Procedure for Optimum Pavement Deflection Test Spacings for Network-Level Applications

Structural models in pavement management systems range from the simple to the relatively complex. The simplest models use deflections or deflection basin parameters to characterize subgrade and pavement structural properties, while the more complex ones use pavement layer moduli (derived from deflections) and pavement layer thicknesses and material types to calculate pavement response, which is then used to predict failure, much like project-level pavement design analysis. Any pavement management system using the latter, more complex approach would undoubtedly need more defection information. In any case, deflection data collection is expensive and time-consuming. Most states and local agencies have few falling weight deflectometers, which are used mainly to collect project-level deflection data for scoping maintenance and rehabilitation work at the project level and for research purposes. This study explores the use of models to estimate the error associated with the choice of different deflection test spacings that can be used to optimize data collection for more efficient and economical applications in pavement management systems.