Paving Alignment, Grade, and Compaction
Posted by Jesse Willoughby on Sat, May 09, 2009 @ 05:08 AM
Alignment is the horizontal positioning of the road orrunway; grade is the vertical positioning. The plans describe the alignment andgrade of a “profile line” for the road, lot, driveway, or taxiway. This is mostoften the centerline of the structure. The alignment and grade of other pointsrelative to the profile line is shown in one or more “typical sections” in theplans.
The alignment and grade must be checked and approvedby the grade inspector prior to priming. This ensures that the road or runwayis in the correct location. This sounds simple but stakes are lost duringconstruction and mistakes do occur.
The surface width of the road must also be checked;sometimes it is narrower than the planned paving width and must be corrected.The position and slope of the crown must be checked too (or just the slope in asuper elevated section).
Compaction of the base course must be checked andapproved prior to priming. The check is made by means of density testsperformed by materials inspectors.