Pavement surveys for layer thickness and base layer material properties
Bridge deck condition surveys for delamination and steel depth
Construction quality control, steel depth and alignment and utility location
Although the technology offers significant promise of cost effective applications for pavements and bridges, there have been ongoing problems with implementation and misrepresentation of interpretation software capabilities and appropriate radar systems for various uses. The Department recently purchased a 1.0 Gigahertz ground-coupled GPR unit for use in evaluating steel location and depth for SD2004-07 Impact, Cause, and Remedies for Excessive Cracking in CRC Pavement. Although the unit only recently arrived, it is proving to be of considerable value though it does have limitations, as does any remote sensing, nondestructive system. Initial results highlight the need for caution when attempting to do everything with one system as the frequency of the radar antennae and the type of coupling used (air or ground) can make considerable differences in resolution and acquisition speed.
Research is needed to assess the current state of GPR technology and available systems for different uses. Once this is accomplished, the proposed utilization of this technology by the Department can move forward in a rational way, if the research suggests the technology is ready for deployment. The research would also examine the suitability of different configurations for different applications, provide a cost-benefit analysis and make recommendations for purchase and deployment of one or more radar systems depending on results. The research would also clearly delineate the shortcomings of various systems and provide a realistic context for usage that would not try to obtain more from the technology than it is capable of or use it inappropriately.