aggregatesMaterial for Civil Engineering
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Aggregate gradation
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UNIFORM G A P CONTINUOUS
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Gradation and Aggregate Building
• Aggregate gradation affects the workability of portland cement concrete mixes, and the stability and durability of bituminous concrete mixes, also affects the stability, drainage and frost resistance of base course
• Aggregate grading: dense; gap; uniform; open graded
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Gradation and Aggregate Building
• Fuller method: P = 100 d/D
p = percentage finer than sieveD = maximum size aggregate to be used (top size)d = sieve size in questionN = coefficient of adjustment which adjusts the curve for
fineness or coarseness
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Fuller curve
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100
90
80
70
60
50
40
30
20
10
0
Per
cent
fine
r by
wei
ght
Diameter in mm – log scale
n = 0.3
n = 0.5n = 0.7
10 1 0.1
Fine aggregates limits
SIEVE SIZE PASSINGmm inch %
9.50 3/8 100
4.75 No. 4 95 - 100
2.36 No. 8 80 - 100
1.18 No. 16 50 - 85
600 m No. 30 25 - 60
300 m No. 50 10 - 30
150 m No. 100 2 - 10
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Graphical distribution
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CONTINUOUS
UNIFORM
Increasing particle size (sieve opening)
Incr
easi
ng c
umul
ativ
e pe
rcen
tage
pas
sing
G A P
Sieve test result
Sieve Size (mm)
no Weight retained (gr)
% retained Cumulative retained (%)
Cumulative passing (%)
4.75 4 0 0 0 100
2.36 8 241.9 11.9 11.9 90.6
1.18 16 388.9 19.1 31.0 74.0
0.60 30 505.5 24.9 55.9 51.7
0.30 50 543.4 26.7 82.6 25.1
0.15 100 340.8 16.8 99.4 8.4
pan 11.3 0.6 100.0 0
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Sieve Test Result
0
20
40
60
80
100
120
no 4 no 8 no 16 no 30 no 50 no 100 pan
cumm retained
cumm passing
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TYPICAL GRADATION
Sieve designation
Percent finer thanA B C
2 in 100 100 100
1 ½ in 100 95 90 – 100
¾ in 63 85 65 – 80
No. 4 25 50 30 – 45
No. 10 15 36 20 – 35
No. 200 3 7 0 - 5
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TYPICAL GRADATION
0
20
40
60
80
100
120
2 in 1 ½ in ¾ in No. 4 No. 10 No. 200
abcc1
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Binding aggregates (2 materials)
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Percent aggregate A
Percent aggregate B
Per
cent
pas
sing
agg
rega
te A
Per
cent
pas
sing
agg
rega
te B
0 20 40 60 80 100
0 20 40 60 80 100
020
4060
8010
0
020
4060
8010
0
1.5”
3/4”
No. 4
No. 10
No. 200
Aggregates Moisture Phase
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Oven Dry Air Dry Saturated surface dry W e t
Absorption Capacity
Effective Absorption
Surface moisture
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Absorption Capacity WSSD - WOD
WOD
X 100
Effective Absorption
Moisture Content
Surface Moisture
WAGG - WOD
WOD
X 100
WWET - WSSD
WSSD
X 100
WSSD - WAD
WSSD
X 100
SPECIFIC GRAVITY Ratio between mass (weight in air) to the mass of an equal
volume of water (for a specific temperature)
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WOD
WSSD - WSW
WSSD
WSSD - WSW
WOD
WOD - WSW
Bulk Specific Gravity, Gb =
Bulk Specific Gravity, Gbsd =Saturated surface dry
Apparent Specific Gravity, Ga =
Flexible Pavement
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Asphalt concrete
Base course
Sub Base course
Sub Grade
TYPICAL CROSS SECTION
Aggregate for Pavement Base
• GRADATION
• PARTICLE STRENGTH
• PARTICLE SHAPE
• SURFACE TEXTURE
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Gradation
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Fine CoarseMedium
GRADATION• Gradation affects: stability, drainage, and frost
susceptibility;
• The type of gradation: dense graded (maximum stability), open graded (maximum drainage or frost protection);
• The hardness of the aggregate (ie.; aggregate degradation)
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Aggregate without fines
Void filled with fines Void overfilling by fines
STRENGTH Grain to grain contact only
Grain contact increaseResistance to deform increase
Contact reduced the strength of mixtureAggregate float in fines
DENSITY Varies (relatively low)Pervious
Density increase Density decrease Practically impervious
STABILITY High in confine structureLow in unconfined structure
High for confine and unconfined structure
Low stability
COMPACTION Hard to compact Relatively easy to compact
No problem
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Particle Strength
• To resist the load without breakdown, minimize degradation
• Requires: strength and toughness
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Particle Shape
• Angular aggregate characteristics give aggregate interlock properties; increase the stability of open graded materials.
• Rounded aggregate: Herrin and Goetz: crushing rounded gravels add significantly only to the
stability of one size aggregate mixes, to open graded mixes a very little,
and to dense mixes not at all • Thin and elongated aggregate: Size segregation; low strength
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Particle Texture (surface)
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Aggregate for Bituminous Mixture
• Gradation and Size: (High volume of traffic: dense graded aggr., with sufficient void to leave
room for fine and asphalt)
• Strength and Toughness: To prevent aggregate breakdown under traffic and subsequent los of
stability)
• Particle shape (angular aggr. gives aggr., interlock properties increasing stability of open
graded materials)
• Porosity
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Gradation for typical sand asphaltSieve
designation passing
Percentage of total by weight
Grading A Grading B Grading C
½” 100 100 100
No. 4 95 – 100 95 – 100 90 – 100
No. 10 80 – 100 80 – 100 50 – 100
No. 40 50 – 80 50 – 95 35 – 70
No. 80 10 – 30 5 – 30 5 – 30
No. 200 0 – 8 0 – 8 0 – 8
Bitumen 4.0 – 6.0 4.0 – 6.0 4.5 – 6.5
hra 28Note: Base course mixture
• This is en of session
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Assignment
1. Jenis batuan yang paling cocok untuk perkerasan jalan adalah “igneous rock”. Mohon komentar dan penjelasan mengenai keterangan tersebut.
2. Bagaimana bentuk (shape) dari partikel mempengaruhi penggunaannya untuk: -beton semen; -beton aspal?
3. Apa yang dimaksud dengan gradasi batuan?
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Sieve Size 4 8 16 30 50 100
Weight Retained (gr)
26 130 240 252 210 138
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1. Analisis saringan dari 1.000 gram batuan halus (fine) menghasilkan data sebagai berikut pada tabel. Mohon saudara gambarkan grafik gradasinya dan hitung modulus kehalusan (fineness modulus) dan apa saran saudara terhadap gradasi tersebut
Assignment
1. Pelajari dan gambarkan grafik gradasinya dari beberapa standar teknis (technical specification) mengacu kepada ASTM standar untuk gradasi batuan yang digunakan untuk:
campuran beton aspal campuran beton semen
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