When targeting a 1-inch thickness, what should the probe be set at?

When aiming for a 1-inch thickness in asphalt paving, the probe should be set at 1 ¼ inches. This adjustment accounts for the compaction and settling that occurs after the asphalt is laid down. New asphalt is generally placed at a thickness greater than the final desired thickness to achieve proper density and compaction during the rolling process.

Setting the probe at a thickness of 1 ¼ inches ensures that as the material is compacted, it will shrink down to the target thickness of 1 inch after the rolling is completed. If the probe were set at the exact target thickness, the final product would likely be under the intended measurement due to settling and compaction. Therefore, the practice of adding a little extra material during installation is essential to achieving the specified final thickness accurately.