This study aims to achieve a further improvement in the mix design of crumb rubber modified (CRM) mixtures maximizing the use of End-of-life tires. The paper contributes to the deeper understanding of the mechanisms characterizing the mix design process of rubberized asphalt (dry process). In particular, it has been verified that an analytical approach can be applied to determining the recovered deformation of the crumb rubber in the post-compaction phase. Knowing the deformation recovered by the rubber allows adjusting the compaction process by using a correction factor in order to finally meet the requirements of voids content for the asphalt mixture considered. It has been seen that the correction factor depends on the crumb rubber quantity and size, the bitumen content and the type of asphalt mixture. Moreover, once the target voids have been established, a mathematical formula can be applied to determining the maximum allowable amount of rubber that can be added to the asphalt mixture. Finally, based on the results obtained in the laboratory, a full-step protocol has been proposed in order to produce and compact rubberized asphalts.
Effect of crumb rubber in dry process on mix design of asphalt mixtures
Sara Bressi;Massimo Losa
2018-01-01
Abstract
This study aims to achieve a further improvement in the mix design of crumb rubber modified (CRM) mixtures maximizing the use of End-of-life tires. The paper contributes to the deeper understanding of the mechanisms characterizing the mix design process of rubberized asphalt (dry process). In particular, it has been verified that an analytical approach can be applied to determining the recovered deformation of the crumb rubber in the post-compaction phase. Knowing the deformation recovered by the rubber allows adjusting the compaction process by using a correction factor in order to finally meet the requirements of voids content for the asphalt mixture considered. It has been seen that the correction factor depends on the crumb rubber quantity and size, the bitumen content and the type of asphalt mixture. Moreover, once the target voids have been established, a mathematical formula can be applied to determining the maximum allowable amount of rubber that can be added to the asphalt mixture. Finally, based on the results obtained in the laboratory, a full-step protocol has been proposed in order to produce and compact rubberized asphalts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
