The results of a comprehensive evaluation of five sensors used in pavement instrumentation are discussed. These five sensors are velocity transducer (geophone), accelerometer, linear variable differential transformer, laser optocator, and proximeter probe. The sensors were selected because of their commercial availability and their potential effectiveness in deflection measurement. The main two parameters studied were the accuracy and precision of each sensor. These parameters were studied in a laboratory environment to minimise the effects of uncertainties that may affect the results. Various impact shapes and duration were investigated. The magnitude of deflection was also varied over a wide range. In addition, factors such as cost and field-worthiness were also considered. It was found that for pavement evaluation, geophones appear to be the optimum sensors. Geophones, if used properly, will provide adequate accuracy and precision at minimal cost. (Author/publisher)
Abstract