Effective volume filling ratio of siliceous fillers within bituminous composites: experimental and micromechanical modelling

Abstract

The effect of different volume filling ratios (VFR) of filler on the flexural creep stiffness and complex shear modulus of bituminous composites can be identified using BBR and DSR test setups. This research compares the findings of extensive experimental studies with the biphasic heterogeneous micromechanical finite element (FE) models to introduce the Effective Volume Filling Ratio (EVFR). The different VFRs from 10 to 40% were selected to fabricate asphalt mastic samples. The effects of loading regime, temperature, loading frequency, and VFR on the mechanical behavior of asphalt mastic were investigated, and practical formulations were proposed to determine the EVFR for both shear and bending stiffening. It was found that for VFR ≤ 20%, the differences between the FE and test results are negligible under both loading schemes. However, higher VFRs cause a further increase in the stiffening and percolation effects which produce more differences between the experimental and FE results.

KEYWORDS:

• Bending beam rheometer (BBR)
• dynamic shear rheometer (DSR)
• microstructure
• finite element (FE)
• biphasic
• effective volume filling ratio (EVFR)

Disclosure statement

No potential conflict of interest was reported by the author(s).