Page 57 - MODELING OF ASPHALT CONCRETE

Modeling of Asphalt Binder Rheology and Its Application to Modified Binders 35

100 100
Unmodified
3 % SB
6 % SB

10 10
Starin at failure, % 1 Stress 1 Stress at failure, MPa

Strain
Test Temperature, °C
.1 .1
−35 −30 −25 −20 −15 −10 −5 0
(a) Modified with SB-Polymer
100 100
Unodified
CRM1
CRM2

10 10
Starin at failure, % 1 Stress 1 Stress at failure, MPa

Strain

Test Temperature, °C
.1 .1
−35 −30 −25 −20 −15 −10 −5 0
(b) Modified with crumb rubber
FIGURE 2-8 Failure strain isochronal curves for an asphalt before and after modifi cation.
(a) Modifi ed with SB-polymer; (b) modifi ed with crumb rubber.

The results shown may not apply to all types of polymer modifiers. The effect of
different polymers on failure properties is expected to depend largely on the type of
interaction between the asphalt and polymer, the molecular nature of the polymer
additives, and the way it is dispersed in the asphalt. The effect of polymers on failure
properties can be hypothesized in different ways. One hypothesis is that polymers form
some kind of molecular network inside the asphalts resulting in more strain-tolerant