The impact of carbon nano-fiber modification on asphalt binder rheology

Nano-reinforced materials hold the potential to redefine the field of transportation materials both in terms of cost effectiveness and long term pavement performance. This study focuses on the exploratory analysis of the mixing procedure of carbon nano-fibers (CNFs) with asphalt cement (AC) and discusses the visco-elastic and fatigue characteristics of neat and CNF-modified AC binders. Three types of AC were modified with varying percentages of CNF. Two CNF-asphalt mixing procedures, dry process and wet process, were investigated. The dynamic shear rheometer was utilized to determine complex shear modulus (G∗), phase angle (δ), and fatigue characteristics of neat and CNF-modified AC for a range of temperatures and loading frequencies. The G∗/sin δ values and rotational viscosity analyses revealed that the CNF-modified AC exhibited improved visco-elastic response and resistance to rutting. Furthermore, substantial increases in fatigue life were observed with CNF modification.

► Optimum carbon nano-fiber dispersion in kerosene was obtained using sonication and high shear mixing.
► Carbon nano-fiber modification increases the viscosity, shear complex modulus and fatigue life of asphalt.
► Improvement in fatigue life was attributed to crack bridging mechanism by carbon nano-fiber in asphalt.