Evaluation of Relationship between Innitial Current, Conductance, Chloride Diffusion Coefficient and Charge Passed of Concrete

2011 ◽  
Vol 399-401 ◽  
pp. 1200-1203 ◽  
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du ◽  
Wei Zhang
Keyword(s):  
Diffusion Coefficients ◽  
Test Methods ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Wetting And Drying ◽  
Alternate Wetting And Drying ◽  
Drying Test

In this study, plain and mineral admixture (slag, fly ash and silica fume) modified concrete prisms were made with three water-to-binder ratios (w/b), and four test methods (Rapid Chloride Permeability Test-ASTM C1202-91, AC Conductance Test, 150-days Ponding Test, Alternate Wetting and Drying Test by cyclic loading with salt solution and drying) were employed to measure the concrete prisms’ chloride penetrability. The effects of mineral admixtures on the concrete chloride permeability were discussed, and the correlation of results separately obtained from the four test methods were analyzed. The experiment results indicate that blending concrete is beneficial with regard to the resistance against chloride ion penetration, and good linear ralationship between charge passed and innitial current, charge passed and conductance, charge passed and chloride diffusion coefficients by 150-days Ponding Test, charge passed and diffusion coefficients by Alternate Wetting and Drying Test were obtained.

Boundary Element Analysis of Accelerated Chloride Diffusion in High Performance Concrete

2013 ◽  
Vol 842 ◽  
pp. 151-155
Author(s):  
Yi Wang ◽  
Wo Cheng Hang ◽  
Lu Feng Yang ◽  
Zheng Chen
Keyword(s):  
Diffusion Coefficient ◽  
Boundary Element ◽  
High Performance ◽  
Numerical Solutions ◽  
High Performance Concrete ◽  
Chloride Concentration ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Chloride Permeability

This paper aims to analyze accelerated chloride diffusion in high performance concrete (HPC) blended with mineral admixture by using boundary element method (BEM). Rapid chloride permeability test (RCPT) was employed and executed. The experiment proves that the highest resistance to chloride permeability can be acquired in the quaternary-blended concretes (ordinary portland cement + fly ash + blast furnace slag + silica fume). A chloride diffusion BEM model was established according to the diffusion coefficient calculated from the charge passed. The numerical solutions agree with experiments well. It can be inferred that the acceleration degree of RCPT is not the same in different mix proportion. Besides, the results also suggest that the low chloride permeability of the concretes with mineral admixtures may be attributed to the lower diffusion coefficient and the lower surface chloride concentration.

Effect of Pore Structure on the Chloride Permeability of Concrete with Mineral Admixture

2013 ◽  
Vol 690-693 ◽  
pp. 835-838 ◽  
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du
Keyword(s):  
Pore Structure ◽  
Total Porosity ◽  
Chloride Ions ◽  
Mineral Admixture ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Evaporative Water ◽  
Chloride Diffusivity ◽  
Chloride Penetration Resistance

In this paper, the effect of pore structure on the chloride ions ingress into concrete was investigated. The most probable diameter was measured by Mercury intrusion porosimetry (MIP) and the total porosity was measured by evaporative water method (EWM). The results indicate that the most probable diameter by MIP has better linear relationship with chloride diffusion coefficient than the total porosity by EWM, the most probable diameter has significant influence on chloride diffusivity, and the smaller most probable diameter will lead to higher chloride penetration resistance.

The Time-Dependence of Chloride Penetration Resistance of Concrete by the Rapid Chloride Permeability Test

2013 ◽  
Vol 357-360 ◽  
pp. 651-654 ◽  
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du
Keyword(s):  
Penetration Resistance ◽  
Chloride Penetration ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Curing Time ◽  
Permeability Test ◽  
Chloride Permeability ◽  
Chloride Penetration Resistance ◽  
Rapid Chloride Permeability

In this paper, the Rapid Chloride Permeability Test (RCPT)-ASTM C1202-91 and Conductance test were employed to measure the effect of curing time on the chloride penetration resistance of concrete. The results indicate that the concrete specimens with longer curing time have higher chloride penetration resistance no matter the concrete with or without mineral admixtures, the concrete conductance has the similar variation trend and similar mathematical descriptions as the chloride diffusion coefficient D with the passage of curing time, and it is a very useful method to measure concrete conductance to estimate the chloride permeability variation at different curing or exposure time.

scholarly journals Comparative Study of Strength and Corrosion Resistant Properties of Plain and Blended Cement Concrete Types

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Velu Saraswathy ◽  
Subbiah Karthick ◽  
Han Seung Lee ◽  
Seung-Jun Kwon ◽  
Hyun-Min Yang
Keyword(s):  
Water Absorption ◽  
Corrosion Behaviour ◽  
Blended Cement ◽  
Effective Porosity ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Corrosion Resistant ◽  
Lower Corrosion Rate ◽  
Portland Slag Cement

The relative performances of mechanical, permeability, and corrosion resistance properties of different concrete types were compared. Concrete types were made from ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Compressive strength test, effective porosity test, coefficient of water absorption, short-term accelerated impressed voltage test, and rapid chloride permeability test (RCPT) were conducted on M30 and M40 grades of concrete designed with OPC, PPC, and PSC cements for 28- and 90-day cured concrete types. Long-term studies such as microcell and electrochemical evaluation were carried out to understand the corrosion behaviour of rebar embedded in different concrete types. Better corrosion resistant properties were observed for PSC concrete by showing a minimum current flow, lowest free chloride contents, and lesser porosity. Besides, PSC concrete has shown less coefficient of water absorption, chloride diffusion coefficient (CDC), and lower corrosion rate and thereby the time taken for initiation of crack extended.

scholarly journals Experimental Study on the Concrete with Compound Admixture of Iron Tailings and Slag Powder under Low Cement Clinker System

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ruidong Wu ◽  
Juanhong Liu
Keyword(s):  
Diffusion Coefficient ◽  
Mineral Admixture ◽  
Chloride Diffusion ◽  
Cement Clinker ◽  
Hydration Reaction ◽  
Chloride Diffusion Coefficient ◽  
Carbonation Depth ◽  
Mixture Ratio ◽  
Slag Powder ◽  
Powder Content

In order to study the performance of concrete with compound admixture of iron tailings and slag powder under low cement clinker system, the mixture ratio of different iron tailings powder and slag powder was designed to prepare C30 and C50 concrete. The workability, strength, carbonation depth, chloride diffusion coefficient, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) of concrete were measured, respectively. The test results show that iron tailings powder is beneficial to improve the workability, and the strength of concrete decreases with the increase of iron tailings powder content, while the carbonation depth and chloride diffusion coefficient increase with the increase of iron tailings powder content. Under low cement clinker system, the iron tailings powder should not be used alone (below 70% of mineral admixture). When the ratio of iron tailings to slag powder is 1 : 1, the strength, carbonation depth, chloride ion permeation coefficient, and the microstructure of concrete are roughly the same to that of concrete with single slag powder. So, the iron tailings powder can replace S95 grade slag powder in the same quantity. Iron tailings powder does not take part in hydration reaction, but it can improve particle gradation, reach close accumulation, and increase the quantity of central grains.

Influence of the Nanomaterials of Kaolin Content on the Chloride Permeability of Cement Mortar

2017 ◽  
Vol 730 ◽  
pp. 406-411 ◽  
Author(s):  
Xiao Yu Guo ◽  
Ying Fang Fan ◽  
Kun Yang
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability

This study investigated the influence of nanokaolin content on the behavior of cement mortar at various curing ages. The fluidity, chloride permeability, bending and compressive strength of cement mortar with various nanokaolin additives were examined. The addition of 0%, 1%, 2%, 3%, 4%, 5% and 6% nanokaolin were taken into consideration. The results showed that the addition of nanokaolin decreases the fluidity of cement mortar, and the fluidity the cement mortar decreases with the increase of nanokaolin additives. It is obtained that the addition of nanokaolin increases both the bending and compressive strength of cement mortar, and with the increase of nanokaolin additives, the bending and compressive strength of cement mortar increase. The addition of 4% nanokaolin can result in a significant low chloride permeability of cement mortar among the seven dosages. The chloride diffusion coefficient of the mortar with the addition of 4% nanokaolin was decreased by 18.93%, 12.68% and 31.05% at 7, 14 and 28 curing days, respectively.

Effect of Mineral Admixtures and Water/Binder Ratios on the Resistance to the Chloride Ions Penetration into Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 758-761
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Chloride Ion ◽  
Test Methods ◽  
Chloride Ions ◽  
Mineral Admixtures ◽  
Chloride Permeability ◽  
Furnace Slag

In this study, concrete prisms were made with three mineral admixtures: fly ash, blast furnace slag or silica fume and with three water-to-binder ratios(w/b). Chloride penetration was measured by the rapid chloride permeability test (RCPT)-ASTM C1202, 150-days ponding test and alternate wetting and drying test by cyclic loading with salt solution and oven drying, and the results by the three test methods were compared. This paper discussed the effects of mineral admixtures and w/b on the concrete chloride permeability. Blending concrete with blast furnace slag, fly ash or silica fume was beneficial with regard to the resistance against chloride ion penetration. Concrete specimens with lower w/b showed lower chloride permeability.

Influence of Curing Age and Water-Binder Ratio on Chloride Permeability under Freeze-Thaw and Load

2013 ◽  
Vol 405-408 ◽  
pp. 2610-2615
Author(s):  
Lei Hong ◽  
Run Min Duo
Keyword(s):  
Diffusion Coefficients ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Diffusion ◽  
Chloride Permeability ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Binder Ratio ◽  
Water Binder Ratio ◽  
Curing Age

The chloride diffusion coefficients of different water-binder ratio high performance concrete (HPC) subjected to different one-way loads，freeze-thaw cycles and different standard curing ages were measured by electro-migration (RCM) tests and the results were analyzed. The test results indicate that with the increase of one-way load, its influence on the chloride permeability of different water-binder ratio HPC rises in the same proportion. The influence of the curing age on the chloride permeability of HPC will decrease with the reduction of the water-binder ratio of HPC. Under the same freeze-thaw cycle conditions, the relationships between chloride diffusion coefficients of different water-binder ratio HPC and curing ages are nearly suitable to power function.

Comparison of chloride penetration into surface-treated concrete in artificial and natural environments

2016 ◽  
Vol 20 (9) ◽  
pp. 1315-1324 ◽  
Author(s):  
Jianfeng Dong ◽  
Yuxi Zhao ◽  
Yueliang Gan ◽  
Chaomei Ding ◽  
Qiming He
Keyword(s):  
Diffusion Coefficients ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Natural Environments ◽  
Nacl Solution ◽  
Normal Concrete ◽  
Wetting And Drying

This study investigated the penetration of chloride into surface-treated high-performance concrete and normal concrete in natural and accelerated environments. Both high-performance concrete and normal concrete were applied in a real port. Concrete specimens that were cast together with the concrete port were transported to the laboratory and subjected to wetting and drying cycles with NaCl solution. The chloride contents of the specimens in the laboratory and the in situ components were tested. The chloride diffusion coefficients and surface chloride contents were calculated based on Fick’s second law. The results show that high-performance concrete and surface treatment clearly slow the chloride penetration into the concrete both in the laboratory and in situ. The chloride contents on the surface and in the concrete in the components of the concrete port are higher during the summer than during the winter. The chloride penetration performance in the concrete of real structures cannot be inferred from its performance in specimens under artificial environments in the laboratory.

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