Calculation of chloride ion concentration in expressed pore solution of cement-based materials exposed to a chloride salt solution

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• 作者：Fuqiang He^a ; ^b ; ^{77163594@qq.com" class="auth_mail" title="E-mail the corresponding author} ; Caijun Shi^c ; Xiang Hu^c ; Ruipan Wang^c ; Zhenguo Shi^d ; Qingling Li^c ; Pingliang Li^c ; Xiaopeng An^c
• 关键词：Free chloride ion concentration ; Expressed pore solution ; Cement-based materials ; Electrical double layer ; Overlapping phenomenon of the diffuse layer
• 刊名：Cement and Concrete Research
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：89
• 期：Complete
• 页码：168-176
• 全文大小：986 K

文摘

To investigate the relationship between the chloride ion concentration of the expressed pore solution (C_e) and the exposure solution (C_es) of cement-based materials exposed to a chloride salt solution, a calculation of the C_e, based on an electrical double layer (EDL) model was proposed. The C_e values were calculated using the proposed equations, applying the measured parameters: relative potential (δψ₀), dielectric constant (ε), porosity (P), bulk density (D), volume percentage (p_i) of pores with diameter d_i. The calculations explain why C_e does not always equal to C_es. The results indicate that the expression method does not test the concentration of free chloride ions in the bulk solution (C_Cl⁻_b) or the average concentration of the transportable chloride ions (C_ttr.a) in the pores. However, the ratio (C_r) of C_e to C_Cl⁻_b and the relationship between C_e and C_ttr.a can be calculated to more accurately measure chloride ion migration in cement-based materials.