Asphalt Rubber Technology Information Center
Field Aging Effects on The Fatigue Of Asphalt Concrete And Asphalt-Rubber Concrete
Document available through TRB
Raad, Lutfi; Saboundjian, Steve and Minassian, George
Mix Properties
Key Words:
asphalt, asphalt rubber, fatigue, aging, pavements, performance, prediction
This paper describes a study to investigate the influence of field aging on the fatigue performance of asphalt concrete
and asphalt-rubber concrete. Two California mixes were investigated: 1) Conventional asphalt concrete dense-graded
mix (CAC-DG) and 2) Asphalt-rubber hot mix gap-graded (ARHM-GG). Laboratory fatigue tests were conducted on beam
specimens obtained from a 10-year old pavement section in southern California. Both stiffness and fatigue were
determined using controlled-strain fatigue beam tests performed at 22° C and –2°C. Results were compared with
previously published data for the original unaged) materials. Stiffness and fatigue data were also used in pavement
analysis in order to assess the influence of aging on predicted fatigue performance. Results indicate that field aging
reduced the beam fatigue resistance of CAC-DG and to a lesser extent, ARHM-GG. Aging effects on beam fatigue life
were more severe at –2°C than at 22°C. The influence of aging on predicted pavement fatigue life depends not only on
the stiffness of the mix and its fatigue properties but also on the stiffness or layer moduli of the pavement components.
For new pavement construction and overlaid pavement sections, longer fatigue life predictions were obtained for ARHM-
GG than CAC-DG, for both aged and unaged conditions. Aging of the CAC-DG could be detrimental to pavement fatigue.
In comparison, aging of ARHM-GG showed increased fatigue life performance.
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