MOISTURE SENSING IN STRUCTURAL MATERIALS USING NEAR-INFRARED FIBER OPTIC EVANESCENT FIELD SPECTROSCOPY

摘要

A fiber optic sensing system is explored for detection of moisture penetration through porous media such as concrete or fiber reinforced polymers. The transduction mechanism is based on the Near-Infrared Fourier Transform Attenuated Total Internal Reflection Spectroscopic (FT-NIR ATR Spectroscopy). The original cladding of an optical fiber is replaced with a new, porous cellulose acetate cladding which allows the penetration of water for optical interrogation. Absorption of OH at 1400nm and H{sub}2O at 1930 nm is shown as an effective technique for moisture monitoring in structural materials.