31
Aggregate Gradation
Aggregate Gradation
CIVL 3137 38
Gradation Analysis
percent coarseror
percent retained
percent fineror
percent pas sing
Percentagesare calculatedby mass
CIVL 3137 39
Gradation Chart
0
20
40
60
80
100
Perc
ent
Pass
ing
Opening Size (mm)
Total mass percent passing each sieve
CIVL 3137 40
Gradation Chart
0
20
40
60
80
100
Perc
ent
Pass
ing
Opening Size (mm)
Total mass percent passing each sieve
Sieves
CIVL 3137 41
Shakers
Gilson Shaker Mary Ann ShakerCIVL 3137 42
CIVL 3137 43
Sieve Sizes
CIVL 3137 47
Gradation Chart
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
(%)
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
Gradation Example 1
Gradation Example 2
CIVL 3137 50
Uniformly Graded Aggregate
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
Uniformlygradedgravel
Uniformlygradedsand
CIVL 3137 51
Uniformly Graded Aggregate
Narrow range of sizesGrain-to-grain contactHigh void contentHigh permeabilityLow stabilityDifficult to compact
CIVL 3137 52
Open-Graded Aggregate
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
Opengradedgravel
Opengradedsand
CIVL 3137 53
Open-Graded Aggregate
Few fine particlesGrain-to-grain contactHigh void contentHigh permeabilityHigh stability Difficult to compact
CIVL 3137 54
screenings
CIVL 3137 55
Gap-Graded Aggregate
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
Opengradedgravel
Opengradedsand
Gapgradedblend
CIVL 3137 56
Gap-Graded Aggregate
Missing middle sizesNo grain-to-grain contactModerate void contentModerate permeabilityLow stability Easy to compact
CIVL 3137 57
Dense-Graded Aggregate
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
Densegradedgravel
CIVL 3137 58
Dense-Graded Aggregate
Wide range of sizesGrain-to-grain contactLow void contentLow permeabilityHigh stabilityDifficult to compact
CIVL 3137 59
Fuller’s Curve
Fuller, W.B. and Thompson, S.E. “The laws of proportioning concrete," Transactions of the ASCE, v. 159, 1907.
0.50i
id
pD
pi = percent passing ith sieve
di = opening size of ith sieve
D = maximum particle size
CIVL 3137 60
CIVL 3137 61
Maximum Density Curve
In 1962 FHWA published a modified version of Fuller’s equation with a different exponent.
0.450.50
ii
dp
D
pi = percent passing ith sieve
di = opening size of ith sieve
D = maximum particle size
CIVL 3137 62
CIVL 3137 65
Dense-Graded Aggregate
0
20
40
60
80
100
0.010.1110100
Perc
ent
Pass
ing
Opening Size (mm)
1½" ¾" 3/8" 4 8 16 30 50 100 200
TDOT 411-D
MaximumDensityCurve for½" NMAS
CIVL 3137 66
Dense-Graded Aggregate
0
20
40
60
80
100
0 1 2 3 4 5
Perc
ent
Pass
ing
Opening Size (mm) Raised to the 0.45 Power
¾"3/8"4830200
TDOT 411-D
1/2" 5/8"
MaximumDensity
Curve for½“ NMAS
Aggregate Sampling
CIVL 3137 67
Aggregate Sampling
CIVL 3137 68
Aggregate Sampling
CIVL 3137 69
Minimum Sample Size
CIVL 3137 70
Sample Quartering
CIVL 3137 71
Sample Splitting
CIVL 3137 72
