What is the significance of plasticity chart?
A plasticity chart , based on the values of liquid limit (WL) and plasticity index (IP), is provided in ISSCS to aid classification. The ‘A’ line in this chart is expressed as IP = 0.73 (WL – 20). Depending on the point in the chart, fine soils are divided into clays (C), silts (M), or organic soils (O).
What is plasticity limit?
Plastic limit is defined as the water moisture content at which a thread of soil with 3.2mm diameter begins to crumble.
How can plasticity index be reduced?
Based on the previous studies: – Lime can be utilized as the additional material of clay soil’s stabilization in order to reduce its plasticity index and enlarge CBR rate by 10%; LL rate by 49.33%; PI by 31.47%; swelling by 27.67%; and CBR by 16.3%.
What is plasticity in soil?
Plasticity of soil is its ability to undergo deformation without cracking or fracturing. Engineering Properties:- The main engineering properties of soils are permeability, compressibility and shear strength. Permiability indicates facility with which water can flow through soils.
Is plasticity chart is a plot of?
Plasticity chart gives the relationship between plasticity index and liquid limit. If the point gets plotted above A-line, classify soil as clay.
Why are Atterberg limits important?
Atterberg limits of soils are very important in construction. Water content drastically influences properties of fine-grained soils. The soil will remain in this plastic state until its liquid limit is exceeded, which causes it to transform into a viscous liquid that flows when jarred.
Is high plasticity clay good?
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.
How plastic limit is determined?
Plastic Limit is determined by repeatedly remolding a small ball of moist plastic soil and manually rolling it out into a 1/8in thread. A plastic limit roller device can also be used to perform this test. The Plastic Limit is the moisture content at which the thread crumbles before being completely rolled out.
What does plasticity index indicate?
In general, the plasticity index depends only on the amount of clay present. It indicates the fineness of the soil and its capacity to change shape without altering its volume. A high PI indicates an excess of clay or colloids in the soil. The greater the PI, the greater the soil compressibility.
Which soil has more plasticity index?
Soils with a high PI tend to be clay, Those with a lower PI tend to be silt, and.
Is high plasticity good for soil?
What is considered high plasticity soil?
The plasticity index (PI) is a measure of the plasticity of a soil. 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.