Segregation that shows as a continuous line of open, rocky texture along the center of the pull. The auger gearbox in the middle of the screed leaves a gap where mix is not pushed forward evenly, and coarse aggregate rolls into that spot. Fixes include reverse-pitch auger flights or kicker paddles next to the gearbox, a steady head of material, and a correct crown setting on the screed.
Got a center streak again, check the kicker paddles by the gearbox, one of them's probably worn down to nothing.
Also heard as
- centerline streak
- gearbox streak
Related terms
Segregation
Separation of coarse and fine aggregate, or of hot and cold mix, that leaves open, low-density spots in the mat.
Head of material
The amount of mix carried in front of the screed by the augers, which must stay level and constant.
Paver
The self-propelled machine that receives hot mix, spreads it to width and lays it as a smooth, partly compacted mat.