Environmental Engineering Reference
In-Depth Information
Table 1.
laboratory test results of cGa samples obtained from stockpile and from trial road sections.
compacted on
existing pavement
compacted on
subgrade of lapilli
From stock-piling
Flakiness index (%)
23
19
19
elongation index (%)
29
25
20
specific
# >20 mm
-
26.19
26.29
gravity of
# 4/20 mm
-
26.49
26.59
solids
# <4 mm
-
27.08
27.08
(kn/m
3
)
Mean
-
26.78
26.78
Water
# >20 mm
-
2.1
2.0
absorption
# 4/20 mm
-
1.9
1.8
(%)
# <4 mm
-
1.2
1.8
Mean
-
1.6
1.8
Modified
-
22.76
22.76
γ
d
(max.)
Proctor
(kn/m
3
)
laboratory
-
7.5
7.5
ω
optim.
(%)
test
γ
d (max.)-c
*
-
23.05
23.05
(kn/m
3
)
ω
optim.-c
* (%)
-
7.0
7.0
* Maximum dry unit weight and optimum moisture content with coarse-particle correction, according to asTM
D-4718-87.
Grading curves and comparison with Portuguese and Spanish
specifications
Grading curves compared with EN 13285 specifications and
tolerance limits
100,00
100,00
Me an grading curve (CGA on existing pave ment)
Me an grading curve (CGA on lapilli s ubgrade)
Stockpiling grading curve
Upper limit EN 13285
Lower limit EN 13285
Upper limit EN 13285 (Declared curve)
Lower limit EN 13285 (Declared curve)
Me an grading curve (CGA on existing pave ment)
Me an grading curve (CGA on lapilli subgrade)
Stockpiling grading curve
Upper limit (EPE, 0/31.5)
Lower limit (EPE, 0/31.5)
Upper limit (PG-3, ZA25)
Lower limit (PG-3, ZA25)
90,00
90,00
80,00
80,00
70,00
70,00
60,00
60,00
50,00
50,00
40,00
40,00
30,00
30,00
20,00
20,00
10,00
10,00
0,00
0,00
100,00
10,00
1,00
0,10
0,01
100,00
10,00
1,00
0,10
0,01
Particle size (mm)
Particle size (mm)
Figure 3. Particle-size distribution curves of cGa sam-
ples and Portuguese and spanish grading envelopes of
road specifications.
Figure 4. Particle-size distribution curves of cGa
samples and allowable tolerance (with respect to manu-
facturer declared grading curve) and grading envelope
specified in en 13285.
erties, owing to their heterogeneous nature) caused
by raw material alterations, aggregate manufacturing
process (crushing, grinding and sieving), and stock-
piling manipulation conditions (Franesqui 2009).
Table 1 summarizes laboratory test results. The
mechanically-crushed local material has resulted
slightly lacking in particle size over 9.5 mm,
according to 0/31.5 grading envelope of Portuguese
specifications (ePe-98), and over 2 mm in accord-
ance with spanish standard PG-3 for Za25. how-
ever, the Uniformity coefficient and coefficient
of curvature (cu = 62; cc = 1.9-2.0) indicate an
easily compactable material. in the same way, ana-
lysed cGa samples are acceptably adjusted to
0/20 gradation according to French specifications
(nF P-98-129).
Particle-size distributions have revealed a grading
modification caused by field compaction with respect
to stockpiling material, although not clearly signifi-
cant (fine aggregate fraction increased by 1.5% and
improvement of coarse aggregate particle shape).
The european standard en 13285 related to
unbound mixtures states requirements regarding
regularity of grading properties, and defines the
tolerance limits with respect to the manufacturer
declared grading curve. Figure 4 illustrates, similarly,
that tested cGa samples were found to satisfy these
allowable tolerances and the grading envelope estab-
lished in the aforementioned standard for the most
severe categories (oc
90
and G
a
), confirming a good
quality manufacturing and stockpiling control.
