New lab helps researchers evaluate materials for constructability and performance.
It takes a specific type of physical infrastructure to systematically test building materials. Thanks to industry support, Oregon State University's new Kiewit Materials Performance Lab gives College of Engineering researchers what they need to evaluate all types of materials and structural systems for constructability and performance.
Construction industry practices are limited by the materials used, said David Trejo, acting school head of Civil and Construction Engineering and Hal Pritchett Chair at Oregon State. Science-based research on improving constructability and deterioration will lead to more efficient, cost-effective construction methods and longer lasting, more reliable structures.
Some of Trejo's work in the Kiewit lab focuses on cementitious materials. Concrete is second only to water as the most widely used construction material in the world, he said, so his research could potentially have a major impact on the construction industry across the globe. To address efficiency, for example, Trejo is testing the applicability of current specification limitations for concrete imposed by most states' highway agencies. Most concrete is prepared at a cement mixing plant and transported in vehicles with rotating drums to a construction site, which can be risky if the materials are transported long distances or if trucks are delayed for any reason.
"In most states, the drum always has to be turning, but it must not exceed 300 revolutions during the trip, according to the specifications," said Trejo. "Contractors will try to do it, but revolutions may go over the limit and they end up having to dump it. If it is still good concrete, this is a waste."
Trejo said the specification was initiated in 1916, before anyone used chemicals to improve performance in specific construction applications. "Nobody knows if there's any relationship between revolutions and the quality of your concrete mix," he said. The end result is that contractors build into their bids the risk of throwing away legally unusable concrete. "If the risk goes up, the cost of the concrete goes up, and it really costs everybody, including taxpayers." That's why he and several graduate students are working with concrete producers in the State of Washington to test different concrete mixes to determine whether existing specifications are actually necessary.
In other projects, Trejo and other Kiewit lab researchers are working to develop a better understanding of how and why materials and structures deteriorate. Trejo's work includes developing and testing new metals and concrete for use in bridge construction.
In addition, he models deterioration mechanisms to determine at what point a structure might become unsafe or fail. "A large portion of our structures are very good, but in aggressive environments it can be a little more challenging," he said. "How will we know if a structure is safe — if it has deteriorated 30 percent or 20 percent? These are areas we're looking at."
Kiewit, the nation's third largest construction company, contributed the lead gift that enabled the lab renovation. Other project partners include Granite Construction, Hamilton Construction, Stacy and Witbeck, Inc., and T. Gerding Construction.
Without the Kiewit lab, these types of research projects would not be possible. "We've been very fortunate to have these contractors provide support to build the lab," said Trejo.
The Kiewit Materials Performance Lab has already bolstered the engineering curriculum, which emphasizes authentic engineering experiences. "Students who do research become better problem solvers, and that is what industry is looking for," said Trejo.
Wednesday, June 27, 2012