9. Compact the surface.
10. Apply a seal coat when necessary.
When you are mixing in place (road mix), here are
some helpful hints:
1. Do not try to buck nature; stop operations when
you are working under adverse weather conditions.
2. Keep the mixture or aggregate in a well-packed
windrow for better water shedding and control.
3. Provide drainage cuts through the windrow
during heavy rains.
4. When a grader comes to the end of a section with
a full blade, lift the blade rapidly to avoid carrying
materials into the next section.
5. The distributor spray must be cut sharply at
sectional joints; carry-over to the next section will cause
undesirable fat joints.
6. Plan the work to avoid inconvenience to traffic.
7. Apply the asphalt at the recommended spraying
viscosity to ensure uniform application.
8. Using a shoe on the outer end of the grader blade
or moldboard helps obtain a good edge during spreading
9. Aggregate in shaded areas usually requires extra
Two methods of road mixing are travel plant mixing
and blade mixing.
Travel Plant Mixing
When a travel plant is used for mixing (fig. 16-7),
the loose aggregate is dumped, mixed, and bladed into
uniform windrows, and evened when necessary. The
windrow should be sufficient to cover the section of the
area to be paved with enough loose material to give the
desired compacted depth and width. As the bucket
loader tows the mixer and elevates the aggregate to the
mixer hopper, the mixer meters the aggregate, sprays it
with the correct amount of bitumen, mixes these two
uniformly, and redeposits the mix into another windrow
behind the plant. The rate of travel and the mixing
operation should be controlled so that all particles of the
aggregate are coated and the mix is uniform. Accuracy
in proportioning the mix is extremely important.
The travel plant method usually produces a more
uniform mix of higher quality than blade mixing.
Figure 16-7.Schematic layout of a travel plant.