Heavy-weight Deflectometer Use on Non-traditional Pavement Structures

Abstract: The Heavy Weight Deflectometer (HWD) is a trailer-mounted, non-destructive testing device used to evaluate the structural capacity of pavement systems by measuring surface deflections created by dynamic loads. While it is most commonly used to back-calculate layer stiffness in conventional flexible and rigid pavements, the HWD also demonstrates effectiveness across a wide variety of non-traditional applications. These include aggregate base layers, chemically stabilized soils, compacted snow surfaces, and many types of large-scale pavement repairs. Its ability to provide real-time estimates of overall stiffness makes the HWD a valuable tool not only for structural assessment, but also for informing critical decisions such as determining if a pavement or repair is ready to open to traffic after construction or after extreme weather events. This paper presents and analyzes HWD data collected from diverse pavement structures, highlighting both traditional and non-traditional applications. Several of these case studies feature repeated HWD testing on the same locations, allowing for evaluation of stiffness development over time. The results are summarized to identify typical stiffness levels for various materials and conditions. These values offer practitioners a useful baseline for interpreting HWD data and establishing their own thresholds for quality control, quality assurance, or other decision-making processes involving overall pavement stiffness.