We talk with leading educators in the field of asphalt technology in an effort to tune in to academia on important industry issues.
Dr. Amlan Mukherjee, PhD is an associate professor in the department of civil and environmental engineering at Michigan Technological University.
What drew you to engineering, and in particular, transportation?
As a child my favorite toy was a model of a Boeing 707 – I imagined all the places I could travel to on it, and that started my early love for all things transportation – highways, airports, trains. I liked tinkering with stuff and putting things together – whether it was jigsaw puzzles or robots involving simple circuitry. I also enjoyed math and science in school – so engineering was the logical direction. During my undergraduate experience, as I began to understand the science behind climate change and appreciate its challenges, I was drawn to understanding how we can engineer functioning systems while reducing the environmental impacts. Personally, I worry about how life on this planet – home to many different species – will adapt to warmer temperatures. As stewards of this planet we owe it to ourselves, and to every species we share this home with, to ensure that we build to sustain. Hence, a love for all things transportation – the many new worlds that our transportation assets provide us access to – and a growing concern for the environment, have largely shaped what I do.
What are some of the top tools for assessing greenhouse gas (GHG) emissions of asphalt highway construction projects?
There are quite a few tools out there. In the UK, they use a tool called asPECT (asphalt Pavement Embodies Carbon Tool). In the Netherlands they use a tool called DuboCalc which also uses LCA (life cycle assessment) based approaches to support decision-making. Athena Institute also has a friendly Pavement LCA based tool that can be used to run some estimates. At Michigan Tech we developed a database called Project Emissions Estimator (PE-2) that can also be used to estimate GHG emissions of an asphalt pavement construction project. A few other efforts such as the LCE4Roads in Europe can also provide tools for assessing highway construction emissions.
How can an asphalt environmental product declaration (EPD) lead to a better understanding of the materials?
The EPD is an ISO Type III environmental label. In order to develop an EPD, an LCA for asphalt mixtures must be conducted. This process provides an opportunity for understanding all the material and energy flows that contribute to the production of the material – indeed, an unique opportunity to identify and improve inefficiencies – whether they be in the supply chain, or in plant processes. Also, the LCA helps indicate design choices that lead to win-win situations improving performance and lowering environmental impact – warm mix and increased use of RAP are simple examples.
How important is a life cycle assessment (LCA) for liquid asphalt?
Liquid asphalt is a co-product of the petroleum refining process – a process that features prominently in the supply chain. While this is an environmentally intensive process, it is important to appropriately allocate the impacts to all the co-products. The liquid asphalt when used in pavements also provides a way of reducing the release of the carbon in it to carbon dioxide – a crucial greenhouse gas that is shaping climate change. Hence, its use as a construction material is possibly an environmentally preferred option, than the energy intensive process of further refining it to produce lighter fractions. LCA is the most effective way to quantitatively measure and communicate these advantages to decision-makers. Currently agencies like the Illinois Tollway are considering LCA in its decision-making process to benchmark and reduce environmental impacts. Other states like California that have legislative mandates to reduce GHG emissions, are also considering LCA in the design process.
Where should today’s students focus their asphalt research?
This is a difficult question to answer. Asphalt is a very interesting material – understanding its chemistry can help design mixes that perform better and have lower environmental impacts. There is also some very interesting work involving nanomaterials in asphalt – I don’t understand those topics very well and would probably go there if I were doing a PhD.