|FHWA > Engineering > Pavements > Publications|
Primary Topic: Materials-General
Description: Recycling processes can be categorized according to material type -asphalt surface recycling, cold-mix asphalt recycling, hot-mix asphalt recycling, and portland cement concrete recycling; or according to procedural type - surface recycling, in-place recycling and central plant recycling. If the project can be restored by making corrections to the surface, with a minimum of new materials, surface recycling will prove satisfactory. If substantial corrections are required, in-place or central plant mixed procedures should be used. Methods of mix design and structural design for pavements containing recycled materials are generally similar to those used for designing mixes containing all virgin materials. The major difference is that variability in the properties of the recycled materials needs to be taken into consideration. This necessitates more frequent sampling and testing than with conventional mixtures and greater engineering judgment on the part of the designer. Cost is thq traditional criterion for selection between various rehabilitation alternatqves. The alternative with the least cost, including initial and maintenancd, is usually selected by the designer. In the case of recycling, the relative cost savings will depend on the costs and availability of other types of treatment, as well as those of the recycling option selected.
FHWA Publication Number: FHWA-TS-87-230
Publication Year: 1987
Document Links: PDF (file size: 8.6 mb)
PDF files can be viewed with the Acrobat® Reader®