Anders Kiledal, What Lives Inside Concrete?

I’d never before thought of concrete as a substance containing living organisms, but Anders Kiledal, a UD Ph.D. student and DENIN Environmental Fellow, tells me it does. He is analyzing the kinds and communities of bacteria in concrete.

Repairing and rebuilding the aging concrete infrastructure of the United States is estimated to cost trillions of dollars. Concrete is the third greatest contributor to carbon dioxide emissions, and it accounts for about a third of landfill waste. Clearly we need to reduce our production of concrete, and a great way to do this would be to build longer lasting structures. Kiledal’s research may help identify concrete degradation before it’s visible to the human eye.

More than 2 years ago, Kiledal’s Ph.D. advisor, Dr. Julie Maresca in the Department of Civil and Environmental Engineering, placed a series of concrete cylinders outside on the roof of Colburn Lab on campus and then collected samples from them every 6 weeks.

Because of the type of rock used to make the concrete, some of the concrete was susceptible to the alkali-silica reaction (ASR), a chemical reaction between the rock in concrete and the cement powder that essentially glues concrete together, and some wasn’t. ASR is a key driver of concrete degradation around the world, but particularly in the Mid-Atlantic area, because of the type of rock typically used in concrete in the region.

Understanding what kinds of bacteria occur in concrete when ASR happens and when it doesn’t could potentially lead to the presence of those bacteria being an indicator of concrete degradation before we can see it. Maresca and Kiledal hypothesize that chemical and physical changes in concrete over time affect the bacterial community in concrete.

Kiledal is using bioinformatics and DNA sequencing to determine how the bacterial communities change over time. Bioinformatics, DNA sequencing, and microbiome research are all burgeoning fields right now, so his experience will outfit him well to work in various sectors or industries.

This project combines Kiledal’s long-standing interests in both ecology and microbiology in an interesting way with important implications.

Kiledal earned a bachelor’s degree in biology from Hillsdale College in Michigan. His experience as an undergraduate teaching assistant for a 3-week marine biology course in the Florida Keys helped him realize that he really enjoys teaching and research.

When he finishes his Ph.D., Kiledal is open to staying in academia or to working in industry. Either way, he hopes to continue researching, teaching, and mentoring. “I’d like to pass down what I’ve learned and help the next generation of scientists,” he says.

Kiledal is the treasurer of the Biology Graduate Student Association and has helped coach or run Science Olympiad events. For fun and stress relief, he can be found running and hiking, and he wants to get back into photography.

by Joy Drohan, Eco-Write, LLC