Civil Engineering Reference
In-Depth Information
The calculations in steps 2-5 are for 4.0% asphalt content as an example. Repeat
for other asphalt contents.
2. Use
G
se
to determine
G
mm
for the other asphalt contents, using Equation 9.5:
100
100
a
100
-
4.0
2.666
G
mm
2.507
=
=
=
a
P
s
G
se
P
b
G
b
4.0
1.031
+
b
+
b
3. Compute voids in the total mix for each asphalt content, using Equation 9.8:
G
mb
G
mm
2.360
2.507
VTM
100
a
1
b
100
a
1
b
5.9
=
-
=
-
=
4. Compute voids in mineral aggregate, using Equation 9.9:
a
G
mb
P
s
1
100
-
4.0
2
2.696
VMA
100
b
100
a
2.360
b
16.0
=
-
G
mm
=
-
*
=
5. Compute voids filled with asphalt, using Equation 9.10:
1
VMA
-
VTM
2
1
16.0
-
5.9
2
VFA
=
100
=
100
=
63.3
VMA
16.0
6. A summary of all calculations is given in the following table:
Corrected
Flow,
VTM
VMA
VFA
P
b
(%)
G
mb
Stability (kN)
(0.25 mm)
G
mm
G
se
(%)
(%)
(%)
4.0
2.360
6.3
9
2.507
5.9
16.0
63.3
4.5
2.378
6.7
10
2.488
4.4
15.8
71.9
5.0
2.395
5.4
12
2.470
2.666
3.0
15.6
80.5
5.5
2.405
5.1
15
2.452
1.9
15.7
87.8
6.0
2.415
4.7
22
2.434
0.8
15.8
95.0
7. Plot stability, flow and volumetric parameters versus
P
b
.
(See Figure SP9.6.)
8. Determine the asphalt content that corresponds to
VTM
=
4
%
and the corre-
sponding parameters.
Compare with criteria:
From Graphs
Criteria
P
b
@ 4%
4.6
Stability (kN)
6.6
5.34 (min)
Flow (0.25 mm)
10.5
8 to 16
G
mb
2.383
NA
VMA (%)
15.7
15.0 (min)
VFA (%)
75
65 to 78
Therefore, the design asphalt content is 4.6%.
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