A mixture design procedure was developed to allow the use of asphalt-rubber binders in concrete for flexible airport pavements. The rubber materialconsidered in this project included only rubbers produced by grinding scrap tires. Such materials are widely available across the United States and have been used in seal coat and interlayer construction for almost 25 years. However, only limited experimentation has been done using this type of asphalt-rubber in concrete for flexible pavements. The asphalt-rubbers chosen for use in this project were produced in the field. The materials used in this study were shown to be similar to materials produced in the laboratory fromthe same combination of ingredients. The results of this study include a suggested laboratory procedure for producing asphalt-rubber for use in the asphalt-rubber concrete mixture design procedure. A suggested setup of equipment is also included along with vendors who have these items on the shelf. The mixture design procedure includes modifications to the standard FAA procedure included in the Asphalt Institute MS-2 manual. These modifications mainly involve mixing and compaction temperatures and gradation changes to accommodate the solid rubber particles added to the asphalt.(A).
Abstract