![]() ![]() The field density and moisture are monitored for quality control purposes. Final compaction should take place no more than two hours after initial mixing of the cement. A pneumatic-tired roller may follow to finish the surface. The compaction is usually performed with vibratory rollers. The mixture is compacted to the required density of at least 96 percent of standard Proctor density (ASTM D558). More than one pass of the mixer may be required to achieve a uniform blend of materials. The aggregate-soil-cement-water mixture is combined and blended with the pulverizing/mixing machinery. Water is then added to bring the aggregate-soil-cement mixture to optimum moisture content (water content at maximum dry density as determined by ASTM D558). FDR with cement recycles existing asphalt pavements and aggregate bases to create a thicker pavement structure and a longer lasting base.Ī measured amount of cement is spread either in dry or slurry form on the surface of the shaped roadway. Final base elevation requirements may necessitate a small amount of material removal or addition. This could involve additional earthwork to widen the roadway. The pulverized material is shaped to the desired cross-section and grade. The depth of pulverization is usually 6 to 10 in., which on secondary roads will typically include all of the surface and base, plus some part of the subgrade. Pulverization construction begins with pulverizing the existing asphalt pavement using equipment that resembles a large roto-tiller. This includes the determination of maximum dry density and optimum moisture content. The mix design procedure is the same as that performed for soil-cement. ![]() Material samples from the site should be pulverized in the laboratory to create an aggregate-soil mix that will be similar to that expected from the reclamation process. If old asphalt and base materials are not recycled, they must be disposed of or stockpiled, increasing transportation costs and utilizing valuable landfill space. And most important, recycling costs are normally 25 to 50 percent less than removal and replacement of the old pavement.įDR with cement conserves virgin construction materials and makes smart economic and strategic sense. The recycled base will be stronger, more uniform, and more moisture resistant than the original base, resulting in a long, low-maintenance life. A surface consisting of a thin bituminous chip seal, hot-mix asphalt, or concrete completes the rebuilt road. FDR recycles the materials from deteriorated asphalt pavement and, with the addition of cement, creates a new stabilized base. Truck traffic is greatly reduced, and there is little or no waste. There's no need to haul in aggregate or haul out old material for disposal. The old asphalt and base materials are pulverized, mixed with cement and water, and compacted to produce a strong, durable base for either an asphalt or concrete surface. This process rebuilds worn out asphalt pavements by recycling the existing roadway. That's why engineers and public works officials are turning to a process called full-depth reclamation (FDR) with cement. Deteriorating roads are a constant problem for cities and counties. ![]()
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