November-December 2022 - 19

PAVEMENT MAINTENANCE
in Airport Runway Pavements, " by
Hall et al., presented PCI data for
both asphalt and concrete pavements
located across 18 large airports and
concluded that asphalt pavements
" generally deteriorate to a PCI of 70
within approximately 12 to 15 years,
requiring a new surface to reinstate
them to a PCI of 100...[while] portland
cement concrete (PCC) pavement
[is] nearly 40 years of age before a PCI
of 70 is reached. "
Resilience in infrastructure -
The Dare County Regional Airport
(MQI), located on Roanoke Island
in the Outer Banks area of N.C.,
replaced its apron in 2021-22.
COURTESY JOHN MASSEY TALBERT-BRIGHT
defined as its ability to recover after a
disruptive event - is a factor in sustainability.
Resilient systems reduce
future reconstruction costs as well as
future societal costs associated with
not being able to use the infrastructure
during rescue, recovery and rebuilding.
The vital role of resilience is highlighted
by research performed in Portland,
Oregon, an area of the globe where
designing in resilience includes considering
seismic events. A study conducted
by the Multi-Hazard Mitigation
Council of the National Institute of
Building Sciences, titled " Mitigation
Saves: A Resilient Runway at Portland
International Airport Could Save Up
to $50 for Every Mitigation Dollar
Invested, " determined installing a seismically
resilient runway at Portland
International Airport (PDX) would
provide a cost-to-benefit ratio of
50-to-one. For the health and medical
category alone, researchers concluded
a resilient runway could achieve $460
million in benefits, a savings realized
through the ability to use PDX for
medical evacuation. Additional benefits
would be associated with speeding
the re-occupancy of homes and
businesses. As of early 2022, the Port
of Portland was beginning its seismic
upgrade by assessing soil liquefaction
in the area surrounding PDX.
" High Water Table or FloodProne
Airfield Pavements: Charleston
Executive Case Study, " by Greg
Dean, executive director, American
Concrete Pavement Association -
Southeast Chapter, examines the effect
of flooding events on pavement resilience.
The presentation identifies two
main considerations: first, the ways in
which flooding reduces a pavement's
ability to carry loads and second, the
recovery time it takes for the pavement
to return to a serviceable condition.
Concrete outperforms asphalt on both
points. Rigid concrete pavements distribute
loads over a larger area than
asphalt pavements. They also experience
only minor deflection and rely
minimally on subgrade base strength.
This means flooding does not affect
concrete's load-carrying capacity as
severely as it affects that of asphalt.
Furthermore, because stiffer pavements
are less impacted by subgrade
strength loss, concrete pavements
suffer less long-term deterioration
attributable to supersaturated subgrades
and are therefore better able to
maintain their original life expectancy
following a flooding event.
For airport pavements in need of
repair, concrete overlays can provide
an excellent solution. Installing an
overlay increases the height of the
pavement, helping raise its elevation
above the water table, and also increases
the structural strength of the pavement.
Charleston Executive Airport
(JZI), located in the " low country " of
Johns Island, South Carolina, installed
an 11-inch unbonded concrete overlay
in 2010. Existing pavements consisted
of a concrete runway that had been
in service for 60+ years, as well as
a section of asphalt. As of 2016, the
6-year-old concrete overlay was still
performing well, according to Dean,
with deterioration rates less than similarly
aged asphalt and asphalt overlays.
In general, asphalt pavements deteriorate
at rate of 1.5 to 2.5 PCI points
per year - an average of 2 points -
whereas concrete pavements deteriorate
at 0.5 to 1.2 PCI points per year.
The world's busiest airport,
Ha r t s fie l d -J a ck s on At l a nt a
International Airport (ATL), is in the
midst of a 20-year capital improvement
program known as ATLNext.
Sustainability is a key focus of the
program, which includes repaving
as well as construction of a new
taxiway. Fortunately, ATL already
NOVEMBER/DECEMBER 2022 \ AVIATIONPROS.COM / 19
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November-December 2022

Table of Contents for the Digital Edition of November-December 2022
