Smart Composite Reinforcing Bar

Abstract

The present invention relates to a smart composite reinforcing bar and a structural monitoring system using the same, characterized by comprising an elastic protective layer formed on the outer surface of the reinforcing bar, a GFRP (Glass Fiber Reinforced Plastic) composite layer formed on the outer side of the elastic protective layer, a sensor receiving channel formed inside the GFRP composite layer, and a smart sensor module disposed in the sensor receiving channel. The smart sensor module includes one or more of an FBG (Fiber Bragg Grating) fiber strain sensor, a corrosion detection sensor, a temperature sensor, and a humidity sensor to measure the strain, cracks, and corrosion status of the reinforcing bar in real time. Additionally, it is equipped with an RFID or NFC communication module to store manufacturing information, construction information, installation location, and maintenance history of the reinforcing bar, or to wirelessly transmit and receive such information to and from an external terminal. The sensor receiving channel is protected by a sealant to protect the sensor from the alkali components of concrete, moisture, and external impact, enabling stable measurement over a long period. Accordingly, the structural integrity can be monitored in real time, improving the efficiency and safety of maintenance. In particular, when applied to environments subject to vehicle collisions and repetitive vibrations, such as sound barrier foundations, it can extend the lifespan of structures and reduce maintenance costs.

Description

Technology Field

[0001] The present invention relates to a smart composite reinforcing bar having a self-diagnostic function equipped with an optical fiber and a corrosion sensor. Background Technology

[0003] Patent inventions 001 and 002 have a technical relationship with the present invention in that they are inventions that reinforce rebar by wrapping FRP around the outside of the core material. Patent invention 001 is similar to the present invention in that it is a fiber-reinforced composite reinforcing bar that contains a sensor, but the present invention does not include a technology that describes or contains the same or similar technical concept of forming a sensor in a segmented FRP sleeve that is provided on the rebar and partially covered on the reinforced part at the site. Prior art literature

[0004] (Patent Document 0001) KR 10-0709292 B1 (Registration Date April 12, 2007)(Patent Document 0002) KR 10-2554753 B1 (Registration Date July 7, 2023) The problem to be solved

[0005] The present invention aims to solve the problem that conventional rebar reinforcement systems cannot check the internal condition of a structure in real time, making it difficult to determine early whether corrosion, cracks, or deformation have occurred.

[0006] In addition, existing structural safety inspections rely on visual inspection or partial non-destructive testing, which makes it difficult to quickly detect early damage and results in the problem of requiring a significant amount of time and cost for inspections.

[0007] In particular, structures continuously exposed to vehicle collisions, repetitive vibrations, and salt-resistant environments, such as sound barrier foundations, may experience structural performance degradation due to the accumulation of rebar corrosion and microcracks; however, there is a lack of rebar reinforcement systems capable of detecting this in real time.

[0008] Accordingly, the present invention provides a smart composite reinforcing bar and a structural monitoring system using the same, which improves construction performance compared to conventional technology where reinforcing bars are manufactured in a factory by selectively reinforcing only specific stress areas such as the ends, anchorage areas, or salt damage sections of the reinforcing bar without wrapping the entire reinforcing bar at the site, and integrates a fiber optic strain sensor, a corrosion detection sensor, and an RFID or NFC-based information management module together with a protective structure on the outer surface or inside of the GFRP layer to monitor the strain, crack, and corrosion status of the structure in real time and efficiently manage maintenance information.

[0009] In addition, it protects the sensor from external impacts and the concrete pouring process, and enables stable measurements over a long period, thereby improving the safety of the structure and reducing maintenance costs. means of solving the problem

[0011] To solve the above problem, the present invention provides a smart composite reinforcing bar comprising a composite reinforcing layer formed on the outer surface of a reinforcing bar, a sensor accommodation channel formed inside the composite reinforcing layer or along the outer surface of the reinforcing bar, and one or more smart sensor modules disposed in the sensor accommodation channel.

[0012] The composite reinforcing layer of the present invention is formed of glass fiber reinforced composite (GFRP), and an elastic resin layer is further formed between the reinforcing bar and the GFRP layer to absorb external shocks and protect the sensor.

[0013] One or more of a fiber optic strain sensor (FBG), a corrosion detection sensor, a temperature sensor, or a humidity sensor may be placed in the sensor receiving channel, and data measured from the sensor is collected in real time to detect strain, cracks, corrosion status, and environmental changes of the structure.

[0014] In addition, the composite reinforcing bar is configured to be integrally equipped with an RFID or NFC module to store unique identification information, construction information, material information, maintenance history, and sensor data of the reinforcing bar, or to wirelessly transmit and receive them with an external terminal.

[0015] A protective channel and a waterproof sealing layer are formed on the outer surface or inside of the above GFRP layer to protect the sensor, thereby protecting the sensor from pressure, moisture, and alkaline environments generated during concrete pouring and enabling stable measurement for a long period of time.

[0016] In addition, sensor data can be transmitted to a structure management server or maintenance system via wired or wireless communication networks and utilized for real-time status diagnosis, anomaly detection alerts, and maintenance decision-making. Effects of the invention

[0018] The smart composite reinforcing bar according to the present invention does not wrap the entire reinforcing bar at the site, but selectively installs a GFRP sleeve at specific stress points such as both ends of the reinforcing bar, anchorage points, or salt damage sections, and integrates an elastic protective layer and a smart sensor module inside the sleeve, thereby having the following effects.

[0019] First, since strain, cracks, corrosion, and the surrounding environment inside the structure can be measured in real time through FBG fiber strain sensors, corrosion detection sensors, temperature sensors, and humidity sensors, abnormal signs in the structure can be detected early to prevent accidents.

[0020] Second, since the sensor is placed inside the sensor receiving channel and sealed by a protective structure, it can be protected from pressure, moisture, and alkaline environments during concrete pouring, ensuring long-term stable measurement performance and high reliability.

[0021] Third, since the open FRP sleeve allows for easy on-site installation without dismantling existing rebar, it offers excellent constructability and can reduce working time and costs for repair and reinforcement work.

[0022] Fourth, since low-viscosity resin is uniformly filled between the rebar and the FRP sleeve through the resin injection channel and resin flow channel formed inside the sleeve, the occurrence of bubbles and voids is prevented, and the adhesive strength and integrity of the rebar and GFRP composite layer are improved, thereby increasing reinforcement performance and durability.

[0023] Fifth, the elastic protective layer absorbs stresses caused by vehicle collisions, repetitive vibrations, and external impacts, thereby simultaneously protecting the rebar and sensors and reducing fatigue cracks, which has the effect of extending the service life of the structure.

[0024] Sixth, since manufacturing information, construction information, installation location, maintenance history, and sensor data of reinforcing bars can be stored or wirelessly transmitted and received through RFID or NFC communication modules, the efficiency of structural maintenance and asset management can be significantly improved.

[0025] Seventh, by linking sensor data with a structure management system, real-time remote monitoring, anomaly alerts, and maintenance decision-making can be performed; thus, compared to existing maintenance methods centered on visual and periodic inspections, the accuracy and speed of inspections can be improved and maintenance costs can be reduced.

[0026] Eighth, the smart composite reinforcing bar of the present invention can be applied to various concrete structures exposed to impact, repetitive loads, and salt-resistant environments, such as sound barrier foundations, bridges, tunnels, retaining walls, port facilities, and coastal structures, and has the effect of simultaneously improving the safety, durability, and maintainability of the structure. Brief explanation of the drawing

[0028] Figure 1 is an exploded view of a smart composite reinforcing bar. FIG. 2 is a perspective view of an FRP sleeve equipped with a sensor module. Figure 3 is a cross-sectional view of a smart composite reinforcement. Figure 4 is a conceptual diagram of sensor detection. Specific details for implementing the invention

[0029] Hereinafter, the most preferred embodiment of the present invention is described in detail to enable a person skilled in the art to easily practice the present invention. The configurations presented in the embodiments may be extended to objects that produce the same purpose and effect. Sub-concepts of the configurations presented in the embodiments may be considered implicit even if not explicitly stated.

[0030] The smart composite reinforcing bar (100) of the present invention includes a reinforcing bar (110), an elastic protective layer (120), a GFRP composite layer (130), a sensor receiving channel (140), a smart sensor module (150), and an RFID / NFC communication module (160), as shown in FIG. 1.

[0031] The reinforcing bar (110) can be an SD400 or SD500 deformed reinforcing bar, and the diameter can be configured in the range of D13 to D32.

[0032] The elastic protective layer (120) is formed by the resin spreading uniformly along the micro-space of 0.5 to 2 mm formed between the reinforcing bar and the GFRP composite layer (130).

[0033] The resin injected to form the elastic protective layer (120) is preferably composed of a low-viscosity epoxy with a viscosity of 400 to 900 cP so that it moves easily along between the reinforcing bar and the GFRP composite layer (130), penetrates between the reinforcing bars without gaps, reduces bubbles, improves adhesive strength, reduces fatigue cracks, and improves impact resistance.

[0034] Therefore, it is preferable that the injected resin consists of 70-85 weight% low-viscosity epoxy, 10-20 weight% amine-based curing agent, 3-8 weight% rubber-based reinforcing agent (Toughener), and 1-5 weight% silica.

[0035] This elastic protective layer protects the sensor and rebar by absorbing shocks generated during vehicle collisions or repeated vibrations.

[0036] A glass fiber reinforced composite GFRP layer (130) is formed on the outer side of the elastic protective layer.

[0037] The GFRP composite layer (130) may be composed of a pair of open FRP sleeves (200) having a semicircular cylindrical cross-sectional shape of '⊂''⊃'. The open FRP sleeves (200) are formed in a shape that is not a circular tube but a circular shape divided in half, and are formed to be locked when wrapped around a reinforcing bar, thereby enabling construction without dismantling the reinforcing bar.

[0038] At this time, one side of a pair of semicircular cylindrical sleeves of the open FRP sleeve (200) may be rotatably connected by a hinge (201), and the other side may have a locking part (202) formed so as to be connected after wrapping around a reinforcing bar. The locking part may be selected from known connection methods, but a groove may be formed on one side and a protrusion on the other side of each semicircular cylindrical sleeve of the open FRP sleeve (200) for fitting connection, or instead of a hinge, a groove or a protrusion may be formed on the end of the semicircular cylindrical sleeve and connected by fitting into the protrusion or groove on the end of the semicircular cylindrical sleeve on the other side.

[0039] In another embodiment, the groove and the protrusion may be formed with a repeating square or triangular shape so that one side and the other side can be fitted together like a puzzle.

[0040] When a semicircular cylindrical sleeve is formed by a bonding method in which the resin injected after being inserted hardens, the ease of construction is improved and the manufacturing cost of the open FRP sleeve (200) is reduced.

[0041] After the open FRP sleeve (200) is joined to surround the reinforcing bar, the resin forming the elastic protective layer (130) can be uniformly spread inside the FRP sleeve (200) through the resin injection channel (210) formed in the FRP sleeve (200).

[0042] The resin injected through the resin injection channel (210) can be formed into a microchannel so that it can spread uniformly inside the FRP sleeve (200) through the resin flow channel (220).

[0043] As the resin spreads uniformly inside the FRP sleeve (200) through the microchannels of the resin flow channel (220), no air remains between the FRP sleeve (200) and the reinforcing bar (100), and the reinforcing bar and the FRP sleeve (200) become one.

[0044] The resin flow channel (220) is formed to create a microspace of about 0.5 to 2 mm between the reinforcing bar and the FRP sleeve (200), so that the resin flows along the space.

[0045] The resin flow channel (220) can be formed in a spiral helical shape inside the FRP sleeve (200) to prevent bubbles or empty spaces from forming when the resin spreads between the reinforcing bar and the FRP sleeve (200).

[0046] Since the resin flow channel (220) is formed with fine irregularities in a spiral helical shape inside the FRP sleeve (200), the resin can move along the spiral groove and spread uniformly over the entire length, thereby increasing the mechanical bonding performance with the reinforcing bar, preventing the resin from slipping, and increasing the bonding surface area.

[0047] To this end, the resin flow channel (220) is preferably formed in a spiral or grid shape with a height of 0.3 to 1.0 mm.

[0048] At this time, in order to spread the resin more evenly throughout the entire interior of the FRP sleeve (200), it is preferable to form an air outlet (240) on the opposite side of the sleeve where the resin injection channel (210) is formed.

[0049] That is, resin is injected through the resin injection channel (210) formed in the FRP sleeve (200), fills the inside of the FRP sleeve (200) along the resin flow channel (220), and the air inside is discharged through the air outlet (240), so that the resin forming the elastic protective layer (130) is injected between the FRP sleeve (200) and the reinforcing bar, and the injected resin forms the elastic protective layer (130).

[0050] Inside the FRP sleeve (200), a sensor receiving channel (140) extending in the longitudinal direction is formed inside the GFRP composite layer. The sensor receiving channel is formed in a groove shape with a width of 2 to 4 mm and a depth of 2 to 3 mm, and a fiber optic sensor and a signal cable are received inside.

[0051] The smart sensor module (150) may include one or more sensors, preferably including one or more of an FBG (Fiber Bragg Grating) fiber strain sensor, a corrosion detection sensor, a temperature sensor, and a humidity sensor. The FBG sensor measures the strain of the rebar in real time, and the corrosion sensor detects a change in the potential of the rebar to determine whether corrosion has occurred.

[0052] An RFID / NFC communication module (160) is installed at the end of the composite reinforcing bar or at a location connected to a sensor receiving channel. The RFID module stores the manufacturing number, construction date, installation location, and maintenance history of the reinforcing bar, and the information can be checked on-site using a smartphone or portable terminal via the NFC module.

[0053] It is preferable that both ends of the FRP sleeve (200) be sealed with packing. By sealing both ends of the FRP sleeve (200) with packing (300), the movement of resin and the discharge of air can be made more smooth.

[0054] The packing may be made of a closed circular material having elasticity and installed in advance before the FRP sleeve (200) is joined to the reinforcing bar and then joined to seal both ends of the FRP sleeve (200), or it may be provided as a tape-shaped packing material having elasticity and installed after the FRP sleeve (200) is joined to the reinforcing bar.

[0055] The FRP sleeve (200) is preferably made of glass fiber and vinyl ester resin so that it has a relatively similar elastic modulus to that of reinforcing steel, does not corrode, and has an electrically insulating effect.

[0056] In particular, to selectively reinforce specific stress zones on-site, such as in sound barriers, and to provide a shock-absorbing layer, using vinyl ester rather than epoxy is advantageous in terms of flame and water resistance and crack resistance, and can provide sufficient performance in environments such as those involving de-icing agents in winter.

[0057] Therefore, the FRP sleeve (200) is preferably made of glass fiber reinforced plastics (hereinafter referred to as GFRP) having a vinyl ester resin as a matrix and containing E-Glass fibers or AR-Glass fibers, and is composed of 65-75 weight% glass fibers, 23-33 weight% vinyl ester resin, and 2-5 weight% additives.

[0058] The protective coating layer (170) is formed from a fluoropolymer or UV blocking coating to protect the GFRP layer from the external environment.

[0059] The smart composite reinforcing bar of the present invention is embedded within the concrete foundation of a sound barrier. When a vehicle collision or repetitive vibration occurs, an FBG sensor measures strain in real time, and a corrosion sensor detects the corrosion status of the reinforcing bar. The measured data is transmitted to a structural management system via RFID or a separate wireless communication device, allowing the manager to check the structural integrity in real time.

[0060] With such a configuration, the present invention can detect corrosion, deformation, and cracking of reinforcing bars in real time, and can improve the safety of structures and reduce maintenance costs compared to conventional visual inspections or periodic inspections. Explanation of the symbols

[0062] 100 : Smart composite reinforcement 110 : Rebar 120: Elastic protective layer 130: GFRP composite layer 140 : Sensor reception channel 150 : Smart sensor module 160: RFID / NFC communication module 210: Resin injection channel 220 : Resin flow channel 240 : Air outlet 300 : Packing

Claims

Claim 1 Reinforcement bar (110); The apparatus comprises an elastic protective layer (130) formed on the outer surface of the reinforcing bar; a glass fiber reinforced composite (GFRP) layer (130) formed on the outer side of the elastic protective layer; and a packing (300) that seals both ends of the composite layer (130). The glass fiber reinforced composite (GFRP) layer (130) is composed of a pair of open FRP sleeves (200) having a semicircular cylindrical cross-sectional shape of '⊂' and '⊃'. A resin injection channel (210) for injecting resin is formed in one side of the FRP sleeve (200), and an air outlet (240) is formed in the other side of the FRP sleeve (200). A resin flow channel (220) with a spiral helical shape and a fine irregular shape with a height of 0.3 to 1.0 mm is formed on the inner side of the FRP sleeve (200). A smart composite reinforcing bar characterized in that resin is injected through a resin injection channel (210), fills the inside of an FRP sleeve (200) along a resin flow channel (220), and air inside is discharged through an air outlet (240) to form an elastic protective layer (130), and the injected resin forms an elastic protective layer (130), and a sensor receiving channel (140) is formed in the longitudinal direction inside the FRP sleeve (200), and includes one or more smart sensor modules (150) inside the sensor receiving channel (140), wherein the smart sensor module (150) is configured to measure one or more of strain, cracks, corrosion, temperature, or humidity of the reinforcing bar or structure in real time. Claim 2 The smart composite reinforcing bar according to claim 1, wherein the smart sensor module (150) comprises one or more of an FBG (Fiber Bragg Grating) optical fiber strain sensor, a corrosion detection sensor, a temperature sensor, and a humidity sensor. Claim 3 The smart composite reinforcing bar according to claim 2, wherein the smart composite reinforcing bar further comprises an RFID module or an NFC module, and the RFID module or NFC module is configured to store individual information, manufacturing information, construction information, installation location, maintenance history, and sensor measurement data of the reinforcing bar or to transmit and receive wirelessly with an external terminal.

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