CAIT project no.: FHWA NJ 2000 004
Fiscal Year: 1996/1997
Rutgers-CAIT Author(s): Ali Maher, Mohammed Labib, NJIT
External Author(s): Robert Baker, NJDOT
Sponsor(s): NJDOT, FHWA-USDOT
The use of recycled fibers in asphalt mixtures were found to be beneficial in some cases only such as when fishing nets were used. In these successful cases, the fibers could be uniformly and consistently incorporated into the asphalt mixture without segregation or introduction of excessive air voids. Fibers typically obtained from recycling operations such as from carpets and car seats were difficult to use with the dry mixing process that was developed at NJIT. The latter sources of fibers produced waste that was entangled. This is why the results were inconsistent with regard to the effect of fibers on the performance of the mixture. Available recycled fibers did not produce consistent results as judged by the Marshall test. The final conclusion of the program was to pursue a systematic study primarily based on using the Superpave design Schedule. The final approach was to use virgin fibers first to clearly understand how fibers affect the mechanical properties of the mixture, and then apply the results to the use of recycled fibers – all the work was to follow the Superpave design approach. A comprehensive review of the results is included in this report.