The truck overturned on a straight stretch of roadway just east of Highway 9 at about 10 a.m., dumping gravel across two lanes.
State troopers and medics responded to the scene. The dump truck driver was treated for minor injuries.
A sweeper truck was brought in to clean up the mess.
There was no immediate word on how the accident happened. Aerial footage from the scene showed skid marks on the pavement before the truck veered toward the grass median and rolled over onto its side.