Mix sampling at the time indicated that the RS-HMA material properties were
similar, or slightly improved, as compared to the convention HMA mix. Six
core samples (two from the control section, four from the RS-HMA section)
were obtained after approximately one year after service; and four additional
RS-HMA cores were obtained after 2-1/2 years. Testing revealed that the
RS-HMA cores compared well with the job mix formulas and plant mix tests.
The only unexpected result was the greater viscosity of the RS-HMA, which
may indicate that the shingle modified mix hardens at a faster rate than
conventional HMA.
Field observations demonstrate that the RS-HMA is showing little distress, and
is performing comparably to the control sections.