Effect of Pavement Stiffness on the Shape of Deflection Bowl

The paper introduces a new method for calculating the elastic moduli of pavement layers. The method requires only two input par ameters: the thickness of the upper „bound” layer and the Falling Weight Deflectometer (FWD) or Improved Benkelman Beam Apparatus (IBBA) measurement data. The authors developed a continuously differentiable regression function, which can be applied to desc ribe the shape of the deflection bowl. Additional parameters of the deflection bowl (e.g. radius of curvature, position of inflexion point) can be calculated based on the regression function. FWD measurements were simulated running the BISAR (Bitumen Stres s Analysis in Roads) software on different pavement variations. Outputs of the simulations were further processed with self - developed software. As a result, a series of diagrams were elaborated, by which the elastic moduli of the pavement layers can be det ermined.