Estimation of Remaining Pavement Life of Low-Volume Roads with Falling Weight Deflectometer Results: A Practical Method

Document Type

Journal Article

Publication Date


Subject Area

place - oceania


Vertical strain, Subgrade (Pavements), Service life, Rutting, Roadbeds, Pavement subgrades, Pavement performance, New Zealand, Low volume roads, Highway subgrade, FWDs, Falling weight deflectometers, Estimating, Design life, Deflection, Backcalculation, Australia, Accelerated tests


A practical method to estimate the remaining pavement life of low-volume roads is presented that uses the results of falling weight deflectometer (FWD) measurements. The method was developed from observations of accelerated pavement tests, and additional field results from Transit New Zealand’s asset management database are presented. Methods currently used in Australia and New Zealand to predict the remaining life of pavements are based on linear elastic backcalculation of FWD tests with the association of Australian and New Zealand road transport and traffic authorities (Austroads) approach, in which the life of the pavement is related to the vertical compressive strain at the top of the subgrade. The vertical compressive subgrade strain is usually determined by linear elastic backcalculation of FWD tests. Industry has highlighted significant concern about the Austroads procedure in New Zealand and whether the traditional FWD analysis with the Austroads subgrade strain criterion can predict pavement life accurately. In response to industry concerns, accelerated pavement test results from the Canterbury Accelerated Pavement Testing Indoor Facility were used to develop a new pavement performance criterion that predicts rutting of a low-volume road. The remaining-life prediction procedure is based on central deflections from the FWD measurement results and uses the change in FWD test results between the start and end of the postcompaction period.