10
8
y = 0.0606x + 3.1239
R2 = 0.96
6
4
2
0
100
0
20
40
60
80
Crushed Aggregate (%)
Figure 31. Effect of percentage of crushed aggregate on particle index.
400
θ = 400 kPa
300
200
θ = 200 kPa
100
0
2
4
6
8
0
10
Particle Index
Figure 32. Effect of particle index on resilient modulus.
of the angle of internal friction (φ) as shown in Figure
gate mixture is higher than the 100% crushed aggre-
33. The limited data were obtained at a void ratio of around
gate. The trend reverses at bulk stresses greater than
0.16. Results indicate that there is a trend between φ and
300 kPa. This suggests that, at lower depths in a thick
PI and that the φ angle increases with increasing PI until
base course layer (60 cm or thicker), the lower half of
around 6, then remains constant.
the base course can be constructed with natural material.
Results also indicated that void ratio has an impact on
the resilient modulus of aggregates containing 50% or
SUMMARY AND CONCLUSIONS
less of crushed aggregates.
On the average, density is about 12% higher for the
With the standard 150-mm-diameter samples, we
large-scale QMOT tests than for the AASHTO T-99
found that the resilient modulus of the 100% natural
tests. The optimum moisture contents were approxi-
material was higher than that of the 100% crushed
mately the same for both tests.
material. Generally, the resilient moduli tended to par-
From large-scale resilient modulus tests, results indi-
allel one another. The resilient modulus was about 35
cate that resilient modulus is a function of the percent-
to 50% higher than that obtained from the large-scale
age of crushed aggregates and bulk stress. At lower bulk
tests.
stress values, resilient modulus of the natural aggre-
From the large-scale shear tests, angle of internal
23
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