CT 227 - Cleanness Value Flashcards
Step 1: What is done first?
Split or quarter material down to mass specified by its nominal size. 1x4 is 2500g ± 125g
What condition should the sample be dried to and at what temp?
Dry to constant mass at 230° F ± 9° F
After the sample has reached constant mass, what is done with the sample?
Cool to room temp.
How much water is added to 1x4 or less?
1000mL ± 5 mL
How long after adding the water should you start shaking the specimen?
1 min ± 10 sec
How long should the sample be agitated for 1” x No.4?
2 min ± 5 sec
How many times do you swirl the specimen in the wash vessel?
5 or 6 times
What sieves are used to pour specimen into after agitation?
No. 8 and No. 200
Is additional water allowed to be used to clean the wash vessel?
Yes a small amount.
What do you do with material caught on No. 8 sieve?
Discard
What do you do to clean concentration of material on No. 200 sieve?
Re-rinse concentration by pouring the wash water through the sieve again as many times until all material smaller than No. 200 has passed.
What is done to material caught on No. 200 sieve?
Discard if thoroughly washed.
How should you adjust the volume of wash water?
Pour all water into graduated cylinder and add fresh water to get back to original amount of water that you started with, 1000mL.
What level is the smaller graduated cylinder filled to?
0.3 in.
Describe the process to get your fines into the small graduated cylinder.
Stir wash water vigorously with one hand until all fines are in suspension. Use circular motion allowing fingers to rub the sides and bottom of the collection pot. Get all particles into suspension.
How high do you fill the small graduated cylinder to?
15 in. mark
How is the graduated cylinder mixed?
Plug the cylinder and thoroughly mix the wash water by inverting 20 times in 35 seconds. Allow the air bubble to traverse the length of the cylinder.
How long does the graduated cylinder sit for?
20 min ± 15 sec.
After 20 min period what is the sediment read to?
Nearest 0.1 mark.
What formula is used for converting height to Cleanness Value?
CV= (3.214-0.214H)/(3.214+0.786H) x 100
What is the rounding of the Cleanness Value?
Round to the nearest whole number.
The following test is applicable for the cleannes test.
CT 201
The temperature of testing water should be maintained at ___________.
72+- 5 deg F
Local tap water should never be used for this test.
False
Dried aggregate not tested for cleanness on the same day they are dried should be re-dried in the oven prior to testing:
True
Pit-run aggregate should be separated on _______ and _________ box sieves.
1” x No.4
At the end of the test you read the height of the sediment of 2.1 in. The cleanness value is most probably _________.
57
The graduated plastic cylinder should be filled with stock calcium chloride to ________.
3 in. mark
The height reading of sediment in the plastic cylinder is normally taken after __________.
20 min +- 15 sec
How long do you leave the cylinder standing undisturbed before taking a sediment reading?
20 min +- 15 sec.
