Csaba Toth, Ibolya Szentpeteri

Last modified: 2017-02-28


Although the pavement structures can be characterized by several condition parameters and thus qualified, some kind of load-bearing capacity parameter is one of the most important features. Nowadays there are many theoretical approaches and practical methods to define but the detection of the deflection of the structure caused by vertical load is still the most widely used. Presently the dynamic falling weight equipment is not only becoming more common but it is accepted in addition to the previous and widely recognized, so-called Benkelman beam method. This type of equipment called FWD is available in Hungary since the 90’s. It is well known that this device can record not only the deflection under load, but the deflections
also at arbitrary distance from load axle. So the new overlay design method that is currently under development by Hungarian Road Administration has been established based on this tool and, contrary to the previously used on, it experienced, requires the recording of the
deflection bowl. However, the deflection bowl and the shape factors describing it depend not only on the load-bearing capacity of the pavement structure and the magnitude of load force, but also
the measurement conditions also, especially the climatic conditions during the measurement (e.g. temperature, precipitation conditions) have significant impacts on it. Because of these effects are quite environment specific, it is advisable to study their impacts through
a more thorough examination of trial section so the distorting effect of these factors can be eliminated. In this paper, evaluations of four-year of meteorological data and deflection measurement series on a Hungarian road section were carried out to examine the change of
the deflection bowl’s parameters at different time points during the tests. In particular, the study focuses on the development of a correction factor that would be made based on the evaluation of the measuring results.


pavement deflection, subgrade modulus, temperature, precipitation, seasonal effect

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