The in-place density at or right next to a longitudinal joint, measured with cores centered on the joint line or with gauge readings within a few inches of it. Because the edge of the first pass is unconfined, joint density usually runs a few points below the mat. Agencies that pay on it set minimums a point or two under the mat requirement, and contractors answer with echelon paving, joint heaters or notched wedge joints.
Joint density's 89.6 on the crown, mat was 93, we're losing it on the cold side, slow that first breakdown pass down.
Also heard as
- longitudinal joint density
Related terms
Longitudinal joint
The seam running lengthwise between two adjacent paving passes, the usual weak spot in an asphalt road.
Density
How tightly a compacted asphalt layer is packed, reported as a percentage of its maximum theoretical density.
Core
A cylinder of pavement drilled out of the finished mat and sent to the lab for density and thickness.
Joint matching
Setting the screed so the new mat overlaps the old edge slightly and sits just high enough to roll down flush.