What must be done to the straightedge before it can be used?

Before using a straightedge in asphalt paving, it is essential to ensure that it is calibrated. Calibration ensures that the straightedge accurately represents a straight line. This is crucial in determining the flatness and smoothness of the surface being measured, which affects the quality of the asphalt pavement.

A properly calibrated straightedge guarantees that measurements taken on the pavement surface are reliable and consistent. If the straightedge is not calibrated, it could lead to incorrect assessments and possibly result in poor paving outcomes such as uneven surfaces or improper drainage.

While options like painting, repairing, or cleaning may be necessary for other maintenance tasks, they do not directly relate to the primary function of the straightedge in achieving accurate measurements necessary for effective asphalt paving practices. Calibration specifically focuses on ensuring measurement accuracy, which is fundamental in this context.