Only focus on 21 as 22 requires use of the 3D move analysis

Only focus on 2.1, as 2.2 requires use of the 3D move analysis software

Problem 2 The following chart shows the dynamic modulus (E*) of an asphalt mixture at 70°F 10 TT iTi TIT 0.1E 0.01 10E-03 .0E-02 1.0E-01 1.0E+00 1.0E 01 10E+02 1.OE+03 Reduced Frequency, Hz 2.1) For an 8 inches AC layer, determine the time of loading and the dynamic modulus under a vehicle traveling at 30 mph and 1 mph, and at depths of 1, 3, and 5 inches below the pavement surface (use a haversine pulse load; loading frequency is equal to the inverse of the equivalent pulse time duration)

Solution

Answer 2.1:

1. The loading will be sinusoidal.

2. The equivalent pulse time duration below the pavement surface depth of 1, 3 & 5 inches for a vehicle velocity of 1mph and 30mph will be calculated from figure 7.3 and is given in table below separately.

3. For a vehicle velocity of 1 mph the pulse times are given in table below:

4. For a vehicle velocity of 30mph the pulse times are given in table below:

5. Now as given that the loading frequency is inverse of pulse time as calculated above.

6. For a velocity of 1mph the loading frequency is taken inverse and shown in the table below.

7. For a velocity of 30mph the loading frequency is taken inverse and shown in the table below.

8. So for the loading frequency calculated above the dynamic modulus can be found out from the graph of dynamic modulus given in the problem.

9. For a velocity of 1mph, the dynamic modulus calculted from the graph is shown in the table below:

10. For a velocity of 30mph, the dynamic modulus calculted from the graph is shown in the table below:

Depth below	Pulse Time [d]
1 in	0.9
3 in	1.01
5 in	1.03