| Light weight deflectometers (LWDs) are increasingly being used in earthwork QC/QA testing to provide rapid determination of elastic modulus, which is an essential input for mechanistic pavement design. To successfully implement the use of these devices, it is important to understand how operating conditions affect the measurements and if differences exist between the various manufacturer devices. This paper provides a review of basic principles, different manufacturer LWD equipment, and correlations between LWD elastic modulus (ELWD) and moduli determined from other in-situ testing devices. Comparison test measurements for three different LWD devices with different plate diameters, plate contact stresses, buffer stiffnesses, and measurement techniques, and correlations with static plate load test measurements are reported in this paper. |
