Surface irregularities and evenness roughness

The irregularities and evenness (or roughness) of the surface(s) or of the surface course are measured for compliance within the specified limits, which is a prime determinant of quality in new construction of asphalt works. Measurements are taken normally after completion of asphalt works, although daily measurements are not uncommon. 

The devices under (a) and (b) are usually employed after completion of short-duration asphalt works or during construction. The devices under (c) and (d) are employed after completion of long-duration asphalt works or for monitoring in-service surfaces. 

The straightedge beam (usually 3 m long) is an apparatus measuring single irregularities attributed to quality defects in new surface(s) or surface course. It can also be used transversely to measure rut depth of in-service roads. This test method is not applicable to providing information on profile or general unevenness. 

With the straightedge, the distance (the deviation) is measured between the surface and the plane of its measurement edge. This distance should be less than the maximum limit specified. Usually, the limit value for a newly constructed surface (surface of an individual layer) is 6 mm, and for a newly constructed surface course, it is 3 mm. The test method is carried out according to CEN EN 13036-7 (2003) or ASTM E 1703 (2010). 

When the rolling straightedge beam and the travelling beam (a similar device) are used, the number of surface irregularities is determined over a specified distance in the longitudinal direction. The number of surface irregularities should be less than the permitted number (see Section 15.3.12.2). 

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