INTRODUCTION
Segregation in asphalt placement has become a major issue in the industry today. As we increased the size of aggregate and modified the mix designs to achieve a more stone on stone structure along with reducing the binder content, mixes have become more prone to segregation. Larger aggregates in these drier more sensitive mixes will accumulate in pockets of segregation as the mix is moved through the mixing, storing, transportation or lay down procedures.

DEFINING SEGREGATION
Segregation is the separation of the larger aggregate particles from the finer particles in the mix, caused mainly by the free movement of material as it passes through the paver. Unconfined or uncontrolled material will segregate as it flows, the longer and the steeper the repose angle, the greater the segregation effect, the larger particles rolling faster and further down the slope than the finer particles. Some material types will segregate easier than others particularly those with larger nominal size aggregates within the mix.

Segregation will result in a non-homogenous mix that could be more difficult to densify which could also allow moisture to permeate into the HMA deteriorating its strength, resulting in premature failure of the pavement.

"End of Load" or "Truck Exchange" segregation is one of the most common patterns showing up on jobs today. But segregation can show up in different patterns that can be identified and reduced tremendously by watching the flow of material through the paver itself.

There are eight areas on the paver that can be monitored and controlled in an attempt to minimize segregation and its effect on the asphalt pavement being laid.

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