|
Recycling saves money and impact
Pavement recycling lets you conserve budget dollars
and gain favor with citizens concerned about the environment.
by Mike Polak
As the populations of the U.S. and Canada grow, the
additional burdens of increased traffic volume and increased tire pressures
and loading will be placed on our roadways and highways. Every community
faces the need for transportation improvements, yet our highway agencies and
contractors face enormous cost pressures ranging from lean public budgets to
extremely high crude oil prices to regional cost and availability problems
with quality aggregate.
Asphalt pavement recycling can help agencies and
primary contractors deal with these budget burdens, and win favor with the
public in other ways as well. Here are a few of the well-established virtues
of pavement recycling:
Recycling is good for the environment and asphalt
is the most recycled of all materials.
In-place recycling eliminates the need to
transport demolished pavement to a remote storage area. This saves fuel,
jobsite congestion and dust, and overall costs.
In-place recycling eliminates stockpiles of
recycled asphalt product, which is an environmental issue in some locations.
All asphalt recycling makes use of the original
aggregate. Not only is this older aggregate often the best quality, it eases
demand on virgin aggregate which is in limited supply in many areas.
Each of the in-place recycling disciplines offers
a cost-effective alternative to total reconstruction of a roadway. Hot and
cold recycling can add years to the life of the original pavement, while
full-depth reclamation can dramatically reduce the cost of rehabilitating a
pavement that has reached the end of its design life. And each of these
disciplines is much less intrusive with regard to traffic than conventional
reconstruction.
Technology advances
Although asphalt recycling has been around for at
least 50 years, the machines, materials, and techniques of recycling have
constantly evolved and improved, resulting in an ever more refined and
durable final product.
Recent improvements include:
Some of the larger recycling trains have been
condensed into small, more efficient components. For example, several pieces
of a cold in-place recycling train can now be built into one unit. Some hot
in-place recycling equipment now uses hot air to heat the old pavement, not
direct flame.
The application of additives and the effectiveness
of those additives have improved. Emulsified asphalts that cure at an
accelerated speed have evolved so that overlays can be placed on the
recycled material earlier.
More technology is being used with full-depth
reclamation and in the field of chemical stabilization. Mix designs and
testing of these materials has improved dramatically.
Recycling’s voice
The Asphalt Recycling & Reclaiming Association is a
trade association formed by the people and companies of the recycling
industry to educate and promote the use of recycled asphalt and reclaimed
material.
The association has five disciplines: cold planing,
cold recycling, full-depth reclamation, soil stabilization, hot in-place
recycling, and hot recycling.
In the field of education, the ARRA has produced the
Basic Asphalt Recycling Manual which is North America’s most complete and
authoritative guide to asphalt recycling. The manual is designed to inform
owners, specifying agencies, consultants, and civil engineering students
about current recycling methods and applications. Available from any ARRA
member, the manual can be used to completely evaluate, design, specify, and
construct an asphalt-recycling project.
The ARRA has also worked with The Foundation for
Pavement Preservation to provide the course work for The National Highway
Institute Asphalt Recycling Course. This course can be sponsored by federal,
state, provincial, or local road agencies in the U.S. or Canada. It is also
available to local technical assistance program centers, associations,
consulting firms, private industry, universities, and other national and
international entities engaged in highway work.
The ARRA supports and participates in the Foundation
for Pavement Preservation. In October 2003, the ARRA and its members helped
open the National Center for Pavement Preservation at Michigan State
University.
The ARRA also conducts seminars such as the recent
North Carolina DOT aviation seminar, Alternative Construction for Asphalt
Pavement Seminar. The seminar covered four disciplines of the ARRA and was
attended by 70 engineering and agency people from four states.
In April, an ARRA member company held a seminar on
full-depth reclamation and soil-cement pavements. The two-day event took
place in Dallas, Texas and attracted audience members from all over the
United States.
Common goals
As the costs of pavement construction,
rehabilitation, and maintenance continue to rise in the years to come,
alternatives to conventional pavement management practices — alternatives
like recycling — will continue to become more attractive.
This trend started with the Federal Highway Agency’s
Recycled Materials Policy, announced in 2002, which calls for an increased
effort in conservation of depleted natural resources such as aggregate and
crude oil. Some of our best and most valuable resources are already in place
on our existing highways. The beneficial use of recycled asphalt has never
been clearer.
Reprinted from Better Roads Magazine
July 2004 |
