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The Arizona Department of Transportation (ADOT) maintains about
12,333km (7,400 centerline miles) of highways, of which approximately
500km (300 miles) are Portland Cement Concrete. A twenty year
old, 16.7km (ten mile) section of concrete pavement on Interstate
40 near Flagstaff, Arizona suffered severe deterioration warranting
reconstruction (Figure 1). Flagstaff is a mountainous area of
2134m (7,000 foot) elevation with an Alpine like climate. High
temperatures in the summer are a pleasant 27°C (80°F)
with winter time lows of -31°C (-23° F). Overall rainfall
is 0.7m (28 inches) per year and winter snows average over 2,500mm
(100 inches) per year. Interstate 40 cuts through this mountainous
area and is built on soils and rock of generally poor engineering
quality. The current traffic is over 20,000 vehicles per day.
The traffic loading has rapidly increased over the years and
is quite heavy, with presently over 35 percent large trucks.
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