Bedford Gives New Life to Old
Streets
Reprinted from Texas Construction July 2000
By Shanna Boats
 Like
many Texas cities, Bedford has initiated a recycling program. But
in this case, the city has been recycling not just paper, glass
and plastic, but some of its own streets. By adding cement to the
existing road base, the city was able to reap surprising benefits
and savings.
Most
of the 455 lane miles that Bedford citizens travel each day were
constructed between 1977 and 1986 with hot mix asphalt. Due to the
age of the infrastructure and the city's explosive population growth,
growing from approximately 5,000 in 1951 to more than 50,000 today
- it became increasingly apparent that most of those streets were
in need of reconstruction or some type of repair.
In
response, the Bedford City Council developed the "4B Program,"
in 1997, an action based on Section 4B of the Economic Development
Corporation Act of 1979. Voters approved a half-cent sales tax on
Nov 4, 1997, allotting $16.3 million for street repair and reconstruction.
The city then hired the architecture/engineering firm HNTB as its
general consultant and design and construction services manager.
Of
the entire project, 12.68 miles of asphalt streets were recycled
in place by Sutton & Associates of Keller. The recycling method
"is for streets that need more extensive work, but don't warrant
complete reconstruction," explained J. C. Wood Jr., EE, director
of public services for the city of Bedford.
Bedford
used the North Central Texas Council of Government's Standard Specification
to govern construction of the new base material. The existing material
varies throughout the city, depending on whether the soil or base
material is untreated, has an existing lime- or cement-treated subgrade
or is a highly plastic clay. The streets being recycled in Bedford
typically consisted of a combined total of six to 12 inches of lime-treated
or cement-stabilized base material and asphalt. These were pulverized
in place with high efficiency pulverizers.
After
the grinding process, cement and water were added and mixed in.
The-entire mixture was then compacted and cured. Austin Bridge and
Road Inc. was subcontracted by Sutton & Associates to apply
a 2-in. layer of hot-mix asphalt wearing course that, in many cases,
was ready to drive on the following day.
Listing
the benefits of the recycling method. Wood said, "It is so
much faster...You gain almost as much life as if you had built a
new street...You've increased the strength of the street by adding
the cement." Because of their strong base, Wood expects the
recycled streets to be rut resistant as well.
Recycling
also saved money, Wood observed. "We spent $760,103 on the
12.68 miles we recycled, whereas we spent $5.8 million on 10.58
miles of new construction. So there is a considerable difference
in cost."
James E Amick, EE, project manager of HNTB-Fort
Worth, said, "It is very environmentally responsible because
you don't waste any material or haul it off to a landfill somewhere.
You reuse those resources that have been there on the street and
that the city has already paid for. All you have to do is mix those
good materials with cement and you have a new street for relatively
little cost. As a consulting company, we have recommended this process
to other cities with which we are involved."
This
cement recycled asphalt base stabilization is a flexible base material
as opposed to a true, strong concrete," Amick added. "We're
projecting anywhere from 7-10 years before there will need to be
some type of maintenance, like another overlay. In essence, we're
trying to give the city streets that will last 20 to 30 years with
proper maintenance."
During
the concentrated effort to improve its city streets, Bedford also
paved 23.8 lane miles with Portland cement concrete. While the recycling
process was used for local and residential streets, concrete was
used for Harwood Road, Central, Ravenswood and Murphy Drives.
The
city of Bedford currently has its last street under contract, Wood
said. "So, except for that one, we are pothole-free in the
city of Bedford. We're pretty proud of that. We have nice-looking
streets all over."
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