Study on understanding functional characteristics of multi-wall CNT modified asphalt binder

Abstract

ABSTRACT This study evaluates important functional characteristics such as dispersion, aging resistivity potential, temperature susceptibility, and high temperature storage stability of Carbon Nano Tube (CNT) modified asphalt binders. CNT content was varied as 0%, 0.4%, 0.75%, 1.5% and 2.25% by weight of control binder (AC-10). Scanning Electron Microscopic (SEM) images was captured to get direct observation of CNT dispersion. Viscosity was further measured to understand the workability and dispersion characteristics. Further, viscosity temperature susceptibility parameters (A and VTS), activation energy and Penetration Index (PI) values were estimated to evaluate temperature susceptibility. SEM images and viscosity data showed that CNT content up to 1.5% may be recommended without potential problem of entanglement/clustering. Similarly, analysis of softening point, complex modulus and phase angle data showed positive effect of CNT on aging resistivity potential. Such improvement in functional characteristics can be attributed to high specific surface area (190 m2/gm), higher aspect ratio (length/diameter = 645) and excellent mechanical properties of CNT. Likewise, high temperature storage stability was evaluated using softening point and Multiple Stress Creep Recovery (MSCR) tests. Though softening point test method showed sufficiently stable nature of CNT under high temperature storage condition, settling of CNT (unstable nature) was observed from MSCR testing approach.