scholarly journals A Spiral Distributed Monitoring Method for Steel Rebar Corrosion

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1451
Author(s):  
Jianzhi Li ◽  
Yiyao Zhao ◽  
Junjie Wang
Keyword(s):  
Curvature Radius ◽  
Distributed Monitoring ◽  
Monitoring Method ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Steel Bar ◽  
Concrete Layer ◽  
Light Loss ◽  
Cracking Process ◽  
Corrosion Of Steel

This paper proposes a novel spiral-wound, optic-fiber sensor to monitor the corrosion of steel bars. At the same time, the winding parameters, such as winding angle and pitch, were first theoretically deduced. Then, to decrease light loss, a practically distributed sensor wound onto the protective mortar layer was developed by increasing the winding curvature radius. The spiral distributed sensors were experimentally verified for their feasibility. Experimental results showed that the spiral fiber strain depended on the thickness of the protective mortar layer. Furthermore, the spiral distributed strain well reflected the cracking process of concrete. In addition, the concrete cracking time depended on the thickness of the protective concrete layer. Accordingly, this method is feasible for evaluating the initial and final cracking behaviors of concrete structures and provides a sight for steel bar corrosion.

scholarly journals Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song
Keyword(s):  
Sensor Networks ◽  
Real Time ◽  
Information Needs ◽  
Localization Algorithm ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Microseismic Events ◽  
The Stability ◽  
Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

All-Solid-State Reference Electrode Based on Polymer Composites for Corrosion Monitoring of Steel in Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 2945-2948
Author(s):  
Li Juan Kong ◽  
Tong Zhang ◽  
Guang Pin Song
Keyword(s):  
Solid State ◽  
Civil Engineering ◽  
Reference Electrode ◽  
Steel Corrosion ◽  
Steel Structures ◽  
Electrode System ◽  
Corrosion Monitoring ◽  
Steel Bar ◽  
State Reference ◽  
Corrosion Of Steel

Corrosion of steel structures has been found to be a problem Corrosion can be managed but not eliminated, so detecting corrosion will remain an issue no matter how effective corrosion prevention programs become. Electrochemical reaction is the basically process of steel corrosion in civil engineering, so electrochemical method is the best way to monitor corrosion grade. Liquid state reference is often used in lab to study steel corrosion by triple electrode system, but it is very difficultly used in steel bar corrosion monitoring in civil engineering. Firstly, liquid reference’s life is, generally speaking, very short. The steel corrosion is a very slow process, corrosion monitoring should be tens of years, so the liquid reference’s life is not long enough for corrosion monitoring; Secondly, the reference electrode’s strength have to be very high. Obviously, liquid electrode reference can not meet the requirement. In this paper, a novel all solid state reference electrode (ASSRE) has been developed. There are three layers in the electrode. Four kinds of components have been included in first and second layer. Additional AgCl powder has been used to inhibit AgCl decrease which is on the surface of Ag wire by complexing effect. There is only one kind of component in third layer. There are four steps to prepare the reference electrode: electrolyze, pre-mixed components, modelling and sintering. Finally, the potential of ASSR has been measured by SCE.

Experiment study on chloride corrosion deterioration of load-bearing concrete segment

2018 ◽  
Vol 22 (4) ◽  
pp. 960-970 ◽  
Author(s):  
Kun Feng ◽  
Sijin Liu ◽  
Chuan He ◽  
Zuzhao Peng ◽  
Chao Gou ◽  
...  
Keyword(s):  
External Load ◽  
Loss Rate ◽  
Failure Pattern ◽  
Shield Tunnel ◽  
Change Rate ◽  
Load Bearing ◽  
Steel Bar ◽  
Bending Load ◽  
Corrosion Of Steel ◽  
Steel Section

In order to study the combined action of compression-bending load and surrounding ion erosive environment on underwater shield tunnel, a series of cofferdam-type electrochemical-accelerated corrosion tests of mini segments are carried out to investigate the segment reinforcement corrosion under different compression-bending loads and the change of internal force and rigidity of mini segments under different load-bearing and corroding conditions. Then, the failure pattern of mini segments under different loading and corroding states are recorded and analyzed. The results indicate that the following: (1) the larger the external load, the shorter the initial rust time of the steel bar; (2) the corrosion rate of steel bar increases linearly with time, and the ratio of corrosion of steel bar increases quadratically with time, the larger the load, the more obvious the increase will be; (3) after the corrosion of steel bar, the change rate of the strain for the steel bar increases as the external load augments, and as a matter of fact, the change rate of the strain increases as well, besides, the degree of strain change for compressive steel is obviously lower compared with that of tensile steel bar; (4) the effect of electric corrosion on the deflection of the segments is more obvious with the increase of external load, and a quadratic increase relationship between the deflection and the corrosion is observed in the process of corrosion; (5) It can be concluded that plastic failure is observed for the segments without loading and for those without cracks in the initial stage of loading, which can be indicated directly by the relatively smaller loss rate of steel section, while brittle failure is presented as the failure pattern for the segments with cracks after loading for certain period, which means the loss rate of steel section is relatively larger. The results can briefly provide useful reference for rational design and durability assessment of shield tunnel segmental linings.

A New Class of Distributed Sensors

1997 ◽  
Vol 119 (4) ◽  
pp. 582-589 ◽  
Author(s):  
A. Baz ◽  
S. Poh
Keyword(s):  
Continuous Monitoring ◽  
Composite Beams ◽  
Distributed Sensors ◽  
Experimental Performance ◽  
Distributed Sensor ◽  
New Class ◽  
Laser Sensors ◽  
Frequency Domains ◽  
Angular Displacements ◽  
Conventional Laser

A new class of distributed sensors is presented which can measure both the linear and angular deflections of composite beams. The sensor relies in its operation on a set of wires which are embedded off the neutral axes of the composite beams. The wires are arranged in a special manner which allows continuous monitoring of the deflection curve of the beam. The output signals of the wires are processed to determine the linear and angular displacements at critical discrete points along the beam axis. The theoretical and experimental performance of the sensor is presented in both the time and frequency domains. Comparisons are given between the experimental performance of the distributed sensor and that of conventional laser sensors in order to demonstrate the accuracy and merits of the distributed sensor. The results obtained suggest the potential of this new class of sensors as a viable means for monitoring the static and dynamic deflections of flexible composite SMART beams and plates.

Effect of Migrating Corrosion Inhibitor on Corrosion Rate of Reinforcing Steel in Concrete with Various Admixed Chloride

2012 ◽  
Vol 204-208 ◽  
pp. 3146-3150 ◽  
Author(s):  
Zhi Yong Liu ◽  
Xin Gang Zhou ◽  
Xiu Lin Li
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Steel Bar ◽  
Average Corrosion Rate ◽  
Corrosion Of Steel ◽  
High Chloride ◽  
Effect Of Surface ◽  
Chloride Contaminated

Effect of surface applied inhibitor on the durability of chloride contaminated reinforced concrete has been investigated in this paper. The C30 concrete samples contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials in the mixing process were experienced adequate curing and subjected to 1 months exposure tests after painting with 400 g/m2 MCIs. The corrosion behavior of the steel rebar in concrete samples was monitored by using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and corrosion currents. The results indicate that, after painting the MCIs for 28d on the surface of concrete samples with 0.5% and 1% NaCl, the average corrosion rate of reinforcements in concrete samples （0.34μA/cm2 ）is lower than that of the control one (No.0, no painted inhibitor), and about 1/4 of the initial corrosion current of the samples with 0.5% and 1% NaCl before painting MCI. But the corrosion current of rebar in No.3 sample with 1.5% NaCl is still higher than that of the control one (No.0). Therefore, painting MCIs on the surface of samples is very effective to inhibit the corrosion of steel bar in concrete at low or middle chloride conditions, but it is not enough to repair severely corroded steel bar in high chloride contaminated concrete.

scholarly journals Chemical Composition of Corrosion Products of Rebar Caused by Carbonation and Chloride

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Jundi Geng ◽  
Junzhe Liu ◽  
Jiali Yan ◽  
Mingfang Ba ◽  
Zhimin He ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Corrosion Products ◽  
Chloride Salt ◽  
Oxide Content ◽  
Passivation Film ◽  
Steel Bar ◽  
Steel Bars ◽  
Main Components ◽  
Corrosion Of Steel ◽  
Peak Value

The microstructures of steel bars were studied by X-ray photoelectron spectroscopy (XPS), and the mechanism of corrosion of steel bars under the corrosion factors was elucidated. The results show that the passivation film and corrosive surface of the steel surface in the solution of the chloride-containing salt were coarser and the surface state was denser. The main corrosion products are FeOOH and FeO. The surface of the steel immersed in the simulated carbonized solution had loose pores. The main components are FeOOH, Fe3O4, and Fe2O3. The surface of the steel bar has a large amount of yellowish brown corrosion products in the simulated carbonization and chloride salt. The surface of the corrosion products was stripped and the main components are FeOOH, Fe3O4, and FeCl3, where the content of FeOOH is as high as 60%. The peak value of iron is gradually increased from the simulated chloride salt solution to the carbonized solution to the combined effect of carbonation and chloride salt; the iron oxide content is increased and corrosion of steel is obviously serious.

scholarly journals Cracking Analysis of Concrete due to the Corrosion of Steel Bar

2006 ◽  
Vol 17 (3) ◽  
pp. 25-34
Author(s):  
Kazuhiro Kawaguchi ◽  
Hiroshi Ueki ◽  
Masaru Shimonishi ◽  
Masaaki Murakami
Keyword(s):  
Steel Bar ◽  
Corrosion Of Steel

scholarly journals Non Destructive Behavior of Corroded Reinforced Geopolymer Concrete Beams

2019 ◽  
Vol 9 (2) ◽  
pp. 5411-5414
Keyword(s):  
Polymer Material ◽  
Concrete Beams ◽  
Experimental Tests ◽  
Steel Bar ◽  
Long Time ◽  
Reinforcement Bar ◽  
Object Of Study ◽  
Corrosion Of Steel ◽  
Non Destructive ◽  
Natural Corrosion

Corrosion of steel reinforcement bar embedded in geo-polymer material has been an object of study to confirm its technical viability. The available alkalinity of geo-polymer material initially was suspected to be harmful for alkali-silica reaction, but then it was found to be beneficial to maintain passivity of the steel bar in concrete. Many researchers carried out studies on the influence of corrosion on bond, generally developed on the basis of experimental tests in specimens subjected to artificial corrosion. The current density applied to accelerate the corrosion influences the bond strength. Since, natural corrosion develops in a very long time, an artificial corrosion has been provided

scholarly journals Monitoring Method of Longitudinal Land Subsidence and Deformation in Seismic Geological Disasters

2020 ◽  
Vol 24 (3) ◽  
pp. 259-266
Author(s):  
Aimei Xu ◽  
Hojatallah Azarkhosh ◽  
Erjun Wu
Keyword(s):  
Optical Fibers ◽  
Land Subsidence ◽  
Confining Pressure ◽  
Ground Subsidence ◽  
Correction Coefficient ◽  
Geological Hazards ◽  
Distributed Monitoring ◽  
Monitoring Methods ◽  
Monitoring Method ◽  
Geological Disasters

Monitoring of longitudinal land subsidence and deformation in seismic and geological hazards plays an important role in preventing and curing land collapse, land subsidence, and ground cracks. In this paper, a distributed monitoring model experiment on vertical land subsidence and deformation of seismic and geological hazards is carried out by Brillouin optical frequency-domain analysis technology (BOTDA). By using the self-made indoor longitudinal land subsidence and deformation simulation box, different intensity seismic ground is simulated by air bag. Distributed optical fibers are used to monitor the longitudinal land subsidence and deformation during different intensity seismic and geological disasters. According to different intensity seismic and geological disasters, distributed sensing optical fibers cooperate with the ground to compress or stretch longitudinally and obtain the data of longitudinal land subsidence and deformation. The correction coefficient is introduced to modify the monitoring data of confining pressure-sensing optical fiber and complete the precise monitoring of vertical land subsidence and deformation in seismic and geological hazards. The experimental results show that this method can monitor the vertical ground subsidence and deformation of seismic and geological hazards under different conditions, and the monitoring efficiency and cost are superior to GPS and inertial monitoring methods, and the practical application value is high.

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