scholarly journals Prediction of Chloride Distribution for Offshore Concrete Based on Statistical Analysis

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 174 ◽  
Author(s):  
Qing-feng Liu ◽  
Zhi Hu ◽  
Xian-yang Lu ◽  
Jian Yang ◽  
Iftikhar Azim ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Penetration Depth ◽  
Large Body ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Proposed Model ◽  
Chloride Attack ◽  
Influential Parameters ◽  
Relevant Factors

Chloride-induced corrosion is the main threat to the service life of concrete structures. In order to better investigate chloride distribution in offshore concrete, this study proposed a new prediction model based on statistical analysis as well as a large body of experimental results collected from various sources. A detailed discussion found that the key influential parameters, such as diffusion coefficient ( D ), surface chloride concentration ( C S ) and penetration depth ( x ) are all highly time-dependent. The exposure zone, water–cement ratio and service time were also considered as relevant factors. The proposed model is then validated by two alternative tests and the results suggest that it is feasible in predicting the chloride content and penetration depth of concrete structures in a marine environment under chloride attack.

Study on Corrosion Resistance of 2205 Stainless Steel Reinforcement in Simulated Concrete Pore Solution

2013 ◽  
Vol 838-841 ◽  
pp. 119-122
Author(s):  
Long Chen ◽  
Yu Qu ◽  
Yan Bing Tang ◽  
Xiang Fang
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Passive Film ◽  
Pore Solution ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Current Time

The steel rebar inside reinforced concrete structures is susceptible to corrosion when the chloride content at the surface of the steel exceeding the critical chloride concentration. Stainless steel reinforcements have proved to be the most reliable methods to assure the durability of reinforced concrete structures in marine environment for the compact passive films forming on its surfaces and higher critical chloride concentration. In the present work, the compactness of passive film on 2205 stainless steel in simulated concrete pore solution (SPS) is compared with carbon steel (Q235). the critical chloride concentration of Q235 and 2205 stainless steel reinforcement are discussed. Results indicate the slope(k) of double-log plot of current time for 2205 stainless steel is higher than Q235 , thekvalue is related with the compactness of passive film, the critical chloride concentration of 2205 stainless steel is much higher than Q235 steel in SPS.

Epic Sanskrit

2017 ◽  
Author(s):  
John J. Lowe
Keyword(s):  
Statistical Analysis ◽  
Large Body ◽  
Detailed Account ◽  
Clear Correlation ◽  
Detailed Review

This chapter provides a detailed account of the transitive noun and adjective categories attested in Epic Sanskrit. The major Sanskrit epics, the Mahabharata and the Ramayana, provide a large body of data in a form of Sanskrit slightly later than Vedic Prose, and close to the ‘Classical’ Sanskrit language. There is considerably more evidence for transitive nouns and adjectives in the epics than in Vedic Prose, but compared with the Rigveda transitive nouns and adjectives are still less common, and show less morphological variety. Again, statistical analysis shows that there is a clear correlation between transitivity and predication. As in the two previous chapters, a number of characteristic stem forms are thoroughly examined and exemplified. Statistics for subject-oriented data precede a section on participles and a detailed review of situation-oriented nouns.

TURBIDITY OF SUSPENSIONS AND MORPHOLOGY OF RED HALOPHILIC BACTERIA AS INFLUENCED BY SODIUM CHLORIDE CONCENTRATION

1960 ◽  
Vol 6 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons
Keyword(s):  
Sodium Chloride ◽  
Salt Concentration ◽  
Morphological Changes ◽  
Halophilic Bacteria ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Wall Structure ◽  
Abrupt Decrease ◽  
High Sodium ◽  
Rigid Cell Wall

The optical densities of suspensions of cells of Halobacterium cutirubrum, H. halobium, or H. salinarium, grown in media containing 4.5 M sodium chloride, increase as the salt concentration of the suspending medium decreases, until a maximum is reached at about 2 M; below this concentration there is an abrupt decrease in optical density. The cells are rod shaped in 4.5 M salt and change, as the salt concentration decreases, through irregular transition forms to spheres; equal numbers of transition forms and spheres are present at the point of maximum turbidity, while spheres predominate at lower salt concentrations. Cells suspended in 3.0 M salt, although slightly swollen, are viable, but viability decreases rapidly with the more drastic changes in morphology at lower salt concentrations. Cells grown in the presence of iron are more resistant to morphological changes but follow the same sequence. Cells "fixed" with formaldehyde, at any point in the sequence, act as osmometers and do not rupture in distilled water although their volume increases 10–14 times. The results indicate that the red halophilic rods require a high sodium chloride content in their growth or suspending medium to maintain a rigid cell wall structure.

Performance assessment on degrading concrete structures including considerations on the time variant alteration

2021 ◽  
Author(s):  
Fritz Binder ◽  
Stefan L. Burtscher ◽  
Alfred Strauss
Keyword(s):  
Prestressed Concrete ◽  
Chloride Content ◽  
Degradation Process ◽  
Analytic Hierarchy ◽  
Reliable Determination ◽  
Chloride Attack ◽  
Durability Assessment ◽  
Condition Indices ◽  
Condition State ◽  
Hierarchy Process

<p>The infrastructure of ASFiNAG is mainly built from reinforced and prestressed concrete, which despite all regular maintenance measures, is subject to ageing and degradation. The major degradation process is chloride attack, followed by carbonation, which both lead to corrosion of the reinforcing steel. In this paper chlorides in the concrete are analysed with a new method, which represents a major improvement over previous assessment. The paper also introduces a new concept for the durability assessment by using objective indicators, like chloride content, electrical resistivity, and corrosion potential. For objectivity and a reliable determination of the condition state, an overall performance index derived from the condition indices using an analytic hierarchy process (AHP) is adopted. The model is applied to excellent and dense data from a monitoring system and investigations taken from reinforced concrete components beside the motorway.</p>

Influence of Geometry Parameters on Durability of Concrete Structures Exposed to Chloride Environment

2012 ◽  
Vol 204-208 ◽  
pp. 3194-3200
Author(s):  
Xin Gang Zhou ◽  
Hui Xia
Keyword(s):  
Concrete Structures ◽  
Chloride Content ◽  
Chloride Diffusion ◽  
Rectangular Section ◽  
Circular Section ◽  
Concrete Members ◽  
Numerical Stimulation ◽  
Numerical Computing ◽  
Chloride Environment ◽  
Cover Thickness

Finite difference method (FDM) is used to numerical stimulation analysis for chloride diffusion in concrete. By numerical computing, comparison of chloride content profile in different concrete members with different sectional shapes is made. Calculation and comparison show the chloride content prolife in rectangular and circular section has obvious difference. If the side length of rectangular section is equal to the diameter of circular section, as well as the material property and environment, the chloride content in rectangular section is higher than that in that in circular section. In the calculation example, the chloride content at the depth of reinforcement of circular section is about 50-60% that of rectangular section. This tendency is more remarkable in less section dimension, as well as less cover thickness. With the increasing of section, the ratio of difference becomes to be less until to a constant value. In durability design and service life prediction of concrete structures, the section shape and dimension influence should be taken to consideration.

scholarly journals Potentiometric Response of Ag/AgCl Chloride Sensors in Model Alkaline Medium

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Farhad Pargar ◽  
Hristo Kolev ◽  
Dessi A. Koleva ◽  
Klaas van Breugel
Keyword(s):  
Alkaline Medium ◽  
Open Circuit Potential ◽  
Dynamic Equilibrium ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Cementitious Materials ◽  
Open Circuit ◽  
Potentiometric Response ◽  
Before And After ◽  
The Stability

The stability and reproducibility of an Ag/AgCl sensors’ response in an alkaline medium are important for the application of these sensors in cementitious materials. The sensors’ response, or their open circuit potential (OCP), reflects a dynamic equilibrium at the sensor/environment interface. The OCP response in an alkaline medium is affected by the presence of hydroxide ions. The interference of hydroxide ions leads to inaccuracies or a delay in the sensors’ response to a certain chloride content. In this article, the potentiometric response (or OCP evolution) of the chloride sensors is measured in model solutions, resembling the concrete pore water. The scatter of the sensors’ OCP is discussed with respect to the interference of hydroxide ions at varying chloride concentration in the medium. The deviation of the sensor’s response from its ideal performance (determined by the Nernst law) is attributed to dechlorination of the AgCl layer and the formation of Ag2O on the sensor’s surface. Results from the surface XPS analysis of the AgCl layer before and after treatment in alkaline medium confirm these observations in view of chemical transformation of AgCl to Ag2O.

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