Current and proposed practices for nondestructive highway pavement testing

Abstract : In September 1994 the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) distributed a short survey on nondestructive testing practices to each of the 50 state Departments of Transportation (DOTs). The compilation of results constituted Phase I of a multiphase effort intended to lead toward the development of a method for optimizing falling weight deilectometer (FWD) test point spacing. Planned spatial statistical analyses on selected data sets will yield (site-specific) optimal FWD test point spacing for road network evaluation and pavement overlay design. Optimal FWD test point spacing reduces conservative overdesign due to undertesting and reduces overtesting. Both of these ultimately reduce expenditures. Although the above effort has not been completed, this interim report outlines the proposed process. Also included (and perhaps of more immediate interest to state DOTs) are direct survey facts and figures, including number of states with nondestructive testing (NDT) devices, average number of miles of annual overlay design, average number of miles of network/inventory testing, and back-calculation programs and overlay design procedures used. All facts and figures are generic and honor state anonymity.