Published: Tue Sep 21, 2010There are no concrete answers for why the most widely used engineering material in the world expands and cracks, but a Tennessee Tech University professor has secured more funding to continue his leading research.
The National Science Foundation recently awarded TTU civil and environmental engineering associate professor Ben Mohr about $300,000 to look at concrete at a nano-scale level and study the mechanisms of degradation that make it crack.
"It's a widespread problem that in the past we thought we could control by controlling the temperature," Mohr said. "But concrete that has been cast and placed under normal conditions still has problems.
"You can't use mitigation strategies for the durability problem if you don't know what causes it," he said. "People think of cement and concrete as very low-tech material. But the only way to understand what everyone sees is to study the materials at the microstructural level where it is apparent that the properties are most complicated."
And that's just what Mohr has been doing for four years, since being named the 2007 Ralph E. Powe Junior Faculty Enhancement Award winner from Oak Ridge Associated Universities.
Advances in instrumentation now allow Mohr to probe beyond the microscale level.
"We are looking at the stages of a product that forms during cement hydration that in later ages causes expansion and cracking," explained Mohr.
"I like to look at the environmental factors and the combination of materials and microstructure to find better solutions," said Mohr, who considers himself a non-traditional civil engineer, willing to take an interdisciplinary approach to his work.
"There is such a focus now on using materials that are more sustainable, but I still ask 'Why can't we make materials we currently use last longer?'" he said.
Mohr teaches a graduate level course focused entirely on concrete durability and his grant-related work. But his education focus reaches beyond campus.
Educational activities associated with the grant will include traveling to local middle and high schools to provide hands-on experiments that give the students a real-life view of how engineering is an important part of the modern world. Local primary school groups will be invited to campus to participate in hands-on learning experiences at Tennessee Tech's STEM Center.
In addition to the educational activities, a residual stress analysis workshop is proposed at the end of the project to disseminate the strong background in this field at Tennessee Tech to other cement and concrete researchers.
He has received about $520,000 as a sole principal investigator with NSF and has been a co-principal investigator on projects totaling more than $450,000 for the Tennessee Department of Transportation and Federal Highway Administration.