SECTION IX
PLANNING THE PAVING JOB
PLANNING THE PAVING JOB
The careful planning of a paving job is essential to fast, efficient, and low cost operation. Some of the
planning factors related to general paving are covered in the following paragraphs:
(a) Material Delivery - The steady delivery of hot material to the paver will often have a bearing on how
a multiple width mat will be divided. The accessibility of roadway to the delivery trucks could possibly override
the advantages gained by laying portions of the mat in the more desirable way from the standpoint of paver
operation.
(b) Two or More Different Mat Widths - When two or more mats of different widths are laid, the narrow
mat which requires the use of a cut-off shoe should be laid first. The final mat can then be laid at full screed
width without the complication of cut-off parts.
(c) Matching One Mat to Another - When matching one mat to another use a 6" or 1 foot screed
extension on the joining end. This will provide a small separate screed bottom surface to absorb the extra wear
that occurs when the slight overlap for matching is made. The extra wear would otherwise take place on one
tip of the long screed bottom and destroy its uniformity.
(d) Straight Center Crown Requirement - When it is necessary to maintain a straight crown in the
middle of a wide multiple mat roadway, it is best to lay the crown section first, then match the adjoining mats to
it.
(e) Narrow Roadways requiring Multiple Mats When planning to pave a narrow roadway which does not
have a shoulder area for screed overhang past the cut-off shoe, pave the narrow mat first with the screed
overhang on the inside. If this road is to have a crown, the cut-off will be made at the center for both mats with
the shoe actually riding on the first mat when the second mat is laid.
(f) Overlapping Mats - Do not overlap mats extensively unless it is required. If required, keep the
overlap to the minimum requirement. Excessive overlap can cause a bridging and tearing of the mat. If a
large overlap is required use a cut-off shoe to block material from coming too far under the screed in the
overlap area. It is the excess material allowed to build up under a screed that eventually supports the end of
the screed to cause bridging and holes in the mat. It also causes very rapid wearing of the screed bottom in the
area that is supporting most of the screed weight.
(g) Maximum Stone Size in Material - The intended mat thickness must be at least 11/2 times the
dimension of the largest stone size in the material. Fewer problems will be experienced if the mat is twice
or three times thicker than the largest stone dimension.
Example: If the roadway specification calls for a 3" thick rolled mat, the largest stone used in the material
should not exceed 11/2" to 2"! If 1" stone can be the maximum size it will cause fewer problems than the
larger stone.
Positioning Screed for Paving Start-up
Figure 1
PAVING
(a) Move the paver into position so that the steering guide marker is aligned and the screed can be
lowered to the exact point at which the mat is to begin. Move both Track Switches to the BRAKE position when
the paver is in place.
(b) Make a careful check of the screed to make sure it is ready for paving. Extensions, cut-off shoes,
etc., should be properly installed. Crown adjustment should be checked with stringline as a start-up setting.
Strike-off should be accurately measured and adjusted.
(c) Set wood support blocks under the ends and center of the screed at the correct mat thickness
height and level for proper screed take-off when paving begins. With engine at full throttle unhook screed
safety cables and lower screed to blocks allowing both lift cables to go completely slack before moving screed
lift switch to center (HOLD) position.
(d) Raise each hopper gate to the 1/4 open position for start-up. When paving starts adjust them as
necessary. See Figure 4.
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