PSI - Issue 64

Jian-Neng Wang et al. / Procedia Structural Integrity 64 (2024) 1605–1612 / Structural Integrity Procedia 00 (2019) 000–000

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0.015% to 12.5% (150~125000 ppm). We conducted a linear regression analysis to study the relationship between sensed responses and sodium chloride solution concentration changes. This least square approach analysis for the measured data is based on the best-fitting linear equation. A linear relationship between transmission loss and the fresh concrete supernatant (W/C = 0.35 and W/C = 0.65) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5% was established (the adj. R-Square values were 0.87207 and 0.97876 for fresh concrete supernatant with W/C = 0.35 and W/C = 0.65, respectively, see Fig. 5). The chloride ion-selective electrode (ISE) sensor (CL-1B) is typically used for sensing chloride ion concentration in fresh concrete or aggregate [see Fig. 2(b)]. Fig. 6 (a) exhibits the plot of the chloride ion concentration versus aqueous samples of fresh concrete supernatant (W/C = 0.35) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5% using the chloride ion-selective electrode (ISE) sensor; Fig. 6 (b) shows the plot of the chloride ion concentration versus aqueous samples of fresh concrete supernatant (W/C = 0.65) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5% using the chloride ion-selective electrode (ISE) sensor. Fig. 6 shows the chloride ion concentration were linear proportional to aqueous samples of fresh concrete supernatant with sodium chloride solutions in different concentration ranges using a chloride ion-selective electrode (ISE) sensor. A linear relationship between chloride ion concentration and the fresh concrete supernatant (W/C = 0.35 and W/C = 0.65) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5% was established (the adj. R-Square values were 0.99892 and 0.99837 for fresh concrete supernatant with W/C = 0.35 and W/C = 0.65, respectively, see Fig. 6).

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Fig. 4. (a) Spectra of the Mach–Zehnder interferometer for sensing in air and aqueous samples of fresh concrete supernatant (W/C = 0.35) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5%; (b) Spectra of the Mach–Zehnder interferometer for sensing in air and aqueous samples of fresh concrete supernatant (W/C = 0.65) with sodium chloride solutions in different concentration ranges from 0.015% to 12.5%.