Page 404 - Mechanics of Asphalt Microstructure and Micromechanics

T
396 Ch a p t e r w e l v e

Shear Stress versus the Ratio of the Elastic Moduli
0
0 10 20 30 40 50 60
-5

Stress (psi) -10
-15

-20

-25
-30
Z-Coordinate (r=1)

E/E'=1 E/E'=0.9 E/E'=0.7 E/E'=0.5 E/E'=0.2
a. Shear Stress vs. Elastic Modulus Ratio

Tensile Stress versus the Ratio of the Elastic Moduli
5
Tensile Stress (psi) 3
4

2
1
0
0 2 4 6 8 10
Z-Coordinate (r = 1)

E/E'=1 E/E'=0.9 E/E'=0.7 E/E'=0.5 E/E'=0.2
b. Tensile Stress vs. Elastic Modulus Ratio
(Note, E=E h and E′=E v)
FIGURE 12.2 Stress distribution versus the ratio of the elastic modulus.

of the APA testing conditions). The block is discretized into 1000 3D 20-node solid ele-
ments after refinement analysis. Two sets of boundary conditions are applied. In set 1,
the bottom surface is fixed in x, y, and z directions (Figure 12.3); the other four lateral
surfaces are fixed in normal directions (horizontal directions). This set of boundary
conditions is similar to an asphalt overlay placed on top of a rigid pavement (strong
base) with excellent bonding. In Set 2, the bottom surface is fixed in z directions only
and the other four lateral surfaces are fixed in normal directions (horizontal direc-
tions). This configuration is similar to the testing configuration of the APA. Because