SMA tensioning-based crack treatment device and use method therefof

Abstract

Disclosed in the present application are an SMA tensioning-based crack treatment device and the use method thereof. The crack treatment device comprises crack-restraining strips and connection rings, and both ends of each crack-restraining strip in the length direction are each provided with a connection ring, connection members being provided on the connection rings, and the crack-restraining strips being made of an iron-based shape memory alloy. The use method thereof comprises: S1: calculating a cracking load of a concrete component; S2: determining the cross-sectional area of each crack-restraining strip and the magnitude of a recovery load; S3: determining the mounting positions of the crack-restraining strips along the direction of the crack, with both ends of each crack-restraining strip straddling the crack on the two sides thereof; S4: according to the determined positions of the crack-restraining strips, cutting grooves and drilling holes; S5: installing the crack-restraining strips in the grooves, and fixedly connecting the crack-restraining strips by using connection members, and coating an epoxy resin adhesive on the surfaces of the crack-restraining strips for curing; and S6: applying an electrical excitation to the crack-restraining strips. The present application has the effects of improving the quality of crack repair and preventing further cracking of cracks.

Description

Crack treatment device based on SMA tensioning and method of use thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of crack repair, and in particular to a crack treatment device based on shape memory alloy (SMA) tensioning and a method of use thereof. BACKGROUND

[0002] Traditional concrete will produce cracks after a long period of use or impact extrusion, and the existence of these cracks will affect the strength of the concrete structure, cause certain safety hazards and affect the aesthetics of the concrete structure surface, and therefore it is necessary to use certain treatment to fill and repair the cracks.

[0003] Traditional concrete crack treatment methods include surface sealing, injection, pressure grouting, and filling sealing. Surface sealing uses the capillary action of cracks to absorb low-viscosity and well-permeable repair glue; injection is to inject low-viscosity, high-strength crack repair glue into the crack cavity under pressure; pressure grouting is to press grouting material into the crack cavity under high pressure for a certain period of time; and filling sealing is to drill a U-shaped or V-shaped groove along the crack direction on the surface of the component, and then fill the crack with modified epoxy resin or elastic joint sealing material.

[0004] In view of the related art described above, the inventors believe that the traditional crack treatment method can repair cracks, but cannot limit the further development of cracks, resulting in poor repair effect. SUMMARY

[0005] In order to limit the further cracking of cracks and improve the repair effect of cracks, the present application provides a crack treatment device based on SMA tensioning and a method of use thereof.

[0006] In a first aspect, the present application provides a crack treatment device based on SMA tensioning, which adopts the following technical solution:

[0007] A crack treatment device based on SMA tensioning, comprising a plurality of crack limiting assemblies, each crack limiting assembly comprising a crack limiting band and a connecting ring, one connecting ring being arranged at each end of the crack limiting band in the length direction, a connecting member being arranged on the connecting ring, and the crack limiting band being made of an iron-based memory alloy.

[0008] By adopting the above technical solution, the two ends of the crack limiting band are installed on the concrete on both sides of the crack by the connecting member, the crack limiting band is energized, the length of the crack limiting band is shortened and has prestress, the crack limiting band pulls the concrete structure on both sides of the crack, and the further expansion of the crack is reduced. Through the mutual cooperation of the crack limiting assembly and the connecting member, the crack repair quality is improved and the further cracking of the crack is prevented.

[0009] Optionally, the surface of the crack limiting zone is provided with an epoxy resin protective layer.

[0010] By adopting the technical scheme, the epoxy resin protective layer improves the structural strength of the crack limiting zone and reduces the possibility of rusting due to moisture on the surface of the crack limiting zone.

[0011] Optionally, the connecting member comprises a high-strength bolt and a fastening nut, the high-strength bolt passes through the connecting ring, and the fastening nut is threadedly connected to the high-strength bolt and abuts against the top surface of the connecting ring.

[0012] By adopting the technical scheme, the high-strength bolt is connected to the concrete structure, and the fastening nut abuts against the connecting ring, thereby achieving positioning of the crack limiting zone.

[0013] Optionally, the high-strength bolt is hollow, a communication inclined hole is formed in the high-strength bolt, the communication inclined hole is in communication with the inner cavity of the high-strength bolt, a stay is arranged in the inner cavity of the high-strength bolt, the bottom end of the stay is connected with a connecting block, the edge of the connecting block is connected with a plurality of insertion strips in the circumferential direction, the plurality of insertion strips are arranged in one-to-one correspondence with the plurality of communication inclined holes, one end of the insertion strip is inserted into the communication inclined hole, an abutting ratchet is arranged on the inner wall of the high-strength connecting bolt along the length direction, the stay is connected with an abutting piece, the abutting piece is arranged obliquely downward, the abutting piece abuts between adjacent teeth of the abutting ratchet, and the abutting piece is made of an elastic material.

[0014] By adopting the technical scheme, after the high-strength bolt is installed in the slot hole, the insertion strip on the connecting block is pulled out of the communication inclined hole and inserted into the surrounding structure, thereby improving the connection strength of the high-strength bolt. The abutting piece abuts against the abutting ratchet, thereby achieving one-way positioning of the abutting piece.

[0015] In a second aspect, the application provides a use method of a crack treatment device based on SMA tensioning, which adopts the following technical scheme:

[0016] A use method of a crack treatment device based on SMA tensioning, comprising the following steps:

[0017] S1: calculating the cracking load of a concrete member according to the design specification;

[0018] S2: determining the cross section of the crack limiting zone and the restoring load size according to the cracking load of the concrete member;

[0019] S3: determining the installation position of the crack limiting zone along the crack direction according to the crack size and length, and respectively arranging the two ends of the crack limiting zone on the two sides of the crack.

[0020] S4: slot drilling according to the determined crack-limiting zone position;

[0021] S5: installing the crack-limiting zone according to the slot position, fixing and connecting the two ends of the crack-limiting zone using the connecting piece, and coating epoxy resin adhesive on the surface of the crack-limiting zone for curing;

[0022] S6: energizing the crack-limiting zone to generate prestress, and simultaneously pulling and fixing the structure at both ends thereof.

[0023] Optionally, the method further comprises the following steps: cleaning the floating dust in the cracks and the slot holes obtained in the S4 step.

[0024] By using the above technical solution, the floating dust in the slot holes is cleaned, and the possibility of affecting the connection strength of the crack-limiting zone by the floating dust is reduced.

[0025] Optionally, the method further comprises the following steps: the setting direction of the crack-limiting zone is perpendicular to the direction of the cracks, and the interval between adjacent crack-limiting zones is greater than the width of the crack-limiting zone.

[0026] By using the above technical solution, since the length of the crack-limiting zone is perpendicular to the length direction of the cracks, the crack-limiting zone can directly pull the concrete on both sides of the cracks, which helps to improve the anti-cracking effect of the crack-limiting zone on the cracks.

[0027] Optionally, the method further comprises the following steps: after energizing the crack-limiting zone, the slot position of the crack-limiting zone is plugged and smoothed using the epoxy resin adhesive, and after the epoxy resin adhesive is cured, the surface of the wall body is subjected to surface sealing treatment.

[0028] By using the above technical solution, the surface of the concrete is subjected to sealing treatment, and the crack-limiting zone is protected, thereby reducing the possibility of moisture corrosion of the surface of the crack-limiting zone.

[0029] In summary, the present application has at least one of the following beneficial technical effects:

[0030] 1. By the mutual cooperation of the crack-limiting assembly and the connecting piece, the crack repair quality is improved, and the further cracking of the cracks is prevented.

[0031] 2. The setting of the plug-in strip improves the connection strength of the high-strength bolt, and improves the connection strength of the high-strength bolt and the concrete structure.

[0032] 3. The surface of the concrete is subjected to sealing treatment, and the crack-limiting zone is protected, thereby reducing the possibility of moisture corrosion of the surface of the crack-limiting zone. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 is a structural schematic diagram of a crack treatment device based on SMA tension according to an embodiment of the present application.

[0034] Fig. 2 is a partial sectional view of a position where a crack limiting band is installed according to an embodiment of the present application.

[0035] Fig. 3 is a structural schematic diagram of a crack treatment device based on SMA tension according to an embodiment of the present application.

[0036] Fig. 4 is a partial sectional view of a connecting member according to an embodiment of the present application.

[0037] Fig. 5 is a partial sectional view of an internal structure of a high-strength bolt according to an embodiment of the present application.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0039] The present application will be further described in detail below with reference to Figs. 1-5. The present application provides a crack treatment device based on SMA tension and a method of using the same, which has the effects of improving crack repair quality and preventing further cracking of cracks.

[0040] Embodiment 1

[0041] Referring to Figs. 1 and 2, a crack treatment device based on SMA tension includes a crack limiting band 1 and connecting rings 2, one of which is provided at each end of the crack limiting band 1. The crack limiting band 1 is made of an iron-based memory alloy, and an epoxy resin protective layer 3 is provided on a surface of the crack limiting band 1, the thickness of the epoxy resin protective layer 3 being not less than 5 mm. When the crack limiting band 1 is connected, the connecting rings 2 at both ends of the crack limiting band 1 are adhesively connected to a concrete structure by means of an epoxy resin adhesive.

[0042] Embodiment 2

[0043] Referring to Figures 3-5, the difference between Embodiment 2 and Embodiment 1 is that a connecting member for connecting with concrete is arranged on each connecting ring 2, the connecting member comprising a high-strength bolt 4 and a fastening nut 11. The high-strength bolt 4 passes through the connecting ring 2, the high-strength bolt 4 is hollowly arranged, and the fastening nut 11 is threadedly connected to the high-strength bolt 4 and is arranged in abutment with the top surface of the crack-limiting zone 1. A plurality of communicating inclined holes 41 are formed in the peripheral wall of the high-strength bolt 4 in a circumferential direction, and the plurality of communicating inclined holes 41 are arranged in communication with the inner cavity of the high-strength bolt 4. A tension bar 5 is arranged in the high-strength bolt 4 along the length direction of the high-strength bolt 4, the top end of the tension bar 5 extends out of the inner cavity of the high-strength bolt 4 and is connected with a pull ring 8, and the bottom end of the tension bar 5 is connected with a connecting block 6. A plurality of insertion strips 7 are fixedly connected to the connecting block 6 in a circumferential direction, the ends of the plurality of insertion strips 7 away from the connecting block 6 extend upwardly and are arranged in one-to-one correspondence with the plurality of communicating inclined holes 41, and the ends of the insertion strips 7 are inserted into the communicating inclined holes 41. An abutting ratchet 10 is fixedly connected to the inner ring wall of the high-strength bolt 4 along the length direction of the high-strength bolt 4, and an abutting piece 9 is connected to the tension bar 5, the end of the abutting piece 9 away from the tension bar 5 extends downwardly and is arranged in abutment between two adjacent teeth of the abutting ratchet 10. The tension bar 5, the connecting block 6, the insertion strips 7, the connecting block 6 and the abutting piece 9 are made of elastic PVC material.

[0044] Referring to Figures 4 and 5, when the crack-limiting zone 1 is connected with the concrete structure, a hole is drilled at a suitable position on the concrete structure and the dust in the hole is cleaned, a chemical agent is put into the hole, and the chemical agent is mixed from substances such as vertical ethylene, quartz particles and curing agent. The bottom end of the high-strength bolt 4 is inserted into the hole by screwing, the chemical agent in the hole is broken and naturally expands. The chemical agent is integrated with the concrete structure under the extrusion of the high-strength bolt 4 to achieve high-strength anchoring effect. After the connection of the high-strength bolt 4 is completed, the tension bar 5 is pulled outwards through the pull ring 8, the insertion strips 7 pass out of the connecting inclined holes and are inserted into the chemical agent mixture, and the connection strength of the high-strength bolt 4 is further improved. The abutting piece 9 is in abutment with two adjacent teeth of the abutting ratchet 10 to achieve one-way positioning of the tension bar 5, and the possibility of the insertion strips 7 retracting into the high-strength bolt 4 is reduced.

[0045] Referring to Figures 1 and 3, a method for using the crack processing device based on SMA tensioning, comprising the following steps: when repairing the crack, the cracking load of the concrete member is calculated according to the “Code for Design of Concrete Structures GB50010-2010”. The cross-sectional area of the crack-limiting zone 1 and the size of the recovery load are determined according to the cracking load, and the cross section of the crack-limiting zone 1 in the application can be designed into various shapes such as circular, square or oval according to needs. The tensile force calculation formula of the memory alloy is: F=n*S*σ (n is the number of SMA crack-limiting zones 1, S is the cross-sectional area of the SMA crack-limiting zone 1, and σ is the recovery coefficient of the deformation of the iron-based memory alloy material).

[0046] Referring to FIG. 1, FIG. 2 and FIG. 4, the position of the crack limiting band 1 is determined along the direction of the crack according to the size and length of the crack, and the direction of the crack limiting band 1 is kept perpendicular to the direction of the crack. The interval between adjacent crack limiting bands 1 is at least the width of one crack limiting band 1. The slotting is performed according to the determined position of the crack limiting band 1, and the shape of the slotting is arranged corresponding to the shape of the crack limiting band 1 to clean the floating dust in the crack and the slotting of the crack limiting band 1. The bottom surface of the crack limiting band 1 is coated with epoxy resin adhesive, and the crack limiting band 1 is placed in the slotting position of the crack limiting band 1, and the connecting ring 2 at both ends is connected to the concrete structure. The slotting position of the crack limiting band 1 is sealed and smoothed using epoxy resin adhesive and is cured to ensure that the thickness of the epoxy resin protective layer 3 on the surface of the crack limiting band 1 is not less than 5 mm, and a hole for energizing the crack limiting band 1 is reserved on the epoxy resin protective layer 3.

[0047] Referring to FIG. 1 and FIG. 3, after the connection of the crack limiting band 1 is completed, the crack limiting band 1 is energized to generate prestress, and the concrete structure on both sides of the crack is pulled to help prevent further cracking of the crack. Since the iron-based memory alloy has a one-way memory effect, it can continuously pull the structure on both sides of the crack. Since the crack limiting band 1 is kept perpendicular to the direction of the crack, the prestress of the crack limiting band 1 can be maximally applied to the concrete on both sides of the crack, reducing the possibility of further cracking of the crack. The surface of the concrete is closed treated, and the surface layer of the concrete is provided with a closed treatment layer 12 to protect the crack limiting band 1 and avoid rusting of the crack limiting band 1 due to moisture.

[0048] The implementation principle of the crack treatment device based on SMA tensioning and the use method thereof in the embodiment of the application is that the crack limiting band 1 made of iron-based memory alloy is connected to the concrete structure on both sides of the crack, and the crack limiting band 1 is energized, the length of the crack limiting band 1 is shortened, and the concrete at both ends is continuously pulled to prevent further cracking of the crack.

[0049] The above are preferred embodiments of the application, which do not limit the protection scope of the application, so that: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A SMA tensioning based crack treatment device, characterized by: The application relates to a crack-limiting assembly, which comprises a crack-limiting band (1) and connecting rings (2) arranged at both ends of the crack-limiting band (1) in the length direction of the crack-limiting band (1), and connecting members arranged on the connecting rings (2), wherein the crack-limiting band (1) is made of an iron-based memory alloy.

2. A crack treatment device based on SMA tensioning according to claim 1, characterized in that: The crack-limiting band (1) is provided with an epoxy resin protective layer (3) on the surface.

3. A crack treatment device based on SMA tensioning according to claim 2, characterized in that: The connecting members comprise high-strength bolts (4) and fastening nuts (11), the high-strength bolts (4) pass through the connecting rings (2), and the fastening nuts (11) are screwed on the high-strength bolts (4) and abut against the top surface of the connecting rings (2).

4. A crack treatment device based on SMA tensioning according to claim 3, characterized in that: The high-strength bolt (4) is hollow, the high-strength bolt (4) is provided with a communication inclined hole (41) which is in communication with the inner cavity of the high-strength bolt (4), a stay (5) is arranged in the inner cavity of the high-strength bolt (4), the bottom end of the stay (5) is connected with a connecting block (6), the edge of the connecting block (6) is connected with a plurality of insertion strips (7) in the circumferential direction, the plurality of insertion strips (7) are arranged in one-to-one correspondence with the plurality of communication inclined holes (41), one end of the insertion strip (7) is inserted into the communication inclined hole, the inner wall of the high-strength bolt is provided with abutting ratchet teeth (10) in the length direction, the stay (5) is connected with an abutting piece (9), the abutting piece (9) is arranged in an inclined downward manner, the abutting piece (9) abuts between adjacent teeth of the abutting ratchet teeth (10), and the abutting piece (9) is made of an elastic material.

5. A method of using a crack treatment device based on SMA tensioning according to claim 2, characterized in that: The application further comprises the following steps: S1: calculating the cracking load of the concrete component according to the design specification; S2: determining the cross section of the crack-limiting band (1) and the restoring load according to the cracking load of the concrete component; S3: determining the installation position of the crack-limiting band (1) along the crack direction according to the crack size and length, and arranging the two ends of the crack-limiting band (1) on the two sides of the crack in a straddling manner; S4: slotting and drilling according to the determined position of the crack-limiting band (1); S5: installing the crack-limiting band (1) according to the slotting position, fixing and connecting the two ends of the crack-limiting band (1) by using the connecting members, and coating epoxy resin adhesive on the surface of the crack-limiting band (1) for curing; S6: energizing the crack-limiting band (1) to generate prestress, and simultaneously pulling and fixing the structure at the two ends of the crack-limiting band (1).

6. A method of use of a crack treatment device based on SMA tensioning according to claim 5, characterized in that: The application further comprises the following steps: Cleaning the floating dust in the cracks and the slot holes obtained in the step S4.

7. A method of using a SMA tension-based crack treatment device according to claim 5, characterized in that: The application further comprises the following steps: The arrangement direction of the crack-limiting band (1) is perpendicular to the direction of the crack, and the interval between the adjacent crack-limiting bands (1) is greater than the width of the crack-limiting band (1).

8. A method of using a SMA tension-based crack treatment device according to claim 5, characterized in that: The application further comprises the following steps: After the crack-limiting band (1) is energized, the slotting position of the crack-limiting band (1) is blocked and smoothed by using the epoxy resin adhesive, and after the epoxy resin adhesive is cured, the surface of the wall body is subjected to surface sealing treatment.

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