 The Rubber
Pavements
Association was
formed in 1993 to
address the post
patent need to
research, develop
and communicate
the benefits of
Asphalt-Rubber
paving materials. For the readers who
may not be familiar with the term
Asphalt-Rubber, it is a paving material
produced from a binder containing an
average of 18% ground tire rubber from scrap tires that is field
blended with hot, liquid asphalt under a time/temperature formula.
It is the only rubber modified asphalt material with an ASTM
definition and a standard binder specification.
While the material has strong environmental
appeal and a lengthy research history, it has been slow in gaining
universal acceptance due to a variety of reasons. A major detriment
to development has been ill-advised
Congressional mandates for use of the material. States DOTs are
generally opposed to being told what materials to use for their
pavements.
Even if they had readily accepted the
mandates, the material was still under patent and the industry,
tightly controlled by the owners, was not in a position to meet
the mandates nor had the engineering benefits been demonstrated
to all the states.
In the last ten years, with the material now
in the public domain, the industry has made an extraordinary
effort to improve the state of the practice through research
and technology transfer. The price has been heavy for the dedicated
members, contractors and tire recyclers, who have invested in
the future of the industry. Of the 2.7 million dollars the RPA
members have contributed through annual dues and assessments
paid on the sale and purchase of crumb rubber used since 1996,
52% has been invested in research and technology transfer. The
national and international needs in these areas are still far
from being met. |
RPA has been fortunate is having a savvy Technical Advisory
Board
(TAB) who volunteer their valuable time to keep the industry
focused on research needs and promotion based on sound engineering
benefits. (See inside cover for list of TAB) To date the TAB
has identified 16 research
projects to improve the state of the industry. These are in addition
to
eight projects RPA has commissioned and funded. The latter includes
the
following:
- Life Cycle Costs for Asphalt-Rubber Paving Materials, Hicks,
Lundy and Epps, 1999
- Evaluation of Caltrans Modified Binder (MB) Specifications,
Hicks and Epps, 1999
- Quality Control for Asphalt-Rubber Binders, Hicks and Epps,
2000
- Evaluation of Asphalt-Rubber Pavements in Texas, Tahmoressi,
2001
- Development of a Mechanistic Overlay Design Method for Asphalt-Rubber
Hot Mixes, Sousa, Stubstad and Pais, 2001
- Influence on Aging on Fatigue Behavior of Asphalt-Rubber
Hot Mix Gap Graded (ARHM GG) and Conventional Asphalt Concrete
Dense Graded (CAC-DG), Lutfi Raad, 2001.
- The Arizona Project Review, Part 1, Evaluation of A-R Pavements
Constructed Before 1992, Morris and Carlson, 2001.
- Evaluation of Texas Department of Transportation Mixture
Design Procedure for Permeable Friction Course, Tahmoressi,
2001.
 RPA
also participated in the funding of the California Center for
Rubberized Asphalt Concrete Technology Center Publication, "Asphalt-Rubber
Design and Construction Guidelines" by Hicks in 2002.
Success of the efforts to date have
brought new people into the industry, unfortunately not all are
willing to participate in meeting the needs.
Having competitors who often enjoy a bidding advantage due to
an unwillingness to sacrifice a few cents on their material costs
to support research, RPA members often have to settle for the
"public service" reward instead of the bid award.
Their willingness to continue to improve both
the product and industry speaks highly of their business integrity
and dedication to future generations. Without their sacrifice
and dedication, where would the millions of scrap tires that
are building longer-lasting, smoother and quieter pavements go?
If you happen to see a contractor, tire recycler
or anyone who displays the RPA "Committed to Quality"logo
on their equipment, hardhats or in their advertising, join me
in saying thanks for your dedication and investment in our future.
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