Rutting Resistance and Microstructural Assessment of Latex Modified Asphalt Binder with Additives

Abstract

As part of the design criteria of flexible pavements, resistance to rutting is typically considered as a crucial factor. Bitumen modification proves the most significant role in ameliorating rutting of asphalt pavement. Modifying the properties of bitumen could lower the rutting potential and mitigate its occurrence. The penetration grade (PEN 60/70) bitumen and natural rubber latex (NRL) modified asphalt (with and without the incorporation of additive) of either wax or silane at respective concentrations of 0.3% and 0.1% were examined in this study. The prepared samples were assessed under both unaged and short-term ageing (RTFO-aged) conditions. The effect of NRL and additive (wax additive or silane additive) on the rutting potential and morphology were evaluated and compared with the control sample. The rutting performance was analyzed in terms of G*/sinδ, non-recoverable creep compliance (J_nr) and accumulated strain characteristics. The influence of additives was further evaluated by simulating dynamic loading using Dynamic Shear Rheometer (DSR) via temperature sweep (46, 52, 58, 64, 70, 76 and 82^oC) and the multiple stress creep recovery (MSCR) test at 64^oC. Experimental results revealed that all rubberized asphalt binders are capable of improving the rutting resistance. Under the influence of short-term ageing condition, the addition of different types of additives had enhanced the homogeneity and stability of the asphalt binders due to evaporation and absorption processes.