The joint formed along the direction of paving where a new pass meets the edge of a previous one. The unconfined edge of the first pass never compacts as well as the interior, so the joint runs a few percent lower in density and becomes the path for water and the first place to ravel or crack. Good practice keeps the joint out of the wheel path, offsets it at least 6 inches between lifts, and overlaps the cold edge by about an inch.
Longitudinal joint's opening up at the crown line again, tighten it up or the state keeps the joint density bonus.
Transverse joints, where a day's paving stops and restarts, get their own routine: cut back to a vertical face and check it with a straightedge before paving off it.
Also heard as
- long joint
- centerline joint
Related terms
Joint matching
Setting the screed so the new mat overlaps the old edge slightly and sits just high enough to roll down flush.
Joint density
The density measured at a longitudinal joint, often specified separately because joints compact poorly.
Bump
To push excess mix off the old side of a joint back onto the hot mat with a lute so the rollers can pinch it in.
Raker
A paving laborer who works behind the screed with a lute, fixing joints, edges and handwork.