High-Temperature Performance and Workability of Crumb Rubber–Modified Warm-Mix Asphalt

Abstract

Abstract Crumb rubber produced from scrap tires has been widely applied in asphalt mixtures to improve the pavement performance. Warm-mix technology has also been employed to lower the production temperature of asphalt mixtures. The objective of this article is to investigate the effects of warm-mix additive types and crumb rubber concentration on the resistance to deformation of crumb rubber–modified (CRM) binders through the repeated creep and recovery test (RCRT), dynamic shear rheometer (DSR), and rotational viscosity test. The CRM binders with crumb rubber concentrations of 10 %, 15 %, 20 %, and 25 % were prepared first as the control binders. Then, three types of warm-mix additives, Sasobit, RH, and Advera, were added into the CRM asphalt to produce CRM warm-mix asphalt (WMA) binder. Generally, the workability of CRM asphalt can be improved with the addition of warm-mix additives. The effect of warm-mix additive on the high-temperature performance is highly dependent on the crumb rubber dosage. The RCRT results overall showed that the warm-mix additives can improve the high-temperature performance of asphalt when the crumb rubber concentration is low. However, according to the DSR test, Sasobit improved the rutting resistance of CRM asphalt, while the RH and Advera sacrificed the rutting resistance. The inconsistency between the RCRT and DSR results suggests that it may be necessary to conduct both the tests when investigating the high-temperature performance of CRM asphalt with warm-mix additives.