Using Evenness Data for the Systematic Application of the Falling Weight Deflectometer on Concrete Roads

Paper by STAMMLER FREUND ROOS from ISCR 10th 2006 Brussels Belgium

In many countries the Falling Weight Deflectometer (FWD) is used to assess bearing capacity and thereby the structural condition of concrete roads. Due to the fact that the FWD is a stationary measuring system it can be used only for object related assessment of bearing capacity, but not for network-level evaluation of structural conditions. While deflection measurement at high speed is still in development there is a need for a guiding system to improve the efficiency of FWD measurements. A chance to develop such a system could be the use of evenness data of High- Speed Profilometer. Both systems FWD and High-Speed Profilometer have been deployed in several research projects having been realised on German highways. It could be shown that evenness data provide information about single structural damage incidents like faulting. Apparently evenness data seem to provide a “fingerprint” of a road section potentially describing the structural condition of a concrete road. To analyse this “fingerprint” an existing method was adjusted to characterise 100 m-sections. By using this characterisation critical sections can be detected and subsequently examined more closely by bearing capacity measurements with the FWD. The whole proceeding is currently reviewed on a 60 km highway section. For this section evenness data from several years as well as surface condition survey data have been analysed. In specific selected sections bearing capacity measurements have already been realised. To verify the above mentioned assumptions the results are being analysed. The proceeding is described and the conclusions drawn are stated.

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