ABSTRACT
The paper addresses the aging of Styrene-Butadiene (SB) and Styrene-Butadiene-Styrene (SBS) modified asphalt in the presence of Carbon Nano Tube (CNT) at nano scale. The binders are modified with CNT and then conditioned for unaged and aged environment and finally evaluated by the means of an Atomic Force Microscopy (AFM). To simulate the chemistry of asphalt, the AFM tips were functionalized with existing functional groups of asphalt binder, namely, amine (–NH3), methyl (CH3), carboxyl (COOH), and hydroxyl (OH). The difference of adhesion/cohesion force for unaged and aged samples indicates the changes in asphalt proprieties at nano level. The evaluation was carried out for 4% and 5% of SB and SBS with CNT (0.5%, 1.00% and 1.5%). It was observed that the increase in percentage of CNT form 0.5% could not resist adhesion loss due to aging. However, CNT modified asphalt behaves differently due to the presence of a different polymer combination in the asphalt. The use of 0.5% CNT with 5% SBS showed more resistance to adhesion loss due to aging and outperform all other combinations of CNT, SB and SBS modified asphalt.
