Topcon mmGPS 3D Paver, Reference Manual

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Paver Components
P/N 7010-0781
4-13
Quality of Base Being Paved
There are factors other than the four main forces that can have an
effect on the quality of the mat. An important one is the quality of the
base to be paved. It makes more sense to build smoothness from the
base up, than to try to smooth a road in the last lift of paving.
However, on overlay paving jobs you have to work with what you
have.
Remember that a mat which appears smooth immediately behind the
paver, may actually contain areas of considerably varying thickness
of material as a result of undulations in the base being paved. Due to
the principle of “Differential Compaction”, high spots do not compact
as much as the low, allowing some of the irregularities to be rolled
back onto the mat (Figure 4-15). To minimize this problem, lay a
leveling course in the low spots or pave multiple lifts to average out
the irregularities.
Figure 4-15. Differential Compaction
Mat Before Rolling
Mat Before Rolling
Mat After Rolling