concrete technology

Segregation of concrete means that the various products used for making the concrete (cement paste, fine aggregates & large aggregates) have become separated from one another. Usually, this condition occurs when concrete is dropped a high distance from the discharge chute or pump hose to the point of deposition. It also occurs when there is inadequate vibration provided in the concrete matrix once the concrete has been deposited.

I suggest that you read up on how to properly place concrete. The very best to read are the US Army Corp of Engineers (USACE) Technical Manuals (TM) and Field Manuals(FM). Also, study PART III (or 3) of any good Concrete technical specification. Usually, a good technical specification will provide step-by-step instructions for the Contractor on how to properly place concrete.

And don't forget these fantastic sources: American Concrete Institute (ACI), and the Portland Cement Association (PCI). There are many many many technical textbooks available online and at your university library that deal with the subject of concrete. The Civil Engineering Handbook by Merritt has a very good chapter section on how to properly place concrete....I'd start there if I were you!