Alexander Moseson, PhD, was featured in the February 2013 issue of ASEE Prism Magazine for his work on alkali-activated cement (AAC). His research was highlighted along with other engineers working on novel solutions to problems associated with urbanization in both the developed and the developing world.
With nearly half of the world’s 6.6 billion people residing in cities and experts estimating that 6 in 10 humans will call a city home by 2030, engineers are looking for new methods to build a cost-effective infrastructure capable of coping with this explosion in growth.
Traditional Portland cement is widely used in construction around the world. While versatile, it presents an environmental challenge. Portland cement is created by melting rocks and other ingredients to 1500 degrees Celsius. Reaching such a high temperature requires a lot of fuel, which in turn leads to a massive amount of CO2. And with nearly 2 tons of concrete poured for every person in the world each year, roughly 5 percent of human-produced carbon emissions are due to the manufacture of Portland cement.
Drexel’s “green cement” was developed by Moseson along with Michel W. Barsoum, PhD, A.W. Grosvenor professor in the Department of Materials Science and Engineering and Dr. Aaron Sakulich, former Drexel graduate student and now assistant professor of civil and environmental engineering at Worcester Polytechnic Institute. Both co-investigators obtained their PhDs. under the supervision of Barsoum. AAC is created using an industrial bi-product called slag, fly ash and common limestone. Moseson and Barsoum’s alkali-activated cement does not require heat to produce. The result is a building material that cuts energy use and carbon emissions by 98 percent. In addition, it costs about 50 percent less to produce. It’s something Moseson refers to as potentially “disruptive technology”.
The biggest hurdle toward widespread use of AAC is the variation in feedstocks, as the main component in the cement can vary from day to day or from plant to plant, something that Moseson and Barsoum are working to overcome.
Aside from the engineering challenges, Moseson and Barsoum see numerous potential uses for AAC as a sustainable building material in the developing world. Working with Amy Slaton, professor of history and politics at Drexel, and D.N. Singh at the Indian Institute of Technology, the group examined the socio-political aspects of using AAC to build a more robust infrastructure in the slums of Mumbai India.
Ironically, the inspiration for this forward leap in cement comes from the past. Drexel’s green cement is similar in nature to building materials used in Egyptian Pyramids (as researched by Barsoum) and ancient Rome. “Although we won’t know for 2000 years if ours has the longevity of Roman buildings, it gives us an idea of the staying power of this material,” Moseson said.
Who knows, maybe 2000 years from now future engineers will say the same thing about Drexel green cement.
Read the full article in this month’s issue for ASEE Prism.
Britt Faulstick contributed to this article.