Remaining service life (RSL) has been defined as the anticipated number of years that a pavement will be functionally and structurally acceptable with only routine maintenance. The Kansas Department of Transportation (KDOT) employs a comprehensive pavement management system with a network optimization system (NOS) that uses the RSL concept. In support of NOS, annual condition surveys are conducted. Currently, KDOT uses an equation to compute RSL of flexible pavements based on surface conditions and deflection from the last sensor of a falling-weight deflectometer. However, a rolling-wheel deflectometer (RWD) can be used to collect deflection data at network-level. Thus, a model that can calculate RSL of pavements in terms of center deflection (the only deflection measured by RWD) is desired for NOS. In this study, FWD deflection data, collected with a Dynatest 8000 FWD on the KDOT network from 1998 to 2006, were analyzed. Nonlinear regression procedure in the Statistical Analysis Software and Solver in Microsoft Excel were also used. The results showed a sigmoidal relationship exists betweenRSL and center deflection. Sigmoidal RSL models have very good fits and can be used to predict RSL at the network level based on the center deflection from FWD or RWD. Sigmoidal equivalent fatigue crack models have also shown good fits, but with some scatter that can be attributed to the nature and quality of the data used to develop these models. Predicted and observed equivalent transverse crack values do not match well, though the difference is insignificant from a practical point of view.
Samenvatting