Novel Application of the Falling Weight Deflectometer Test: Detection of Surface and Subsurface Distresses

Falling Weight Deflectometers (FWD) and Traffic Speed Deflectometers (TSD) have become increasingly popular for monitoring the structural performance of roadway pavements. However, many transportation agencies measure the functional performance of the pavement (given by surface distresses such as cracking, rutting and raveling) for maintenance purposes. This study explored the feasibility of estimating surface and subsurface distresses using FWD tests. It was found that the presence of pavement cracking can be detected through FWD tests but not pavement rutting. A random forest classifier was used to predict the presence of cracking between layer interfaces below the pavement surface. The classifier achieved an accuracy of 92.3%. With the methodology presented in this paper, FWD tests can be used to measure the structural as well as functional performance of pavements. The methodology also serves as a proof-of-concept for using TSDs to measure the functional performance of pavements at high speeds. This provides an alternative to unsafe and laborious on-foot survey practices.