DETERMINATION OF PAVEMENT THICKNESS WITH A NEW ULTRASONIC DEVICE.

Abstract

An instrument used primarily to monitor the thickness of PCC slabs has been designed. In addition, the device provides information about the quality of concrete. The quality and the thickness are determined by estimating Young's and shear modui in the PCC from the following wave propagation measurements: 1) Impact Echo, 2) Ultrasonic Surface Wave, and 3) Ultrasonic Body Wave Velocity. The instrument designed and constructed to make these measurements contains two accelerometers. Data acquisition, instrument control, and interpretation are computer controlled, with measurements and interpretations reported in both screen and database formats. In this report, the construction of the device is described. The problems associated with it are also discussed, along with the results from several field testing programs. In general, it was found that the device is quite promising but needs some modifications. These modifications are currently being implemented. Implementation Statement At this time, the implementation of this study's results is quite possible. A prototype of the device has been delivered to TxDOT, along with the necessary software packages. In our opinion, the fmdings should be immediately implemented on a trial basis so that any logistical or practical problems associated with the device or algorithms can be addressed.