Used to measure individual irregularities that can be attributed to quality defects in both newly constructed surface courses of roads, airfields, and other trafficked surfaces.
This test method cannot be used to gather information about the overall profile or general unevenness. Single irregularities are inherently random, and as a result, there are no specified routine sampling rates or precision data for them.
A straightedge is utilized to determine the distance of a surface from the plane of its measuring edge. The measurement edge of the straightedge must be easily distinguishable.
The straightedge has a length of 3 meters and a sturdy construction, ensuring that when suspended at its endpoints, its measuring edge remains within ±0.5 mm of a true plane at any point. Additionally, the straightedge must be perfectly straight along its entire length.
To measure the distance between the measurement edge and the surface, a calibrated wedge of length (300 ± 1) mm and width (25 ± 1) mm shall be used. The wedge will have permanent markings on the slope plane, with increments of 1 mm for the first 10 mm and 2.5 mm increments beyond that point. The true height at each marked increment must be accurate to ±0.1 mm.