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

Vertical Rotation: At least 90% of the dowels were placed within
the specification for vertical rotation on all inserter and
basket projects. The mean rotation varied from 0.14 to 0.25
inches on the individual p,rojects. In conclusion, the dowel bar
inserter performed satisfactorily with respect to the vertical
rotation parameter.
Horizontal Rotation: At least 90% of the dowels were placed
within the specification for horizontal rotation on all of the
inserter projects. Somewhat surprisingly, 17% to 22% of the
dowels on the three basket projects did not meet the specified
limit of I/2 inch of horizontal rotation. The mean horizontal
rotation for the inserter projects ranged from 0.21 to 0.26
inches, while the mean for the basket projects ranged ranged from
0.32 to 0.40 inches. In conclusion, the dowel bar inserter
performed satisfactorily with respect to the horizontal rotation
parameter, and was superior to basket performance.
Lonaitudinal Translation- This parameter is mpre closely
associated with the marking and sawing of joints than with the
actual performance of the dowel bar inserter itself. However,
whether placement is by inserter or baskets, it is imperative
that the sawed joint is aligned properly with the midpoint of the
dowels. The number of joints which were improperly aligned with
the dowels ranged from 1% to 15% on the inserter projects, and
from 1% to 22% on the basket projects. Hence, there is
definitely room for improvement of the joint locating techniques
used both on inserter and basket projects. An economical means
by which to improve performance in this area would be to have
available a magnetic rebar locator on all doweled FCC
construction projects. This could be used to verify the location
of the dowels relative to the pre-established locating marks,
especially in the early stage of paving on a project, until the
joint marking and sawing procedure is refined to an acceptable
level. It was the experience of t? re field crew doing the coring
for this study,
that the position L ? the dowel ends could be
accurately established (plus,or minus 1 inch) using a magnetic
rebar locator. In conclusion, performance with respect to
longitudinal translation needs improvement on both inserter and
basket projects.
Ride Quality: Concern has been expressed over adverse effects on
the ride quality of pavements where dowel bar inserters are used.
Pavement serviceability index (PSI) is measured on all newly
constructed pavements in Wisconsin to assess the ride quality of
these projects. These ride quality measurements are collected
after diamond grinding has been completed to meet the California
Profilograph based WisDOT smoothness specifications which are
part of the construction‘contract. The total amount of original
roughness on a project can then be qualitatively assessed as a
combination of the final PSI, and the amount of grinding which
was done to achieve that level of ride quality. It is important
to remember that some or most of the roughness on a project may
originate from paving problems which are independent of the dowel
3.5.14