Tải bản đầy đủ

Aggregate Gradation and Sampling

Aggregate Gradation


Gradation Analysis
percent coarser
or
percent retained

percent finer
or
percent pas sin g

CIVL 3137

















Percentages
are calculated
by mass

38


Gradation Chart
Percent Passing

100
80
60

Total mass percent passing each sieve

40
20
0
Opening Size (mm)
CIVL 3137

39


Gradation Chart
Percent Passing

100
80
60


Total mass percent passing each sieve

40
20
0
Opening Size (mm)
CIVL 3137

40


Sieves

CIVL 3137

41


Shakers

Gilson Shaker
CIVL 3137

Mary Ann Shaker
42


Sieve Sizes

CIVL 3137

43


Gradation Chart
1½" ¾"

Percent Passing (%)

100

3/ "
8

4

8

16

30

50

100 200

80
60
40
20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

47


Gradation Example 1


Gradation Example 2


Uniformly Graded Aggregate
1½" ¾"

Percent Passing

100

3/ "
8

4

8

16

80

30

50

100 200

Uniformly
graded
sand

60
Uniformly
graded
gravel

40
20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

50


Uniformly Graded Aggregate
Narrow range of sizes
Grain-to-grain contact
High void content
High permeability
Low stability
Difficult to compact

CIVL 3137

51


Open-Graded Aggregate
1½" ¾"

Percent Passing

100

3/ "
8

4

8

16

30

50

100 200
Open
graded
sand

80
60
Open
graded
gravel

40
20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

52


Open-Graded Aggregate
Few fine particles
Grain-to-grain contact
High void content
High permeability
High stability
Difficult to compact

CIVL 3137

53


screenings
CIVL 3137

54


Gap-Graded Aggregate
1½" ¾"

Percent Passing

100

3/ "
8

4

8

16

30

50

100 200
Open
graded
sand

80
60
Gap
graded
blend

Open
graded
gravel

40
20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

55


Gap-Graded Aggregate
Missing middle sizes
No grain-to-grain contact
Moderate void content
Moderate permeability
Low stability
Easy to compact

CIVL 3137

56


Dense-Graded Aggregate
1½" ¾"

Percent Passing

100

3/ "
8

4

8

16

30

50

100 200

80
60
40

Dense
graded
gravel

20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

57


Dense-Graded Aggregate
Wide range of sizes
Grain-to-grain contact
Low void content
Low permeability
High stability
Difficult to compact

CIVL 3137

58


Fuller’s Curve
Fuller, W.B. and Thompson, S.E. “The laws of
proportioning concrete," Transactions of the
ASCE, v. 159, 1907.

 di 
pi   
D
CIVL 3137

0.50

pi = percent passing ith sieve
di = opening size of ith sieve
D = maximum particle size

59


CIVL 3137

60


Maximum Density Curve
In 1962 FHWA published a modified version of
Fuller’s equation with a different exponent.

 di 
pi   
D
CIVL 3137

0.45
0.50

pi = percent passing ith sieve
di = opening size of ith sieve
D = maximum particle size

61


CIVL 3137

62


Dense-Graded Aggregate
1½" ¾"

Percent Passing

100

3/ "
8

4

8

16

30

50

100 200

80

TDOT 411-D

60
Maximum
Density
Curve for
½" NMAS

40
20
0
100

10

1

0.1

0.01

Opening Size (mm)
CIVL 3137

65


Dense-Graded Aggregate
200

Percent Passing

100

30

8

4

3/ "
8

1/ " 5/ "
2
8

¾"

80
TDOT 411-D

60

Maximum
Density
Curve for
½“ NMAS

40
20
0
0

1

2

3

4

5

Opening Size (mm) Raised to the 0.45 Power
CIVL 3137

66


Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Tải bản đầy đủ ngay

×