8 / 24
Concrete Pavement Progress
www.acpa.org6
continues on page 8 »
A 5,700-foot by 75-foot runway,
taxiways,
hangars, aprons and an access road at the new
Bowman Regional Airport in North Dakota is
all concrete after the Federal Aviation Authority
(FAA) and the North Dakota Aeronautics
Commission allowed for a 12 percent Life-Cycle
Cost Allowance in the bid process.
In the end, a 6-inch-thick concrete bid was only
6.8 percent higher than the asphalt bid alterna-
tive, which consisted of 4 inches of asphalt and
2 inches of additional base course.
“Concrete is not an option for many general avia-
tion airports due to the thinner pavement sec-
tions, even with Life-Cycle Cost Analysis and
alternate bid processes,” said Gary Brennan, PE,
senior project engineer with Brosz Engineering.
“We had a rare opportunity with this project
because the cost of oil had risen, which closed
the gap between the cost of asphalt and concrete.”
There were several welcome advantages to build-
ing a new facility versus renovating or expanding
an existing airport, explained Brennan. “The
overall project had to be bid inmultiple contracts
to fit the available budget, which allowed for the
surfacing improvements to be bid separately,”
he said. “This made it easier to complete the
surfacing improvements in a single construc-
tion season.”
Because the subgrade and base work was com-
pleted in the construction season prior to paving,
the subgrade went through a winter exposure to
deep frost. “This exposure allowed us to discover
frost impacted soils and repair them prior to
paving operations,” explained Brennan.
While working at a new airport does not carry
the same security concerns as an operating air-
port, Brennan noted that he would recommend
more access control. “A security fence around
Concrete Selected for
General Aviation Project af ter
Life-Cycle Cost Analysis
By Sheryl S. Jackson
the perimeter would have been cost prohibi-
tive during construction, but some temporary
access control would have limited the number
of ‘windshield inspections’ we experienced as
people drove by,” he said. “We had no major
problems, but everyone had to be cautious of
cars and people who came onto the site to just
have a look at what we were doing.”
One of the key challenges of the project was re-
lated to the FAA specifications that require alkali-
silica reactivity (ASR) testing of the aggregates
b o w m a n a i r p o r t