Study of the Stiffening in Asphalt Mastic at Low Temperatures Using a Heterogeneous Micromechanical Model

The investigation pertains to the influence exerted by varying volume filling ratios (VFR) of filler materials upon the flexural creep stiffness of asphalt mastic. This inquiry is facilitated through the utilization of the Bending Beam Rheometer (BBR). This study engages in a comparative analysis, aligning the outcomes derived from exhaustive experimental inquiries with numerical models rooted in biphasic heterogeneous micromechanics, known as finite element (FE) models. The principal aim herein is the introduction and elucidation of the concept termed the Effective Volume Filling Ratio (EVFR). To this end, a range of distinct VFRs spanning from 10% to 40% has been deliberately selected for the fabrication of asphalt mastic specimens. The observed outcomes underscore that when the VFR is confined to values less than or equal to 20%, the disparities between the finite element model predictions and experimental results remain inconsequential. However, as the VFR surpasses this threshold, a conspicuous escalation in stiffening tendencies and percolation phenomena is witnessed, engendering heightened disparities between the empirical findings and the computational predictions derived from the finite element models.