CN115326615B - A concrete strength testing device - Google Patents

Abstract

The present invention relates to a concrete strength detection device, including a rebound tester and a grinding mechanism; the grinding mechanism includes a bearing tube, a guide member and a grinding member, a sliding hole is provided at the upper end of the peripheral wall of the bearing tube, a guide rod is vertically connected to the upper end of the inner wall of the bearing tube on the left side of the sliding hole, a movable ring is provided on the outer sleeve of the bearing tube, a driving rod passing through the sliding hole is connected to the inner wall of the movable ring, and a guide member is connected to the left end of the bearing tube; the guide member includes a first circular ring and a second circular ring; the grinding member includes a rotating drum and a grinding wheel, a spiral groove and an annular groove are provided on the outer wall of the rotating drum, the lower ends of the guide rod and the driving rod are respectively located in the spiral groove and the annular groove, and the grinding wheel includes a plurality of fan-shaped grinding wheel plates. The present invention solves the problem that when there are potholes, honeycombs, pockmarks or loose layers on the side of concrete, the detection accuracy of the rebound tester on concrete will be affected.

Description

A concrete strength testing device

Technical Field

The invention relates to the technical field of construction, and in particular to a concrete strength detection device.

Background technique

Concrete strength generally refers to the tensile strength and compressive strength of concrete. One of the main indicators of concrete quality is compressive strength. The main factors affecting concrete compressive strength are cement strength and water-cement ratio. At present, the methods for testing concrete compressive strength include rebound method, ultrasonic rebound method and core drilling method. Since the rebound method causes little damage to the surface of concrete during the testing process, the rebound method is widely used in the process of testing concrete compressive strength. The rebound method refers to the use of a rebound tester to test concrete. The basic principle of the rebound tester is to use a spring to drive a heavy hammer, which hits the impact rod in vertical contact with the side of the concrete with constant kinetic energy, causing the local concrete to deform and absorb part of the energy, and the other part of the energy is converted into the weight of the hammer. Rebound kinetic energy. When all the rebound kinetic energy is converted into potential energy, the weight rebounds to the maximum distance. The instrument displays the maximum rebound distance of the weight in the name of the rebound value (the ratio of the maximum rebound distance to the initial length of the spring). However, the rebound hammer will be affected by many factors during use, and the concrete compressive strength test is not accurate enough. For example, the article "A Brief Discussion on Internal and External Factors Affecting the Determination of Concrete Strength by Rebound Method" published in "Guangdong Building Materials" shows that when there are potholes, honeycombs, rough surfaces or loose layers on the side of the concrete, it will affect the detection accuracy of the rebound hammer on the concrete. Therefore, a concrete strength detection device is needed that can first perform surface treatment on the concrete before testing the concrete strength.

Summary of the invention

In order to solve the problem that the presence of pits, honeycombs, rough surfaces or loose layers on the side of concrete will affect the detection accuracy of the rebound hammer on concrete, the present invention provides a concrete strength detection device, which can perform surface treatment on the concrete before the concrete strength detection, thereby improving the detection accuracy of the concrete strength detection device on the concrete.

In order to solve the above problems, the technical solution of the present invention is:

A concrete strength testing device comprises a rebound tester and a grinding mechanism;

The grinding mechanism includes a bearing tube, a guide member and a grinding member, a sliding hole is provided at the upper end of the peripheral wall of the bearing tube, a guide rod is vertically connected to the upper end of the inner wall of the bearing tube on the left side of the sliding hole, a movable ring is provided on the outer shell of the bearing tube, a driving rod passing through the sliding hole is connected to the inner wall of the movable ring, a first spring is connected between the driving rod and the left end of the sliding hole, a screw passing through the sliding hole is threadedly connected to the right part of the movable ring, one end of the rebound instrument with the impact rod extends into the bearing tube, the casing is connected to the right end of the bearing tube in a horizontal sliding state, a retaining ring for pressing the screw on the left side is sleeved on the outer wall of the casing close to the impact rod, and the left end of the bearing tube is connected to the guide member;

The guide member includes a first circular ring and a second circular ring, the first circular ring is connected to the left end of the bearing tube, the second circular ring is connected to the left end surface of the first circular ring, and a plurality of first balls are inlaid on the inner wall of the left part of the second circular ring;

The grinding part includes a rotating drum and a grinding wheel. The rotating drum is arranged on the outer periphery of the rebound tester on the left side of the screw, and the left end passes through the first ring. The outer wall of the rotating drum is provided with a spiral groove and an annular groove. The lower ends of the guide rod and the driving rod are respectively located in the spiral groove and the annular groove. The grinding wheel includes a plurality of fan-shaped grinding wheel plates. The tips of the plurality of grinding wheel plates are relative, and every two adjacent grinding wheel plates are in sliding contact. The outer peripheral wall of the grinding wheel is pressed by the first ball to form a disc-shaped grinding wheel. A first T-shaped groove is arranged on the right side of each of the grinding wheel plates. A first T-shaped block connected to the peripheral wall of the rotating drum is arranged in the first T-shaped groove, and a second spring is connected between the first T-shaped block and the inner end of the first T-shaped groove.

Furthermore, the upper and lower ends of the outer wall of the housing of the rebound instrument are slidably connected to the supporting cylinder via a connecting piece, and the connecting piece at the upper end of the rebound instrument includes a cross bar and a connecting rod. The cross bar is connected to the upper end of the outer wall of the rebound instrument along the length direction of the housing of the rebound instrument, and a second T-shaped groove is provided on the top surface of the cross bar. The second T-shaped groove has a second T-shaped block corresponding to the second T-shaped groove, and the upper end of the second T-shaped block is connected to the right end of the top of the inner wall of the supporting cylinder via the connecting rod, and the impact rod of the rebound instrument is coaxial with the supporting cylinder and the rotating cylinder.

Furthermore, the thickness of the grinding wheel plate is equal to 1/2 of the thickness of the second circular ring, the inner wall of the second circular ring is composed of an equal-diameter inner ring on the left and an inclined inner ring on the right that is smaller on the left and larger on the right, the diameter of the inner ring on the left is equal to the left end diameter of the inner ring on the right, the right end of the inner ring on the right coincides with the right end of the outer ring of the second circular ring, and the distance between the left and right ends of the inclined inner ring of the second circular ring is greater than the thickness of the grinding wheel plate.

Furthermore, when the tips of the multiple grinding wheel plates are in relative contact to form a grinding wheel, the second spring in the first T-shaped groove on each grinding wheel plate is in a stretched state, the lower end of the guide rod is located in the middle of the spiral groove, and the first spring is in a compressed state.

Furthermore, when the movable ring drives the driving rod to move to the left, the driving rod drives the rotating drum to move to the left, and under the guidance of the guide rod, the rotating drum rotates from back to front.

Furthermore, the rotating drum drives the grinding wheel to move to the right. When each grinding wheel plate on the grinding wheel is separated from the top pressure of the first ball, each grinding wheel plate slides to the right along the inclined inner wall of the right part of the second circular ring until the right side surface of each grinding wheel plate contacts the left side surface of the first circular ring, and the rotating drum moves to the right to the extreme state.

Furthermore, when the drum moves rightward to the limit state, the second spring on each grinding wheel plate is in a natural state, and the diameter of the circle where the inner end of each grinding wheel plate is located is larger than the diameter of the rebound tester housing on the left side of the retaining ring.

Furthermore, a walking member is provided outside the guiding member, and the walking member includes a third ring, and the third ring is fixedly mounted outside the first ring and the second ring, and a plurality of connecting rods are arrayed on the third ring, and the left end of each connecting rod is flush with the left side surface of the third ring, and a second ball is embedded in the left end of the connecting rod, and the right end of the connecting rod passes through the third ring and is connected to a baffle, and a third spring is connected between the baffle and the third ring.

Furthermore, a grip rod is connected to the lower end of the peripheral wall of the bearing tube.

Through the above technical solution, the beneficial effects of the present invention are:

1. The present invention drives the driving rod to rotate the drum through the movable ring. When the drum rotates and drives the grinding wheel to the left, the concrete side can be grinded. After the grinding is completed, when the drum retracts into the second circular ring and contacts the first circular ring, it can detect the flat concrete side without interfering with the rebound tester. Since the concrete side has been grinded flat, the detection accuracy of the rebound tester can be improved.

2. The impact rod and the bearing tube of the rebound tester of the present invention are coaxial, which can ensure that the impact rod of the rebound tester vertically impacts the concrete surface polished and flattened by the grinding wheel, further improving the detection accuracy of the rebound tester.

3. The walking member of the present invention can facilitate the present invention to move on the side of concrete without damaging the side of concrete, and can quickly complete multi-point detection on the side of concrete.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic structural diagram of the present invention;

Fig. 2 is a cross-sectional view of the present invention;

FIG3 is a partial enlarged view of point A in FIG2;

FIG4 is a schematic diagram of the structure of the movable ring connecting the drive rod and the screw rod of the present invention;

FIG5 is a schematic structural diagram of a second ring of the present invention;

FIG6 is a schematic structural diagram of a rotating drum according to the present invention;

Fig. 7 is a left side view of the present invention;

FIG8 is a schematic structural diagram of a grinding wheel plate of the present invention;

FIG. 9 is a diagram showing the use state of the present invention.

The numbers in the accompanying drawings are: 1 is the first circular ring, 2 is the third circular ring, 3 is the connecting rod, 4 is the third spring, 5 is the baffle plate, 6 is the sliding hole, 7 is the movable ring, 8 is the connecting rod, 9 is the cross bar, 10 is the second closing plate, 11 is the rebound tester, 12 is the bearing tube, 13 is the grip rod, 14 is the grinding wheel plate, 15 is the second spring, 16 is the first T-block, 17 is the first T-slot, 18 is the first closing plate, 19 is the first ball, 20 is the second circular ring, 21 is the second ball, 22 is the guide rod, 23 is the first spring, 24 is the driving rod, 25 is the spiral groove, 26 is the second T-slot, 27 is the rotating cylinder, 28 is the second T-block, 29 is the annular groove, 30 is the impact rod, 31 is the baffle ring, 32 is the screw rod, and 33 is the handle.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

As shown in FIGS. 1 to 9 , a concrete strength testing device includes a rebound hammer 11 and a grinding mechanism;

The grinding mechanism includes a bearing cylinder 12, a guide member and a grinding member. The bearing cylinder 12 is a cylindrical body with openings at both ends. The bearing cylinder is a transparent cylinder made of polycarbonate material. A sliding hole 6 is provided at the upper end of the peripheral wall of the bearing cylinder 12, and a gripping rod 13 is connected to the lower end. The gripping rod 13 is a U-shaped rod body. Both ends of the gripping rod 13 are fixedly connected to the peripheral wall of the bearing cylinder 12 facing upward. The sliding hole 6 is a strip-shaped through hole arranged along the length direction of the bearing cylinder 12 and penetrating the inner and outer walls of the bearing cylinder 12. A guide rod 22 is vertically connected to the upper end of the inner wall of the bearing cylinder 12 on the left side of the sliding hole 6. The guide rod 22 is a round rod body. A movable ring 7 is provided on the outer sleeve of the bearing cylinder 12. The movable ring 7 is a round ring body whose inner wall and the outer wall of the bearing cylinder 12 are in sliding contact. The movable ring is located between the two ends of the gripping rod 13. A driving rod 24 with a lower end passing through the sliding hole is fixedly connected to the inner wall of the movable ring 7. The driving rod 24 is a round rod body. The driving rod 24 is connected to the left end of the sliding hole. There is a first spring 23, the right part of the movable ring 7 is threadedly connected with a screw 32 whose lower end passes through the sliding hole 6, and the upper end of the screw 32 is connected with a circular plate-shaped handle 33, the end of the rebound tester 11 with the impact rod 30 extends into the bearing tube 12, the housing of the rebound tester 11 is in a horizontal sliding state connected to the right end of the bearing tube 12, and a retaining ring 31 with a left side pressing the lower part of the screw 32 is fixed on the outer wall of the housing near the impact rod 30, and the retaining ring 31 is a circular ring plate. The right end of the housing extends out of the right end of the bearing tube 12, and the left end of the bearing tube 12 is connected with a guide, and the guide includes a first ring 1 and a second ring 20. The first ring 1 is a ring body with an outer diameter greater than the outer diameter of the bearing tube 12 and an inner diameter less than the inner diameter of the bearing tube 12. The right end face of the first ring 1 is fixedly connected to the left end of the bearing tube 12, and the second ring 20 is fixedly connected to the left side face of the first ring 1. The outer diameter of the second ring 20 is equal to the outer diameter of the first ring 1, and the inner diameter is greater than The inner diameter of the first ring 1 and the inner wall of the left part of the second ring 20 are inlaid with a plurality of first balls 19. The grinding member includes a rotating drum 27 and a grinding wheel. The rotating drum 27 is a cylindrical body with openings at both ends and an outer diameter corresponding to the inner diameter of the first ring 1. The rotating drum 27 is coaxially arranged in the bearing cylinder 12 on the left side of the screw 32. The right part of the rotating drum 27 is sleeved on the outer periphery of the rebound tester 11 in the bearing cylinder 12, and the left end passes through the inner ring of the first ring 1. The outer wall of the rotating drum 27 and the inner ring surface of the first ring 1 are slidable. The inner diameter of the drum is larger than the outer diameter of the retaining ring 31. The left and right parts of the outer wall of the drum 27 are respectively provided with a spiral groove 25 and an annular groove 29. The spiral groove 25 is a left-handed groove. The lower ends of the guide rod 22 and the driving rod 24 are respectively located in the spiral groove 25 and the annular groove 29. The driving rod is in sliding contact with the annular groove 29, and the guide rod is in sliding contact with the spiral groove 25. The grinding wheel is connected to the left end of the drum 27. The grinding wheel includes a plurality of fan-shaped grinding wheel plates 14. The tips of the grinding wheel plates 14 are relative, and every two adjacent grinding wheel plates 14 are in sliding contact. The outer peripheral wall of the grinding wheel is pressed by the first ball to form a disc-shaped grinding wheel. The grinding wheel and the bearing tube are coaxial. A first T-shaped groove 17 is arranged on the right side of each grinding wheel plate 14. Each of the first T-shaped grooves 17 is arranged along the radial direction of the grinding wheel. The first T-shaped groove 17 is a T-shape that is wide on the left and narrow on the right. A first T-shaped block 16 is provided in the first T-shaped groove on each grinding wheel plate 14, and the right end extends out of the first T-shaped groove 17 and connects to the left end of the peripheral wall of the rotating cylinder 27. A second spring 15 is connected between each of the first T-shaped blocks 16 and the inner end of the first T-shaped groove 17 (the end of the first T-shaped groove close to the tip of the grinding wheel plate is the inner end). The first T-shaped block 16 is in sliding contact with the first T-shaped groove 17. The outer end of each of the first T-shaped grooves 17 passes through the annular surface of the grinding wheel plate 14, and the outer end opening of each of the first T-shaped grooves 17 is blocked by a first sealing plate 18.

The upper and lower ends of the outer wall of the casing of the rebound instrument 11 are slidably connected to the supporting tube 12 through connecting pieces. The connecting piece at the upper end of the rebound instrument 11 includes a cross bar 9 and a connecting rod 8. The cross bar 9 is a long rod body. The cross bar 9 is connected to the upper end of the outer wall of the rebound instrument 11 along the length direction of the casing of the rebound instrument 11. A second T-shaped groove 26 is provided on the top surface of the cross bar 9. The right end of the second T-shaped groove 26 passes through the right end of the cross bar 9. The right end of the second T-shaped groove 26 is blocked by a second sealing plate 10. A second T-shaped block 28 corresponding to the second T-shaped groove 26 is provided in the second T-shaped groove 26. The upper end of the second T-shaped block 28 is connected to the right end of the top of the inner wall of the supporting tube 12 through the connecting rod 8. The rebound instrument 11 is in a horizontal sliding state along the central axis of the supporting tube 12. The impact rod 30 of the rebound instrument 11 is coaxial with the supporting tube 12 and the rotating cylinder 27.

The thickness of the grinding wheel plate 14 is equal to 1/2 of the thickness of the second circular ring 20. The inner wall of the second circular ring 20 is composed of an equal-diameter inner ring on the left and an inclined inner ring on the right that is smaller on the left and larger on the right. The diameter of the inner ring on the left is equal to the left end diameter of the inner ring on the right. The right end of the inner ring on the right coincides with the right end of the outer ring of the second circular ring 20. The distance between the left and right ends of the inclined inner ring of the second circular ring 20 is greater than the thickness of the grinding wheel plate 14.

When the tips of the plurality of grinding wheel plates 14 are in relative contact to form a grinding wheel, the second spring 15 in the first T-shaped groove 17 on each grinding wheel plate 14 is in a stretched state, the lower end of the guide rod 22 is located in the middle of the spiral groove 25, and the first spring 23 is in a compressed state.

The width of the spiral groove 25 matches the diameter of the guide rod 22, and the width of the annular groove 29 matches the diameter of the driving rod 24. The driving rod 24 drives the rotating drum 27 to move leftward, and under the guidance of the guide rod 22, the rotating drum 27 rotates from back to front.

The rotating drum 27 drives the grinding wheel to move to the right. When each grinding wheel plate 14 on the grinding wheel is released from the top pressure of the first ball 19, each grinding wheel plate 14 slides to the right along the inclined inner wall of the right part of the second ring 20 until the right side surface of each grinding wheel plate 14 contacts the left side surface of the first ring 1, and the rotating drum 27 moves to the right to the limit state.

When the drum 27 moves rightward to the limit state, the second spring 15 on each grinding wheel plate 14 is in a natural state, and the diameter of the circle where the inner end of each grinding wheel plate 14 is located is larger than the diameter of the housing of the rebound tester 11 on the left side of the retaining ring 31.

A walking member is also provided outside the guide member, and the walking member includes a third ring 2, and the third ring 2 is sleeved and fixed outside the first ring 1 and the second ring 20, and the left side surface of the third ring 2 is aligned with the left side surface of the second ring 20. A plurality of connecting rods 3 are arrayed on the third ring 2, and the left end of each connecting rod 3 is flush with the left side surface of the third ring 2, and the left end of the connecting rod 3 is inlaid with a second ball 21 with a diameter smaller than that of the connecting rod 3, and the right end of the connecting rod 3 passes through the third ring 2 and is located on the right side of the third ring 2, and is connected to a baffle 5, and a third spring 4 is connected between the baffle 5 and the third ring 2.

The first spring 23 is a compression spring, and the second spring 15 and the third spring 4 are both tension springs.

When the present invention is in use, the screw is rotated to move the screw downward until the lower end is lower than the upper end of the retaining ring. The user holds the gripping rod 13 with one hand to press the left side of the second ring and the third ring 2 against the concrete side. The user pushes the rebounding hammer to the left with the other hand. The retaining ring 31 on the rebounding hammer pushes the screw to drive the movable ring 7 to move to the left. Since the lower end of the driving rod 24 on the movable ring 7 is located in the annular groove 29 and the lower end of the guide rod is located in the spiral groove 25, the driving rod 24 drives the rotating drum 27 to move to the left, and under the guidance of the guide rod 22, the rotating drum 27 rotates from back to front, so the rotating drum 27 can drive the grinding wheel composed of multiple grinding wheel plates 14 to extend out of the second ring to grind the parts with pits, honeycombs, and pitted surfaces on the side of the concrete. When the rebounding hammer 11 is no longer pushed, the driving rod 24 on the movable ring 7 moves to the right under the action of the first spring 23. When the movable ring 7 drives the driving rod 24 to move to the right, the driving rod 24 drives the rotating drum 27 to move to the right, and under the guidance of the guide rod 22, The rotating drum 27 rotates from front to back, and the rotating drum 27 drives the grinding wheel to move to the right. When each grinding wheel plate 14 on the grinding wheel is separated from the top pressure of the first ball 19, each grinding wheel plate 14 slides to the right along the inclined inner wall of the right part of the second ring 20, until the right side of each grinding wheel plate 14 contacts the left side of the first ring 1, the rotating drum 27 moves to the right to the limit state, and pushes the rebound hammer to the left again. In the process of the rotating drum driving the grinding wheel plate to move to the left, multiple grinding wheel plates approach each other along the inclined annular surface of the right part of the second ring 20, until the outer peripheral wall of the grinding wheel is pressed by the first ball. At this time, multiple grinding wheel plates form a disc-shaped grinding wheel again, and the grinding wheel extends out of the second ring to grind the side of the concrete again. This process is repeated until the parts with potholes, honeycombs, and hemp surfaces on the side of the concrete are polished flat. The present application uses manual control grinding, which can avoid excessive grinding caused by excessive force of electric grinding. When the drum 27 moves to the right to the limit state and no longer pushes the rebound hammer to the left, the diameter of the circle where the inner end of each grinding wheel plate 14 is located is larger than the diameter of the rebound hammer 11 casing on the left side of the retaining ring 31. The screw is rotated so that the lower end of the screw is higher than the upper end of the drum 27, and the rebound hammer 11 is pushed to the left. The impact rod 30 on the rebound hammer 11 and the casing of the rebound hammer 11 on the left side of the retaining ring 31 pass through the tips of multiple grinding wheel plates 14, and the impact rod hits the side of the concrete and retracts into the rebound hammer to perform concrete compressive strength testing. Since the side of the concrete has been polished flat, the detection accuracy of the rebound hammer 11 can be improved. The supporting cylinder is a transparent cylinder, which can conveniently read the rebound hammer.

Since the impact rod 30 of the rebound tester 11 and the supporting tube 12 are coaxial, it can ensure that the impact rod 30 of the rebound tester 11 vertically impacts the surface polished by the grinding wheel, further improving the detection accuracy of the rebound tester 11;

Since the rebound tester 11 needs to perform multi-point detection on the side of the concrete, it is necessary to make the second ball on the walking member roll and contact with the side of the concrete when performing multi-point detection. To easily perform multi-point movement, it is also possible not to separate the present application from the side of the concrete, which plays a supporting and labor-saving role, and prevents multi-point detection. Long-term lifting is easy to get tired. When testing at a certain point, the left side of the walking member of the present invention is pressed against the side of the concrete, and the second ball on the walking member enters the third ring 2. The third spring 4 is in a stretched state, and the present invention can remain stable, thereby ensuring the accuracy of the test results. When it is necessary to move the present invention to detect concrete at another position, the present invention is slightly moved to the right. Under the action of the restoring force of the third spring 4, the second ball 21 on the walking member leaks out of the third ring 2, which can facilitate the movement of the present invention on the side of the concrete.

The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Without violating the spirit of the present invention, that is, within the scope of disclosure, any multiple equivalent or equivalent modifications or replacements of the technical solutions of the invention shall fall within the protection scope of the present invention.

Claims (9)

1. A concrete strength testing device, comprising a rebound tester (11) and a grinding mechanism, characterized in that; The grinding mechanism comprises a bearing tube (12), a guide member and a grinding member. A sliding hole (6) is provided at the upper end of the peripheral wall of the bearing tube (12). A guide rod (22) is vertically connected to the upper end of the inner wall of the bearing tube (12) on the left side of the sliding hole (6). A movable ring (7) is provided on the outer sleeve of the bearing tube (12). A driving rod (24) passing through the sliding hole is connected to the inner wall of the movable ring (7). A first spring (23) is connected between the driving rod (24) and the left end of the sliding hole. A screw (32) passing through the sliding hole (6) is threadedly connected to the right part of the movable ring (7). One end of the rebound tester (11) with the impact rod (30) extends into the bearing tube (12). The casing is connected to the right end of the bearing tube (12) in a horizontal sliding state. A retaining ring (31) for pressing the screw (32) on the left side is sleeved on the outer wall of the casing close to the impact rod (30). The left end of the bearing tube (12) is connected to the guide member. The guide member comprises a first circular ring (1) and a second circular ring (20), the first circular ring (1) being connected to the left end of the bearing tube (12), the second circular ring (20) being connected to the left end surface of the first circular ring (1), and a plurality of first rolling balls (19) being inlaid on the inner wall of the left portion of the second circular ring (20); The grinding member comprises a rotating drum (27) and a grinding wheel. The rotating drum (27) is arranged on the outer periphery of the rebound tester (11) on the left side of the screw rod (32), and the left end thereof passes through the first circular ring (1). The outer wall of the rotating drum (27) is provided with a spiral groove (25) and an annular groove (29). The lower ends of the guide rod (22) and the driving rod (24) are respectively located in the spiral groove (25) and the annular groove (29). The grinding wheel comprises a plurality of fan-shaped grinding wheel plates (14). The tips of the plurality of grinding wheel plates (14) are opposite to each other, and each two adjacent grinding wheel plates (14) are in sliding contact. The outer peripheral wall of the grinding wheel is pressed by a first ball to form a disc-shaped grinding wheel. A first T-shaped groove (17) is arranged on the right side of each grinding wheel plate (14). A first T-shaped block (16) connected to the peripheral wall of the rotating drum (27) is arranged in the first T-shaped groove. A second spring (15) is connected between the first T-shaped block (16) and the inner end of the first T-shaped groove (17). 2. A concrete strength testing device according to claim 1, characterized in that the upper and lower ends of the outer wall of the housing of the rebound tester (11) are slidably connected to the supporting cylinder (12) through connecting pieces, and the connecting piece at the upper end of the rebound tester (11) includes a cross bar (9) and a connecting rod (8), and the cross bar (9) is connected to the upper end of the outer wall of the rebound tester (11) along the length direction of the housing of the rebound tester (11), and a second T-shaped groove (26) is provided on the top surface of the cross bar (9), and a second T-shaped block (28) corresponding to the second T-shaped groove (26) is provided in the second T-shaped groove (26), and the upper end of the second T-shaped block (28) is connected to the right end of the top of the inner wall of the supporting cylinder (12) through the connecting rod (8), and the impact rod (30) of the rebound tester (11) is coaxial with the supporting cylinder (12) and the rotating cylinder (27). 3. A concrete strength detection device according to claim 1, characterized in that the thickness of the grinding wheel plate (14) is equal to 1/2 of the thickness of the second circular ring (20), the inner wall of the second circular ring (20) is composed of an equal-diameter inner ring on the left and an inclined inner ring on the right, the diameter of the inner ring on the left is equal to the left end diameter of the inner ring on the right, the right end of the inner ring on the right coincides with the right end of the outer ring of the second circular ring (20), and the distance between the left and right ends of the inclined inner ring of the second circular ring (20) is greater than the thickness of the grinding wheel plate (14). 4. A concrete strength detection device according to claim 1, characterized in that when the tips of the plurality of grinding wheel plates (14) are in relative contact to form a grinding wheel, the second spring (15) in the first T-shaped groove (17) on each grinding wheel plate (14) is in a stretched state, the lower end of the guide rod (22) is located in the middle of the spiral groove (25), and the first spring (23) is in a compressed state. 5. A concrete strength detection device according to claim 1, characterized in that when the movable ring (7) drives the driving rod (24) to move leftward, the driving rod (24) drives the rotating drum (27) to move leftward, and under the guidance of the guide rod (22), the rotating drum (27) rotates from back to front. 6. A concrete strength testing device according to claim 5, characterized in that the rotating drum (27) drives the grinding wheel to move rightward, and when each grinding wheel plate (14) on the grinding wheel is released from the top pressure of the first ball (19), each grinding wheel plate (14) slides rightward along the inclined inner wall of the right part of the second circular ring (20), until the right side surface of each grinding wheel plate (14) contacts the left side surface of the first circular ring (1), and the rotating drum (27) moves rightward to the limit state. 7. A concrete strength testing device according to claim 6, characterized in that when the rotating drum (27) moves rightward to the limit state, the second spring (15) on each grinding wheel plate (14) is in a natural state, and the diameter of the circle where the inner end of each grinding wheel plate (14) is located is larger than the diameter of the rebound tester (11) housing on the left side of the retaining ring (31). 8. A concrete strength detection device according to claim 1, characterized in that a walking member is further provided outside the guide member, the walking member comprises a third circular ring (2), the third circular ring (2) is sleeved and fixed outside the first circular ring (1) and the second circular ring (20), a plurality of connecting rods (3) are arranged in an array on the third circular ring (2), the left end of each connecting rod (3) is flush with the left side surface of the third circular ring (2), a second ball (21) is embedded in the left end of the connecting rod (3), the right end of the connecting rod (3) passes through the third circular ring (2) and is connected to a baffle (5), and a third spring (4) is connected between the baffle (5) and the third circular ring (2). 9. A concrete strength detection device according to claim 1, characterized in that a gripping rod (13) is connected to the lower end of the peripheral wall of the bearing tube (12).