What is the purpose of using a manual straightedge before placing the rolling straightedge?

The purpose of using a manual straightedge before placing the rolling straightedge is to find a flat area. A manual straightedge is a tool that helps assess the surface of the pavement for small deviations or irregularities. By using it first, workers can identify any high or low spots that need to be addressed. This ensures that the surface is as flat as possible, which is critical for the performance and longevity of the asphalt pavement. If any issues with flatness are detected, they can be corrected before applying the more comprehensive rolling straightedge, which checks larger areas for uniformity and helps ensure that the final surface meets the required specifications.