2 - Aggregate Gradation and Sampling

7/23/2019 2 - Aggregate Gradation and Sampling

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Aggregate Gradation


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CIVL 3137 38

Gradation Analysis

percent coarser

or

percent retained

percent finer

or

percent pas sing

Percentages

are calculatedby mass


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CIVL 3137 39

Gradation Chart

0

20

40

60

80

100

PercentPassing

Opening Size (mm)

Total mass percent passing each sieve


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CIVL 3137 40

Gradation Chart

0

20

40

60

80

100

Percent

Passing

Opening Size (mm)

Total mass percent passing each sieve


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Sieves

CIVL 3137 41


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Shakers

Gilson Shaker Mary Ann Shaker

CIVL 3137 42


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CIVL 3137 43

Sieve Sizes


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CIVL 3137 47

Gradation Chart

0

20

40

60

80

100

0.010.1110100

Pe

rcentPassing(%)

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200


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Gradation Example 1


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Gradation Example 2


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CIVL 3137 50

Uniformly Graded Aggregate

0

20

40

60

80

100

0.010.1110100

Percent

Passing

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200

Uniformly

graded

gravel

Uniformly

graded

sand


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CIVL 3137 51

Uniformly Graded Aggregate

Narrow range of sizes

Grain-to-grain contact

High void content

High permeabilityLow stability

Difficult to compact


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CIVL 3137 52

Open-Graded Aggregate

0

20

40

60

80

100

0.010.1110100

Percent

Passing

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200

Open

graded

gravel

Open

graded

sand


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CIVL 3137 53

Open-Graded Aggregate

Few fine particles


High void content

High permeabilityHigh stability



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CIVL 3137 54

screenings


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CIVL 3137 55

Gap-Graded Aggregate

0

20

40

60

80

100

0.010.1110100

Percent

Passing

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200

Open

graded

gravel

Open

graded

sand

Gap

graded

blend


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CIVL 3137 56

Gap-Graded Aggregate

Missing middle sizes

No grain-to-grain contact

Moderate void content

Moderate permeabilityLow stability

Easy to compact


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CIVL 3137 57

Dense-Graded Aggregate

0

20

40

60

80

100

0.010.1110100

Percent

Passing

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200

Dense

graded

gravel


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CIVL 3137 58


Wide range of sizes


Low void content

Low permeabilityHigh stability



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CIVL 3137 59

Fullers Curve

Fuller, W.B. and Thompson, S.E. The laws ofproportioning concrete," Transactions of the

ASCE, v. 159, 1907.

0.50

ii

dp

D

pi = percent passing ith sieve

di = opening size of ith sieve

D = maximum particle size


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CIVL 3137 60


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CIVL 3137 61

Maximum Density Curve

In 1962 FHWA published a modified version ofFullers 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


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CIVL 3137 62


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CIVL 3137 65


0

20

40

60

80

100

0.010.1110100

PercentPassing

Opening Size (mm)

1" " 3/8" 4 8 16 30 50 100 200

TDOT 411-D

Maximum

Density

Curve for

" NMAS


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CIVL 3137 66


0

20

40

60

80

100

0 1 2 3 4 5

Percent

Passing

Opening Size (mm) Raised to the 0.45 Power

"3/8"4830200

TDOT 411-D

1/2" 5/8"

Maximum

DensityCurve for

NMAS


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Aggregate Sampling

CIVL 3137 67


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Aggregate Sampling

CIVL 3137 68


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Aggregate Sampling

CIVL 3137 69


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Minimum Sample Size

CIVL 3137 70


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Sample Quartering

CIVL 3137 71


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Sample Splitting

CIVL 3137 72

Documents

2 - Aggregate Gradation and Sampling