Evaluation of Road Materials with Ultrasonic Method

Abstract

　　　Our study demonstrates the ultrasonic system installed on the moving vehicle, which is capable to detect the conditions of road materials, i.e., to distinguish among dry, wet, icy and snowy surfaces. Initially, five kinds of road material were used to examine and verify the possibility of their detection by ultrasonic measurement during moving. The airborne ultrasonic wave (the central frequency of 40 kHz) propagates toward the specimen, and reflects at the interface of air and material surface due to the difference acoustic impedance as well as surface condition. The reflected ultrasonic wave is received by the ultrasonic transducer and recorded to the oscilloscope. The ultrasonic system was set on the hand cart and moved 10m with walking speed. Five kinds of road material were detected and characterized using the deviation of maximum amplitude of the ultrasonic wave.