Alternative FWD evaluation concepts

The following paper describes a more dynamic backcalculation approach that focuses on the time history of the
FWD. The time history allows a presentation of deflection against stress and vice versa. This consideration
represents a hysteresis loop, which allows a further interpretation of the deflection results. This alternative
evaluation methods is being utilised and compared to common evaluation methods, based on an actual
measuring campaign. The measuring site is a federal highway (B 22) in Bavaria: 2 km long, asphalt pavement
with surface cracks, measuring grid of 100 m. The result of this comparison is that common, as well as
alternative evaluation methods indicate structural deficiencies within the pavement – a rather strong correlation
can be drawn between the utilised evaluation methods. Furthermore, the alternative evaluation methods provide
further structural information that refine the possible range of significance and validity of FWD measurements.