Detecting Voids under Pavements

Several accidents involving aircraft punching through airfield pavements prompted the U.S. Navy to develop a technology for void detection. Initially, a successful void detection survey was completed at a naval air station where several voids were generated by leakage of large underground drainpipes. Various methods were used, such as internal videotaping of the pipes, heavy weight deflectometer (HWD) testing, testing with a ground-penetrating radar, and testing with a dynamic cone penetrometer (DCP). A state-of-the-art review was also completed to assess all existing technology applicable to void detection under pavements. However, the optimum technology (visual inspection and testing with an HWD and a DCP) still presented limitations because of the availability and speed of data acquisition, requiring prioritization of the work. A risk analysis was then completed and established work prioritization within each airfield and providing a prioritization of all U.S. Navy and Marine Corps airfield pavements. An interim policy and technical guidance (IP&TG) was issued on March 23, 2000, to establish the void detection methodology developed. This IP&TG was recently updated and included as an appendix in U.S. Department of Defense Unified Facilities Criterion UFC 3-260-03 and routinely applied at all 70 major U.S. Navy and Marine Corps airfields. This paper summarizes the methodology used and presents some recent field cases.