Which observation indicates poor uniformity during discharge?

Which observation indicates poor uniformity during discharge?

• A. Consistent flow with no segregation and uniform slump.
• B. No color change in the discharge stream.
• C. Segregation or lumpiness observed in the discharge stream.
• D. Temperature reading confirms compliance.

Answer: (C)

Uniformity during discharge means the concrete stream stays homogeneous as it leaves the truck, without parts separating or gathering into pockets. The clearest sign of poor uniformity is segregation or lumpiness in the discharge stream—heavier aggregates separating from the cement paste and fines, causing uneven texture and composition along the flow. This separation means some portions are stiffer or coarser than others, which can lead to weak spots and inconsistent strength in the placed concrete. The other observations don’t directly indicate poor uniformity: a consistent flow with no segregation shows good uniformity; no color change isn’t a reliable indicator of uniformity since color can stay the same even if components have started to separate; a temperature reading doesn’t reflect how uniformly the concrete is blending during discharge.

Uniformity during discharge means the concrete stream stays homogeneous as it leaves the truck, without parts separating or gathering into pockets. The clearest sign of poor uniformity is segregation or lumpiness in the discharge stream—heavier aggregates separating from the cement paste and fines, causing uneven texture and composition along the flow. This separation means some portions are stiffer or coarser than others, which can lead to weak spots and inconsistent strength in the placed concrete. The other observations don’t directly indicate poor uniformity: a consistent flow with no segregation shows good uniformity; no color change isn’t a reliable indicator of uniformity since color can stay the same even if components have started to separate; a temperature reading doesn’t reflect how uniformly the concrete is blending during discharge.