A new dynamic apparatus for asphalt mix fatigue and stiffness modulus: development, validation and numerical simulations

ABSTRACT

The main aim of this paper is to describe the development and validation of a new test apparatus for measuring complex stiffness modulus and fatigue of asphalt mix, so-called FADECOM. Both evaluations are executed with cyclic loading and continuous modes, in order to demonstrate the effectiveness of test results when applied to asphalt pavement design solutions. Results obtained with the new apparatus are compared to existing methods designed on the same mechanical principles, and which are already calibrated and taken as international standardized references. Methods presented in this paper are based on Discrete Fourier Transform (DFT) analysis of data recorded by the test apparatus; a parametric code which executes the analysis was implemented in C++. Interlaboratory comparisons of test results with FADECOM indicate random deviations of approximately 3 microstrains (x 10^-6 µdef) for determination of fatigue strain at 10⁶ cycles, and less than 10% relative difference for complex stiffness modulus. Agreement with FADECOM demonstrates direct applicability of the new method for obtaining accurate data for dynamic numerical simulations comprising asphalt pavement design.

Keywords
Rheological-mechanical performance evaluation; Complex modulus; Fatigue; Asphalt mix; Pavement design