Preliminary Mixture Design Procedure for Recycled Asphalt Materials

Abstract

This paper summarizes the findings of a study to evaluate the strength, fatigue, and elastic characteristics of recycled asphalt pavement materials and to develop a preliminary mixture design procedure. Mixtures with different types and amounts of additives for three recycling projects in Texas were evaluated. The primary method of evaluation was the static and repeated-load indirect tension test. Estimates of tensile strength, resilient elastic characteristics, and fatigue characteristics were obtained. A preliminary mixture design procedure was formulated which was based on the results of this study and standard tests on the mixture and extracted asphalt and a review of pertinent literature and past experience. The objective of this preliminary design procedure is to allow engineers to begin routinely to design mixtures involving recycled, deteriorated asphalt cements. Preliminary findings indicate that recycled asphalt mixtures can be treated through the addition of asphalt or reclaiming agents to produce a material which exhibits satisfactory engineering properties as measured by laboratory tests on both laboratory-prepared specimens and field cores. A preliminary mixture procedure which can be used to design recycled mixtures is presented. Future work will lead to modifications of this procedure. However, at present it is felt that the procedure is practical and capable of being used routinely.