Atterberg Limits and Plasticity Questions and Answers

Q: The maximum moisture content below which, the soil ceases to decrease in volume on further drying is known as:

It is the Shrinkage limit.As a saturated clay dries, it shrinks in volume until it reaches the shrinkage limit; below that water content the soil particles are in contact and further drying removes water from the pores without reducing the volume. The shrinkage limit is the lowest of the Atterberg limits.The liquid limit marks the change from liquid to plastic state, the plastic limit from plastic to semi-solid, and the plasticity index is the difference between them, not a moisture content at which shrinkage stops.

Q: A soil with plasticity index equal to zero may be called as :

A soil with a plasticity index of zero is Non Plastic.The plasticity index is the liquid limit minus the plastic limit, the range of water content over which the soil behaves plastically. If it is zero, there is no such range, as with sands and non-plastic silts, so the soil is called non-plastic.In the usual classification, a plasticity index below 7 is low plasticity, 7 to 17 medium, and above 17 high. All three describe soils that do have some plastic range, unlike a soil with an index of zero.

Q: At the liquid limit :

At the liquid limit the shearing strength is small but definite.The liquid limit is the water content at the boundary between the plastic and liquid states. The soil still has a small, measurable shear strength there, of the order of 2 kN/m2, and the standard cup test is in effect a way of finding the water content at which the soil has that strength.The soil is fully saturated at the liquid limit, so A is wrong. Zero strength would describe a true liquid, beyond the limit. Easy moulding describes the plastic state between the plastic and liquid limits rather than the limit itself.

Q: Which of the following soils has more plasticity index ?

Clay has the highest plasticity index.The plasticity index is the range of water content over which a soil behaves plastically, the liquid limit minus the plastic limit. Clay minerals are fine, plate-shaped and electrically charged, so they hold water films and stay mouldable over a wide range of moisture; clays typically have plasticity indices well above 17.Silt has low plasticity. Sand and gravel are coarse and non-plastic, with a plasticity index of practically zero.

The maximum moisture content below which, the soil ceases to decrease in volume on further drying is known as:

A.Liquid limit
B.Plastic limit
C.Shrinkage limit
D.Plasticity index

Exam Year(s)

RSMSSB JE - 2025, RSMSSB - 2025,

Answer: C

It is the Shrinkage limit.

As a saturated clay dries, it shrinks in volume until it reaches the shrinkage limit; below that water content the soil particles are in contact and further drying removes water from the pores without reducing the volume. The shrinkage limit is the lowest of the Atterberg limits.

The liquid limit marks the change from liquid to plastic state, the plastic limit from plastic to semi-solid, and the plasticity index is the difference between them, not a moisture content at which shrinkage stops.

Discuss in Forum

A soil with plasticity index equal to zero may be called as :

A.High Plastic
B.Medium Plastic
C.Non Plastic
D.Low Plastic

Exam Year(s)

RSMSSB JE - 2025, RSMSSB - 2025,

Answer: C

A soil with a plasticity index of zero is Non Plastic.

The plasticity index is the liquid limit minus the plastic limit, the range of water content over which the soil behaves plastically. If it is zero, there is no such range, as with sands and non-plastic silts, so the soil is called non-plastic.

In the usual classification, a plasticity index below 7 is low plasticity, 7 to 17 medium, and above 17 high. All three describe soils that do have some plastic range, unlike a soil with an index of zero.

Discuss in Forum

At the liquid limit :

A.the soil is not fully saturated.
B.the shearing strength of soil is zero.
C.the shearing strength is small but definite.
D.the soil is plastic and can be easily moulded.

Exam Year(s)

RSMSSB JE - 2025, RSMSSB - 2025,

Answer: C

At the liquid limit the shearing strength is small but definite.

The liquid limit is the water content at the boundary between the plastic and liquid states. The soil still has a small, measurable shear strength there, of the order of 2 kN/m², and the standard cup test is in effect a way of finding the water content at which the soil has that strength.

The soil is fully saturated at the liquid limit, so A is wrong. Zero strength would describe a true liquid, beyond the limit. Easy moulding describes the plastic state between the plastic and liquid limits rather than the limit itself.

Discuss in Forum

Which of the following soils has more plasticity index ?

A.Gravel
B.Sand
C.Silt
D.Clay

Exam Year(s)

RSMSSB JE - 2025, RSMSSB - 2025,

Answer: D

Clay has the highest plasticity index.

The plasticity index is the range of water content over which a soil behaves plastically, the liquid limit minus the plastic limit. Clay minerals are fine, plate-shaped and electrically charged, so they hold water films and stay mouldable over a wide range of moisture; clays typically have plasticity indices well above 17.

Silt has low plasticity. Sand and gravel are coarse and non-plastic, with a plasticity index of practically zero.

Discuss in Forum

Loading…

Topics

Other Subjects

Tags: Atterberg Limits and Plasticity Questions and Answers || Atterberg Limits and Plasticity MCQ Questions and Answers || Atterberg Limits and Plasticity GK Questions and Answers || Atterberg Limits and Plasticity GK MCQ Questions || Atterberg Limits and Plasticity Multiple Choice Questions and Answers || Atterberg Limits and Plasticity GK || GK on Atterberg Limits and Plasticity || Soil Mechanics Questions and Answers || Soil Mechanics MCQ Questions and Answers || Soil Mechanics GK Questions and Answers || GK on Soil Mechanics

Atterberg Limits and Plasticity Questions and Answers

Topics

Other Subjects

About Us

Stay informed about all important Dates & Notifications