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

State personnel informed us they believe there has been a significant
increase in the number of distress areas in the overlay areas (middle and
fast lanes) in the last couple of years.
The results of the petrographic eximination are given in Attachment 3.
Briefly, none of the cores contained reinforcing steel. They all appeared
to contain sound concrete. One core, however, appeared to have a
shale-type, limestone aggregate while the others had a marble-limestone
aggregate. The Team did not have any data that showed whether one or more
sources of aggregate were used on the project. State personnel who were
present during construction indicated there was only one aggregate source.
They did believe the project was shut down several times due to mudballr
in the aggregate; however, there was no evidence of this problem in the
cores we received.
VII. Recommendations and Conclusion
Information on this project was provided by the State. The information
consisted of condition data only for the 6-inch CRCP overlay section
(middle and high speed lanes). It must be recognized that we based our
proposed alternatives on this limited information.
There are strong indications this pavement is rapidly deteriorating. The
relatively thin (6-inch) CRCP over‘njy specification called for
2 l/2 - 2 It/lb-inch cover over the reinforcing steel. The pachometer
survey showed there were some areas with as little cover as 1.5 inches and
many areas where the cover was in the range of 2 to 2.5 inches. The
chloride studies, delamination surveys, and corrosion surveys show there
is widespread corrosion in the test sections. The cores confirmed that
there was active corrosion in the transverse bars.
If the corrosion occurring in the test sections is representative of the
entire project, there is probably very little wr.ich can be done to prevent
the disintegration of the pavement. Assuming this is the case, the
ultimate solution to this problem is a reconstruction alternative.
A detailed distress and corrosion survey of the entire project needs to be
made to quantify the amount of pavement that needs repair. An economic
analysis should then be made to determine if it is more cost effective to
continue heavy maintenance by patching the currently distressed sections
or immediately reconstructing this section. Alte:natives :-rat need to be
considered:
1. Continue heavy maintenance by patrhing identified distressed
sections.
2. Remove the existing PCC and construct a new pavement section. The
existing pavement may be suitable for recyciing into a new PCC or
AC pavement. If it is recycled, we believe the State will need to
remove the existing pavement structure (including the or.lginal
roadway), and construct an adequate drainage system. If a new PCC
3.7.9