Amma Wakefield, P.Eng, is the Asphalt Institute’s newest Regional Engineer. She is a PhD candidate at the University of Waterloo in Ontario, Canada.
What drew you to engineering and transportation?
As a kid, I asked a lot of questions, and I enjoyed working with my classmates to solve problems. I actually wanted to become a detective or a lawyer! In high school, my dad encouraged me to choose math and science classes to keep my options open, and I am glad I listened. Taking those courses helped me understand and appreciate how engineering is used to answer questions and solve so many problems. I studied materials engineering in my undergrad, and worked as a summer student in a construction materials testing lab in my third year. I had a lot of fun that summer, I really enjoyed having the flexibility of testing in both the lab and at the job sites. I learned a lot from the construction crews, and saw how my work directly impacted the real world.
How do you alter your message when teaching in different countries and climates?
Teaching Superpave in Ghana definitely required some modification in the teaching slides. There was less focus on low-temperature performance of the asphalt (bitumen). More emphasis was placed on properties related to rutting and moisture susceptibility of mixes. To provide the most relevant information I learned about their challenges and needs from local contractors and mix designers, then tailored the content accordingly. For multi-day seminars, I partner with local highway authorities to teach, which also helps to stimulate discussion. A couple words may change and the focus may shift depending on the audience, but the underlying fundamentals for quality asphalt pavements is consistent.
You have researched WMA (warm mix asphalt), do you see it being used in more areas in North America?
Absolutely. When I was researching WMA, it was a relatively new technology in North America. The industry was aware of the environmental and health benefits of using a technology that allows us to reduce the production and placement temperatures. What we needed was data to understand its performance relative to the conventional hot mix. There has since been extensive research to provide that data, and industry has gained field experience in that time leading to several publications of best practice guides for achieving performance with WMA. Agencies are specifying WMA, and some are recognizing contractors with awards of innovation or environmental stewardship, when they used WMA successfully.
How has increased use of RAP changed asphalt mix design?
RAP usage in asphalt mixes introduces other variables related to binder aging, which influence the performance of the mix because of its effect on the virgin binder. Understanding the quality of aged binder becomes more critical when RAP content is increased. Current mix design technologies do not provide enough information about the asphalt mix to reliably predict performance, especially when RAP is incorporated into the mix. Many agencies and designers are exploring performance testing at mix design and production to complement the current Superpave technology, for determining material properties that can correlate to the field. Performance testing allows the mix designer to engineer the mix for the desired performance, balancing stability and durability – to keep recycling sustainable.
What are some focus areas for future asphalt research?
Future research must address the needs of the industry with respect to how we characterize the materials to accurately predict their field performance – to close the gap between asphalt mix design and pavement design. There are many aspects impacting the performance of asphalt materials, and researchers should take advantage of available technologies that enable collaborations across the different disciplines to answer more complex problems. The world is changing so fast, and there is still so much we don’t know about asphalt, making it a very dynamic and challenging area of study. Yet, the underlying goal remains the same: to improve the quality and sustainability of asphalt. And we must always keep in mind how research findings can be translated to field practice.
Follow her on Twitter: @AmmaWakefield
