Introducing combination of nano-clay and bio-char to enhance asphalt binder’s rheological and aging characteristics

The life expectancy of Asphalt Binder is negatively impacted by the harsh bombardment of ultraviolet (UV) rays. UV rays cause asphalt to oxidize faster which results in deterioration of asphalt’s rheological characteristics that can lead to pavement distresses. This paper investigates merits of application of combination of nano-clay and bio-char to increase effectiveness of nano-clay to reduce asphalt oxidative aging while enhancing nan-clay dispersion. The study was conducted using one control binder (PG 64-22), two nano-clay sources and one type of bio-char, as such several modified binder blends were prepared at varying concentrations of nano-clay;the specimens were then analyzed in terms of their rheological characteristics before and after laboratory oxidation aging. The modifiers used in this study wereorgano clays (Cloisite-11 and Cloisite-15) along with bio-char, which is derived from swine manure. Rolling Thin Film Oven (RTFO) wasused to age all specimens; aged and un-aged samples were then tested using a Rotational Viscometer (RV) to evaluate the changes in their rheological behavior before and after aging. Four modified blends were formulatedincorporating 3% and 6% of Cloisite-11 and Cloisite-15, in presence of 3% Bio-char. Bio-char was used to improve dispersion, flow and liquidity retention, while enhancing oxidation resistance.