This existing 9 foot diameter corrugated metal pipe (CMP) was corroding or rusting through the invert or base of the pipe. At some points, water was just beginning to undermine the culvert forcing the township to take some action or risk affecting the roadway embankment potentially forcing an unscheduled replacement of the culvert. Stormwater runoff in this agricultural area magnifies the corrosion rate of the metal culvert, whether as a result of the areas soils or fertilizers used or both. In addition, there was just beginning to be some significant erosion at the inlet and outlet of the culvert which needed to be addressed.
Pouring concrete in the invert to reestablish the bottom of the pipe was considered. Liners and complete replacement were also considered but they were deemed too expensive. Further complicating some of these options was the difficult access to the inlet and outlet of the pipe. Nature had created a stilling basin at the outlet of the pipe and the meander of the water course at the inlet along with fencing impacted what would be easy or difficult.
Once a Road Commissioner along with the County Engineer agreed to share the
cost with the Township using joint bridge funds, the project was a go. The road
commissioner stated, “This (Combat Concrete) seemed to be so logical a solution, I wanted to try it”
Day 1 Access to the site was cleared and riprap was placed nearby. In addition, a load of rock was staged close to the culvert ends so that the remaining riprap could be placed after the CC GCCM was installed.
Day 2 Combat Concrete GCCM was placed and powder actuated fasteners were used to fix the material to the culvert. Then CC GCCM was hydrated so that it would harden in place. The entire second day of work took 2.5 hours to complete.
Day 3 25 gallons of mastic was used along the high edge of the GCCM to prevent water from getting between the material and the metal culvert.