chapter 3 rigid pavement - DOT On-Line Publications - Department ...

lack coior of the asuhait shoulder. However, economic ram:i:c~::on,j oi zc;2,2r-- s.?- -
pavement deteriorahon far exceed potential maintenarce bene5;its or :r,creas;r.g :+.e
effective stripe life.
-Most design engineers acknowledge the advantages or’ extended zav?xez:
slabs in keeping the traffic off of the shoulders. However, :h.e controi o; :he a!crAal
paincng oi the edge line stripes is in the hands of traffic and - ..,aiz-iter,ar.ce engineers.
Until design concepts and concerns are thoroughiy understood bv this grou?, many
extended slab designs will be wasted because of improper edge lme piacemen:.
When comparing the costs of annual or bi-annual painting of edge lines and a 20-X
percent extended pavement life, the benefit-cost ratio supports correctly piaced and
maintained edge stripes. There is also little conclusive data that supports the cor.ceFt
of better edge Iine delineation on AC pavements than on KC pavements.
CLOSING STATEMEVI-S
When gathering data for this paper, many research reports on differing
subjects were reviewed that briefly mention extended pavement slabs and their
benefits. information regarding extended slabs and stresses, strains, deflections, and
overall pavement deterioration is limited to portions of studies done on other
subjects; there have been only a few studies performed recently that concentrate
solely on lateral wheel load distribution and KC pavement fatigue.
‘_
The greatest use of extended slabs is concentrated in the midwest (Iowa,
-Minnesota, South Dakota, and Wisconsin), with each State’s design a little different.
They are all building extended slabs for the same reason; to move the heavy truck
wheel loads away from the edge of pavement. Extended pavement slabs have also
been used in Georgia, Idaho, Louisiana, and Oregon. Deiaware wiil be constructing
its first extended pavement slab project during their 1989 construction season. &
more pavements are built with extended slabs, much more information will be
avaiiable on their performance.
.
There are points in the previous text that deserve repeating.
.
l Resent wheel load distribution will be an average of 20 to 22 in (508 to
559 mm) away from the lane edge stripe on 12 ft (3.7 m) PCC slabs.
l The edge stripe, and not the overall width of the lane, controls lateral
truck wheel distribution.
l Studies have shown that detrimental edge loads are reduced
significantly at 26 to 20 in (406 to 508 mm> away from the KC
pavement edge.
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