How a Screed Works
P/N 7010-0341 www.topconpositioning.com
2-5
The screed has four main forces acting on it at all times, whether
paving in manual or with automatics (Figure 2-7). A change in any
one of the forces will cause the screed to rise or fall, changing the
mat depth. The key to smoother paving is to keep these forces as
constant as possible. The following sections review these forces and
the factors that will have an effect on the paving.
Figure 2-7. Forces Affecting the Screed
Tow Point Force (“P”)
The tow point force (P) is the resistance to forward travel
(Figure 2-8).
Figure 2-8. Tow Point Force (“P”)
The P force will remain constant if the paver is kept moving at a
consistent speed at all times. If the paver is allowed to stop, the
screed will settle in the fresh mat and leave a mark. The mark
cannot be fully smoothed out by the roller and a bump will end
Tow Point
Force "P")
Reaction of Material
Under Screed
(Force "R")
Head of
Material
(Force "M")
(Force "W")
R
W
M
P
Tow Point
P
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