Aim: To Determine the Shrinkage Limit of a Specimen of the Remoulded Soil
The shrinkage limit refers to the propertion of the soil when the water is rightly adequate to fill up all the pores of the soil and the soil is saturated to the right extent. The size of the soil will not have diminished when the water proportion is condensed beneath the shrinkage limit. It could be assessed from the following relation:
Where = initial wet mass,
= original volume
= dry mass
- = volume after drying.
Tool and equipment
1. Shrinkage dish with a flat base, with dimensions 45mm diameter and 15 mm stature
2. Two big evaporating dishes with dimensions of about 120mm diameter with a pour out and flat base.
3. One small mercury dish with dimensions of 60mm diameter
5. Straight Edge
7. Weighing balance preciseness 0.01g
11. IS sieve 425
12. Glass cup 50mm diameter and 25 mm stature
1. First of all, take a specimen of mass approximately 100g from a methodically blended soil passing 425 sieve.
2. Now, take approximately 30g of soil specimen in a big evaporating dish. Blend it with distilled water so that if forms a smooth paste which could be freely functioned so that it doesn’t entrap the air bubbles.
3. Now take the shrinkage dish. Clean it thoroughly and compute its mass.
4. Fill up the mercury in the shrinkage dish. Eliminate the extra mercury by pressing the plain glass plate on the top of the shrinkage dish. The plate has to be flush with the crest of the dish. Make sure that no air could be entrapped.
5. Shift the mercury of the shrinkage dish to a mercury measuring dish and assess the weight of the mercury to a preciseness of 0.1g. The size of the shrinkage dish is equivalent to the volume of mercury in grams divided by the specific gravity of the mercury which is 13.6.
6. Generously coat the interior part of the shrinkage dish with a layer of silicon grease or we can substitute it with Vaseline. Position the soil sample in the middle of the shrinkage dish equivalent to approximately one-third the size of the shrinkage dish. Tap the shrinkage dish on a stable cushioned surface and permit the paste to flow to the edges.
7. Augment additional soil and carry on the tapping until the shrinkage dish is fully packed and additional soil mix projects out about its brim. Strike out the crest surface of the plate with help of a straight edge. Gently wipe of all soil abiding by to the exterior of the shrinkage dish. Regulate the weight of the wet soil ( ).
8. Now, leave the soil to dry the soil in the shrinkage dish in air until the huw of the pat transform from dark to light. After dry the pat in the oven at 105 to 110 0C to persistent mass.
9. Leave to cool the dry pat in a desiccator. Eliminate the dry pat from the desiccator after cooling, and mass the shrinkage dish with the help of dry pat to control the dry mass of the soil ( ).
10. Positon a glass cup in a big evaporating dish and pack it up with mercury. Eliminate the additional mercury by pressing the glass plate with spikes determinedly over the crest of the cup. Now, thoroughly wipe off any mercury sticking to the outside of the cup. Detach the glass cup full of mercury and position it in alternative evaporating dish making sure not to spill any mercury from the cup.
11. Now, take out the dry pat of the soil from the shrinkage dish and saturate it in the glass cup packed with mercury. Pay attention not to trap air under the pat. Press the plate with prongs on the crest of the cup strongly.
12. Gather the mercury exiled by the dry pat in the evaporating dish and shift it to the mercury measuring dish. Compute the weight of the mercury to a preciseness of 0.1g. The size of the dry pat ( ) is equivalent to the mass of the mercury divided by the specific gravity of the mercury.
13. Undertake the process test at least 3 times.
DATA SHEET FOR SHRINKAGE LIMIT TEST
|Sl. No.||Observations and Calculations||Determination No.|
|1||Mass of empty mercury dish|
|2||Mass of mercury dish, with mercury equal to volume of the shrinkage dish|
|3||Mass of mercury = (2) – (1)|
|4||Volume of shrinkage dish = (3)/13.6|
|5||Mass of shrinkage dish|
|6||Mass of shrinkage dish + wet soil|
|7||Mass of wet soil = (6) – (5)|
|8||Mass of shrinkage dish + dry soil|
|9||Mass of dry soil = (8) – (5)|
|10||Mass of mercury dish + mercury equal to in volume of dry pat|
|11||Mass of mercury displaced by dry pat
=(10) – (1)
|12||Volume of dry pat = (11)/13.6|
Shrinkage limit = ……… %