Seismic Pavement Analyzer Vs Falling Weight Deflectometer For Pavement Evaluation

The purpose of using nondestructive testing techniques (NDT) for pavement evaluation is to obtain material properties at relatively low strain levels. Backcalculation methods that utilize surface deformation such as falling weight deflectometer (FWD) and Dynaflect assume linear elastic modeling for the pavement layers. Although the same assumption was considered for the seismic pavement analyzer (SPA) method, results obtained from these testing techniques did not conform to each other. To narrow the gap between the obtained pavement moduli values, a total of 22 pavement sites have been tested in Florida using deflection and seismic methods. Using the time-history records as well as the frequency response functions, pavement deformations from deflection and seismic methods were measured and related to the obtained moduli values. Relationships between deformation vs. pavement stiffness are presented. These relationships can be used to extract moduli values at any level of pavement deflection.