American Journal of Engineering and Applied Sciences 7 (1): 66-76, 2014 ISSN: 1941-7020 © 2014 R.C. Walters et al., This open access article is distributed under a Creative Commons Attribution (CC-BY) 3.0 license doi:10.3844/ajeassp.2014.66.76 Published Online 7 (1) 2014 (http://www.thescipub.com/ajeas.toc) Corresponding Author: Elham H. Fini, Department of Civil, Architectural and Environmental Engineering, North Carolina A and T State University, 1601 E. Market Street, Greensboro, NC 27411, USA Tel: (336) 285-3676 Fax: (336) 334-7126 66 Science Publications AJEAS ENHANCING ASPHALT RHEOLOGICAL BEHAVIOR AND AGING SUSCEPTIBILITY USING BIO-CHAR AND NANO-CLAY Renaldo C. Walters, Elham H. Fini and Taher Abu-Lebdeh Department of Civil, Architectural and Environmental Engineering, North Carolina A and T State University, Greensboro, NC 27411, USA Received 2014-01-31; Revised 2014-02-13; Accepted 2014-03-24 ABSTRACT The life expectancy of Asphalt Binder (AB) has been negatively impacted by the harsh bombardment of UV rays. UV rays cause asphalt to oxidize faster, which results in deterioration of asphalt rheological characteristics that can lead to pavement distresses. This study investigates the impact of bio-char and nano- clay of asphalt rheological properties. Two nano scale materials were used for this study were nano-clay and bio-char. Nano-clay (Cloisite 30B) is a naturally occurring inorganic mineral. Bio-char is the waste product from bio-binder production. Bio-binder is produced from swine manure using a thermochemical conversion process. This process is then followed by a filtration procedure where the bio-char is produced. Chemical and physical properties of bio-char showed a significant presence of carbon which could in turn enhance asphalt flow properties and reduce the rate of asphalt oxidation. In this study several mixtures are designed and evaluated using Rotational Viscometer testing (RV) and X-Ray Diffraction (XRD). Nano-clay is blended at 2 and 4% by weight, with and without bio-binder (5% by weight of dry mass). Bio-char is grinded to nano scale and added to the virgin asphalt binder (PG 64-22) at 2, 5 and 10% by weight. The study results showed that introduction of nano-clay could be effective in reducing temperature susceptibility of asphalt binder. Keywords: Oxidation, Nano-Particle, Bio-Modification, Rheological Properties, Aging Susceptibility 1. INTRODUCTION The physiochemical mechanisms of asphalt oxidative aging and changes in the performance-related properties of asphalt have been the subject of numerous research investigations and much speculation for many decades. In this study two nano materials: Nano-clay and bio-char are blended separately with Asphalt Binder (AB) and Bio- Modified Binder (BMB) to reduce enhance asphalt properties and reduce oxidation aging. The selected AB was PG 64-22, which is commonly used in North Carolina and BMB was a bio-asphalt produced at NC A&T farm mainly from swine manure (Fini et al., 2011a). Due to increasing concerns about the service life of asphalt binders, this study strives to decrease the rate of asphalt oxidation, which is known as one of the main causes of pavement distresses. This in turn will enhance rheological behavior of asphalt and extend pavement service life by reducing asphalt aging susceptibility. Asphalt binders are most commonly characterized by their physical properties. Asphalt binder’s physiochemical properties determine how it will perform as a constituent in Asphalt Concrete (AC) pavement. Although asphalt binder viscosity grading is still common, new binder tests and specifications have been developed to more accurately characterize asphalt binders for use in AC pavements (ASTM, 2013). These tests and specifications are specifically designed to