After you start paving, allow the screed to travel a few lengths of the paver before you make adjustments. This will allow all of the forces that act on the screed to reach equilibrium. This will reduce the need for adjustments that are repeated.
Lines in the Mat
Usually, the first adjustments will be made due to lines in the mat because the extenders are too high or too low. Establish the proper depth for the mat. Frequent changes in depth will cause frequent changes in the vertical height adjusters for the extenders.
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| Illustration 1 | g00697142 |
(1) Main screed (2) Right extender (3) Line that is caused by the extender (4) Line that is caused by the main screed | |
If extender (2) is lower than main screed (1), the edge of the extender will leave a line in mat (3). Raise the extender with the height adjuster until the line disappears. If extender (2) is higher than main screed (1), the edge of the main screed will leave a line in mat (4).
Open Textured Mat
The second type of adjustment will occur with a new screed. This will also occur after you install new screed plates.
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| Illustration 2 | g00696875 |
(5) Left extender (6) Main screed (7) Mat (8) Open texture | |
The dark section indicates an open textured mat (8) that is behind the left extender (5). The remainder of the mat (7) is good. The open texture may occur behind one extender or both extenders. This open texture, or tearing is usually the result of improper adjustment to the trailing edge of the extender. Adjust the trailing edge of the screed downward in order to fix the problem.
Open texture (8) may also occur behind main screed (6). This open texture is usually the result of improper adjustment of the trailing edge of the main screed. To eliminate the problem, adjust the trailing edge of the main screed. The main screed must be adjusted downward in order to fix the problem.