Quality assessment during road formation and foundation construction use of falling-weight deflectometer and light drop weight

Mechanistic empirical-based specifications, which focus on the mechanical properties of materials, facilitate quantitative evaluations of alternative construction practices and materials such as reclaimed materials. Thus, to represent these mechanical properties, quality-control and -assurance testing would be expected to include stiffness along with density measurements. In two case studies, a falling-weight deflectometer (FWD) was used during the construction of two major interchanges in Israel. FWD testing was found to be very useful in identifying local spots with poor performance, thus enabling execution of the required remedy actions. The two studies also indicated that, for a given feature, both a representative central deflection at the 95 percent reliability level and a coefficient of variability of measured deflections may serve as potential quality-control indicators. The possible use of the German light drop-weight (LDW) device for measuring the mechanical properties of the formation of flexible pavements was also examined. Based on the cost per test, rate of testing, and quality of the data, the German LDW can serve as a cost-effective testing device for quality control and assurance during subgrade and capping-layer compaction.