AMES, Iowa - The same technologies that Iowa State
University's David J. White is developing to build better
roads and foundations could also be used to build better river
levees.
White, the Waldo W. Wegner Associate Professor in Civil Engineering, leads the
crew working with Iowa State's Geotechnical
Mobile Lab. In six years of operation, the lab has visited
construction sites in 22 states to test new ideas for making
sure solid, long-lasting earthen foundations are built under
roads and buildings.
"The work we're doing is extremely important,"
White said.
First, "Earth materials are the world's most abundant
construction materials - and the most variable construction
materials."
And second, "The improper use of earth materials
contributes to billions of dollars in taxpayer expense for
roadbeds, levees, foundations for buildings and slopes that
fail."
White, for example, said up to $100 billion a year is spent
because of bad roads. That includes the cost of road repairs,
the wear on cars and time lost to traffic delays. If better,
smarter construction practices can save just 1 percent of that,
that's $1 billion that can be spent on other needs.
So what can contractors do to build better roads and
foundations?
White - plus mobile lab researchers Heath Gieselman and Pavana
Vennapusa - are testing and developing technologies that equip
those big, heavy rollers that smooth roadways with sensors that
can detect the hard and soft spots in a road or roadbed. The
technology's color-coded data instantly tells the operator
exactly where the roadbed is good and where it needs more work.
The technology, in fact, collects a million times more data
than typical roadbed sampling and testing.
The Iowa State engineers are also
working with new instruments, including a $75,000 resilient
modulus triaxial device. White said Iowa State's device is
the only one in the world that's part of a mobile lab. It
quickly subjects earthwork samples to thousands of load tests
to determine the long-term performance of a roadbed or
foundation.
And the Iowa State engineers are starting to work with
nondestructive evaluation techniques. White said microwaves and
near infrared waves can tell researchers about the water or
mineral content in soil.
White said the mobile lab's work has been supported by
grants from the Federal Highway Administration and state
departments of transportation. He said the construction
industry and its manufacturers are also following and
supporting the research.
And, in these days of prolonged flooding causing Missouri River
levees to fail, White said the same techniques and instruments
that lead to better roadbeds and foundations could also be
applied to the construction and monitoring of earthen
levees.
"These new technologies could be used to test river levees
for stability," White said. "Normally, you have some
lead time before floods come down the Missouri River. You could
see this technology rapidly deployed to do an assessment. Then
you can identify that badger hole and plug it."
And, he said, whenever Iowa State's mobile lab pulls into a
construction site, it's starting to change some minds about
the best construction practices.
"This is not just a research project," White said.
"We now have a network of people around the country who
are becoming more interested and motivated to research and
implement these emerging technologies."