Development and Calibration of a Laser-based Highway Deflection Measuring System

Despite recent developments, the measurement of actual pavement surface deflections under the axles of a moving truck at a network level remains a challenge in pavement engineering. Several pieces of equipment have been developed in the past decade but they fail to accurately measure actual deflection. Most of them measure indicators of deflection or deflection averages over a given distance. Pavement engineers recognize the usefulness of pavement deflection data to evaluating and monitoring pavement response and performance, assessing pavement structural conditions, and serving as an input for rehabilitation design. Network-level studies of pavement deflections are possible but have major limitations such as the lack of accurate measurements (actual deflection is not measured at any point), the inherent complexity, and safety concerns. Some accurate devices are available but they work at very low speed, posing safety concerns. The purpose of this project is to develop a laser-based highway deflection measuring system for network-level studies that continuously moves along the pavement at speeds of at least 10 mph.  This report is available online from the University of Texas at Austin's Center for Transportation Research at https://library.ctr.utexas.edu/ctr-publications/0-6873-2.pdf