Rheological and Engineering Properties of Rubberized Asphalt Concrete Mixtures Containing Warm Mix Asphalt Additive



In recent years, warm mix asphalt (WMA) is widely used for reducing energy requirements and emissions in hot mix asphalt (HMA) industry. In addition, the use of rubberized asphalt in the past has proven to be economical, environmentally sound and effective in improving the performance of pavements across the U.S. and the world. WMA additives reduce the mixing and compaction temperatures and achieve ideal workability of HMA without significantly affecting the engineering properties of the mixtures. The objective of this research was to investigate the performance characteristics (e.g. rheological and engineering properties) of rubberized warm asphalt mixtures through a series of laboratory tests on binders (viscometer, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) on the binders), and indirect tensile strength, rutting resistance, resilient modulus, and fatigue behavior of mixtures. The experimental materials included one virgin binder (PG 64-22), one crumb rubber modified (CRM) binder (PG 64-22 + 10% -40 mesh rubber), two aggregate sources, and two WMA additives (Aspha-min® and Sasobit®), and a total of twelve mixtures were used in this study. The results of the experiments indicated that the uses of WMA additives in rubberized HMA do not significantly reduce the rheological and engineering
properties of these mixes at lower mixing and compacting temperatures than the conventional rubberized asphalt mixture.

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