The article is devoted to the method of calculating the effective frequency of the load impulse FWD, which allows establishing a correspondence between the laboratory-determined viscoelastic characteristics of asphalt concrete layers included in the road pavement and the modulus of elasticity calculated by backcalculation based on the deflection  bowl determined in field tests using FWD. The article proposes an algorithm for finding this frequency, presents the results of its calculations, and compares the elastic moduli obtained in the laboratory and by the results of the backcalculation. The conducted numerical experiment confirms that for the deflection cups generated within the viscoelastic calculation model, the difference in modules does not exceed 8%. At the end of the work, ways are proposed for the practical application of the calculated parameter and further improvement of the method on real deflection  bowl obtained on  road pavements.

Keywords: dynamic loading system, road surface, deflection bowl, asphalt concrete, elastic modulus, relaxation modulus, AMPT test, master curve, backcalculation, effective pulse frequency

The article is devoted to assessing the influence of possible inhomogeneities in the layers of road pavements on the results of backcalculation of elastic moduli based on testing data of falling weight deflectometres (FWD). The article discusses the influence of different locations of theoretically specified inhomogeneities of structural layers within the roadway. Additionally, the influence of the location of the edge of the pavement on the results of calculating elastic moduli by backcalculation is considered. The conducted numerical experiment confirms that possible inhomogeneities of the road pavement can significantly influence the results of reverse calculations, and as a consequence, the decision-making on the appointment of repair measures. The boundaries are also determined at which the presence of a shoulder with a pavement design that differs from the roadway significantly distorts the results obtained. At the end of the work, ways to practically take into account inhomogeneities and further improve the method of inverse calculation of the elastic moduli of non-rigid road pavements are proposed.

Keywords: dynamic loading system, road pavement,structural layers, deflection bowl, asphalt concrete, elastic modulus, backcalculation, heterogeneity of layers, roadway, roadside