Discussion of Plastic Limit test

Plastic Limit Test

Name: Hisham Alrawas

Class: CNST111L, 401

Location: 0118 TA lab

Group Name: Mud Team

Date: 29, March 2017

Equipment Used:

· Moisture Cans numbers: 1, 2

· Ground glass plate

· Balance sensitive

· Spatula

· Porcelain evaporating dish

· Oven with temperature 110 °C

· Plastic squeeze bottle with Water

· Container to hold soil sample for weighting

· Trash can to throw dry soil

Procedure:

1. Obtain all the equipment that will be use in the test.

2. Put nearly 30 g of air- dry soil sample, passed through a U.S. No.40 sieve, into a porcelain evaporating dish.

3. Add water by using plastic squeeze bottle to the soil and mix thoroughly.

4. Determine the mass of 2 moisture cans in grams and record it on the date sheet.

5. Get the moist soil prepared in step 3, prepare some ellipsoidally shaped soil masses by squeezing the soil with fingers.

6. Take one of the ellipsoidally shaped soil masses and roll it on a ground glass plate using the palm of your hand, the rolling should be done at the rate of 80 strokes per minute.

7. When it being rolled in step 6 reaches 1/8 in, break it up to several small pieces and with your fingers to form again an ellipsoidal mass.

8. Do step 6 and 7 until the thread crumbles into several pieces until reaches a diameter of 1/8 in.

9. Collect the small pieces in the first and second moisture cans and put the cover on them.

10. Determine the mass of the moisture cans 1, 2 plus the wet soil M2 and record it on the date sheet.

11. Remove the cap from the cans 1, 2 and place the cans in the oven.

12. After a week, remove the cans from the oven and determine the mass of the cans plus the dry soil and record it on the date sheet.

13. Throw dry soil of the 2 simples into trashcan.

Plastic Limit Test

Description of soil: air- dry soil

Sample no: 5

Location: TA 0118, CNST111L

Tested by: Mud team

Date: 29, March 2017

Item Can no. Mass of can, M1 (g) Mass of can+ moist soil M2 (g) Mass of can+ dry soil M3 (g) Moisture content, W% = M2 – M3 X 100 M3 – M1

Test No. 1 2 39.7 (g) 39.3 (g) 55.8 (g) 57.4 (g) 53.3 (g) 54.6 (g) 18.38% 18.30%

· Average value of plastic limit = 18.3

· Plasticity index PL = LL – PL = 24.68 – 18.3 = 6.4

Discussion:

Adding water to dry soil can change it shape to liquid. Also, adding a lot of water to soil can be unsuccessful experiment. The liquid limit test is water content at soil cut by a groove to join together for a distance of ½ Inch, before 25 blows. I think the important of liquid limit test is to determine the moisture in the soils and gives us the information of the change in shape from hard to soft or paste.