Road Materials and Pavement Design. Vol. 9, No. 1, pp. 31-57, 2008
H.M. Yin
Transportation Lab, 5900 Folsom Blvd, Sacramento, CA 95819 USA
W.G. Buttlar
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Newmark Laboratory, 205 North Mathews Avenue, IL 61801, USA
G.H. Paulino
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Newmark Laboratory, 205 North Mathews Avenue, IL 61801, USA
H. Di Benedetto
Lab ENTPE, Dept Genie Civil & Batiment, Vaulx En Velin, France
Abstract
Micromechanical models have been directly used to predict the effective complex modulus of asphalt mastics from the mechanical properties of their constituents. Because the micromechanics models traditionally employed have been based on elastic theory, the viscoelastic effects of binders have not been considered. Moreover, due to the unique features of asphalt mastics such as high concentration and irregular shape of filler particles, some micromechanical models may not be suitable. A comprehensive investigation of four existing micromechanical methods is conducted considering viscoelastic effects. It is observed that the self-consistent model well predicts the experimental results without introducing any calibration; whereas the Mori-Tanaka model and the generalized self-consistent model, which have been widely used for asphalt materials, significantly underestimate the complex Young's modulus. Assuming binders to be incompressible and fillers to be rigid, the dilute model and the self-consistent model provide the same prediction, but they considerably overestimate the complex Young's modulus. The analyses suggest that these conventional assumptions are invalid for asphalt mastics at low temperatures and high frequencies. In addition, contradictory to the assumption of the previous elastic model, it is found that the phase angle of binders produces considerable effects on the absolute value of the complex modulus of mastics.
KEY WORDS: asphalt mastics; micromechanics; viscoelasticity; homogenization; stress and strain; complex modulus