Detection system and method for crack repair degree of cracked concrete test piece

Abstract

The invention discloses a system and method for detecting the crack repairing degree of a cracked concrete test piece, and the system comprises a frame system, a crack impermeability testing system, an array type ultrasonic wave and resistivity testing system, a water collection and drainage system, and an electric control system. The water collection and drainage system is installed at the bottom of the frame system and used for bearing a tested piece and collecting water discharged from the tested piece, and the electric control system is used for controlling the crack impermeability testing system and the array type ultrasonic wave and resistivity testing system and monitoring and processing data measured by the testing systems. By arranging the crack impermeability testing system and the array type ultrasonic wave and resistivity testing system, the crack sealing effect is comprehensively evaluated in multiple dimensions on the basis of the water seepage resistance of the test piece after crack repairing, the ultrasonic wave propagation speed in the test piece and the resistivity of the two sides of the crack of the test piece, operation is easy, the integration degree is high, and the effect is good. And the accuracy of the repair test result is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete repair detection, and in particular to a detection system and method for the degree of crack repair of a cracked concrete specimen. Background Art

[0002] Cracks are the most common disease of concrete, and the main form of damage to concrete materials is the generation of various cracks that affect its basic properties. However, concrete will inevitably produce cracks during service due to drying shrinkage, temperature stress and external loads. For some non-structural cracks, the use of post-repair methods can effectively restore their basic properties and extend the durability of the building structure. In recent years, the repair technology of concrete cracks has been highly concerned by many scholars and technicians in the field of civil engineering. At present, the repair of non-structural cracks in concrete mainly adopts manual repair, which uses the injection or filling of repair materials into the concrete cracks to achieve the effect of crack sealing. Several commonly used grouting materials include epoxy resin slurry, polyurethane slurry, acrylic rubber, etc., but the viscosity and curing degree of each material are different, and the repair effect of concrete cracks is also significantly different. On the other hand, there is also a self-repair technology for concrete cracks that uses mineral expansion crystallization and microbial mineralization, which can complete the sealing of concrete cracks without manual exploration and repair operations.

[0003] According to the different service environments of concrete components, choosing the most suitable crack repair method can not only increase the durability of the building, but also save costs. However, the evaluation methods and testing methods for the repair effects of concrete cracks with different technologies and different repair materials are still immature, so the selection of appropriate crack repair methods also faces difficulties. At the same time, there is a lack of integrated, high-precision, and comprehensive testing equipment for the degree of repair of cracked concrete specimens. In general, there is an urgent need for a testing system and method that can accurately test the repair effect of cracked concrete cracks. Summary of the invention

[0004] Purpose of the invention: In view of the above shortcomings, the present invention provides a system and method for detecting the degree of crack repair of cracked concrete specimens.

[0005] Technical solution: To solve the above problems, the present invention adopts a detection system for the degree of crack repair of cracked concrete specimens, including a frame system, a crack impermeability test system, an array ultrasonic and resistivity test system, a water collection and drainage system, and an electric control system. The water collection and drainage system is installed at the bottom of the frame system to support the tested specimen and collect water from the specimen. The electric control system is used to control the crack impermeability test system, the array ultrasonic and resistivity test system, and monitor and process the data measured by the crack impermeability test system and the array ultrasonic and resistivity test system.

[0006] The crack anti-seepage capacity testing system comprises a lifting device and a cylinder, wherein the lifting device is installed on the frame system, and the cylinder is detachably installed on the lifting device. A booster piston and a water level pressure test sensor are arranged inside the cylinder, and the water pressure in the cylinder is regulated by adjusting the position of the booster piston; a water inlet is arranged at the top of the cylinder, and a water outlet is arranged at the bottom of the cylinder, and the opening and closing of the water outlet is controlled by an electronic control system;

[0007] The array type ultrasonic wave and resistivity testing system comprises two test panels arranged in parallel, the test panels are movably mounted on a frame system, and ultrasonic measuring point probes and voltage transmitting probes are arranged on two opposite surfaces of the test panels.

[0008] Furthermore, the frame system includes a supporting frame, the upper portion of the supporting frame is provided with a slot for installing a lifting device, and the lower portion of the supporting frame is provided with an opening for installing an array type ultrasonic and resistivity testing system.

[0009] Furthermore, the lifting device includes a lifting suspension plate, a lifting adjustment knob installed on a supporting frame, and pulleys installed at both ends of the lifting suspension plate. The lifting adjustment knob is connected to the pulley through a steel wire rope, and the pulley is controlled to slide up and down in the slot by rotating the lifting adjustment knob.

[0010] Furthermore, a mounting hole matching the cross section of the cylinder is opened in the middle of the lifting suspension plate, an internal thread is arranged in the mounting hole, and an external thread is arranged on the outside of the cylinder, and the detachable installation of the cylinder is realized by the threaded cooperation.

[0011] Furthermore, the array ultrasonic and resistivity testing system also includes a sliding rod and a movable support member mounted on the sliding rod, circular holes are opened on both sides of the test panel, both ends of the sliding rod are installed in the openings, and the sliding rod passes through the circular holes on the test panel; the movable support member is against both sides of the test panel to support the test panel, and a roller is provided on the inner side of the movable support member to drive the test panel to move along the sliding rod, and the roller is controlled by an electronic control system.

[0012] Furthermore, the movable support is made of rubber.

[0013] Furthermore, the water collection and drainage system includes a mesh specimen supporting box, a water containing box, and an asbestos net. The top of the mesh specimen supporting box is a hollow grid, the interior is hollow and the sides are open. The water containing box is installed in the mesh specimen supporting box in a drawer style, and the asbestos net is laid on the top of the mesh specimen supporting box.

[0014] Furthermore, the test panel is provided with four columns of 1×2 ultrasonic measuring point probes and one column of 1×2 voltage transmitting probes, and the four columns of ultrasonic measuring point probes are arranged in groups of two on both sides of the voltage transmitting probes.

[0015] Furthermore, the electronic control system includes a transmission wire and an electronic control screen. The transmission wire is used for connecting and transmitting data between the crack impermeability test system, the array ultrasonic and resistivity test system and the electronic control system. The electronic control screen is used for controlling the test system and monitoring and processing data.

[0016] The present invention also provides a detection method of the detection system, comprising the following steps:

[0017] Step 1: Place the test piece on the water collection and drainage system and place the test piece between two test panels;

[0018] Step 2, close the water outlet and add water into the cylinder, after adding water, install the cylinder on the lifting device, and adjust the lifting device so that the bottom of the cylinder is in contact with the upper end surface of the test piece;

[0019] Step 3, controlling the two test panels to move and to contact with the two side surfaces of the test piece;

[0020] Step 4: Set the water pressure inside the cylinder, the ultrasonic emission frequency, and the potential difference of the panels on both sides through the electronic control system;

[0021] Step 5, open the openable drain outlet to start the test, observe the changes in key indicator parameters on the electronic control screen, the parameters include water flow permeability, ultrasonic velocity, resistivity, and analyze the crack repair effect of the specimen based on the parameters;

[0022] Step 6: Close the water outlet, adjust the ultrasonic emission frequency and potential difference of the two test panels to 0, control the test panels to move to both sides, remove the cylinder, and end the test.

[0023] Beneficial effect: Compared with the prior art, the significant advantage of the present invention is that by setting up a crack impermeability testing system and an array ultrasonic and resistivity testing system, the resistance of the repair material to the external water pressure is tested by water flow impact, and the deep and internal repair effects of the cracks are evaluated by array ultrasonic and resistivity. Based on the water impermeability of the specimen after crack repair, the ultrasonic propagation speed inside the specimen, and the resistivity on both sides of the crack of the specimen, a multi-dimensional and comprehensive evaluation of the crack sealing effect is made. The operation is simple, the integration is high, and the accuracy of the repair test results is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The overall structural diagram of the detection system for the degree of crack repair of cracked concrete specimens of the present invention;.

[0025] Figure 2 This is a schematic diagram of the structure of the crack anti-seepage capacity testing system of the present invention;

[0026] Figure 3 The array type ultrasonic wave and resistivity testing system of the present invention

[0027] Figure 4 This is a schematic diagram of the test panel structure of the present invention;

[0028] Figure 5 It is a schematic diagram of the structure of the water collection and drainage system of the present invention;

[0029] Figure 6 It is a schematic diagram of the test status of the test system of the present invention. DETAILED DESCRIPTION

[0030] Embodiment 1

[0031] like Figure 1 As shown, a crack repair degree detection system for cracked concrete specimens in this embodiment includes a frame system, a crack impermeability test system, an array ultrasonic and resistivity test system, a water collection and drainage system, and an electric control system. The frame system includes support frames 1 located on both sides, the upper part of the support frame 1 is provided with a slot 11 for installing a lifting device, and the lower part of the support frame 1 is provided with an opening 12 for installing the array ultrasonic and resistivity test system.

[0032] The crack impermeability test system includes a lifting device and a cylinder 2. A booster piston 22 and a water level pressure test sensor 23 are arranged inside the cylinder 2. The water pressure in the cylinder is regulated by adjusting the position of the booster piston 22. The water level pressure test sensor 23 is used to monitor the water pressure and water level inside the bucket. A water inlet 28 is arranged on the upper part of the cylinder 2, and a water outlet 21 is arranged at the bottom of the cylinder 2. The opening and closing of the water outlet 21 is controlled by an electric control system. The lifting device includes a lifting suspension plate 25, a lifting adjustment knob 26 installed on the support frame 1, and pulleys 27 installed at both ends of the lifting suspension plate 25. The lifting adjustment knob 26 is connected to the pulley 27 through a steel strand 29. The pulley 27 is controlled to slide up and down in the slot 11 by rotating the lifting adjustment knob 26. A mounting hole matching the cross section of the cylinder 2 is opened in the middle of the lifting suspension plate 25. An internal thread 24 is arranged in the mounting hole, and an external thread is arranged on the outer side of the cylinder 2. The detachable installation of the cylinder 2 is realized by thread matching. The crack impermeability test system uses Darcy's law (water permeability coefficient = water mass (m 3 / s)×specimen height (m) / specimen cross-sectional area (m 2 ) / head difference (m)) calculates the water permeability coefficient (water flow velocity) of the crack in real time and feeds back on the electronic control screen.

[0033] The array type ultrasonic and resistivity test system comprises two test panels 3 arranged in parallel, a slide bar 33, and a movable support 34 sleeved and mounted on the slide bar 33. There are circular holes on both sides of the test panel 3, and both ends of the slide bar 33 are installed in the opening 12, and the slide bar 33 passes through the circular holes on the test panel 3. The movable support 34 abuts against both sides of the test panel 3 to support the test panel 3. The movable support 34 is made of rubber material to increase the friction between the test panel 3 and the test panel 3, thereby improving the stability during support. A roller is provided on the inner side of the movable support 34 to drive the test panel 3 to move along the slide bar 33, and the roller is controlled by the electric control system. Ultrasonic measuring point probes 31 and voltage transmitting probes 32 are provided on the two opposite surfaces of the test panel 3 to test the ultrasonic propagation velocity and resistivity of the test piece. Each test panel 3 is provided with four rows of 1×2 ultrasonic measuring point probes 31 and one row of 1×2 voltage transmitting probes 32, and the four rows of ultrasonic measuring point probes 31 are arranged in pairs on both sides of the voltage transmitting probe 32. The ultrasonic measuring point probe 31 is used to transmit and receive ultrasonic signals, and the multi-measuring point and array arrangement are used to accurately test the repair of cracks inside the specimen. The voltage transmitting probe 32 is used to form a potential difference on both sides of the concrete specimen 6 to test the resistivity of different parts of the specimen. When testing, specimens of different sizes are placed in different positions, but it is necessary to ensure that they are closely connected with the ultrasonic measuring point probe (at least one pair of left and right panels) and the voltage transmitting probe (at least one of the left and right panels).

[0034] The water collection and drainage system includes a mesh specimen support box 41, a water carrying box 42, and an asbestos net 43. The top of the mesh specimen support box 41 is a hollow grid, the interior is hollow and the sides are open. The water carrying box 42 is installed in the mesh specimen support box 41 in a drawer-like manner, and the asbestos net 43 is laid on the top of the mesh specimen support box 41. The asbestos net 43 has good water flow penetration effect and insulation. The water flow passing through the cracks quickly penetrates through the mesh specimen support box 41 and flows into the inner water carrying box 42, thereby collecting and carrying the water flow.

[0035] The electric control system includes a transmission wire 51 and an electric control screen 52. The transmission wire 51 is used for connecting and transmitting data between the crack impermeability test system, the array ultrasonic wave and resistivity test system and the electric control system. The electric control screen 52 is used to control the booster piston 22, the water outlet 21, the roller, the ultrasonic measuring point probe 31, and the voltage transmitting probe 32, so as to adjust the water pressure in the crack impermeability test system, the ultrasonic wave transmitting frequency in the array ultrasonic wave and resistivity test system, and the potential difference between the two side panels 3, and to display the permeability coefficient of the water flow through the crack, the ultrasonic wave propagation speed on both sides of the crack, and the resistivity of the test piece in real time. When setting the booster piston position, the ultrasonic wave transmitting frequency, and the potential difference between the two side panels, it is necessary to observe whether the data displayed on the electric control screen is stable. If it is unstable, it is necessary to readjust the parameters or the placement position of the test piece.

[0036] Embodiment 2

[0037] This embodiment provides a detection method of the above-mentioned crack repair degree detection system of the cracked concrete specimen, comprising the following steps:

[0038] Step 1: Place the specimen with cracks repaired by injecting epoxy resin on the mesh specimen support box 41. The specimen has a 1 mm wide through crack before crack repair and a specimen size of 100 mm × 100 mm × 400 mm. The specimen is located between two test panels 3, with the 100 mm × 400 mm side of the specimen facing the panels.

[0039] Step 2, close the water outlet 21 and add water into the cylinder 2 to 1 / 3 of the cylinder volume. After adding water, install the cylinder 2 on the lifting device, and adjust the lifting device so that the bottom of the cylinder 2 abuts against and is in close contact with the upper end surface of the test piece.

[0040] Step 3: Control the two test panels 3 to move and contact with the two side surfaces of the test piece, so that the ultrasonic measuring point probe 31 and the voltage transmitting probe 32 are in close contact with the side surfaces of the test piece.

[0041] Step 4: Use the electronically controlled screen 52 to adjust the water pressure inside the cylinder 2 to 1 MPa, the ultrasonic emission frequency to 2 MHz, and the potential difference between the two side panels to 500 V.

[0042] Step 5: Open the openable drain port 21 to start the test. It is observed that the water flow permeability coefficient on the electronically controlled screen is stable at 3.1×10 -4 m / s, the ultrasonic velocity is maintained at around 1.9km / s, and the resistivity fluctuates in a very small range of around 300Ω·cm, indicating that after the epoxy resin fills the cracks, the cracks have a strong resistance to water flow and basically no leakage occurs. Compared with concrete with through cracks (ultrasonic velocity is less than 0.2km / s), the ultrasonic velocity is significantly increased, indicating that the deep cracks are also effectively filled; the resistivity is greatly improved compared to the resistivity of uncracked concrete (around 100Ω·cm), which is because epoxy resin is a good insulating material. This also proves that epoxy resin is not compatible with concrete matrix and there are differences in material properties. Overall, the crack repair effect is significant.

[0043] Step 6, close the water outlet 21, and adjust the ultrasonic emission frequency and potential difference of the two test panels 3 to 0, control the test panels 3 to move to both sides, take out the water carrying box, and find that there is basically no infiltrated water flow in it. Rotate the disassembly thread to remove the cylinder, pour out the excess water, clean the mesh specimen support box, and end the test.

[0044] Embodiment 3

[0045] This embodiment provides a detection method of the above-mentioned crack repair degree detection system of the cracked concrete specimen, comprising the following steps:

[0046] Step 1: Place the specimen whose crack is repaired by microbial self-repairing method on the mesh specimen support box 41. The crack of the specimen is 1 mm wide before repair. The specimen size is 100 mm × 100 mm × 400 mm. The specimen is located between two test panels 3, with the 100 mm × 400 mm side of the specimen facing the panel.

[0047] Step 2, close the water outlet 21 and add water into the cylinder 2 to 2 / 3 of the cylinder volume. After adding water, install the cylinder 2 on the lifting device, and adjust the lifting device so that the bottom of the cylinder 2 abuts against and is in close contact with the upper end surface of the test piece.

[0048] Step 3: Control the two test panels 3 to move and contact with the two side surfaces of the test piece, so that the ultrasonic measuring point probe 31 and the voltage transmitting probe 32 are in close contact with the side surfaces of the test piece.

[0049] Step 4: Use the electronically controlled screen 52 to adjust the water pressure inside the cylinder 2 to 0.5 MPa, the ultrasonic emission frequency to 1 MHz, and the potential difference between the two side panels to 500 V.

[0050] Step 5: Open the openable drain port 21 to start the test. It is observed that the water flow permeability coefficient on the electronically controlled screen is stable at 8.2×10 -4 m / s, the ultrasonic velocity is maintained at around 1.7km / s, and the resistivity fluctuates in a very small range of about 90Ω·cm, indicating that after the microbial mineralization fills the cracks, the cracks' resistance to water flow is significantly improved, and basically no leakage occurs. Compared with concrete with through cracks (ultrasonic velocity is less than 0.2km / s), the ultrasonic velocity is significantly increased, indicating that the deep cracks are also effectively filled; the resistivity is slightly lower than that of uncracked concrete (about 100Ω·cm), which is because the microbial mineralization material is mainly composed of calcium carbonate, which proves that the mineralization product has good compatibility with the concrete matrix, and the material properties are not much different. In general, the cracks are effectively filled and the leakage phenomenon is significantly improved.

[0051] Step 6, close the water outlet 21, and adjust the ultrasonic emission frequency and potential difference of the two test panels 3 to 0, control the test panels 3 to move to both sides, take out the water carrying box, and find that there is basically no infiltrated water flow in it. Rotate the disassembly thread to remove the cylinder, pour out the excess water, clean the mesh specimen support box, and end the test.

[0052] The present invention sets up a crack anti-seepage ability testing system and an array ultrasonic and resistivity testing system, uses water flow impact to test the resistance of the repair material to the external water pressure, uses array ultrasonic and resistivity to evaluate the deep and internal repair effects of the cracks, and makes a multi-dimensional and comprehensive evaluation of the crack sealing effect based on the anti-seepage ability of the specimen after the crack repair, the ultrasonic propagation speed inside the specimen, and the resistivity on both sides of the crack of the specimen. The operation is simple, the integration is high, and the accuracy of the repair test results is improved.

Claims

1. A system for detecting the degree of crack repair of cracked concrete specimens, characterized in that: It includes a frame system, a crack anti-seepage capacity test system, an array ultrasonic and resistivity test system, a water collection and drainage system, and an electric control system. The water collection and drainage system is installed at the bottom of the frame system to support the tested piece and collect water from the test piece. The electric control system is used to control the crack anti-seepage capacity test system and the array ultrasonic and resistivity test system and monitor and process the data measured by the crack anti-seepage capacity test system and the array ultrasonic and resistivity test system. The crack impermeability test system comprises a lifting device and a cylinder (2), wherein the lifting device is mounted on a frame system, and the cylinder (2) is detachably mounted on the lifting device. A booster piston (22) and a water level pressure test sensor (23) are arranged inside the cylinder (2), and the water pressure in the cylinder is regulated by adjusting the position of the booster piston (22); a water inlet (28) is arranged at the top of the cylinder (2), and a water outlet (21) is arranged at the bottom of the cylinder (2), and the opening and closing of the water outlet (21) is controlled by an electronic control system; The array type ultrasonic wave and resistivity testing system comprises two test panels (3) arranged in parallel, wherein the test panels (3) are movably mounted on a frame system, and ultrasonic measuring point probes (31) and voltage transmitting probes (32) are arranged on two opposite surfaces of the test panels (3).

2. The detection system according to claim 1, characterized in that: The frame system comprises a support frame (1), the upper part of the support frame (1) is provided with a slot (11) for installing a lifting device, and the lower part of the support frame (1) is provided with an opening (12) for installing an array type ultrasonic and resistivity testing system.

3. The detection system according to claim 2, characterized in that: The lifting device comprises a lifting suspension plate (25), a lifting adjustment knob (26) installed on the supporting frame (1), and pulleys (27) installed at both ends of the lifting suspension plate (25). The lifting adjustment knob (26) and the pulley (27) are connected through a steel strand (29). The lifting adjustment knob (26) is rotated to control the pulley (27) to slide up and down in the slot (11).

4. The detection system according to claim 3, characterized in that: The lifting suspension plate (25) has a mounting hole in the middle thereof that matches the cross section of the cylinder (2). An internal thread (24) is provided in the mounting hole, and an external thread is provided on the outside of the cylinder (2). The cylinder (2) can be detachably mounted by means of thread matching.

5. The detection system according to claim 2, characterized in that: The array type ultrasonic wave and resistivity testing system further comprises a slide bar (33) and a movable support member (34) sleeved and mounted on the slide bar (33); round holes are opened on both sides of the test panel (3); both ends of the slide bar (33) are installed in the openings (12), and the slide bar (33) passes through the round holes on the test panel (3); the movable support member (34) abuts against both sides of the test panel (3) to support the test panel (3), and a roller is provided on the inner side of the movable support member (34) to drive the test panel (3) to move along the slide bar (33), and the roller is controlled by an electric control system.

6. The detection system according to claim 5, characterized in that: The movable support member (34) is made of rubber.

7. The detection system according to claim 1, characterized in that: The water collection and drainage system comprises a mesh specimen support box (41), a water carrying box (42), and an asbestos net (43); the top of the mesh specimen support box (41) is in the shape of a hollow grid, the interior is hollow and the sides are open; the water carrying box (42) is installed in the mesh specimen support box (41) in a drawer-like manner; and the asbestos net (43) is laid on the top of the mesh specimen support box (41).

8. The detection system according to claim 1, characterized in that: The test panel (3) is provided with four rows of ultrasonic measuring point probes (31) arranged in a 1×2 pattern and one row of voltage transmitting probes (32) arranged in a 1×2 pattern. The four rows of ultrasonic measuring point probes (31) are arranged in groups of two on both sides of the voltage transmitting probes (32).

9. The detection system according to claim 1, characterized in that: The electric control system comprises a transmission wire (51) and an electric control screen (52); the transmission wire (51) is used for connecting and transmitting data between the crack impermeability test system, the array ultrasonic wave and resistivity test system and the electric control system; and the electric control screen (52) is used for controlling the test system and monitoring and processing data.

10. A detection method of the detection system according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1, placing the test piece (6) on the water collection and drainage system, and making the test piece (6) between two test panels (3); Step 2, closing the water outlet (21) and adding water into the cylinder (2), after adding water, installing the cylinder (2) on the lifting device, and adjusting the lifting device so that the bottom of the cylinder (2) is in contact with the upper end surface of the test piece (6); Step 3, controlling the two test panels (3) to move and to abut against two side surfaces of the test piece (6); Step 4: setting the internal water pressure of the cylinder (2), the ultrasonic emission frequency, and the potential difference of the panels on both sides through the electronic control system; Step 5, opening the openable drain port (21) to start the test, observing the changes in key indicator parameters on the electronic control screen, the parameters including water flow permeability, ultrasonic velocity, and resistivity, and analyzing the crack repair effect of the test piece based on the parameters; Step 6: close the water outlet (21), adjust the ultrasonic emission frequency and potential difference of the two test panels (3) to 0, control the test panels (3) to move to both sides, remove the cylinder (2), and end the test.

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