Capabilities and Potential Applications of Continuous Pavement Deflection Measuring Devices

Abstract

Continuous pavement deflection measurment devices, or continuous deflectometers, were recently evaluated as part of a recent Strategic Highway Research Program 2 project number R06(F). Multiple devices were assessed, their capabilities evaluated and practical applications identified and illustrated. The objective of this paper is to present the results of a study that evaluated current technologies implemented in continuous deflection measuring devices with a focus on their potential use to obtain network level structural indices that can be used to support pavement management decisions. The evaluated indices are the Surface Curvature Index (SCI), the Base Damage Index (BDI), the strain at the bottom of the asphalt layer, and the effective structural number (SN eff ). These indices were calculated using the Traffic Speed Deflectometer (TSD) which is a continuous deflection device that was evaluated in the study and compared with indices calculated using the Falling Weight Deflectometer (FWD). The results suggest reasonable agreement between the TSD and FWD for the purpose of network level pavement management.