Asphalt Rubber Technology Information Center
Babbitt Minnesota: A Case Study of Pretreated Crumb Rubber Modified Asphalt Concrete
Document available through TRB
Stroup-Gardiner, Mary; Chadbourn, Bruce and Newcomb, David E.  
January, 1996  
Key Words:
Moisture susceptibility; Scrap tires; Temperature susceptibility
Today’s growing tire disposal problem has motivated many public and private agencies to engage in research to find
useful and cost effective long-term uses for waste tires.  Minnesota agencies were further motivated when landfilling
waste tires became illegal in 1985.  The Intermodal Surface Transportation Efficiency Act (ISTEA), passed by Congress in
1992, provided further impetus by requiring the states to use an increasing percentage of rubber in the construction of
asphalt concrete pavements over the next five years. The project selected for evaluation was the reconstruction of a
main city street in Babbit, Minnesota.  Variables included 1% by weight (slightly less than 3% by volume) pretreated and
untreated crumb rubber in either just the wear coarse or the full depth of the pavement section.  Laboratory testing
programs were developed to evaluate the optimum aggregate gradations, binder content, and fundamental mixture
properties.  The testing program was repeated for the behind the paver materials.
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