How do you calculate the liquid limit of soil?
Subtract the weight of a dry soil sample from the weight of a wet soil sample and multiply by 100. Divide the result by the weight of the wet sample to get the percent water content for that sample.
When the plastic limit of a soil is greater than liquid limit then the plasticity index is reported as?
c) When the plastic limit is equal to or greater than the liquid limit, report the plasticity index as NP (non-plastic). 3.3 The plasticity index gives an indication of, among other things, the reduction in moisture content required to convert a soil from a liquid to a semisolid state.
Can liquid limit be less than plastic limit?
Plasticity index The PI is the difference between the liquid limit and the plastic limit (PI = LL-PL). Soils with a high PI tend to be clay, those with a lower PI tend to be silt, and those with a PI of 0 (non-plastic) tend to have little or no silt or clay. Soil descriptions based on PI: (<7) – Slightly plastic.
What is the plasticity index of soil with liquid limit of 50?
9.2. 1 Consistency and Plasticity
| Soil | Liquid limit wL (%) | Plasticity Ip (%) |
|---|---|---|
| Silt, low plasticity | 25–35 | 4–11 |
| Silt, medium plasticity | 35–50 | 7–20 |
| Clay, low plasticity | 25–35 | 7–16 |
| Clay, medium plasticity | 40–50 | 16–28 |
How do you do a plastic limit test?
The Plastic limit test is performed by repeated rolling of an ellipsoidal-sized soil mass by hand on a non-porous surface. Casagrande defined the plastic limit as the water content at which a thread of soil just crumbles when it is carefully rolled out to a diameter of 3 mm (1/8”).
What is the purpose of plastic limit test?
objective Determination of Plastic Limit is as important as Liquid Limit so as to ascertain Plasticity Index, Ip of the soil. The plastic limit of a soil is the moisture content, expressed as a percentage of the weight of the oven-dry soil, at the boundary between the plastic and semi-solid states of consistency.
Why are plastic limits and liquid limits important?
It is the water content at which a soil changes from plastic to liquid behavior. Those limit of soil are very important property of fine grained soil and its Value is used to classify fine grained soil and calculate activity of clays and toughness index of soil.
What is meant by liquid limit?
Liquid limit (LL) is defined as a limiting water content separating the viscous liquid state and plastic state of soil consistency.
How do you find the shrinkage limit?
Procedure of Shrinkage Limit Test
- Take a sample of mass about 100g from a thoroughly mixed soil passing 425 micron sieve.
- Take about 30g of soil sample in a large evaporating dish.
- Take the shrinkage dish.
- Fill the mercury in the shrinkage dish.
What are the various shrinkage parameters How do you determine linear shrinkage?
LSN = linear shrinkage, expressed as a percentage of the original wet length of 150 mm, when the moisture content corresponding to N taps in the liquid limit test is reduced to an oven-dry state. The linear shrinkage is reported to the nearest 0.5 % on Form A1/2, or a similar form.
What is soil shrinkage?
The soil shrinkage is defined as the specific volume change of soil relative to its water content and is mainly due to clay swelling properties (Haines, 1923; Stirk, 1954). This process is reversible with changes in water content and the reverse to shrinkage is swelling.
What is a shrinkage factor?
1. A percentage in short fall of a planned output amount. 2. a percent of inventory lost due to errors, theft and spoilage or waste.
Why does clay swell with water?
A type of damage in which formation permeability is reduced because of the alteration of clay equilibrium. Clay swelling occurs when water-base filtrates from drilling, completion, workover or stimulation fluids enter the formation. Clay swelling can be caused by ion exchange or changes in salinity.
What causes soils to expand?
Expansive soils are soils that expand when water is added, and shrink when they dry out. This continuous change in soil volume can cause homes built on this soil to move unevenly and crack.