Using Cement to Reclaim Asphalt Pavements

The rehabilitation of old asphalt pavements is often an expensive process, especially if the pavement has base or subgrade problems and a simple overlay will not result in a long-term solution. This is often the case with low-volume roads, where minimum pavement structures can carry heavy traffic and experience serious pavement deterioration. A procedure is available, called Full Depth Reclamation (FDR), which allows old deteriorated asphalt pavements to be recycled and stabilized with an additive, creating a new base that will provide an excellent foundation for long-term pavement performance. The principal stabilizing additives in use today for FDR are cement, asphalt emulsion, foamed asphalt, and lime/fly-ash. This paper will briefly discuss the differences in how the stabilizing additives work, and present in detail the specific use of cement in the FDR process. The concept of recycling existing pavement materials is especially attractive in locations where quality aggregates may not be readily available. Instead of using new aggregate sources, the aggregates from the old pavement can be recycled, and with the addition of cement the materials will form a much stronger base to improve the pavement foundation. Cost savings and environmental benefits result from use of existing pavement materials, reduced hauling associated with removing old materials and placing new materials, and from the longer expected life of a pavement with a cement-stabilized base. The paper will include the engineering and construction steps involved in designing and building a reclamation project, with examples of successful projects in northern climates.