Sustainable Asphalt Material and Paving Technologies

Moderator(s): Shihui Shen, Penn State Altoona and Linbing Wang, Virginia Tech

Recycling Efficiency for Hot-in-Place Recycling of Asphalt Pavements

• Baoshan Huang, Edwin G. Burdette Professor, University of Tennessee — Knoxville

Balanced Mix Design Implementation — Virginia’s Progress

• Stacey Diefenderfer, Senior Research Scientist, Virginia Transportation Research Council, the Virginia Department of Transportation

Evaluating Recycling Agents for Use in Asphalt Concrete Mixtures

• Shane Underwood, Associate Professor, North Carolina State University

The use of asphalt mixtures containing previously used asphalt concrete from milled pavements, so-called reclaimed asphalt pavements or RAP, has been around for more than half a century. For many years, the typical content levels were low enough that the asphalt mixtures containing recycled materials could be reliably designed using the methods used to design mixtures that did not contain recycled materials without any substantial modifications. However, recently there has been a greater interest in using higher RAP contents where special considerations of the resultant properties of the blended system need to be considered more carefully. One solution to this issue is to incorporate chemical admixtures, so-called recycling agents, to help ensure that the asphalt binder is not overly stiff and prone to durability issues. This presentation will first review the basics of recycling agent classification and their usage of in asphalt mixtures. It will then present results from ongoing studies at North Carolina State University, in collaboration with the Virginia Department of Transportation and Virginia Transportation Research Center as well as the North Carolina Department of Transportation, to evaluate the efficacy of recycling agents with those agencies. Finally, the presentation will present areas of further study that are needed and issues to consider when considering the use of recycling agents.

Use of Recycled Plastics in Asphalt — Opportunities, Challenges & Ongoing Research at NCAT

• Fan Yin, PhD, P.E., Assistant Director, National Center for Asphalt Technology (NCAT)

Use of recycled plastics in asphalt has gained increasing interest among the asphalt pavement industry and the plastics industry worldwide. Social media and other news outlets have trumpeted this as a golden opportunity to improve the longevity of asphalt pavements while eliminating the waste plastic crisis. However, science development and research and development (R&D) efforts in this area are still at an early very stage. This presentation will discuss the opportunities and challenges associated with the use of recycled plastics in asphalt from the 3E (i.e., engineering, environment, and economics) perspective. Furthermore, the presentation will introduce NCAT’s research efforts related to the asphalt binder formulation, asphalt mixture characterization, and pavement performance modeling of asphaltic materials containing recycled plastics.

Bios

Baoshan Huang is a scholar in civil infrastructure engineering and a civil engineering practitioner in pavement and geotechnical engineering. He received his Ph.D. degree in civil engineering from the Louisiana State University, his M.S. and B.S. degrees from Tongji University in Shanghai, China.  His professional career includes over 30 years of experience in transportation and geotechnical engineering with academia, industry and government agencies.  Dr. Huang has been the principal investigators for over $13million of infrastructure research over the last two decades. He has published over 230 peer reviewed journal papers that have received over 6500 Web of Science citations. He has been awarded four US patents as the primary inventor and has two additional pending patents.

Stacey Diefenderfer is a Senior Research Scientist at the Virginia Transportation Research Council, the Virginia Department of Transportation’s research division. She has been with the Department since 2003 and has bachelors, masters, and doctoral degrees in civil engineering from Virginia Tech. She is currently leading research efforts to develop and implement balanced mix design methodologies and to responsibly increase the use of RAP. Her research focuses on both improving mixture durability and fostering the use of innovative materials and methods.

Shane Underwood is an Associate Professor in the Department of Civil, Construction, and Environmental Engineering at North Carolina State University. Prior to this appointment he was an Assistant Professor of Civil Engineering at Arizona State University. He received his doctorate degree in Civil Engineering from North Carolina State University December of 2011. Underwood’s primary area of expertise is in transportation infrastructure and materials. Broadly, his research focuses on materials and their interaction with society and the natural and built environments in order to better engineer infrastructure that consumes less energy, maximizes material resources, reduces environmental impacts, and increases productivity. He and his students pursue this goal by using experimental mechanics to understand and model asphalt materials and systems studies to understand the role of climate and other use conditions on pavement performance. Underwood has served as PI on a diverse set of projects funded by the North Carolina, Arizona, and California Departments of Transportation, Federal Highway Administration, National University Transportation Center at the University of Maryland, and others. His work has been published in more than 100 peer reviewed journal papers and he has spoken at various national and international venues on topics related to pavements and paving materials.

Fan Yin is an Assistant Director at the National Center for Asphalt Technology (NCAT) in the United States. He received M.S. and Ph.D. in Civil Engineering from Texas A&M University. His research expertise includes balanced mix design, advanced asphalt materials characterization, and sustainable pavement materials. Yin has served as a PI or Co-PI on research projects with over $4.5 million in grants. He is a registered Professional Engineer in the state of Texas.