1992-11-16 Regular Meeting - Laserfiche WebLink

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• tI • Current Status Finally, the Engineering Department began looking into a process which is relatively new to the United States, but which has been used in Europe and other parts of the world since 1975. The Uretek process, developed in Finland, utilizes high density polyurethane injected through half-inch diameter holes between the slab and subgrade to successfully resolve concrete slab and pavement settlement problems. As the polyurethane expands and hardens, it exerts a lifting force of four tons per square foot raising the slab to it's required level. Precise control of the lifting process is provided by "state of the art" laser leveling devices. Essentially, this process will raise the low areas along Coupland Drive and restore a more uniform crown to the road, as well as a relatively consistent longitudinal slope of about 0.10%. While this is certainly well below design standards, it will provide sufficient grade to allow the runoff to drain off the road in a relatively short time. This process should eliminate any ponding in the street in as short a time as thirty minutes after a heavy rainfall. The Uretek process will also underseal the entire road which will prevent any further slab settlement. Also, since the polyurethane hardens to 90% of it's full strength in only 15 minutes, there will be very minimal disruption to traffic. The process is guaranteed for ten years and would take approximately seven days to complete. Uretek, USA is the exclusive licensee for the URETEK method in the United States. Pressure grouting or "mud jacking" is a similar process which was also investigated, but was rejected based on the following: According to a report prepared by the University of Illinois and the Illinois Department of Transportation "pressure grouting was very effective in reducing pavement deflections, but that currently used grouts quickly break up under the pounding of traffic so the treatment has a very short life expectancy (less than one year)". Hayward Baker, one of the well known pressure grouting contractors, would not guarantee their process.