Better Roads August 2014 9
"In general, the control mixes resulted in lower perfor-
mance scores compared to the new mixtures," Son and
Al-Qadi. "The 4.75-mm SMA section with a 1-inch wearing
surface provided the highest overall performance score."
In Washoe County, Nevada, County Highway 447 was im-
proved by cold in-place recycling, placement of a fi ber-
reinforced SAMI, and fi nished with a Type III slurry surfacing
as the fi nal wearing surface instead of a costly total reconstruc-
"With fuel prices going up, we are seeing a lot more truck
traffi c on 447," says Bill Gooch, road supervisor, County of
Washoe Road Division, Gerlach, Nev. "It's a short cut; one
truck driver told me taking 447 saves him three hours driving
from Portland or Seattle to Phoenix or Las Vegas."
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In Illinois thin-lift asphalt study, only stone matrix asphalt (SMA) mixes scored higher in overall performance than steel slag/polypropylene-aramid fi ber blend with
PG 70-22, SBS-modifi ed asphalt cement