Atterberg limits – definition of shrinkage limit: The maximum water content at which further reduction in water content does not cause a decrease in the total volume of a soil mass is called what?

Introduction / Context:
Atterberg limits classify fine-grained soils according to consistency changes with water content. The shrinkage limit complements the liquid and plastic limits by describing behavior in the semi-solid to solid range, relevant to volumetric stability and cracking in clays.

Given Data / Assumptions:

• Soil is fine-grained (silt/clay) with measurable volume change on drying.
• Standard laboratory method for shrinkage limit determination is implied.

Concept / Approach:
The shrinkage limit w_s is defined as the water content at which further drying does not reduce the volume of the soil mass; below w_s, loss of water occurs only from pores without additional shrinkage. It separates the semi-solid state (where volume still reduces) from the solid state (volume constant).

Step-by-Step Solution:

Verification / Alternative check:
Graph of volume versus water content flattens at w_s; below this, points lie on an approximately horizontal line indicating no further volume reduction.

Why Other Options Are Wrong:

• Liquid and plastic limits concern transitions at higher water contents (liquid–plastic and plastic–semi-solid), not volume constancy.
• Permeability limit is not an Atterberg limit.

Common Pitfalls:
Confusing shrinkage limit with shrinkage ratio; reporting w_s in percent without specifying oven-dry mass basis.

Final Answer:
Shrinkage limit