ABSTRACT
The stiffness-based nondestructive devices have become popular for quality control purposes during construction of earthwork and unbound aggregate materials. Light Weight Deflectometers (LWDs) have been gaining popularity as a tool for quality control. The variability and uncertainty associated with their results should be evaluated under various field conditions and for different sources of geomaterials. Such variability could be either device-related, material-related or operator-related. This paper aims at studying the variability of two LWD devices. A number of laboratory and field studies were performed to estimate the variability of the LWD with respect to soil properties and moisture conditions. The sources of variability were then identified and correlated to moisture conditions. The differences in moisture contents at the time of compaction and quality control testing seems to affect the uncertainty of LWD test results. Furthermore, the operational mechanism of the device measurements impacts the estimated moduli.
