PSI - Issue 64

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

1612

8

8.07, 9.75. The transmission intensity of the MZI sensor incited by the broadband light source was discovered to possess linear relationship with the increase of the sodium chloride solution concentration. A linear fit (adj. R-Square = 0.87207 and 0.97876 for fresh concrete supernatant with W/C = 0.35 and W/C = 0.65, respectively) for the graph of sensing response, transmission loss, as a function of the chloride solution concentration for this MZI sensor with sensing length of 8 cm. The optical fiber MZI sensing platform has shown the capacity for monitoring of chloride ion concentrations in the ranges from 150 ppm to 125000 ppm. Based on the optical fiber pH sensing results, a linear fit for the maximum intensity (counts) as a function of the different pHs of the standard solution for this optical fiber pH sensing system. We found a linear increase in the maximum intensity (counts) as the pH of standard solution increased from1 to 9.75 (adj. R-Square = 0.91367). Hopefully, the optical fiber sensing for either sensing chloride ion concentrations or pHs reported here could benefit the development and applications such as the field of civil engineering especially for monitoring chloride ion concentration and pHs of concrete structures. References Al-Hayali, S. K., Salman, A. M., & Al-Janabi, A. H. , 2022. Low-cost high-sensitivity pH sensor based on a droplet-shaped single-mode fiber Mach–Zehnder interferometer. Optical Fiber Technology, 71, 102944. Behnood, A., Van Tittelboom, K., & De Belie, N., 2016. Methods for measuring pH in concrete: A review. Construction and Building Materials, 105, 176-188. Lin, J., 2000. Recent development and applications of optical and fiber-optic pH sensors. TrAC Trends in Analytical Chemistry, 19(9), 541-552. Liu, J., Qiu, Q., Chen, X., Xing, F., Han, N., He, Y., & Ma, Y., 2017. Understanding the interacted mechanism between carbonation and chloride aerosol attack in ordinary Portland cement concrete. Cement and Concrete Research, 95, 217-225. Nguyen, T. H., Venugopala, T., Chen, S., Sun, T., Grattan, K. T., Taylor, S. E., ... & Long, A. E., 2014. Fluorescence based fibre optic pH sensor for the pH 10–13 range suitable for corrosion monitoring in concrete structures. Sensors and Actuators B: Chemical, 191, 498-507. Tang, J. L., & Wang, J. N., 2007. Measurement of chloride-ion concentration with long-period grating technology. Smart materials and structures, 16(3), 665. Villatoro, J.; Minkovich, V.P.; Pruneri, V.; Badenes, G., 2007. Simple All-Microstructured-Optical-Fiber Interferometer Built Via Fusion Splicing. Optics Express, 15, 1491-1496. Villatoro, J.; Kreuzer, M.P.; Jha, R.; Minkovich, V.P.; Finazzi, V.; Badenes, G.; Pruneri, V., 2009. Photonic Crystal Fiber Interferometer for Chemical Vapor Detection with High Sensitivity. Optics Express,17, 1447-1453. Wang, J. N., 2011. A microfluidic long-period fiber grating sensor platform for chloride ion concentration measurement. Sensors, 11(9), 8550-8568. Wang, J. N., & Tang, J. L., 2012. Photonic crystal fiber Mach-Zehnder interferometer for refractive index sensing. Sensors, 12(3), 2983-2995.