Segregation means separation of designed fresh concrete ingredients from each other resulting in the non-uniform mix.
More specifically, this implies the separation of coarse aggregates from the mortar because of differences in size, density, shape and other properties of ingredients in which they are composed. Because of segregation honey comb is created in the concrete and it basically affects the strength of the concrete and its porosity.
During concrete work, segregation in concrete can occur on site and it affects the durability of your structures. In good concrete all the ingredients are properly distributed and make a homogeneous mixture.
If a concrete sample exhibits a tendency for separation of coarse aggregates from the rest of the ingredients, it indicates segregation in concrete