Aggregates

Question 1

Main uses for aggregates

Answer 1

underlying materials for foundations and pavements, riprap for erosion protection, and ingridients in portland cement and concrete

Question 2

Aggregate Sources

Answer 2

Natural Sand, gravel pits, and quarries

Question 3

Rocks forming from volcanic action

Answer 3

igneous

Question 4

rocks forming from inorganic remains of marine animals, or disintegrated in existing rock

Answer 4

sedimentary rocks

Question 5

aggregate material retained on a sieve with 4.75 mm openings

Answer 5

coarse

Question 6

aggregate material passing through a 4.75 mm sieve

Answer 6

fine

Question 7

largest sieve size that allows all aggregates to pass

Answer 7

max aggregate size

Question 8

the first sieve to retain some aggregate, usually less than 10%

Answer 8

Max nominal Size

Question 9

What aggregates give strength and stability of asphalt?

Answer 9

angular and rough

Question 10

What aggregate gives workability of concrete?

Answer 10

Smooth and round

Question 11

texture and angularity indicates what?

Answer 11

fractured faces

Question 12

How are fine aggregates analyzed?

Answer 12

determining the uncompacted void content of a sample of aggregates

Question 13

What test helps evaluating the load resistance damage?

Answer 13

LA Abrasion test

Question 14

If there is negative free moisture in aggregates

Answer 14

aggregates will absorb water

Question 15

If there is positive free moisture in aggregates

Answer 15

aggregates will release water

Question 16

Specific gravity

Answer 16

mass of solid/mass of water

Question 17

Apparent Specific Gravity (Gsa)

Answer 17

Dry Weight/(Volume not accesible to water*62.4)

Question 18

Bulk Specific Gravity (Gsb)

Answer 18

Dry weight/(total volume)*62.4

Question 19

Bulk specific gravity, saturated surface dry

Answer 19

SSD Weight/Total particle volume*62.4

Question 20

What is Gsb,ssd used for ?

Answer 20

concrete mix design

Question 21

the weight of aggregate required to fill a “unit” volume. Typical units are cubic meters and cubic feet

Answer 21

Bulk unit weight

Question 22

Strength of concrete cannot exceed strength of aggregates

Answer 22

true

Question 23

typical compressive strength for aggregates

Answer 23

5000-50000 psi

Question 24

has a good mix of all particles sizes which means the aggregates use most of the volume and less cement and asphalt is used

Answer 24

high density gradation (well-graded)

Question 25

all the same size

Answer 25

one size gradation (uniform)

Question 26

missing some sizes

Answer 26

gap-graded

Question 27

missing small aggregates which fill holes between larger ones

Answer 27

open graded

Question 28

a measure of the gradation fineness, used for concrete mix design

Answer 28

fineness modulus

Question 29

What sieves are not included in fineness modulus?

Answer 29

2.00 and 0.075 mm