Agenda - Public Works Committee - 07/15/2008

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CASE # DISCUSSION ON CONCRETE STREETS By: Tim Himmer, Assistant City Engineer Background: The Public Works Committee previously inquired about the potential use of concrete for the construction of City streets. Staff has investigated the request and offers the following information for discussion. Observations: In general terms the initial cost to construct a concrete street is approximately 50% - 100% higher than a bituminous section, depending on design. These additional costs are primarily associated with the material cost. The other major factor that influences the cost of installation is the underlying soil condition, and Ramsey may have an advantage here in that most of the City has a good sand base. Savings could potentially be seen over the design life of the street due to decreased maintenance compared to what is associated with bituminous streets (seal coating and overlays). Concrete streets typically have a design life of 40 years, whereas bituminous is approximately 30 years. When concrete streets are constructed they generally don't require maintenance other than some minor rehab/joint sealing every 12 - 15 years. It is possible that the road wouldn't need to be resurfaced for the entire design life, or beyond. As you are probably aware from our existing street maintenance program, bituminous streets require routine maintenance far more frequently; crack sealing and seal coating every 3 - 5 years and overlays every 10 - 15 years. Concrete streets are also typically designed to higher standards, thereby resulting in a minimum 9 ton design versus the 5 ton design of our standard bituminous road section. Some concerns associated with concrete streets would include appearance and cost . considerations. Since there is less maintenance associated with concrete, these roads are usually built and then deteriorate over time until it is time for replacement. If areas begin to fail they still need to be patched or replaced. Bituminous patches to concrete streets result in bad aesthetics and rideability, and replacing concrete panels is more expensive and could result in a patchwork appearance of varying color. Utilizing the standard maintenance practices on bituminous streets results in a uniform appearance at regular intervals; potentially a new road appearance every 5 - 10 years. When it comes to maintenance of U11derground facilities (utilities) concrete usually requires a larger removal area to accommodate the repair alld the curing time of the patch requires a longer downtime for the traveling public. Underground repairs on bituminous roads could be completed and open to traffic the same day. Additionally, the public works department doesn't have the expertise to perform this work, whereas we now have a bituminous paving machine and our crews can perform some of this work in house. Deicing chemicals also take a greater toll on concrete streets. Action: This item is strictly for informational purposes and discussion. Reviewed By: City Engineer PW: 7/15/08 61