The City of San Diego Department Public Works released a white paper detailing the history of utilizing fibers to reinforce asphalt mixes. This well-researched and documented analysis traces the route the paving industry has taken since it began experimenting with fiber-reinforced asphalt concrete (FRAC) back in the 1980s.
Co-authored by Phil Blankenship, Blankenship Asphalt Tech and Training, and Brandon Milar, CalAPA Technical Director, the paper points out that a backlog of capital needs has forced the increased use of recycled asphalt pavement (RAP) to overcome higher asphalt binder prices over the past 10 years. The resulting pavements have tended to be more brittle for a variety of reasons, leading to early cracking and lowered useful life.
The paper states that “solutions to this dilemma are usually solved through polymer modification and coordination with asphalt binder terminals to supply alternate asphalt grades.” And, “we should not limit solutions to aggregate and asphalt binder-only combinations when many more options are available to improve our HMA directly at the plant.”
From here, the paper reviews a variety of HMA site solutions that have been tried and tested over the past 30 years. One can readily see the progression of improvements, and the paper concludes by stating that “numerous experimental studies have shown that adding synthetic polymer fibers to dense-graded mixes can improve the field performance and their mechanical performance, particularly with regard to rutting and fatigue resistance.”
At Surface Tech, we’ve succeeded in developing an aramid polymer fiber solution that vastly improves crack resistance in both pavement and interlayer applications. Aramid is a unique, man-made, high-strength polymer fiber boasting high tensile strengths over 400,000 psi (5x steel), a superior stress/strain relationship and decomposition temperatures of 350˚F. And because of the enhanced properties generated with our additives, project costs are reduced.
For more information on the innovative, engineered polymer fiber products available from Surface Tech, visit https://surface-tech.com/asphalt-ace-xp/
Download the white paper here.