FATIGUE ANALYSIS OF 12 BRAZILIAN ASPHALT BINDERS AND MIXTURES USING
VISCOELASTIC CONTINUUM DAMAGE THEORY
Abstract
Fatigue characterization of asphalt mixtures is imperative for
predicting pavement performance. Moreover, since cracking begins in
asphalt binders, obtaining fatigue properties in these materials makes
it possible to establish cause and effect relationships with cracking of
mixtures and pavement structures. In this paper, 12 Brazilian asphalt
binders and mixtures were fatigue characterized, and correlations among
scales were evaluated to verify the potential for predicting fatigue
from binder scale. The characterization protocols include Linear
Amplitude Sweep (LAS) test for binders and Direct Tension Cyclic Fatigue
test for mixtures. Simplified viscoelastic continuous damage theory
(S-VECD) was used to interpret the results, allowing the simulation of
accumulated damage (N/Nf) in a pavement using FlexPAVE
TM software. The main findings are that the type of
binder alone is not able to predict fatigue class by the fatigue factor
of binder (FFB), requiring rheological damage analysis. Most of the
mixtures performed well in pavement simulations, and only fatigue factor
of mixtures (FFM) and fatigue classes (FFM along with stiffness) are not
enough to predict performance. There is a promising increasing linear
correlation between FFB and FFM, but not between FFB and N/Nf. Despite
this, excellent FFB values tend to dominate mixture’s behavior,
generating low simulated damage.