Structural Field Testing of Flexible Pavement Layers with Seismic Methods for Quality Control

Current mechanistic procedures for structural design of flexible pavements consider the modulus and Poisson’s ratio of each layer. Unfortunately, the construction specifications are not based on these engineering properties. The acceptance criteria typically are based on adequate density of the placed and compacted materials. To successfully implement any mechanistic pavement design procedure, and to move toward performance-based specifications, it is essential to develop tools that can measure the modulus and Poisson’s ratio of each layer. Presented is an approach to such a program based on seismic testing. Field protocols and test equipment, which in a rational manner combine the results from laboratory and field tests with those used for quality control during construction, are discussed. A series of simplified laboratory tests that are compatible with the field tests also can be used; these methods are discussed. Several case studies are included to present some results that can be obtained with the methodology. Several issues that remain to be addressed are included.