CT 229 - Durability Index

Question 1

Which test is most applicable for Durability Index test:

Answer 1

CT 217

Question 2

It is not necessary for the No. 8 and No. 200 sieves required for this test to be in 8” diameter frames.

Answer 2

False

Question 3

To prepare sand equivalent stock solution in the lab, a ________USP glycerin (95%) is needed.

Answer 3

542g

Question 4

To prepare working calcium chloride solution in the labratory, _________ of stock solution is needed.

Answer 4

85mL

Question 5

Working solution that is more than two weeks old may be used:

Answer 5

False

Question 6

If the temp of the testing water could not be maintained at 72 +- 5 deg F:

Answer 6

Temperature correction factors should be established.

Question 7

Samples tested for durability index need to be sampled in accordance with ____________.

Answer 7

CT 125

Question 8

Materials with a minimum nominal size larger than 3/4 in must be crushed to pass the _________ sieve.

Answer 8

3/4”

Question 9

Coarse Durability (Dc) is determined for material retained on __________sieve.

Answer 9

No.4

Question 10

After the cylinder is on working bench that is free of vibrators and allowed to stand undisturbed for 20 min, the top of the sediment column reads 72.5 units. The durability is most probably______.

Answer 10

34

Question 11

The specific gravity of the light weight aggregate tested for durability index was determined to be 2.56. The adjusted specimen weight is most nearly ___________.

Answer 11

2463g

Question 12

What is general different between the Coarse Durability and Cleanness Value test test methods?

Answer 12

CV determines the amount of clay size material clinging to coarse aggregate whereas Coarse Durability is resistance of an aggregate to produce clay size fines when subjected to abrasion in the presense of water.

Question 13

What additional steps of specimen prep are required for Coarse Durability versus Cleanness Value?

Answer 13

The Coarse Durability specimen must be thorough washed and dried prior to conducting the test, and must be prepared by combining gradded fractions by weight as specified.

Question 14

What container is used to wash the specimen?

Answer 14

A wash vessel with a clamping lid.

Question 15

How much water is added to the vessel?

Answer 15

1000mL +- 5mL

Question 16

How soon after adding the water do you start agitating?

Answer 16

1 min +- 10 sec

Question 17

How is the specimen agitated and for how long?

Answer 17

By placing the vessel in a mechanical shaker for 2 min +- 5 sec.

Question 18

What is the final step for washing the coarse aggregate?

Answer 18

Pour the contents of the vessel into a No.4 sieve and rinse with fresh water until water passing through is clear.

Question 19

After the aggregate wash, what is the only difference between the CT 229 Coarse Durability and CT 227 Cleanness Value testing procedures?

Answer 19

In Coarse Durability, the sampe is agitated for 10 min+- 15 sec.

Question 20

How is coarse durability determined?

Answer 20

The sediment height is read and correlated to the Durability Index of Coarse Aggregate and chips table.

Question 21

If both coarse and fine durability tests are conducted, which number is reported as the Durability Index?

Answer 21

The lower number of the two.

Question 22

What is the general difference between the Fine durabiilty and the SE test methods?

Answer 22

SE determines the fine dust or clay in fine aggregate. Fine durability is the resistance of an aggregate to produce clay sized fines.

Question 23

What container is used to wash the specimen?

Answer 23

A wash vessel with clamping lid

Question 24

How much water is added to the vessel?

Answer 24

1000 mL +- 5 mL

Question 25

How soon after adding the water do you start agitating?

Answer 25

10 min +- 30 s

Question 26

how is the specimen agitated and for how long?

Answer 26

By placing the vessel in a mechanical shaker for 2 min +- 5 sec.

Question 27

What is the final step for washing the fine aggregate?

Answer 27

Pour the contents of the bessel into a No. 200 sieve and rinse with fresh water until water is passing through is clear.

Question 28

After the aggregate wash, what is the only difference between the CT 229 Fine Durabilty and CT 217 SE testing procedures?

Answer 28

Fine Durability, the specimen is agitated for 10 mins +- 15s instead of 45sec

Question 29

How is the fine durability determined?

Answer 29

The same as SE, find the clay reading and sand reading. Calc by Sand / Clay

Question 30

If both coarse and fine durability tests are conducted, which number is reported as the Durability index?

Answer 30

The lower of the two numbers.

Question 31

Wash Coarse size sample over what sieve?

Answer 31

No. 4

Question 32

Wash Fine size sample over what sieve?

Answer 32

No. 200

Question 33

When should the Basic Test Specimen Gradings Table for mass of each size material be used?

Answer 33

When all sieve specified fractions have more 10% or more retained.

Question 34

What is done when a material has less than 10% on any fraction specified?

Answer 34

The specimen is prepared using the actual calculated percentage for deficient fraction and proportionally increase the weights of the remaining fractions.

Question 35

If either the Coarse or Fine side of the grading doesn’t contain at least ______%, then do not test that side.

Answer 35

15%