This test method covers the determination of pavement surface deflections as a result of the application of an impulse load to the pavement surface. The resulting deflections are measured at the center of the applied load and at various distances away from the load. Deflections may be either correlated directly to pavement performance or used to determine the in-situ material characteristics of the pavement layers. Some uses of data include structural evaluation of load carrying capacity and determination of overlay thickness requirements for highway and airfield pavements.

1.1 This test method covers the measurement of deflections of paved and unpaved surfaces with a falling-weight-type impulse load device. These devices are commonly referred to as falling weight deflectometers or FWDs.

1.2 This test method describes the measurement of vertical deflection response of the surface to an impulse load applied to the pavement surface. Vertical deflections are measured on the load axis and at points spaced radially outward from the load axis.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A specific hazard statement is given in Section 6.