Application of deflection bowl parameters for assessing different structures of road pavement

Abstract

To date, non-destruction testing (NDT) method is the most popular method to assess the condition of road pavement. Among all evaluation procedures of the NDT method, load-deflection backcalculation analysis is one that is developed widely to understand the structural behavior of road pavement. On one side, the use of this analysis is greatly beneficial for presenting the layer characteristic accurately. However, the analysis requires specialist expertise. To overcome this, deflection bowl parameter application could become one alternative. The parameters are very easy to use; however, the intention of the parameters so far is only as an indication of the condition of the structural layer of the road pavement. Therefore, the parameters have to be used with careful consideration. In this study, the parameters were evaluated to determine the optimal usage of the parameters against different structures of road pavements. The results showed that a simplification of the number of parameters and a reformulation of the parameters were required by taking into account the ease of use in practice, the accuracy of subgrade modulus determination and the possibility to evaluate pavement structures with a layer number less than four.