A soft rock cave slag concrete performance test equipment

Abstract

The application relates to the technical field of concrete performance test, and discloses a soft rock hole slag concrete performance test equipment, which comprises an anti-permeation instrument body, a plurality of test mold seats are arranged at the top of the anti-permeation instrument body, a clamping pin is slidably connected to the top of the test mold seat, and an air bag is fixedly installed on the inner side wall of the test mold seat. The pressure change of the pressing ring caused by the extrusion ring before and after the magnet is approached during the upward movement of the adjusting block and the test block, the air bag can be turned upward with the test block to expose the surface of the test block, the broken particles can be easily cleaned and will not fall into the test mold seat, the broken particles will not fall on the inner bottom wall of the test mold seat and enter the water storage tank through the backwater pipe or block the water inlet, the water pressure during the next batch test is affected, the water pressure is uniformly transmitted, the probability of equipment failure and test error is reduced, and the accuracy of the test result is maintained.

Description

Technical Field

[0001] This application relates to the field of concrete performance testing technology, and in particular to a test device for the performance of soft rock cavitary concrete. Background Technology

[0002] Soft rock slag concrete is an environmentally friendly and economical new type of concrete material made by mixing cement, multi-scale modified admixtures, soft rock slag, water, and additives according to a calculated mix proportion. After mixing and molding according to the mix proportion, relevant performance tests need to be carried out to determine whether it meets the usage conditions. The performance tests mainly include hardened state (compressive strength test, impermeability test, freeze-thaw resistance test, resilience test) and non-hardened state (slump test, setting time test).

[0003] The concrete permeability test is usually conducted using a concrete permeability tester. During the test, a cylindrical test block is placed inside the mold base of the permeability tester, and air is pumped into the air bladder inside the mold base so that the air bladder is in contact with the side surface of the test block. During the test, due to the low strength of the aggregates (such as mudstone, shale, and phyllite) in soft rock slag concrete, the loose surface layer is easily broken and falls off. During the test, some broken particles will fall off and be placed between the outer surface of the test block and the air bladder. After the test is completed and the test block is removed, some broken particles will be removed with the test block. Some broken particles remaining on the surface of the air bladder will fall off and accumulate on the bottom wall of the mold base if not cleaned in time. They may flow into the water storage tank through the return water pipe or fall into the inlet water pipe through the inlet, causing blockage. This blockage is difficult to clean, resulting in water pressure fluctuations during the test and uneven pressure transmission, which affects the accuracy and repeatability of the test results. Summary of the Invention

[0004] This application proposes a performance testing device for soft rock cavitary concrete, which is easy to clean and prevents broken particles from falling into the mold base during cleaning. This prevents broken particles from falling onto the bottom wall of the mold base and entering the water storage tank through the return water pipe or clogging the inlet, thus affecting the water pressure in the next batch of tests. It ensures uniform water pressure transmission, reduces the probability of equipment failure and test errors, and maintains the accuracy of test results. This solves the problem that the pressure cannot be uniformly transmitted during the water pressurization process due to the failure to clean the broken particles remaining on the surface of the airbag in time, which affects the accuracy of test results.

[0005] To achieve the above objectives, this application adopts the following technical solution: a soft rock slag concrete performance testing device, comprising a permeability meter body, wherein multiple mold seats are provided on the top of the permeability meter body, and the top of the mold seats are slidably connected with locking pins; further comprising an airbag fixedly installed on the inner wall of the mold seats; multiple adjusting rods are provided on the side of the airbag away from the mold seats, and the bottom of the adjusting rods is fixedly connected to the airbag; a pressing ring is fixedly installed on the side of the adjusting rod away from the airbag; a connecting rod is internally limited and slidably connected on the side of the adjusting rod near the airbag; and extrusion rings are symmetrically fixedly installed at both ends of the connecting rod. The pressure ring is used to compress the test block. Multiple support rods are fixedly installed on the top of the permeability tester body, and each support rod is adapted to a corresponding adjustment rod. A magnet is fixedly installed at the top of the support rod, and the magnet is connected to the connecting rod. During the test, the connecting rod and the pressure ring compress the test block to eliminate the gap between the bottom of the air bladder and the test block. After the test, when the operator removes the test block, the pressure ring is still attached to the test block through the transmission connection between the magnet and the connecting rod, so that the side of the air bladder that is attached to the test block is turned upward to prevent the broken particles attached to the surface of the air bladder from falling onto the inner bottom wall of the test mold base.

[0006] Furthermore, the compression ring is positioned between the pressing ring and the airbag, and the bottom end of the compression ring is arc-shaped. As the compression ring moves downward, the compression force exerted by the compression ring on the pressing ring and the airbag gradually increases.

[0007] Furthermore, two limiting slide rods are symmetrically fixedly installed on the top of the connecting rod. An adjusting block is fixedly installed on the top of the two limiting slide rods. The adjusting block is made of ferromagnetic material. When the adjusting block gradually moves upward so that the side of the airbag that is in contact with the test block is flipped out, the adjusting block approaches the magnet. Under the action of the magnet's attraction force on the adjusting block, the adjusting block drives the connecting rod and the compression ring through the limiting slide rod to release the compression of the pressing ring, so that the test block is no longer subjected to the tension of the pressing ring. The operator can then naturally remove the test block and place it at the placement point.

[0008] Furthermore, the adjusting rod has a limiting groove inside that is slidably connected to the connecting rod. A spring is fitted on the outside of the limiting rod. The top end of the spring is fixedly connected to the inner top wall of the limiting groove, and the bottom end of the spring is fixedly connected to the connecting rod. The elastic force of the spring keeps the connecting rod and the compression ring moving downward.

[0009] Furthermore, the adjusting rod has an internal movable groove that is slidably connected to the adjusting block, and the movable groove is positioned above the limiting slide groove. The top ends of the two limiting slide rods movably penetrate the interlayer between the limiting slide groove and the movable groove.

[0010] Furthermore, the top end of the adjusting rod is slidably connected to a fixed plate, and the movable groove and the fixed plate are slidably connected by an elastic element. The fixed plate is made of ferromagnetic material. During the test, the fixed plate is placed above the test block. When the operator removes the test block, the fixed plate moves upward together with the test block to assist the upward movement of the adjusting rod and the bottom of the airbag.

[0011] Furthermore, a pressure sensor is fixedly installed inside the side of the adjusting rod away from the airbag. The pressure sensor is electrically connected to the controller, and a buzzer is electrically connected to the controller. When water seeps from the side of the test block, the pressure sensor detects pressure fluctuations and provides timely warnings to the operator.

[0012] Furthermore, the inner side of the airbag is provided with multiple mounting grooves, and each mounting groove is adapted to the corresponding adjusting rod and pressing ring to ensure the sealing effect between the airbag and the test block.

[0013] Furthermore, the top of the airbag is fixedly connected to the inner wall of the mold base, and the top of the airbag is fixedly connected to an air supply pipe. Multiple air supply pipes are fixedly connected to an air pump through a connecting pipe.

[0014] Furthermore, the bottom of the airbag is fitted to the inner bottom wall of the mold base to prevent gaps between the lower end face of the test block and the inner bottom wall of the mold base, which would cause water to enter the return water pipe prematurely.

[0015] The beneficial effects of this invention are as follows: This application provides a performance testing device for soft rock slag concrete. During the removal of the test block after the test, the spring force first applies pressure to the pressing ring and air bladder via the compression ring, keeping them in contact with the bottom outer surface of the test block. The friction between the test block and the pressing ring causes the bottom of the air bladder to move upwards, exposing the side of the air bladder in contact with the test block, preventing broken particles from falling off during the upward movement. As the adjusting block approaches the magnet, the magnet's attraction releases the compression ring from the pressing ring, allowing the operator to naturally separate the test block from the air bladder. The operator can then clean the broken particles adhering to the side of the air bladder in contact with the test block, ensuring easy cleaning and preventing broken particles from falling into the mold base. This prevents broken particles from falling onto the bottom wall of the mold base and entering the water storage tank via the return water pipe, or clogging the inlet, affecting the water pressure in the next batch of tests. This ensures uniform water pressure distribution, reduces the probability of equipment failure and test errors, and maintains the accuracy of the test results. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort: Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the anti-permeability meter body of the present invention; Figure 3 This is a schematic diagram of the structure of the airbag, adjusting rod, and fixing plate of the present invention; Figure 4 This is a schematic diagram of the front cross-sectional structure of the airbag and adjusting rod of the present invention; Figure 5 This is a schematic diagram of the front cross-sectional structure of the airbag of the present invention; Figure 6 This is a schematic diagram of the structure of the adjusting rod, pressing ring, and squeezing ring of the present invention; Figure 7 This is a partial front view cross-sectional structural diagram of the adjusting rod of the present invention; Figure 8 This is a schematic diagram of the connecting rod, extrusion ring, and adjusting block of the present invention.

[0017] In the diagram: 1. Permeability tester body; 2. Test mold base; 3. Locking pin; 4. Airbag; 5. Adjusting rod; 6. Pressing ring; 7. Connecting rod; 8. Extrusion ring; 9. Support rod; 10. Magnet; 11. Limiting slide rod; 12. Adjusting block; 13. Limiting slide groove; 14. Spring; 15. Movable groove; 16. Fixing plate; 17. Pressure sensor; 18. Mounting groove. Detailed Implementation

[0018] 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.

[0019] See Figures 1 to 8A permeability testing device for soft rock cavitary concrete includes a permeability meter body 1. Multiple test mold seats 2 are provided on the top of the permeability meter body 1. A locking pin 3 is movably connected to the top of each test mold seat 2. An air bladder 4 is installed on the inner wall of each test mold seat 2. The top of the air bladder 4 is fixedly connected to the inner wall of the test mold seat 2, and a gas supply pipe is fixedly connected to the top of the air bladder 4. Multiple gas supply pipes are connected to an air pump via connecting pipes. When conducting a permeability test on soft rock cavitary concrete, a cured test block is placed inside the air bladder 4. Gas is then pumped into the air bladder 4 through the connecting pipes and gas supply pipes, causing the air bladder 4 to adhere to the outer surface of the test block and seal the side of the test block. The locking pin 3 is then locked onto the top of the test mold seat 2 to limit the position of the test block and prevent it from floating under water pressure during the test, thus preventing uneven stress.

[0020] See Figures 4 to 5 An installation groove 18 is provided on the inner side of the airbag 4. The installation groove 18 is inverted T-shaped. An adjusting rod 5 is provided on the inner wall of the installation groove 18. The bottom of the adjusting rod 5 is fixedly connected to the side wall of the installation groove 18 on the side of the bottom of the adjusting rod 5 away from the airbag 4. A pressing ring 6 is fixedly installed on the bottom of the adjusting rod 5 away from the airbag 4. After the test block is placed inside the airbag 4 and gas is pumped into the airbag 4, the side of the adjusting rod 5 and the pressing ring 6 near the test block are also in contact with the surface of the test block under the squeezing action of the airbag 4. The installation groove 18 accommodates the adjusting rod 5 and the pressing ring 6, eliminating the gap between the side of the test block and the airbag 4 caused by the adjusting rod 5 and the pressing ring 6.

[0021] See Figures 6 to 8A limiting groove 13 is formed inside the bottom of the adjusting rod 5 on the side away from the pressing ring 6. A connecting rod 7 is slidably connected inside the limiting groove 13. Compression rings 8 are symmetrically fixed at both ends of the connecting rod 7. The compression rings 8 are placed between the pressing ring 6 and the airbag 4, and the bottom of the compression rings 8 is arc-shaped. Two limiting rods 11 are symmetrically fixed at the top of the connecting rod 7. An adjusting block 12 is fixedly fixed at the top of the two limiting rods 11. The adjusting block 12 is made of ferromagnetic material. A spring 14 is fitted on the outside of the limiting rod 11. The top of the spring 14 is fixedly connected to the inner top wall of the limiting groove 13, and the bottom of the spring 14 is fixedly connected to the connecting rod 7. Under the action of the elastic force, the connecting rod 7 and the compression ring 8 maintain a downward movement trend, thereby squeezing the pressing ring 6 and the air bladder 4, so that the pressing ring 6 is firmly pressed onto the surface of the test block. Multiple support rods 9 are fixedly installed on the top of the permeability tester body 1. Each support rod 9 is adapted to the corresponding adjusting rod 5. A magnet 10 is fixedly installed on the top of the support rod 9. After the test, the gas inside the air bladder 4 is pumped out by the air pump. As the gas in the air bladder 4 is lost, under the action of the elastic force of the spring 14, the connecting rod 7 and the compression ring 8 slide downward to continue to press the pressing ring 6 onto the surface of the test block, preventing gaps from appearing between the inside of the air bladder 4 and the test block, which would affect the sealing effect.

[0022] Subsequently, when the operator removes the test block, the friction between the test block and the pressing ring 6 causes the pressing ring 6, adjusting rod 5, and adjusting block 12 to slide upwards. Simultaneously, this causes the bottom of the airbag 4 to move upwards, thus flipping the empty airbag 4 upwards and exposing the side of the airbag 4 that is in contact with the test block. This prevents any remaining broken particles from falling onto the inner bottom wall of the mold base 2. During this process, under the elastic force of the spring 14, the bottom of the airbag 4 remains in contact with the outer surface of the test block, preventing broken particles from falling through the gaps. As the adjusting block 12 gradually approaches the magnet 10, the magnet 10 attracts the adjusting block 12, causing it to slide upwards. 2. The limiting slide rod 11 drives the connecting rod 7 and the compression ring 8 to move upward, gradually releasing the compression ring 8 from the pressing ring 6 and the air bag 4. After the side of the air bag 4 that is in contact with the test block is fully exposed, the compression ring 6 is released from the test block. The operator can then naturally separate the test block from the air bag 4. After removing multiple test blocks, the operator can clean the broken particles attached to the side of the air bag 4 that is in contact with the test block. This is to ensure that the broken particles are easy to clean and will not fall into the interior of the test mold base 2 during cleaning. This prevents the broken particles from falling onto the bottom wall of the test mold base 2 and entering the water storage tank through the return water pipe or clogging the water inlet, which would affect the water pressure in the next batch of tests, ensure uniform water pressure transmission, and maintain the accuracy of the test results.

[0023] See Figure 7The adjusting rod 5 has an internal movable groove 15 that is slidably connected to the adjusting block 12. The movable groove 15 is positioned above the limiting slide groove 13. The top end of the limiting slide rod 11 moves through the interlayer between the limiting slide groove 13 and the movable groove 15, and the movable groove 15 provides a sliding space for the adjusting block 12.

[0024] See Figure 4 The top end of the adjusting rod 5 is slidably connected to a fixed plate 16. The movable groove 15 and the fixed plate 16 are slidably connected by an elastic element. The fixed plate 16 is made of ferromagnetic material. In contrast, in this application, except for the adjusting block 12 and the fixed plate 16, all other structures are made of non-ferromagnetic materials. During the test, the fixed plate 16 is placed above the test block under the action of the elastic element. When the test block is removed at the end, the test block moves the adjusting rod 5 upward synchronously through the fixed plate 16 to prevent the friction between the pressing ring 6 and the test block from being unstable and causing relative sliding between them. When the fixed plate 16 gradually approaches the magnet 10, under the attraction of the magnet 10, the fixed plate 16 slides towards the magnet 10 and is no longer placed above the test block, thus releasing the limitation on the test block and allowing the operator to remove the test block naturally.

[0025] A pressure sensor 17 is fixedly installed inside the side of the adjusting rod 5 away from the airbag 4. The pressure sensor 17 is electrically connected to the controller, which is also electrically connected to a buzzer. During the test, the adjusting rod 5 is subjected to the squeezing force of the airbag 4 and the reaction force from the side of the test block. When water normally seeps into the test block from the lower end face, the force on the adjusting rod 5 remains unchanged even if the water pressure increases normally. When water seeps out from the side of the adjusting rod 5 due to the loose aggregate, the water flow enters the test block from the lower end face and the osmotic pressure on the adjusting rod 5 from the side of the test block decreases. The pressure sensor 17 detects the pressure change and sends the signal to the controller. The controller then controls the buzzer to turn on based on the signal processing result to warn the operator, interrupt the current test, and start the next batch of tests in time. This avoids the situation where the test results are distorted due to water seeping out from the side of the test block, and improves the accuracy of the test.

[0026] Working principle: When a permeability test is required on soft rock slag concrete, the cured test block is placed inside the air bladder 4. Then, gas is pumped into the air bladder 4 through the connecting pipe and the air supply pipe (the air inlet is not shown in the figure) so that the air bladder 4 fits against the outer surface of the test block and seals the side of the test block. Then, the locking pin 3 is locked and installed on the top of the test mold base 2 to limit the test block and prevent the test block from floating up under the action of water pressure during the test, which would cause uneven force. At this time, under the action of the elastic force of the spring 14, the connecting rod 7 and the compression ring 8 maintain a downward movement trend, which in turn compresses the pressing ring 6 and the air bladder 4, so that the pressing ring 6 is firmly pressed against the surface of the test block.

[0027] After the test, the gas inside the airbag 4 is pumped out by the air pump. As the gas in the airbag 4 is lost, the connecting rod 7 and the compression ring 8 slide downward under the action of the spring force of the spring 14, and continue to press the pressing ring 6 on the surface of the test block to prevent gaps from appearing between the inside of the airbag 4 and the test block, which would affect the sealing effect. Then, the locking pin 3 is removed, and the operator uses a clamp to remove the test block from the top of the test block from the inside of the airbag 4. When the test block is removed, the test block drives the pressing ring 6, the adjusting rod 5 and the adjusting block 12 to slide upward through the fixing plate 16 and the friction between the test block and the pressing ring 6, thereby flipping the airbag 4, which is empty inside, upward, so that the side of the airbag 4 that is in contact with the test block is exposed, thus preventing the remaining broken particles on the airbag 4 from falling onto the inner bottom wall of the test mold base 2.

[0028] During this process, under the action of the spring force 14, the bottom end of the airbag 4 remains in contact with the outer surface of the test block, thus preventing broken particles from falling through the gaps. As the test block moves upward, the magnet 10 attracts the fixing plate 16, causing the fixing plate 16 to no longer be positioned above the test block. When the adjusting block 12 also gradually approaches the magnet 10, the magnet 10 attracts the adjusting block 12, causing the adjusting block 12 to slide upward. The adjusting block 12 drives the connecting rod 7 and the compression ring 8 to move upward through the limiting slide rod 11, gradually releasing the compression ring 8 from the pressing ring 6 and the airbag 4, so that the airbag 4 and the test block are in contact. After the mating side is fully exposed, release the pressure ring 6 from the test block. The operator can then naturally separate the test block from the airbag 4. After removing all the test blocks, the operator can clean the broken particles attached to the mating side of the airbag 4 and the test block. This ensures easy cleaning and prevents the broken particles from falling into the mold base 2 during cleaning. This prevents broken particles from falling onto the bottom wall of the mold base 2 and entering the water storage tank through the return water pipe or clogging the water inlet, which would affect the water pressure in the next batch of tests. This ensures uniform water pressure transmission, reduces the probability of equipment failure and test errors, and maintains the accuracy of the test results.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test device for the performance of soft rock caving concrete, comprising a permeability tester body (1), wherein a plurality of test mold seats (2) are provided on the top of the permeability tester body (1), and a locking pin (3) is slidably connected to the top of the test mold seats (2), characterized in that, It also includes an airbag (4) fixedly installed on the inner wall of the mold base (2). The airbag (4) is provided with multiple adjusting rods (5) on the side away from the mold base (2), and the bottom of the adjusting rod (5) is fixedly connected to the airbag (4). A pressing ring (6) is fixedly installed on the side of the adjusting rod (5) away from the airbag (4). A connecting rod (7) is internally limited and slidably connected on the side of the adjusting rod (5) close to the airbag (4). Squeezing rings (8) are symmetrically fixedly installed at both ends of the connecting rod (7). Multiple support rods (9) are fixedly installed on the top of the permeability tester body (1), and each support rod (9) is respectively connected to the corresponding The adjustment rod (5) is adapted to the support rod (9). The top of the support rod (9) is fixedly installed with a magnet (10), and the magnet (10) is connected to the connecting rod (7) in a transmission connection. During the test, the connecting rod (7) and the extrusion ring (8) extrude the test block to eliminate the gap between the bottom of the airbag (4) and the test block. After the test, when the operator takes out the test block, the pressing ring (6) is still attached to the test block through the transmission connection between the magnet (10) and the connecting rod (7) so that the side of the airbag (4) attached to the test block is turned up to prevent the broken particles attached to the surface of the airbag (4) from falling onto the inner bottom wall of the test mold base (2). Two limiting slide rods (11) are symmetrically fixedly installed on the top of the connecting rod (7). An adjusting block (12) is fixedly installed on the top of the two limiting slide rods (11). The adjusting block (12) is made of ferromagnetic material. When the adjusting block (12) gradually moves up so that the side of the airbag (4) that is in contact with the test block is flipped out, the adjusting block (12) approaches the magnet (10). Under the attraction of the magnet (10) to the adjusting block (12), the adjusting block (12) drives the connecting rod (7) and the squeezing ring (8) through the limiting slide rod (11) to release the squeezing of the pressing ring (6), so that the test block is no longer subjected to the pulling force of the pressing ring (6). The operator naturally takes out the test block and places it at the placement point. The adjusting rod (5) has a limiting groove (13) inside that is slidably connected to the connecting rod (7). A spring (14) is fitted on the outside of the limiting rod (11). The top of the spring (14) is fixedly connected to the inner top wall of the limiting groove (13). The bottom of the spring (14) is fixedly connected to the connecting rod (7). The elastic force of the spring (14) makes the connecting rod (7) and the compression ring (8) maintain a downward movement trend. The adjusting rod (5) has an internal movable groove (15) that is slidably connected to the adjusting block (12), and the movable groove (15) is positioned above the limiting slide groove (13). The top ends of the two limiting slide rods (11) move through the interlayer between the limiting slide groove (13) and the movable groove (15).

2. The soft rock caving slag concrete performance testing equipment according to claim 1, characterized in that, The compression ring (8) is placed between the pressing ring (6) and the airbag (4), and the bottom end of the compression ring (8) is arc-shaped. As the compression ring (8) moves down, the compression force of the compression ring (8) on the pressing ring (6) and the airbag (4) gradually increases.

3. The soft rock caving slag concrete performance testing equipment according to claim 2, characterized in that, The top end of the adjusting rod (5) is slidably connected to a fixed plate (16). The movable groove (15) and the fixed plate (16) are slidably connected by an elastic element. The fixed plate (16) is made of ferromagnetic material. During the test, the fixed plate (16) is placed above the test block. When the operator takes out the test block, the fixed plate (16) moves upward together with the test block to assist the adjusting rod (5) and the bottom of the airbag (4) to move upward.

4. The soft rock caving slag concrete performance testing equipment according to claim 3, characterized in that, A pressure sensor (17) is fixedly installed inside the side of the adjusting rod (5) away from the airbag (4). The pressure sensor (17) is electrically connected to the controller, and a buzzer is electrically connected to the controller. When water seeps from the side of the test block, the pressure sensor (17) detects pressure fluctuations and provides timely warnings to the operator.

5. The soft rock caving slag concrete performance testing equipment according to claim 4, characterized in that, The airbag (4) has multiple mounting slots (18) on its inner side, and each mounting slot (18) is adapted to the corresponding adjusting rod (5) and pressing ring (6) to ensure the sealing effect between the airbag (4) and the test block.

6. The soft rock caving slag concrete performance testing equipment according to claim 5, characterized in that, The top of the airbag (4) is fixedly connected to the inner wall of the mold base (2), and the top of the airbag (4) is fixedly connected to an air supply pipe. Multiple air supply pipes are fixedly connected to an air pump through a connecting pipe.

7. The soft rock caving slag concrete performance testing equipment according to claim 6, characterized in that, The bottom of the airbag (4) is in contact with the inner bottom wall of the mold base (2) to prevent the lower end face of the test block from having a gap with the inner bottom wall of the mold base (2), which would cause water to enter the return water pipe in advance.

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