Characterization of rubberized asphalt for railway sub-ballasts

The use of a bituminous sub-ballast layer has been pointed out as an exciting alternative to the granular sub-ballast design traditionally applied in most railroad tracks. Frequently, unbound granular materials are replaced by bituminous sub-ballast that provide additional benefits to the subgrade protection. Much research has been conducted on finding other alternative material to be used as a modifier in asphalt mixes to improve its properties. Rubberized asphalt mixtures (RUMAC) are regarded as a proper solution for improving the strength of the rail-track section. This work presents a laboratory evaluation of the performance of HMA-DRY bituminous mixes to study its application as sustainable railway sub-ballast manufactured from scrap tires at the end of their service life. Several tests were used and different techniques for mixing-compaction (Superpave, Marshall, ASRC...). The research presented was carried out as part of the Marie Curie Initial Training Network (ITN) action, FP7-PEOPLE-2013-ITN. This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement nº 607524.