Which practice contributes to preventing segregation during paving?

• A. Vary the paving speed randomly
• B. Stop and start the paver at random intervals
• C. Maintain a uniform paving operation
• D. Use different mix designs within same mat

Answer: (C)

Segregation during paving happens when the mat isn’t uniform in temperature and material distribution, allowing heavier aggregates to settle or asphalt to separate as the mix cools and moves. Keeping the paving operation uniform helps maintain a steady rate of material flow into the screed, consistent temperature, even mat thickness, and uniform compaction. When these conditions stay constant, the mat cools and drains evenly, reducing the tendency for different parts of the mat to behave differently.

If you vary the paving speed randomly, stop and start the paver, or introduce different mix designs within the same mat, you disrupt that uniformity. These actions create abrupt changes in heat, flow, and compaction, producing spots where coarse material can segregate or asphalt content becomes uneven.

So, maintaining a uniform paving operation directly minimizes the factors that lead to segregation, making it the best practice for preventing it.