scholarly journals Investigation on the transport properties of chlorides in concrete II Numerical simulation

2018 ◽  
Vol 199 ◽  
pp. 02014 ◽  
Author(s):  
TIAN Ye ◽  
JIN Xianyu ◽  
JIN Nanguo
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Transmission Model ◽  
Test Results ◽  
Surface Scanning ◽  
Parallel Transmission ◽  
Transmission Process ◽  
Chloride Ions Diffusion

The chloride ions diffusion in concrete is an important problem inducing the corrosion of reinforcement under marine environment. Based on a parallel transmission model, the diffusion coefficient of chloride ions in ITZ was determined. Thereafter, the measured parameters of ITZ were integrated into a numerical model to simulate the chloride ions diffusion and the reliability of the model was verified by comparing the numerical simulation with the surface scanning results collected from the electron microprobe. The test results show that if the concrete is taken as a threephase composites, the numerical model can reflect the real transmission process of chloride ion more accurately.

Numerical Simulation on Chloride Ions Diffusion in Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 348-351 ◽  
Author(s):  
Qing Wang ◽  
Gang Xu ◽  
Jun Wei
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Concentration Distribution ◽  
Chloride Concentration ◽  
Simulation Method ◽  
Chloride Ions ◽  
Test Results ◽  
Exposure Test ◽  
Modified Model ◽  
Chloride Ions Diffusion

Allowing for the analogy between ions diffusion and heat transfer, the numerical simulation on chloride ions diffusion in concrete can be realized following the thermal analysis module in the large general FEA software ANSYS, by reasonable equivalent of parameters. It is based on the modified model for Fick’s second diffusion law, taking the factors of temperature, humidity and time etc. into account. Hereby, the numerical simulation method is established for predicting the chloride concentration distribution with time in concrete, testified by the coastal exposure test. The test results confirm the efficiency and feasibility of the method.

scholarly journals Effect of Fly Ash as Cement Replacement on Chloride Diffusion, Chloride Binding Capacity, and Micro-Properties of Concrete in a Water Soaking Environment

2020 ◽  
Vol 10 (18) ◽  
pp. 6271 ◽  
Author(s):  
Jun Liu ◽  
Jiaying Liu ◽  
Zhenyu Huang ◽  
Jihua Zhu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Chloride Content ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Binding ◽  
Test Results ◽  
New Equation

This paper experimentally studies the effects of fly ash on the diffusion, bonding, and micro-properties of chloride penetration in concrete in a water soaking environment based on the natural diffusion law. Different fly ash replacement ratio of cement in normal concrete was investigated. The effect of fly ash on chloride transportation, diffusion, coefficient, free chloride content, and binding chloride content were quantified, and the concrete porosity and microstructure were also reported through mercury intrusion perimetry and scanning electron microscopy, respectively. It was concluded from the test results that fly ash particles and hydration products (filling and pozzolanic effects) led to the densification of microstructures in concrete. The addition of fly ash greatly reduced the deposition of chloride ions. The chloride ion diffusion coefficient considerably decreased with increasing fly ash replacement, and fly ash benefits the binding of chloride in concrete. Additionally, a new equation is proposed to predict chloride binding capacity based on the test results.

scholarly journals Diffusion Behavior of Chloride Ions in Concrete Box Girder under the Influence of Load and Carbonation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2117
Author(s):  
Yinglong Liu ◽  
Pengzhen Lin ◽  
Junjun Ma
Keyword(s):  
Coupling Effect ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Scale Model ◽  
Test Results ◽  
Box Girder ◽  
Concrete Box Girder ◽  
The Difference

In order to study the durability degradation characteristics of concrete box girder under load and carbonation and chloride ion erosion, a scale model of concrete box girder was made for experimental research. According to the test results, the diffusion characteristics of chloride ions in the concrete box girder under the coupling effect of load and carbon dioxide were analyzed. By revising the calculation formula of the existing chloride ion concentration considering multiple factors, a calculation model of chloride ion concentration considering the influence of carbonation was proposed, and the test results were verified. The results show that the chloride concentration of the box girder on the same cross section is non-uniformly distributed due to the shear lag effect and the spatial structure. After considering the effect of carbonation, the difference rate of the improved model proposed in this paper is generally within 10%. Compared with the original model, the difference rate is reduced by a maximum of 19%.

scholarly journals Analysis of the porous bone-implant fixation – experimental verification of numerical model

2018 ◽  
Vol 157 ◽  
pp. 05002
Author(s):  
Maciej Berdychowski ◽  
Janusz Mielniczuk
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Cancellous Bone ◽  
Experimental Verification ◽  
Test Results ◽  
Implant Fixation ◽  
Bone Implant ◽  
New Type ◽  
Fixation System

In this paper a new type of endoprothesis THRA with needle-palisade fixation system has been described. A numerical model of such fixation has been created. The developed model was subjected to experimental verification. During the test, the prototype of the needle palisade structure was inserted into the cancellous bone. The test results were compared with numerical simulation.

scholarly journals Concrete with Improved Chloride Binding and Chloride Resistivity by Blended Cements

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Katalin Kopecskó ◽  
György L. Balázs
Keyword(s):  
Binding Capacity ◽  
Experimental Studies ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Binding ◽  
Chloride Binding ◽  
Test Results ◽  
Blended Cements ◽  
Water To Cement Ratio ◽  
Selection Of

Durability and service life of concrete structures can be endangered by chloride ions. Two phenomena help to keep control of chloride effects. On one hand cements are able to bind chloride ions by their aluminate clinker phases or by the clinker substituting materials. On the other hand resistivity of concrete against chloride penetration can be improved by careful selection of concrete constituents and production. Detailed results of two series of extensive experimental studies are presented herein. Chloride ion binding capacity of tested cements in decreasing sequence was the following: (1) CEM III/B 32,5 N-S; (2) CEM III/A 32,5 N; (3) CEM II/B 32,5 R; (4) CEM II/B-M (V-L) 32,5 R; (5) CEM I 42,5 N. Test results indicated that the increasing substitution of clinkers by GGBS improves the chloride resistivity in concrete made with the same water to cement ratio. The application of air entraining agent increases considerably the values of Dnssm. Based on the migration coefficients (Dnssm) the following sequence of efficiency was found (from the best): CEM III/B 32,5 N > CEM V/A (S-V) 32,5 N > CEM III/A 32,5 N > CEM II/B-S 42,5 R > CEM II/A-S 42,5 N > CEM I 42,5 N.

The Characteristics of MEMS Based Seismic Sensors Using the Electrochemical Approach

2013 ◽  
Vol 562-565 ◽  
pp. 486-489 ◽  
Author(s):  
Yun Jie Fan ◽  
Jun Bo Wang ◽  
Tao Deng ◽  
De Yong Chen ◽  
Wen Tao He
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Vibration Test ◽  
Test Results ◽  
Seismic Sensors ◽  
Electrochemical Approach ◽  
The Difference ◽  
Set Up

The characteristics of MEMS based electrochemical seismic sensors (EC seismic sensors) are presented in this paper. A numerical model is set up, and a series of vibration test is established. The numerical simulation and vibration test results are illustrated and the difference between them is discussed.

Durability Performance of Concrete Containing CFBC Fly Ash and Coal-Fired Fly Ash

2014 ◽  
Vol 627 ◽  
pp. 283-287
Author(s):  
Mao Chieh Chi ◽  
Ran Huang
Keyword(s):  
Fly Ash ◽  
Circulating Fluidized Bed ◽  
Negative Relationship ◽  
Chloride Ion ◽  
Sulfate Attack ◽  
Chloride Ions ◽  
Test Results ◽  
Fluidized Bed Combustion ◽  
Cfbc Fly Ash ◽  
Durability Performance

This study presents an investigation into durability performance of concrete with various combinations of circulating fluidized bed combustion (CFBC) fly ash and coal-fired fly ash. All cylindrical specimens with the same binder content of 420 kg/m3 and water/binder ratio of 0.5 were cast and cured in the saturated limewater. Permeability test, sulfate attack resistance test, rapid chloride ion penetration test (RCPT) and carbonization test were performed. Test results demonstrate that the adding of CFBC fly ash and coal-fired fly ash would reduce the water permeability and chloride ions penetration, and increase the sulfate attack resistance, but an increase in carbonization depth. The carbonization depth increases with an increasing contents of CFBC fly ash and coal-fired fly ash. There exists a negative relationship between compressive strength and carbonization rate. Based on the test results, CFBC fly ash and coal-fired fly ash can be considered as cement replacement materials and employed in concrete.

scholarly journals EVALUATION OF CONCRETE RESISTANCE TO CHLORIDE IONS PENETRATION BY MEANS OF ELECTRIC RESISTIVITY MONITORING

2005 ◽  
Vol 11 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Marta Kosior-Kazberuk ◽  
Walery Jezierski
Keyword(s):  
Portland Cement ◽  
Salt Solution ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Chloride Salt ◽  
Test Results ◽  
Ion Permeability ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Concrete Resistivity

The chloride‐induced corrosion of reinforcing steel is the major reason for the premature deterioration and degradation of field concrete structures built in a salt‐laden environment. The results of investigation of the bituminous addition effect on Portland cement concrete resistance to chloride ions penetration are presented in this paper. Chloride penetration was simulated by subjecting samples to cyclic loading with salt solution and drying. Concrete resistivity development was monitored during 12 months. The test results have been analysed to verify the effect of addition content, the time of exposure in aggressive environment, as well as the sort of cement on chloride ion permeability of Portland cement concrete. The statistical analysis showed that bituminous addition significantly improves the concrete resistance to chloride salt solution penetration.

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