Which condition can cause periodic edge segregation during paving?

• A. Augers run too slow or starved
• B. Augers run too fast
• C. High ambient temperature causing rapid drying
• D. Too much vibration from the roller

Answer: (A)

Edge segregation shows up when the edge of the mat has a different distribution of aggregate than the center, often appearing as bands of material near the edge. The feed of asphalt to the screed is controlled by the augers, so when those augers are not delivering material steadily—running too slowly or becoming starved—the edge zone doesn’t receive a consistent flow. That inconsistent supply lets the fines and coarser particles separate as the mat is laid and compacted, creating the periodic edge bands you see along the pavement. If the augers were pushed too fast, you’d risk other surface issues from overfeeding, but the characteristic periodic edge segregation isn’t driven by a too-fast feed. High ambient temperature causing rapid drying changes the mix properties over time but doesn’t produce the distinct edge-segregation pattern during placement. Excessive roller vibration tends to compact and may reduce segregation rather than create the periodic edge bands.