One word of caution when determining proper rolling speeds. Many times roller operators exhibit a tendency to slow down while running over the test strip and then increase their speed during production. Depending on the difference in speed, this can substantially increase the impacts per foot achieved in the test strip as opposed to that accomplished elsewhere. In turn, this will greatly skew the ability of the test strip to determine expected results and develop a proper rolling pattern. Again, the key is to always run the rollers at the same speed over the test strip as you would during production in order to ensure a reliable baseline comparison.

Troubleshooting
In addition to finding a pass density pattern and establishing the proper production speed, the test strip also allows an opportunity to troubleshoot other common problems. For instance, when a mat is overworked, the roller begins crushing aggregate and a white film appears on the surface. At this point, the stability of the material has been diminished and the mix formula changes from its original specifications, leading to unforeseen results. Of course, it's much better to encounter this problem during a test strip than to realize the material has been compromised in the middle of production. Establishing another test strip area, operators can reduce the number of passes or adjust the impacts per foot to determine the appropriate practice for the entire job.

Rippling of the mat is another warning sign to look for when rolling a test strip. If a roller is traveling at too fast a speed in relation to the vibrations per minute delivered, it may not achieve the proper impact spacing for the job. This will result in a noticeably coarse surface on the test strip. By slowing the travel speed of the roller or increasing vibration frequency, the chance of rippling is minimized.