Agenda - Public Works Committee - 01/21/2020

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details. I would encourage everyone that this study include street maintenace personnel (field people) in addtion to City engineers/Public Works Directors (office people). As a rule of thumb, we will seal coat a street twice over a 15 to 20 year period prior to mill and overlay. Stripping more common after second seal coat. We have one road we sealed when it was only a year old and the stripping has not occured on that road yet You know all our comments about the chip seal material on sticking to our truck engines and tranny's... The City has been very consistent over the last 10 years or more about seal coatingand keeping up with the 5 year timing. To date we have not noticed any problems with the surface coat below the chip seal. We use MC oil and no emulsifiers which helps prevent this from happening. Our experience is limited to stripping on 61 wear course roads, we haven’t seen other significant stripping issues on other roads. We have attributed the problem more to the wear course being chip sealed then the chip seal itself Maplewood, like other metro cities is dealing with this issue and there are a number of state aid roadways with this problem. We are currently formulating an approach to fix these streets since it is very difficult to patch the great number of thin failures areas. According to our Street Superintendent the issue could be a result of using trap rock which is left for only 2-3 days before being swept up. Streets with pea rock left down for 2-3 weeks such as North Saint Paul and Lake Elmo don’t seem to be having the failures. We have not seen this problem in Faribault County. Marshall County has not completed a chip seal. So far this has only shown up in our first recycled asphalt wear courses installed from 1996 to 1998. We have heard that there was a problem with the Mn/DOT formula that hopefully has been corrected.