Falling Weight Deflectometer
A falling weight deflectometer is a device used to evaluate the physical properties of road pavement.
The apparatus is heavy and is often trailer-mounted. It is designed to simulate and measure the effect of a wheel passing over a road pavement. A large weight is dropped onto a circular load plate on the pavement surface, and the resulting deflection is measured by sensors placed around the load plate. The sensors are typically geophones or force-balance seismometers.