Re: conversion of disposed tires into energy

[Salman.Dave@epamail.epa.gov]

...and crumb rubber in asphalt concrete


  from <http://dpw.co.la.ca.us/epd/TireRecycling/RAC-REAS.cfm>


                                 ? RUBBERIZED ASPHALT CONCRETE ?
                     Rubberized Asphalt Concrete (RAC) is produced when
crumb rubber is
                     blended with asphalt and aggregate material under
specified conditions.
                     Crumb rubber is usually made from recycled rubber that
is ground and
                     processed into small, uniform pieces. When
appropriately used on road
                     resurfacing projects, RAC has many advantages over
conventional asphalt.
                     For example, RAC is cost-effective, saving as much as
$22,000 per lane
                     mile over conventional asphalt projects. RAC also
provides excellent long
                     lasting color contrast for striping and marking, is
highly skid-resistant, and
                     uses more than 2,000 waste tires per lane mile,
thereby conserving our
                     natural resources and landfill capacity. These
advantages have led the
                     County to use RAC on approximately 75 percent of its
highway resurfacing
                     projects. Since 1993, the County has applied RAC to
more than 680 lane
                     miles of roads, diverting more than 1.4 million waste
tires from landfill
                     disposal. This has made Los Angeles County the State's
leader in utilizing
                     RAC to pave streets and highways.
                           ? RUBBERIZED EMULSION AGGREGATE SLURRY ?
                           Rubberized Emulsion Aggregate Slurry (REAS) is
produced
                      when crumb rubber is blended into asphalt emulsion at
ambient
                      temperature and used as a slurry to repair roadways.
Although the
                      cost of REAS is higher than for conventional slurry,
the advantages
                      include an approximate 50 percent increase in
longevity, long lasting
                      color contrast for striping and marking, and high
skid-resistance. In
                      addition, REAS uses more than seventy-eight waste
tires per lane
                      mile, thereby diverting waste tires from traditional
disposal.

                      To ensure the success of the Program and stimulate
the market for
                      waste tires through the slurry seal projects, the
County Department of
                      Public Works, in conjunction with Petrochem
Marketing, Inc.,
                      developed specifications and testing criteria for the
REAS material.
                      As a result of the successful use of REAS, these
specifications and
                      testing criteria have been incorporated into the 1998
supplement of
                      the Standard Specifications for Public Works
Construction,
                      commonly referred to as the "Green Book." [To date,
more than 200
                      cities, counties, and agencies in the State have
adopted the Green
                      Book as their standard.]

                      The County also aggressively identifies and awards
contracts for the
                      use of REAS on many road projects, funding millions
of dollars in
                      projects each fiscal year. Since 1993, the County has
applied REAS
                      to more than 1,500 lane miles of roads, diverting
nearly 120,000
                      waste tires from landfill disposal as of 1999.