title: Fiber-optic refractive-index sensor for use in fresh concrete.
abstract: We describe the development of a portable fiber-optic refractive-index sensor for detecting the air-bubble content in fresh concrete. The sensor uses a low-power visible laser diode as the light source. Data processing is performed in real time by a lap-top microcomputer. We introduce a new digital image-processing methodology for the interpretation of reflected-light intensity signals. Sensor performance is examined through laboratory and field studies on concrete poured at actual highway sites.
authors: F
authors: F
authors: Ansari
authors: Q Y
authors: QY
authors: Chen