Evaluating interaction of fibre reinforcement mechanism with mesostructure of asphalt concrete

ABSTRACT

Published studies generally demonstrate positive benefits from using Mechanically Fibre-Reinforced Asphalt Concrete (M-FRAC). However, improvements vary with the particular asphalt mixture used in previous studies. The specific objectives of this study were to evaluate the mechanical properties of various asphalt mix designs reinforced with and without aramid fibres, to identify and quantify the key factors in the composition of asphalt mixtures that facilitate to the reinforcement mechanism of fibres, and finally associate the effect of asphalt mixture constituents on laboratory modulus, rutting and fatigue performance of M-FRAC. A total of seven different asphalt mix designs from across the United States were used in this study. For each mixture a non-fibre-reinforced variant and an M-FRAC variant were created and compared. Results showed that while overall fibres can improve the mechanical performance of asphalt mixtures, the degree of improvement varies from one mix to another. Further analysis and interpretation of the mixtures constituents revealed that there is a strong link between fibre reinforcement efficiency and composition of the asphalt mixtures. In particular, it was found that the effective binder content and gradation of the asphalt mixtures are good indicators of the likely performance benefit of M-FRAC with respect to rutting and fatigue cracking, respectively.

KEYWORDS:

• Mechanically fibre-reinforced asphalt concrete
• aramid fibres
• mechanical performance
• asphalt mixture composition/mesostructured
• effective binder volume voids $(V_{be})$
• fine aggregate mixture/matrix (FAM)

Disclosure statement

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

Additional information

Funding

This work was supported by FORTA Corporation [grant numbers FP00003688, FP00007244, P00015493].