Limit Asphalt-Loading Segregation

Staff | September 28, 2010

Large stone in asphalt mix is prone to segregate from the smaller stone and binder when the mix is handled. Large stone tends to roll down the outside of the pile. Caterpillar's publication "Segregation Prevention" suggests some basic ways to minimize segregation from the plant to the hopper.

Load trucks from pug and surge systems with at least three drops — front, rear and center — to prevent piling the mix into cones in the dump body. When the truck is in place to dump into the paver or MTV hopper and the tarp is removed, raise the bed slightly before releasing the tailgate. When the tailgate is released, it will flood the hopper, rather than allowing large stone to dribble off the pile first.

Raise the truck bed frequently to keep the hopper at least 25 percent full at all times. Never allow material conveyors in the hopper to be uncovered. The Cat publication warns, "running the hopper dry before recharging can cause random segregation, which is difficult to distinguish from random segregation caused by loading improperly from silos."