Evaluation of the Pavement Structure of Concrete Road Constructions Using the Falling Weight Deflectometer (FWD)

In view of increasing operation and maintenance requirements on existing concrete roads, it is im-portant to gain knowledge about their present bearing capacity. For this task, the Falling Weight Deflectometer (FWD) has proved to be of practical value for years in Germany and other countries worldwide. The FWD is a non-destructive dynamic system. It uses a defined pulse which is applied by a load to the pavement to simulate the magnitude and duration of a heavy moving wheel load. The reac-tion to this pulse in the form of a deflection bowl in the pavement is recorded. Measurements on concrete roads concentrate on the concrete joints, so that the deflection bowl at the loaded and unloaded slab is used for evaluation and the shear force transmission at the slab joint can be evaluated. Furthermore it is also possible to evaluate the bearing conditions of the subgrade, the bearing capacity of the construction and the bearing behavior. Therefore different evaluation patterns have been developed by the Institute of Highway and Rail-road Engineering.