Wordweb dictionary defines the term “segregation” as – Separation or isolation of one thing from another and place in a group apart from others.
In concrete technology, segregation can be of two types. Firstly the coarse aggregate may separate from the main mass of concrete in its plastic state. Secondly, the grout (cement+paste) may separate from the mix. The second one is generally occurs if a concrete is too wet.
What Causes Segregation in Concrete (Theoretical Aspect)
Concrete is a mixture of aggregate, cement, water & admixture. The sizes and their specific gravities are different from each other. For example the specific gravity of most of the aggregates fall in the range between 2.6 to 2.7 and that of most of the cement is in between 3.1 to 3.2. Because of this they show a tendency to separate from each other.
The separation can be of three types as mentioned below.
Coarse aggregate separating out or settling down from rest of the matrix (Type-1 segregation)
The paste separating away from coarse aggregate (Type-2 segregation)
Water being lowest in specific gravity, separating out from the rest of the material (Type-3 segregation, called Bleeding)