An optical fiber sensor combination for reinforced concrete corrosion monitoring

Abstract

The invention discloses an optical fiber sensor combination for monitoring the corrosion of reinforced concrete. The optical fiber sensor combination comprises an optical fiber sensor and a compensation sensor, wherein the optical fiber sensor and the compensation sensor comprise reinforcing steel bar elements, reinforced fiber glass reinforced plastic support bases, optical fiber Bragg gratings and connecting optical fibers, protective sleeves, silicon sheets, reinforcing steel bar coating regions, reinforcing steel bar un-coating regions, and mortar housings, wherein the reinforcing steel bar elements of the optical fiber sensors are reinforcing steel bars to be tested, and the reinforcing steel bars of the compensation sensor are 316L stainless steel bars. According to the optical fiber sensor combination, a reaction force of mortar is counteracted to a certain extent, the local corrosion of the reinforcing steel bars is favorably monitored, and the sensitivity of monitoring is improved. The compensation sensor is made by adopting a manner of replacing common reinforcing steel bars by 316L stainless steel, and is simple in principle and convenient to operate. The optical fiber sensor combination is simple in structure, convenient to manufacture, low in cost, good in sensitivity, high in accuracy, strong in anti-electromagnetic interference, high in reliability, good in durability, and high in stability, and is suitable for monitoring the long-term durability of reinforcing steel concrete structures such as saline and alkaline land, seawater and deicing salt under multiple environments.

Description

technical field [0001] The invention belongs to an optical fiber sensor, and in particular relates to a combination of optical fiber sensors for reinforced concrete corrosion monitoring that can perform on-line non-destructive quantitative monitoring of steel bar corrosion in a reinforced concrete structure in a corrosive environment, and can be applied to durability monitoring and evaluation of civil engineering structures. Background technique [0002] Reinforced concrete structures in a corrosive environment tend to gradually deteriorate in material properties during use, resulting in insufficient durability of the overall structure. At present, the durability of concrete structures has become the focus of the world's engineering circles. Common factors affecting the durability of reinforced concrete structures include concrete carbonation, steel corrosion, and freeze-thaw damage. Among them, steel bar corrosion is the primary reason affecting durability, and it has the ...

AI Technical Summary

Problems solved by technology

However, there are still the following problems: the production process of the corrosion-sensitive film is complex; at present, it is only possible to qualitatively judge whether corrosion has occurred; the corrosion-sensitive film has the risk of falling off in pieces, and the thickness of the corrosion-sensitive film is often uneven; the sensor is relatively fragile and cannot meet the requirements Rough way construction requirements for concrete structures

However, it still has the following problems: the corrosion form of the rebonded steel bar after splitting the two halves is different from the original overall steel bar, so the simulation effect is doubtful; The gap will be filled first, resulting in insufficient monitoring sensitivity, and it is difficult to monitor the local corrosion outside the close part; when the corrosion product fills the gap, the sensor will be subjected to expansion force around the sensor, which will offset the expansion between the close parts force, making the monitoring results inaccurate

The sensor makes good use of the BOTDR measurement technology, but because the bare optical fiber is tightly wound on the surface of the lubricating layer of the steel bar, the intrusion of the corrosive medium will be affected, and the corrosion environment on the surface of the steel bar will change, which will affect the accuracy of the sensor in simulating the corrosion of the steel bar.

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