Using bacteria to protect roads from deicer deterioration

April 09, 2019

Tiny bacteria could soon be chipping in to keep roads from chipping away in the winter, according to Drexel University researchers who are looking into new ways to make our infrastructure more resilient.

Chemicals, like calcium chloride - commonly called "road salts" - are used to prevent the ice formation and snow accumulation that can lead to dangerous travel conditions. But they are also known culprits behind potholes and road surface deterioration. This degradation is caused by the chemicals reacting with the concrete and the water in ice and snow to form an expansive compound that can break down concrete by generating internal expansions and distresses. The deleterious compound, called CAOXY - short for calcium oxychloride - can also wedge out chunks of concrete as it infiltrates the road surface before freezing and thawing.

In their research, recently published in the journal Construction and Building Materials, Yaghoob Farnam, PhD, Christopher Sales, PhD, and Caroline Schauer, PhD, researchers in Drexel's College of Engineering, show how mixing a bit of bacteria into concrete can curtail the formation of CAOXY.

The pair arrived at their theory while studying a strain of bacteria called Sporosarcina pasteurii. S. pasteurii is rather unusual because it is able to induce the chemical reaction that creates calcium carbonate, a substance often referred to as "nature's cement." Only a few types of bacteria are able to pull of this trick, called microbial induced calcium carbonate precipitation, or "biomineralization," but you can see their work in the mineral depositions that form limestone and marble.

More:
https://www.brightsurf.com/news/article/040919480521/using-bacteria-to-protect-roads-from-deicer-deterioration.html