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Mr. Culver reviewed the overall purpose of a Pavement Condition Index model <br /> where roads are periodically rated and an inventory taken of cracks, potholes, or <br /> other distresses and a subsequent calculation based on the condition index based <br /> on those distresses, providing an ongoing and consistent projection for <br /> maintenance and/or replacement. <br /> Mr. Culver reviewed the City's current maintenance program from when new <br /> pavement was installed, and a following program of seal coating in years 2 or 3, a <br /> second application of seal coating in years 7 to 10; a third application in years 15 <br /> to 8; a mill and overlay to a depth of two inches when the condition index reaches <br /> 35-60, with a full depth mill and overlay with any condition indexes found under <br /> 30. Mr. Culver noted that staff did annual crack sand joint sealing ahead of sea <br /> coat projects, and other patching with a goal to maintain an average condition <br /> index of 75. However, Mr. Culver noted that budget factors often dictated the <br /> amount of roadway in miles that could be addressed in any given year based on <br /> available resources. Therefore, Mr. Culver advised that those budget <br /> ramifications and limitations had created a funding backlog under the current <br /> policy and current goals of the average condition index. <br /> Mr. Culver advised that another factor and new reality to consider was the <br /> delamination problem being experienced in the area, with distressed pavements <br /> from the top layer peeling off in strips. Mr. Culver noted that this was being <br /> found exclusively on roadways with a seal coat application; and the current theory <br /> in the industry was that moisture is being trapped by the seal coating and eroding <br /> the wear course (top layer of pavement). Since it was a difficult thing to duplicate <br /> in a laboratory setting, Mr. Culver admitted that the definitive cause and a <br /> complete range of pavements affected remain an unknown at this time, but the <br /> biggest issue seen to-date is delamination in early stages followed by a rapid <br /> acceleration at that point. Mr. Culver noted further research was needed to <br /> determine if this issue was exclusive to Minnesota pavement mixes only, and <br /> determining how and where the problem is in the interaction between the <br /> pavement mix and seal coating. <br /> As background information, staff advised that since 2005, local agencies <br /> including the City began using a different "super pavement" mix versus the <br /> previous low and mid-volume pavement mixes, with the hopes that switching <br /> would eliminate delamination issues. Mr. Culver advised that MnDOT and <br /> Ramsey County had begun using the super mix earlier than local municipalities; <br /> and since most counties as well as MnDOT didn't do seal coating, they were not <br /> experiencing the same problems but whether or not it was a seal coating issue or <br /> pavement mix was difficult to determine from their experiences. <br /> Mr. Culver provided photos taken earlier today of this issue in various areas <br /> throughout the City, as well as a map showing the street segments affected and <br /> showing the City's potential exposure. Based on the City's potential exposure, <br /> Mr. Culver reviewed the new reality of a future condition index curve as the <br /> Page 7 of 17 <br />