Concrete pavements, long
considered the prime material for high-volume, high-load-bearing
applications, are being specified increasingly for applications
where cost is a key consideration. In fact, the low life-cycle
costs are making concrete pavements good investments for a
growing number of applications where volume and weight are
lighter.
A number of changes are affecting this, including
changes in materials, equipment and process methodologies.
Examples include in-place recycling, improved dowel-bar
insertion techniques, high-performance concrete, fast-track
construction methods, and ultrathin whitetopping. The result is
a fundamental shift in the economics and the perceptions about
the cost of concrete pavements.
"Concrete pavements have a
well-earned reputation for strength and durability," explained
Marlin J. Knutson, president and CEO of the American Concrete
Pavement Association (ACPA). "Unfortunately, there is also a
misperception among many people that concrete pavements take too
long, are difficult to repair and are more expensive than other
pavements.
"The reality is that today's concrete pavements
are well-suited for an increasingly wide range of applications,"
Knutson said.
Product differentiation
Like many other
industries, the concrete pavement industry has differentiated
its products to match marketplace needs, Knutson explained.
"Concrete is being used for a variety of paving applications
because engineers and contractors, working closely with owners,
can match concrete pavements to a wide range of performance and
cost parameters," said Larry Cole, vice president of research
and engineering, ACPA. "The performance benefits of concrete are
well-documented, but many people are finding that concrete
pavements also make sense on the basis of cost.
"Research is
helping us find new ways to reduce cost, and the result is that
concrete pavements are becoming more competitive on the basis of
both life-cycle costs and, in many applications, a first-cost
basis," Cole said.
A recent study by ACPA surveyed
contractors from throughout the U.S. to evaluate the effects of
certain features on pavement construction costs. The study
examines a number of features, including: concrete pavement
thickness, foundation, shoulders, cross-section variation
(trapezoidal section), joint spacing, transverse joint load
transfer, and transverse joint sealant.
The contractors were
asked to focus on the highlighted features and develop quotes
based on common circumstances and conditions for their
respective areas. The study determined that the selection of
concrete pavement features has a significant impact on
construction costs. The information, when used in conjunction
with related pavement performance information, should enhance
the life-cycle costs of concrete pavement designs.
As an
extension of this research project, the ACPA plans further study
of these features and usage factors to further align
construction cost and performance criteria.
Another study is
evaluating the use of high-performance concrete (HPC), which is
currently being used by architects, contractors and engineers in
a number of construction applications to reduce initial
construction costs while enhancing the quality of the structure.
The study seeks to define HPC and develop an appropriate model
that will help determine when HPC is indicated, based on cost
and performance parameters.
"This research, along with field
and academic research, is eradicating the misperception that
concrete pavements are too expensive, too costly to repair and
take too long," Knutson said.
A two-pavement system
As
concrete pavements become more cost competitive, the benefits of
a two-pavement system become more apparent.
"As an industry,
we encourage a two-pavement system, which creates a fair,
equitable and competitive environment," Knutson said, adding,
"Competition is good for the pavement industry, because it
breeds a spirit of innovation and creates value that benefits
specifiers, as well as the general public."
