Pavement Preservation Journal - Fall 2017 - 29
HOW FP 2 WORKS FOR YOU
Southeast PPP Ponders Early Treatment Failures
BY JUDITH CORLEY-LAY, P.E.
n the not-too-distant past, an early
failure would result in a categorical "we will never use THAT treatment again" reaction by the agency
regarding the preservation treatment.
This mindset could set back an agency's
preservation program-or at least that
preservation treatment-for a decade.
At the most recent meeting of the
Southeast Pavement Preservation
Partnership, each agency was asked to
report on one of their early failures. What
happened? Why did it happen? How did
the agency and the contractor deal with
the issue? What was changed to prevent
a similar failure from happening again?
How was the public kept in the loop?
What were some of the causes?
In one case, the contractor requested
to place a micro surfacing job in midNovember and the agency approved the
request, despite a time and temperature restriction in the specifications.
The weather turned cold and ultimately the job failed. Both the contractor and the agency knew better, but each
wanted to finish up during the current
In another case, the contractor changed
emulsion from the job mix design. The
contractor was in a hurry to complete
the work on the contract after a supply
disruption of the original emulsion caused
him to seek an alternate solution. The
new emulsion did not adhere properly to
the aggregate, resulting in excessive loss
of aggregate. In this case, the contractor
should have performed laboratory testing to assure that the existing design
was still appropriate. Developing a new
mix design with the new emulsion would
have identified the issue between the
aggregate and the emulsion. Once the
material is placed on the roadway, both
the agency and the contractor must deal
with the results of the failure.
A third case was caused by a sudden
and unexpected thundershower immediately after application of the emulsion.
Summer heat coupled with high humidity
in the southeastern states can trigger
these very localized convective showers.
In this case, it was unfortunate that the
shower did not come an hour later and
spare both the agency and the contractor
the failure. Fortunately, the area impacted
in this case was relatively small, and the
portions of the work where the emulsion
had broken and chips had been rolled
Texas DOT has a pavement forensics
group that evaluates any pavement
project that fails to perform as designed,
including new construction, rehabilitation and preservation. This group includes
experts in materials, design, construction
and pavement testing. When evaluating
a particular project, they include local
personnel, and for complex projects they
may use university consultants. The goal
of the group is to identify the root cause of
the failure through a comprehensive study
of construction records, cores, field testing, laboratory studies and interviews.
The group disseminates their findings to
field divisions and maintains a database
so trends in issues and performance can
be identified. This is a comprehensive
best practice approach that has built inhouse expertise over time.
Another example comes from the
Kentucky Transportation Cabinet, which
experienced failure of a micro-surfacing project on U.S. 23 in Pikeville. This
2.2-mile project has four lanes carrying
35,000 ADT. The failure resulted in severe
raveling in the wheel paths. Kentucky
responded with a four-part plan: lead the
discussion, accept responsibility, reiterate
the long-term goals of the program, and
identify weaknesses. They took positive
steps as a result, including investment in
research, establishment of a preventive
maintenance engineer position, development of stronger program messaging,
and founding the Preventive Maintenance
Alliance to keep the dialogue going.
The program of preventive maintenance in Kentucky has matured since
the failure. Tracy Nowaczyk stated in her
presentation to SEPPP, "As you push the
limits of treatments, you must have permission to fail." Kentucky Transportation
Cabinet's holistic response to the U.S. 23
failure is a best practice approach that
turned failure into success.
Corley-Lay is director, National Center for
Fall 2017 | PAVEMENT PRESERVATION JOURNAL
12/22/16 6:48 PM