Full-Depth Reclamation - (Page 11) county engineer, noticed a FDR article in a trade magazine and directed Fred Landrum, transportation project manager, to look into the process. Coweta's roads and other Georgia counties' roads are alike because they were built on what GDOT terms a sandclay base. In other words, the asphalt for the roadway was placed directly over the underlying soil rather than being constructed on a crushed stone or soilcement base. This construction technique has been used throughout Georgia for many years. Most of these roads performed quite well over the years. However, Coweta and many other counties are experiencing exponential growth, which has lead to new development for residential, retail and industrial. Development and construction involves moving many heavy products. This type of heavy wheel loadings eventually takes its toll, especially on roads built with a sand-clay base. Because these roads were not designed for current traffic conditions, they began to deteriorate. Some signs of deterioration are the appearance of potholes and serious rutting along with alligator cracking, which can then lead to substantial failures. “Resurfacing a roadway that has a failed base is a waste of time and money,” said Cawthorne. “We had to do something different!” For years, Coweta addressed its road problems by deep patching most of the isolated failures prior to resurfacing, but some of their roads were beyond having isolated failures. “With deep-patching contracts now costing the county in excess of $100 per ton of asphalt, full-depth reclamation using cement was an alternative that made sense,” said Landrum. Traditional reconstruction techniques were totally cost prohibitive, not to mention the extended time element in reconstruction. A traditional reconstruction can take months and cost can be over- whelming he said. “FDR can rebuild the road in-place in a matter of days and the cost savings are about one-third of traditional methods,” said Landrum. “We can essentially rebuild an entire section of roadway for relatively the same investment of dollars spent for deep patching.” In 2005, their first project was reclaiming a one-mile section of Palmetto-Tyrone Road. The Miller work closely and were impressed with the results. The county was concerned about the cost and speed of construction. But after some discussion they decided to give FDR a try. “The project went very well, and when we were finished they were ready to consider other county projects,” said Stokes. FDR with cement makes the reconstruction of roads a largely self-sustaining Coweta County uses FDR with cement as an economical, environmentally sound method of rehabilitating roads. Group was the successful low bidder, and the county officials were anxious to get started to see how it would perform. “After seeing the process we were pretty convinced that FDR using cement was a viable alternative to extensive deep patching,” said Landrum. Regional Manager for the Miller Group, Kim Stokes, explained “We had just been hired by a private developer to reclaim a private sub-division in Coweta County that had somehow been built to substandard conditions.” Landrum and other county officials watched their process. The complete recycling process can be finished in one day, and traffic can be maintained throughout construction. The old asphalt and any existing base material are pulverized, mixed with portland cement and water, and then compacted to produce a strong durable base for either an asphalt or concrete surface. FDR uses the old asphalt and base material for the new cement stabilized roadway base. There is no need to haul in aggregate or haul out old material for disposal. Construction truck traffic is greatly reduced, and there is little or no waste of Special advertising supplement to the McGraw-Hill Construction Regional Publications 11 http://www.cement.org/fdr
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