Model to Estimate Pavement Structural Number at Network Level with Rolling Wheel Deflectometer Data

Abstract

Nondestructive testing provides key information about the structural integrity and the capacity of in-service pavements. The rolling wheel deflectometer (RWD) was introduced to support existing nondestructive testing techniques by providing a screening tool for structurally deficient pavements at the network level. The objective of this study was to develop and validate a direct and simple model for determining the pavement structural number (SN) by using RWD deflection data. To achieve this objective, the relationship between the average RWD surface deflection and the peak falling weight deflectometer (FWD) deflection was investigated. The developed model correlated pavement SN with three RWD-measured properties: average and standard deviation of RWD deflection and RWD index. The developed model was fitted to RWD data collected in 16 road sections (each 1.5 mi long), referred to as research sites, in Louisiana. The model was then validated on the basis of data from the FWD and RWD collected on 52 road sections in Louisiana. Results showed agreement between SN calculations obtained from FWD and those from RWD deflection testing. Although the developed model is independent of pavement thickness and layer properties, it provides promising results as an indicator of pavement structural integrity at the network level. The fitting statistics support the use of the proposed model as a screening tool for identifying structurally deficient pavements at the network level.