ROLLING STRAIGHTEDGE APPARATUS

The Rolling Straightedge measures depressions on the pavement surface on analogue scale 0-12mm + 0.25mm. The straightedge also has an odometer for accurate determination of distance travelled in units of 1 meter.

The Rolling Straightedge is pushed at 1-2km/h and the number of irregularities, their length, and distance from the start, are recorded.

The national specifications for surface regularity are then compared and the pavement accepted or rejected and or remedial work undertaken.

The Rolling Straightedge simulates a 3m rigid straightedge sliding along the road surface, and consists of a rigid frame supported on rubber-tyred wheels arranged in two parallel rows, with the centers of the wheels in one row opposite the gaps between the two parallel rows of supporting wheels, is free to move such that it detects vertical movements of this wheel which are then transmitted to a pointer and scale, on the instrument head.