Learning Objective:
Recognize
the principles of asphalt
finishers (pavers).
12–61.
The primary job of an asphalt
paver is receiving and spreading
asphalt in a predetermined uniform
length, width, thickness, and
shape.
1.
True
2.
False
12-62.
Hot-mix asphalt that is dumped in
the hopper is transported to the
distributing augers in what way?
1.
It is carried by the vibrating
screed
2.
It is pushed by the tamper bar
3.
It is pushed by the bevel end
plates
4.
It is carried by the feed
conveyor
12–63.
During paver operations, which of
the following conditions can cause
unnecessary movement of the paver
that is transmitted to the screed
and results in an uneven pavement
surface?
1.
Low tire pressure or loose
crawler tracks
2.
The screed is too hot
3.
The vibratory unit is not
set properly
4.
Oversteering by the operator
12-64.
A paver engine is not working
properly and a power lag occurs
that causes a temporary failure of
the vibrators or tamping bars in
the screed unit.
What condition
results from this failure?
1.
A stretch of pavement that
is less dense or contains
slightly less material
2.
A stretch of pavement that
has more material
3.
The fines in the asphalt
mix separate
4.
The asphalt mat is higher
in that area after it is
rolled
12–65.
During operations, the speed of
the conveyor and the opening of
the control gates at the back of
the hopper of the paver should be
adjusted to allow just enough
mixture to be delivered to the
augers so they are operating what
minimum percentage of the time?
1.
65%
2.
75%
3.
85%
4.
95%
12-66.
What component of the asphalt
paver irons the asphalt mixture
surface, leaving the hot mat
thickness at a depth that conforms
with job specifications?
1.
The screed
2.
The tamper
3.
The conveyor
4.
The hopper
12-67.
Tamping bars and vibratory
mechanisms are designed to perform
which of the following functions?
1.
Strike off and heat the
asphalt
2.
Strike off and adjust the
amount of asphalt
3.
Strike off and compact the
asphalt
4.
Strike off and roll the
asphalt
12-68.
What condition results if the
tamping bar travels too far
downward below the screed plate
on a tamping bar type of screed?
1.
The hot-mix builds asphalt
upon the screed face and this
condition tends to scuff the
surface of the mat
2.
The hot-mix asphalt decreases
in thickness and the surface
pits
3.
Overcompaction occurs
resulting in too thin of a mat
4.
The tamper over compacts,
crushing the aggregate and
causing the mat to break apart
95
