 is located below the bond strength detector 1. The pulling rod 12 of the bond strength detector 1 is fixedly connected to the concrete test block 4. It should be noted that the bond strength detector 1 is an instrument in the prior art, and the specific structure can refer to the patent with the application number CN201921440330.7. The structure of the bond strength detector 1 is usually a portal structure as Figure 1 shown, generally used for detecting the bond strength of facing decorative bricks and external wall thermal insulation materials. The detection principle is roughly as follows: The main body of the instrument is a portable hydraulic jack, adopting mechatronic design and an embedded test display circuit. Rotating the handle 1 can drive the pulling rod 12 (i.e., the hydraulic piston rod) to move, and the current pulling force reading is displayed on the display screen, which will not be elaborated here.

[0019] The bond strength detector 1 has applicable standards and cannot be directly used to detect the bond strength between the rock 3 and the concrete test block 4. The main reason is that the wall itself will not move. After the pulling rod 12 is fixedly connected to the decorative brick, the pulling force applied by the pulling rod 12 will not cause the external wall thermal insulation material to move. However, it is not easy to fix the rock 3 and the concrete test block 4, and the rock 3 is easily directly lifted when a pulling force is applied. This solution restricts the displacement of the rock 3 by setting an auxiliary limiting device 2 to apply the bond strength detector 1 to the test for detecting the bond strength between the rock 3 and the concrete test block 4. The bond strength detector 1 can just be erected above the limiting device 2, which can save the test space.

[0020] Specifically, the limiting device 2 includes two side plates 25 and at least two uniformly arranged limiting rods 21. Both ends of the limiting rod 21 are connected to the two side plates 25 respectively. The limiting rod 21 is located above the rock 3 and is in contact connection with the top surface of the rock 3. The limiting device 2 further includes a bottom plate 24 perpendicular to the side plate 25. The bottom plate 24 and the side plate 25 are of an integral structure. The bottom plate 24 is fixedly connected to the test bench through bolts 23. During use, the rock 3 and the concrete test block 4 are placed on the bottom plate 24. When a tensile force is applied upward, the limiting device 2 is fixed to the test bench through the bottom plate 24 and will not be lifted. Therefore, the limiting device 2 does not require manual pressing, saving manpower and being convenient to use.

[0021] In an embodiment of this solution, the two side plates 25 are uniformly provided with mounting holes 22 arranged in an array. The number of vertical columns of the mounting holes 22 is an even number, and the vertical columns are symmetrically distributed along the center line of the side plate 25; both ends of the limiting rod 21 extend into the mounting holes 22 and are movably connected to the mounting holes 22. According to the different heights and surface areas of the rock 3, two or more limiting rods 21 can be correspondingly installed in different mounting holes 22. In order to ensure uniform limitation of the rock 3, two or more limiting rods 21 need to be centrosymmetric. The pre-opened centrosymmetric mounting holes 22 can ensure the centrosymmetry of the limiting rods 21.

[0022] When the surface area of the rock 3 to be measured is small, the limiting rod 21 is preferably two. Increasing the number of limiting rods 21 can increase the limiting ability and enhance the uniform stress level of the rock 3, avoiding detection errors caused by torque. The aperture of the mounting hole 22 is slightly larger than the rod diameter of the limiting rod 21. The limiting rod 21 can be taken out from the mounting hole 22, but the gap between the two should be minimized to reduce the radial displacement of the limiting rod 21. The bond strength detector 1 is not fixed to the test bench and can be moved away at any time without affecting the taking and placing of the limiting rod 21. The preferred test sequence is: install the rock 3 and the limiting rod 21 and then connect the pulling rod 12 and the concrete test block 4.

[0023] Preferably, a cushion block for increasing the installation height of the rock 3 is placed on the bottom plate 24. The cushion block is used to raise the height of the rock 3. When the height of the rock 3 is less than the distance between the limiting rod 21 and the bottom plate 24, the cushion block can ensure that the limiting rod 2 is in contact with the top surface of the rock 3. The cushion block is preferably made of a rigid material, which can be stacked wooden boards or books, papers and other materials that are easy to find indoors.

[0024] As an embodiment of this solution, a test block joint 13 is threadedly connected to one end of the drawing rod 12 close to the limiting device 2. The bottom surface of the test block joint 13 is a planar structure, and the concrete test block 4 is fixedly connected to the bottom surface of the test block joint 13. The concrete test block 4 and the test block joint 13 are preferably fixedly connected by ab glue, and the connection is firm. After the test is completed, the test block joint 13 is disassembled from the drawing rod 12, and the test block joint 13 and the concrete test block 4 can be separated by burning. The cross-sectional area of the test block joint 13 is larger than that of the drawing rod 12. The contact area with the concrete test block 4 can be increased, and the stress area can be increased, making the fixation of the two more firm.

[0025] During implementation, the preferred method for manufacturing the bonded test block of the rock 3 and the concrete test block 4 is as follows: Brush oil on the bottomless test mold and place it on the rock 3. Pour the prepared concrete into the bottomless test mold, and then place it on the vibrating table to vibrate it sufficiently to make the concrete dense. Cure it with the mold for 3 h or 8 h or 1 d and then remove the mold. Compared with the traditional method for manufacturing test blocks, the mold removal is simple and the bonded test block is not easily damaged.

[0026] The working principle of the present utility model is as follows: The rock 3 is bonded to the concrete test block 4. During the test, rotate the handle 11 to raise the drawing rod 12. The drawing rod 12 applies a tensile force perpendicular to the horizontal direction to the concrete test block 4, and the bond strength detector 1 can detect the magnitude of the tensile force. The rock 3 is limited by the limiting rod 21 and cannot perform vertical displacement. Continuously rotate the handle 11 and apply a tensile force to the concrete test block 4 through the drawing rod 12 until the bonding interface between the rock 3 and the concrete test block 4 is damaged. At this time, the reading displayed on the bond strength detector 1 is the magnitude of the tensile force, which is also the sum of the bonding force between the concrete test block 4 and the rock 3 and the gravity of the concrete test block 4. Subtract the self-weight of the concrete test block 4 from the tensile force to obtain the magnitude of the bonding force.

[0027] In summary, the present utility model enables the concrete test block 4 to be only subjected to tensile force, gravity, and bonding force, and there is no eccentricity phenomenon and shear force between the rock 3 and the concrete test block 4, and the measurement is convenient and accurate.

Claims

1. An indoor concrete and rock bonding strength testing device, characterized in that: The invention comprises a bonding strength detector (1) for detecting the magnitude of the pulling force and a limiting device (2) for limiting the vertical displacement of the rock (3), wherein the limiting device (2) is located below the bonding strength detector (1); a pulling rod (12) of the bonding strength detector (1) is fixedly connected to a concrete test block (4); the limiting device (2) comprises two side plates (25) and at least two evenly arranged limiting rods (21), wherein the two ends of the limiting rod (21) are respectively connected to the two side plates (25), and the limiting rod (21) is located above the rock (3) and is in contact with and connected to the top surface of the rock (3).

2. The indoor concrete-rock bonding strength testing device according to claim 1 is characterized in that: The limiting device (2) further comprises a bottom plate (24) perpendicular to the side plate (25); the bottom plate (24) and the side plate (25) are an integrated structure; the bottom plate (24) is fixedly connected to the test bench via bolts (23).

3. The indoor concrete-rock bonding strength testing device according to claim 1 is characterized in that: The two side panels (25) are evenly provided with mounting holes (22) arranged in an array, the number of vertical rows of the mounting holes (22) is an even number, and the vertical rows are symmetrically distributed along the center line of the side panels (25); both ends of the limit rod (21) extend into the mounting holes (22) and are movably connected to the mounting holes (22).

4. The indoor concrete-rock bonding strength testing device according to claim 2 is characterized in that: A pad for adjusting the installation height of the rock (3) is placed on the bottom plate (24).

5. The indoor concrete-rock bonding strength testing device according to claim 1 is characterized in that: One end of the pull rod (12) close to the limiting device (2) is threadedly connected to a test block joint (13); the bottom surface of the test block joint (13) is a plane structure; the concrete test block (4) is fixedly connected to the bottom surface of the test block joint (13).

6. The indoor concrete-rock bonding strength testing device according to claim 5, characterized in that: The cross-sectional area of ​​the test block joint (13) is greater than the cross-sectional area of ​​the pull rod (12).

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