What Is Plastic Limit?

What is the formula of shrinkage?

Shrinkage is another way of expressing what used to be called Utilisation.

Utilisation is simply the number of hours that employees are available to work on their primary task (measured hours), divided by the total paid hours.

So a Shrinkage Figure of 30% equates to a Utilisation figure of 70%..

What is the formula of shrinkage limit?

Data Sheet for Shrinkage Limit TestSl. No.Observations and Calculations1Mass of empty mercury dish2Mass of mercury dish, with mercury equal to volume of the shrinkage dish3Mass of mercury = (2) – (1)4Volume of shrinkage dish V1= (3)/13.614 more rows

What is a high liquid limit?

A high liquid limit normally indicates a high compressibility and a high shrinkage/swelling potential. A high-plasticity index Ip generally results in a low shear strength. A low Ip means that a soil used as foundation will change significantly in consistency even with a small change in water content.

What is shrinkage limit?

The shrinkage limit of cohesive soils is defined as the water content at which further loss of moisture will not cause a decrease in volume. … A soil specimen with moisture content above the liquid limit is placed in the shrinkage dish and struck off with the straightedge.

Why is plastic limit important?

The plastic limit (PL) is the water content, in percent, at which a soil can no longer be deformed by rolling into 3.2 mm (1/8 in.) … 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 does a high plastic limit mean?

A high PI indicates an excess of clay or colloids in the soil. Its value is zero whenever the PL is greater or equal to the LL. The plasticity index also gives a good indication of compressibility (see Section 10.3). The greater the PI, the greater the soil compressibility.

What does plastic soil mean?

“Plastic soil” generally means the soil is predominantly clay – and the more plastic the soil, the more expansive it will likely be. The soil’s plasticity is measured by two tests: the Plastic limit and the Liquid limit.

What is the importance of liquid limit?

Value of liquid limit is used to classify fine grained soil. It gives us information regarding the state of consistency of soil on site. Liquid limit of soil can be used to predict the consolidation properties of soil while calculating allowable bearing capacity & settlement of foundation.

What is the use of shrinkage limit?

This limit is needed for studying the swelling and shrinkage properties of cohesive soil. The shrinkage factor helps in the design problems of structure made up of this soil or resting on such soil. It helps in assessing the suitability of soil as a construction material in foundations, roads, embankments, and dams.

Why are plastic limits and liquid limits important?

This is very important when trying to build with or build on these type of materials. The two commonly determined Atterberg Limits represent the moisture contents at which a specific soil’s behavior changes from solid to plastic (Plastic Limit) and from plastic to liquid (Liquid Limit).

What is plastic limit of soil?

DEFINITION. 2.1 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 semisolid states of consistency. It is the moisture content at which a soil will just begin to crumble when rolled into a thread ⅛ in.

What is liquid limit and plastic limit?

Liquid Limit (LL) is the water content at which soil changes from a plastic to a liquid state when the soil specimen is just fluid enough for a groove to close when jarred in a specified manner. Plastic Limit (PL) is the water content at the change from a plastic to a semi-solid state.

How is plastic limit calculated?

Calculate the plastic limit wp by dividing the “weight of moisture” by the “dry weight of sample” and multiply by 100. Plasticity Index (Ip) of a soil is the numerical difference between its Liquid Limit and its Plastic Limit.

What is Atterberg limit of soil?

The Atterberg limits are a basic measure of the critical water contents of a fine-grained soil: its shrinkage limit, plastic limit, and liquid limit. Depending on its water content, a soil may appear in one of four states: solid, semi-solid, plastic and liquid.

How do I get liquid limit?

x) Liquid limit is determined by plotting a ‘flow curve’ on a semi-log graph, with no. of blows as abscissa (log scale) and the water content as ordinate and drawing the best straight line through the plotted points. Report the water content corresponding to 25 blows, read from the ‘flow curve’ as the liquid limit.