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

T?&e se Oi ?XieF.LeC TaL’e- . ..ent Gabs wiil !ead to imarot.ei ~a...e~,2~.I
oer&mance. The extended Iiie wiil ‘be due to lower edge jtra:rs, :e~~;c~~ c’.‘iy’.; ‘.
itress, lower edge and corner derlecsons, and less water inii!caton :h.:o:~k -A<
longitudinal pavement shouider joint. It should be possible to design a :;&r~&
pavement section with extended pavement slabs and obtain the 5am.e oerform.-arGce ~5
that of a thicker pavement without extended slabs. “Results or’ a stud; conduczed 5..
the Construction Technology Laboratories for the Federal Highway &hinist;acon ’
indicate that lane widening is an effident method of improving Ravement ;es?or,s(r
under traffic load.“‘“’ Improved performance can realistically be expected irorn the
use, of extended pavement slabs without drastic changes of design. K’ith :he correct
information available, highway designers will support the construction oi 2x:enCed
pavement slabs to extend the life of the pavement, with no decrease in jar’s:); cr
inaease in initial (unit price) costs.
It should be noted that the benefits of extended slabs can oniv be realized ii
the siabs are properly.striped. Since the stripe appears to control tie lateral wheel
distribution, placement of the lane-shouider stripe must be done at the 12 ft (3.7 T-J
mark and not at the edge of the extended slab or even on the adjacent shoulder.
SAFETY CONCERNS
The .issua of safety is also a subject that should be addressed when discussing
the use of extended slabs with the traffic lane striped at 12 ft (3.7 m). Discussion
with the Office of Highway Safety and Regional Safety Engineers indicates that there
are no increased safety problems with the use of extended lanes when compared to
standard 12 ft (3.7 m) lanes: In fact, widened lanes are equal or superior to rhe
conventional ianes, from the standpoint of user safety. However, it should be noted
that extended KC slabs should not be considered a replacement for a shoulder
structure.
In the area of user safety, lane edge stripe maintenance and location on
extended pavement slabs has been a debated subject. Practices on standard I2 it
(3.7 m) pavements differ from Stqe to State and even between different areas of a
State. There are two basic theories about where to put the pavement lane edge snipe
when shoulder structures differ from mainline pavement’ type. One practice places
the edge line stripe on the PCC pavement (mainline) to keep the load off of the
pavement/shoulder joint. The advantages of keeping the wheel loads 18 to 36 in (457
to 914 mm) away from the pavement have already been discussed and documented:
The second practice is to place the pavement edge line stripe beyond the
pavement/shoulder joint and onto the shoulder (usually AC). One of the reasons tor
this practice is that the edge line will last a longer period of time, therefore reducing
the associated maintenance costs (paint, trucks, crew). The other support for this
practice lies in the color contrast between the white paint of the edge line and the
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