Evaluation of the Lightweight Deflectometer for In-Situ Determination of Pavement Layer Moduli

摘要

The quality of base and subgrade construction has conventionally been evaluated using specifications based on density and moisture content. Such specifications for highway base and subgrade require the use of a nuclear density and/or moisture gauge that poses potential health hazards to the operator and requires expensive certification and monitoring. Moreover, density and moisture do not relate to pavement design input parameters or performance. The fundamental material properties such as elastic and resilient moduli that are key inputs in the new mechanistic empirical-based design cannot be obtained from density and moisture content measurements. The primary objective of this study was to investigate the suitability of the lightweight deflectometer (LWD) to measure in-situ pavement layer moduli. The LWD, along with two other devices, the GeoGauge and dynamic cone penetrometer (DCP), were used to measure and monitor subgrade and base layer moduli during construction. Three existing gravel roads were also tested.