Concrete pier column prestress active constraint and cathode protection integrated device and method

Abstract

The invention provides a concrete pier column prestress active constraint and cathode protection integrated device and method.The device comprises a shape memory alloy, an external power source and outer wrapping mortar, the shape memory alloy is wound around the circumference of a concrete pier column, and the outer wrapping mortar is used for wrapping the shape memory alloy; when the concrete pier column is reinforced, a temporary power source is communicated with the two ends of the pre-deformed shape memory alloy to form a structure prestress constraint reinforcing system, the shape memory alloy is subjected to electric heat excitation to generate restoring force, and therefore the repairing effect of prestress active constraint is generated on the concrete pier column. When anti-corrosion operation is carried out on the concrete pier column, the positive electrode of an external power source is connected with the shape memory alloy serving as an auxiliary anode, the negative electrode of the external power source is connected with a plurality of steel bars in the concrete pier column serving as a cathode to form an impressed current cathode protection system, and protection current flows out of the shape memory alloy; and reaching the surface of the reinforcing steel bar through the inorganic cementing material and the concrete, thereby inhibiting and eliminating the corrosion of the reinforcing steel bar.

Description

Technical Field

[0001] The invention relates to the technical field of structural reinforcement and anti-corrosion of concrete piers, and in particular to a device and method for integrating prestressed active restraint and cathode protection of concrete piers. Background Art

[0002] The main hazard to the durability of reinforced concrete structures is the corrosion of internal steel bars. Chloride ions carried by the concrete itself or chloride ions that penetrate from the outside are considered to be the main cause of steel bar corrosion. This corrosion will cause the mechanical properties of the concrete structure to continue to decay, posing a potential risk to the safety of the structure. Therefore, preventing steel bar corrosion in concrete structures is an effective way to ensure the durability and safety of concrete structures.

[0003] At present, there are two main ways to treat concrete steel bar corrosion. One is to use structural reinforcement methods to improve structural performance so that it meets the requirements of structural performance indicators; the other is to prevent further corrosion of the steel bars by adopting anti-rust measures so that the structural performance will no longer be attenuated by corrosion.

[0004] However, although structural reinforcement methods can improve the short-term mechanical properties of the structure, they still cannot prevent the corrosion process of the steel bars, which in turn threatens the long-term mechanical properties of the structure. On the other hand, rust prevention measures for piers, such as impressed current cathodic protection, can effectively inhibit the corrosion of steel bars, but cannot restore and improve the bearing capacity of the structure. Currently, the commonly used concrete pier reinforcement technology can only play a passive restraint repair effect, and it is difficult to achieve active restraint. It cannot inhibit the damage and crack development inside the concrete, and the reinforcement material has a lag in force.

[0005] In addition, the two management approaches of prestressed active restraint and steel bar corrosion protection belong to different disciplines and are difficult to achieve in a coordinated manner, that is, to simultaneously achieve the management effects of improving the structural performance of concrete piers and inhibiting steel bar corrosion. Summary of the invention

[0006] The content of the present invention is used to introduce the concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of the present disclosure is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0007] Some embodiments of the present invention provide an integrated device and method for active prestressing restraint and cathodic protection of concrete piers to solve the technical problems mentioned in the above background technology section.

[0008] In the first aspect, some embodiments of the present invention provide an integrated device for prestressed active restraint and cathodic protection of a concrete pier, the device comprising a shape memory alloy, an external power supply and an outer mortar, wherein the shape memory alloy is wrapped around the circumference of the concrete pier after pre-stretching and deformation, and the outer mortar is used to wrap the shape memory alloy; when reinforcing the concrete pier, a temporary power supply is connected to both ends of the shape memory alloy to form a structural prestressed restraint reinforcement system, and the shape memory alloy is thermally excited to generate prestress; when the concrete pier is subjected to an impressed current cathodic protection anti-corrosion operation, the positive pole of the external power supply is connected to the shape memory alloy, and the negative pole of the external power supply is connected to a plurality of steel bars to form an impressed current cathodic protection system.

[0009] In the second aspect, some embodiments of the present invention provide a method for the above-mentioned integrated device of prestressed active constraint and cathodic protection of concrete piers, the method comprising winding a pre-stretched and deformed shape memory alloy around the circumference of a concrete pier; wrapping the shape memory alloy with an external mortar so that the shape memory alloy is connected to the concrete pier; connecting the positive and negative poles of a temporary power source to the two ends of the shape memory alloy to form a structural prestressed active constraint reinforcement system, performing a thermal excitation operation on the shape memory alloy so that the shape memory alloy generates prestressed constraint on the concrete pier to complete the reinforcement operation; connecting the positive pole of the external power source to the shape memory alloy, and connecting the negative pole of the external power source to the steel bars inside the concrete to form an impressed current cathodic protection system, and performing an electrochemical anti-corrosion operation on the steel bars by an impressed current.

[0010] The above-mentioned embodiments of the present invention have the following beneficial effects: the two treatment approaches of prestressed reinforcement and steel bar anti-corrosion belong to different technical fields, and the synergistic realization of the two has not been reported in any reports. The integrated device of active prestressed restraint and cathodic protection of concrete piers of the present invention integrates the active prestressed restraint reinforcement system of the structure and the impressed current cathodic protection system, thereby synergistically achieving the dual purposes of active prestressed restraint of concrete piers and electrochemical corrosion protection of steel bars.

[0011] Specifically, the shape memory alloy included in the device has the advantages of superelasticity, shape memory characteristics, corrosion resistance, high fatigue resistance and high strength. After being electrically thermally excited, it can stimulate the shape memory effect of the shape memory alloy to generate a restoring force, thereby causing the shape memory alloy to generate prestress on the concrete pier column. The shape memory alloy is wrapped with mortar to form a structural prestressed active constraint reinforcement system. Compared with the passive constraints of related reinforcement technologies, the shape memory alloy can achieve the reinforcement effect of actively constraining the concrete pier column, thereby improving the axial compressive bearing capacity, ductile deformation and energy dissipation capacity of the concrete pier column. At the same time, compared with traditional prestressed reinforcement methods, the prestressed active constraint method of the device is easy to construct and consumes less time and energy, and does not require cumbersome processes such as tensioning of other mechanical equipment.

[0012] In addition, when the concrete pier is subjected to corrosion protection, the positive pole of the external power supply is connected to the shape memory alloy as an auxiliary anode, and the negative pole of the external power supply is connected to the multiple steel bars in the concrete pier as the cathode to form an impressed current cathodic protection system. The protective current flows out from the shape memory alloy, passes through the outer mortar and concrete, and reaches the surface of the steel bar, thereby inhibiting and eliminating the corrosion of the steel bar to achieve an electrochemical protection effect, which can fundamentally inhibit the continued corrosion of the steel bar. In this way, based on the mechanics, memory effect and conductivity of the shape memory alloy, a structural prestressed active reinforcement system and an impressed current cathodic protection system are constructed, achieving an integrated reinforcement and anti-corrosion repair effect, which can synergistically achieve the dual purposes of active reinforcement of concrete piers and anti-corrosion of steel bars. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 It is a structural schematic diagram of an embodiment of the integrated device for active restraint and cathodic protection of prestressed concrete pier column of the present invention;

[0015] Figure 2 The flowcharts are of some embodiments of the method for integrating active restraint of prestressing force and cathodic protection of concrete piers according to the present invention.

[0016] Description of reference numerals:

[0017] 1: Concrete pier; 2: Shape memory alloy; 3: External mortar; 4: Steel bar; 5: External power supply; 61: Anode wire; 62: Main wire; 63: Branch wire. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0022] First see Figure 1 , Figure 1 FIG. 1 is a schematic structural diagram of an embodiment of the present invention's integrated device for active prestressing restraint and cathodic protection of concrete piers. Figure 1As shown, the device includes a shape memory alloy 2, an external power supply 5 and an outer mortar 3. After the shape memory alloy 2 is pre-stretched and deformed, it is wrapped around the outer wall circumference of the concrete pier 1. The outer mortar 3 is sprayed onto the shape memory alloy 2, so that the shape memory alloy 2 is connected to the outside of the concrete pier 1. Next, a temporary power supply can be used to connect the two ends of the shape memory alloy 2, and after power is turned on, the thermal excitation operation of the shape memory alloy 2 is realized, the shape memory effect of the shape memory alloy 2 is stimulated to generate a restoring force, and then the shape memory alloy 2 generates prestress on the concrete pier, thereby forming a structural prestressed active constraint reinforcement system. In this way, the shape memory alloy 2 can achieve the reinforcement effect of actively constraining the concrete pier 1, thereby improving the axial compressive bearing capacity of the concrete pier 1, inhibiting crack expansion, increasing structural toughness and ductility, and improving energy dissipation capacity. It should be noted that after completing the thermal excitation operation of the shape memory alloy 2, the temporary power supply is removed or disconnected.

[0023] It should be noted that the above-mentioned shape memory alloys include but are not limited to nickel-titanium alloys and nickel-titanium-niobium alloys. Those skilled in the art can select shape memory alloys such as nickel-titanium alloys and nickel-titanium-niobium alloys according to actual conditions. However, other shape memory alloys that have poor corrosion resistance at present but have sufficient corrosion resistance after improvement in the future are not excluded, such as iron-based shape memory alloys, and such changes do not exceed the scope of protection of the present invention.

[0024] When the concrete pier is subjected to impressed current cathodic protection anti-corrosion operation, the positive electrode of the external power source 5 can be connected to the shape memory alloy 2 as an auxiliary anode, and the negative electrode of the external power source 5 is connected to the multiple steel bars 4 in the concrete pier 1 as a cathode, thereby forming an impressed current cathodic protection system. The generated cathodic protection current flows out from the shape memory alloy, passes through the outer mortar 3 and the concrete pier 1, and reaches the surface of the steel bars 4. Thus, the corrosion of the steel bars 4 can be suppressed. It should be noted that since the shape memory alloy 2 has good electrical conductivity and corrosion resistance, it can serve as an auxiliary electrode for the cathodic protection current generated by the external power source 5.

[0025] Specifically, the positive electrode of the external power source 5 is connected to the shape memory alloy 2 through the anode wire 61. The negative electrode of the external power source 5 is connected to the multiple steel bars 4 through the main wire 62 and multiple branch wires 63. One end of the main wire 62 is connected to the negative electrode of the external power source 5, and the other end of the main wire 62 is connected to each of the multiple branch wires 63. The multiple branch wires 63 are connected to the multiple steel bars 4 one by one. The outer mortar 3 can be an inorganic binder material with conductive properties. Then the external power source 5, the shape memory alloy 2, the steel bars 4 and the outer mortar 3 form a loop. It should be noted that the inorganic binder material can be determined by those skilled in the art based on common knowledge or prior art.

[0026] Furthermore, the main conductor 62 and the plurality of branch conductors 63 may be connected via a connection assembly. As an example, the connection assembly may include but is not limited to a connection box and a terminal block. Those skilled in the art may select the connection assembly based on common knowledge or prior art.

[0027] Furthermore, the device may also include a control device, which is connected in series with the shape memory alloy 2 and the steel bar 4. The control device is used to adjust the current in the circuit. As an example, the control device may be a rheostat or a current regulator.

[0028] It should be noted that shape memory alloy (SMA) is a material composed of two or more metal elements, which realizes shape memory effect (SME) through thermoelasticity and martensitic phase transformation and its inversion. SMA has the advantages of superelasticity, shape memory characteristics, corrosion resistance, high fatigue resistance and high strength, and is widely used in aerospace, bridge construction, mechanical electronics, biomedicine and other fields. In the field of civil engineering, SMA materials have received more and more attention due to their excellent mechanical properties, and have achieved some applications, mainly focusing on the bending reinforcement of beams, the seismic reinforcement of columns and repositionable buckling braces. Among them, the most widely used is nickel-titanium shape memory alloy (NiTi-SMA). In addition, SMA also has good electrical conductivity and corrosion resistance. After sufficient research and careful demonstration, it can be used as an auxiliary electrode in the impressed current cathodic protection system of concrete structures. Based on the comprehensive utilization of SMA mechanics, memory effect and conductivity, a concrete pier column prestressed active constraint and cathodic protection integrated device can be proposed. This concept has not been reported in any report.

[0029] The present invention also provides a method for integrating active prestressing restraint and cathodic protection of concrete pier columns, which can be used in the integrated device for active prestressing restraint and cathodic protection of concrete pier columns in the above-mentioned embodiments. Figure 2As shown, it shows a flow chart 200 of an embodiment of the method for integrating active restraint and cathodic protection of prestressed concrete piers provided by the present invention. The method may include the following steps:

[0030] Step 201 , winding the pre-stretched and deformed shape memory alloy around the circumference of a concrete pier.

[0031] In some embodiments, the staff first performs a pre-stretching deformation operation on the shape memory alloy, and then winds the shape memory alloy around the circumference of the concrete pier in a variety of ways, such as by using a crane or a hoist.

[0032] Step 202: Wrapping the shape memory alloy with mortar to connect the shape memory alloy to the concrete pier.

[0033] In some embodiments, an outer coating mortar having conductive properties, such as a conductive inorganic binder material, is provided on the concrete pier of the wound shape memory alloy.

[0034] Step 203, connect the positive and negative electrodes of the temporary power supply to the two ends of the shape memory alloy to form a structural prestressed active restraint reinforcement system, perform thermal excitation operation on the shape memory alloy, so that the shape memory alloy generates prestressed restraint concrete piers, and completes the reinforcement operation.

[0035] In some embodiments, a temporary power source is connected to a shape memory alloy through a wire to form a structural prestressed active constraint reinforcement system. The temporary power source applies a preset current to the shape memory alloy, performs a thermal excitation operation on the shape memory alloy, excites the shape memory effect of the shape memory alloy to generate a restoring force, and then causes the shape memory alloy to generate prestress on the concrete pier column, thereby forming an active constraint on the concrete pier column. As an example, the preset current can be determined by a person skilled in the art based on repeated experiments or based on the parameters of the shape memory alloy. After completing the thermal excitation operation on the shape memory alloy 2, the temporary power source is removed or disconnected.

[0036] Step 204, connecting the positive electrode of the external power source to the shape memory alloy, and connecting the negative electrode of the external power source to the steel bars inside the concrete, to form an impressed current cathodic protection system, and performing electrochemical corrosion protection operation on the steel bars through impressed current.

[0037] In some embodiments, when the concrete pier is subjected to impressed current cathodic protection anti-corrosion operation, the external power supply can be connected to the shape memory alloy and multiple steel bars through the anode wire, the main wire and the branch wire respectively to form an impressed current cathodic protection system. Since the concrete pier is covered with an outer mortar having conductive properties, a passage is formed. Finally, the external power supply applies a preset current, which can inhibit the corrosion of the steel bars. The preset current can be determined by a person skilled in the art based on repeated experiments.

[0038] In addition, those skilled in the art can also determine the specifications of the shape memory alloy according to the specifications of the concrete pier. For example, when the diameter of the C35 concrete pier is 150 mm, a shape memory alloy with a diameter of 8 mm can be used for winding. After the thermal excitation of the shape memory alloy is completed, 8 mA / m can be passed during the anti-corrosion operation. 2 In this embodiment, the active constraint of the concrete column by the shape memory alloy can increase the axial bearing capacity of the concrete column by 15% and extend the service life of the concrete pier column by 20 years.

[0039] As another example, when the diameter of a C35 concrete pier is 200 mm, a shape memory alloy with a diameter of 10 mm can be used for winding. After the thermal excitation of the shape memory alloy is completed, a 12 mA / m 2 In this embodiment, the active constraint of the concrete column by the shape memory alloy can increase the axial bearing capacity of the concrete column by 20% and extend the service life of the system by 20 years.

[0040] As another example, when the diameter of a C35 concrete pier is 400 mm, a shape memory alloy with a diameter of 12 mm can be used for winding. After the thermal excitation of the shape memory alloy is completed, a 20 mA / m 2 In this embodiment, the active constraint of the concrete column by the shape memory alloy can increase the axial bearing capacity of the concrete column by 15% and extend the service life of the system by 15 years.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prestressed active restraint and cathodic protection integrated device for concrete piers, characterized in that: It includes shape memory alloy, external power supply and external mortar, wherein: The shape memory alloy is wrapped around the circumference of the concrete pier after pre-stretching and deformation, and the outer mortar is used to wrap the shape memory alloy; when reinforcing the concrete pier, a temporary power supply is connected to both ends of the shape memory alloy to form a structural prestressed active constraint reinforcement system, and the shape memory alloy is thermally excited to generate prestress; When the concrete pier is subjected to impressed current cathodic protection anti-corrosion operation, the positive electrode of the external power source is connected to the shape memory alloy, and the negative electrode of the external power source is connected to a plurality of steel bars to form an impressed current cathodic protection system.

2. The integrated device for active restraint and cathodic protection of prestressed concrete pier column according to claim 1, characterized in that: The outer mortar is an electrically conductive inorganic cementitious material.

3. The integrated device for active restraint and cathodic protection of prestressed concrete pier column according to claim 1, characterized in that: A main conductor and a plurality of branch conductors connected to the plurality of steel bars in one-to-one correspondence are connected between the negative pole of the external power source and the plurality of steel bars, and the main conductor is also connected to each of the branch conductors.

4. The integrated device for active restraint and cathodic protection of prestressed concrete pier column according to claim 3, characterized in that: The main conductor and the branch conductor are connected via a connecting component.

5. The integrated device for active restraint and cathodic protection of prestressed concrete pier column according to claim 3, characterized in that: The connection component includes one of the following: a connection box, a connection terminal.

6. The integrated device for active restraint and cathodic protection of prestressed concrete pier column according to claim 1, characterized in that: The device also includes a control device, which is connected in series with the shape memory alloy and a plurality of steel bars and is used to adjust the current during the anti-corrosion operation.

7. A method for the integrated device for active restraint and cathodic protection of prestressed concrete piers as claimed in any one of claims 1 to 6, the method comprising: Winding the pre-stretched and deformed shape memory alloy around the circumference of the concrete pier; Wrapping the shape memory alloy with mortar so that the shape memory alloy is connected to the concrete pier; Connect the positive and negative electrodes of the temporary power supply to the two ends of the shape memory alloy to form a structural prestressed active restraint reinforcement system, perform thermal excitation operation on the shape memory alloy, so that the shape memory alloy generates prestressed restraint concrete piers to complete the reinforcement operation; The positive electrode of the external power source is connected to the shape memory alloy, and the negative electrode of the external power source is connected to the steel bars inside the concrete to form an impressed current cathodic protection system, and the steel bars are electrochemically protected against corrosion by the impressed current.

Images