Effects of polypyrrole coated rebar on corrosion behavior of tunnel lining with the combination effect of sustained loading and pre-existing cracks when exposed to chlorides

Hu, Xiongyu; He, Chuan; Feng, Kun; Liu, Sijing; Walton, Gabriel

doi:10.1016/j.conbuildmat.2019.06.092

Cited by 18 publications

(6 citation statements)

References 18 publications

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“…In this section, gprMax based on FDTD is used to simulate the process of GPR lining detection. This software is widely used to simulate the propagation law of electromagnetic waves in isotropic homogeneous bodies [26][27][28][29][30]. To save calculation time and facilitate the investigation of the influence of a single factor, the forward simulation is based on the following assumptions.…”

Section: Forward Simulation Based On Fdtdmentioning

confidence: 99%

Evaluation of Void Defects behind Tunnel Lining through GPR forward Simulation

Bao

Shen

et al. 2022

Sensors

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Voids, a common defect in tunnel construction, lead to the deterioration of the lining structure and reduce the safety of tunnels. In this study, ground-penetrating radar (GPR) was used in tunnel lining void detection. Based on the finite difference time domain (FDTD) method, a forward model was established to simulate the process of tunnel lining void detection. The area of the forward image and the actual void area was analyzed based on the binarization method. Both the plain concrete and reinforced concrete lining with various sizes of air-filled and water-filled voids were considered. The rationality of the model was verified by measured data. It was observed that the response mode of voids can be hyperbolic, bowl-shaped, and strip-shaped, and this depends on the void’s width. Compared with the air-filled voids, water filling increases the response range of the voids and produces a virtual image. Although the diffracted wave caused by a steel bar will bring about significant interference to the void response, the center position of the voids can be accurately located using 3D GPR.

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Section: Forward Simulation Based On Fdtdmentioning

confidence: 99%

Evaluation of Void Defects behind Tunnel Lining through GPR forward Simulation

Bao

Shen

et al. 2022

Sensors

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“…(2) The potential distribution in concrete and the diffusion of oxygen in cracked segment are calculated by Equations (16)(17)(18);…”

Section: Calculation Process Of Numerical Simulationmentioning

confidence: 99%

“…Zhang et al 17 used a rectangular member with load-induced cracks as a substitute for cracked tunnel segments to study the relationship between the residual strength and rust layer morphology. Hu et al 18 similarly studied the rust layer distribution of tunnel lining with pre-existing cracks under DC current and chloride ion. However, the transverse cracks and distribution form of rebar in the model test were unlike those of tunnel segments.…”

Section: Introductionmentioning

confidence: 99%

Study on rust layer distribution of cracked segment at tunnel arch waist under stray current and chloride ion corrosion

Jin

Sun

et al. 2022

Structural Concrete

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During subway operation, cracks may appear at the arch waist of tunnel segment surface. Under the acceleration of stray current, chloride ion in groundwater will penetrate into the surface of rebar through cracks, resulting in segment rebar corrosion and structural stiffness degradation. In this article, the rebar corrosion calculation model of tunnel segment contained transverse crack under stray current and chloride ion was established, and the coupling of electric field and chemical field in cracked concrete was realized. The effects of chloride ion content and input voltage on the rust layer distribution of cracked segment were studied. The results shows: Under the action of stray current and chloride ion, the 3D rust layer of cracked segments at the arch waist can be described by Gaussian mixture function. In the longitudinal direction, the rust layer at the crack section is located at the peak of the rust layer curve, and the increase of chloride ion content has a greater influence on the rust layer shape than the increase of stray current. When the chloride ion content and stray current are doubled, respectively, the maximum rust layer thickness of rebar will increases by 34% and 16%, respectively. In the circumferential direction, the nonuniform coefficient of elliptical rust layer will change with the increase of segment crack width and chloride ion content, but it will not be affected by stray current intensity.

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“…Zhang et al 32 used a rectangular member with load‐induced cracks as a substitute for cracked tunnel segments to study the relationship between the residual strength and corrosion rate. Hu et al 33 similarly studied the mechanical behavior of a tunnel lining with pre‐existing cracks under rebar corrosion. However, the transverse cracks and distribution form of rebar in the model test were unlike those of tunnel segments.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of corrosion effect on bending deflection of shield tunnel segment containing transverse cracks

Zhang

Jin

et al. 2022

Structural Concrete

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Corrosion of the steel rebar will be generated in the cracked concrete of the shield tunnel during the operation period, which will reduce the bending performance of the tunnel segment. In this study, the effect of the rebar corrosion on the bending deflection of the shield tunnel segment that contains transverse cracks is investigated by experimental tests. The initial transverse cracks of the segment are simulated by a bending load device, and the galvanostatic method is used to simulate the corrosion of the segment rebar. The degradation of the segment bending deflection after the rebar corrosion process is measured and compared with the non‐corroded segment. The results reveal that when the depth of the transverse crack does not exceed the thickness of the protective layer, the corrosion of the rebar has little effect on the bending degradation. However, when the width and depth of the transverse crack reach approximately 1.2 and 210 mm, respectively, the degradation rate of bending deflection begins to increase rapidly.

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Effects of polypyrrole coated rebar on corrosion behavior of tunnel lining with the combination effect of sustained loading and pre-existing cracks when exposed to chlorides

Cited by 18 publications

References 18 publications

Evaluation of Void Defects behind Tunnel Lining through GPR forward Simulation

Evaluation of Void Defects behind Tunnel Lining through GPR forward Simulation

Study on rust layer distribution of cracked segment at tunnel arch waist under stray current and chloride ion corrosion

Experimental investigation of corrosion effect on bending deflection of shield tunnel segment containing transverse cracks

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