Chloride Diffusion Analysis of Concrete Members Considering Depth-Dependent Diffusion Coefficients and Effect of Reinforcement Presence

2016 ◽  
Vol 28 (5) ◽  
pp. 04015183 ◽  
Author(s):  
Yuanzhan Wang ◽  
Qingmei Li ◽  
Chen’anpan Lin
2012 ◽  
Vol 204-208 ◽  
pp. 3194-3200
Author(s):  
Xin Gang Zhou ◽  
Hui Xia

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.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1166 ◽  
Author(s):  
Ahmed Abd El Fattah ◽  
Ibrahim Al-Duais ◽  
Kyle Riding ◽  
Michael Thomas ◽  
Salah Al-Dulaijan ◽  
...  

Reinforcing steel corrosion, caused by chloride ingress into concrete, is the leading cause of reinforced concrete deterioration. One of the main findings in the literature for reducing chloride ingress is the improvement of the durability characteristics of concrete by the addition of supplementary cementitious materials (SCMs) and/or chemical agents to concrete mixtures. In this study, standard ASTM tests—such as rapid chloride permeability (RCPT), bulk diffusion and sorptivity tests—were used to measure concrete properties such as porosity, sorptivity, salt diffusion, and permeability. Eight different mixtures, prepared with different SCMs and corrosion inhibitors, were tested. Apparent and effective chloride diffusion coefficients were calculated using bound chloride isotherms and time-dependent decrease in diffusion. Diffusion coefficients decreased with time, especially with the addition of SCMs and corrosion inhibitors. The apparent diffusion coefficient calculated using the error function was slightly lower than the effective diffusion coefficient; however, there was a linear trend between the two. The formation factor was found to correlate with the effective diffusion coefficient. The results of the laboratory tests were compared and benchmarked to their counterparts in the marine exposure site in the Arabian Gulf in order to identify laboratory key tests to predict concrete durability. The overall performance of concrete containing SCMs, especially fly ash, were the best among the other mixtures in the laboratory and the field.


Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5522
Author(s):  
Jerzy Jasielec ◽  
Jakub Stec ◽  
Krzysztof Szyszkiewicz-Warzecha ◽  
Artur Łagosz ◽  
Jan Deja ◽  
...  

A non-equilibrium diffusion–reaction model is proposed to describe chloride transport and binding in cementitious materials. A numerical solution for this non-linear transport with reaction problem is obtained using the finite element method. The effective chloride diffusion coefficients and parameters of the chloride binding are determined using the inverse method based on a diffusion–reaction model and experimentally measured chloride concentrations. The investigations are performed for two significantly different cements: ordinary Portland and blast furnace cements. The results are compared with the classical diffusion model and appropriate apparent diffusion coefficients. The role of chloride binding, with respect to the different binding isotherms applied, in the overall transport of chlorides is discussed, along with the applicability of the two models. The proposed work allows the determination of important parameters that influence the longevity of concrete structures. The developed methodology can be extended to include more ions, electrostatic interactions, and activity coefficients for even more accurate estimation of the longevity.


2017 ◽  
Vol 69 (3) ◽  
pp. 134-144 ◽  
Author(s):  
Qing-feng Liu ◽  
Dave Easterbrook ◽  
Long-yuan Li ◽  
Dawang Li

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