What is segregation in concrete, and how can the inspector identify it during delivery?

• A. Segregation is the separation of coarse aggregate from cement paste; it can be identified by a rough surface, exposed aggregate, loose or separated material, or a slurry of fines at discharge.
• B. Segregation is the separation of water from cement; identified by clear water at discharge
• C. Segregation is the uniform mixing of components; identified by consistent texture
• D. Segregation is the complete separation of air voids; identified by bubbly discharge

Answer: (A)

Segregation in concrete means the coarse aggregate has separated from the cement paste, so the mix isn’t uniformly blended. This can happen during handling and placement when the concrete is dumped or moved too vigorously, allowing larger particles to settle or the paste to flow away, creating a nonuniform mix. An inspector can identify it during delivery by looking for exposed aggregates on the surface, a rough or rocky texture, loose or separated material at the discharge point or along the chute, and a visible slurry of fines separating from the coarse material. The other options don’t fit: water separating from cement would indicate a bleeding-type issue, not aggregate segregation; uniform texture implies good mix consistency; complete separation of air voids relates to air entrainment rather than aggregate distribution.