High and low temperature properties of crumb rubber modified binders containing warm mix asphalt additives

• The four additives reduced the viscosity of the CRM binder.
• The four additives worsened the characteristics of the binder at low temperatures.
• The four additives increased stiffness obtained with the BBR test.
• The four additives decreased the m-values obtained with the BBR test.
• Mixtures containing these binders are more prone to cracking at low temperatures.

In recent years, warm mix asphalt (WMA) has become an important new research topic in the field of pavement materials due to a growing concern over global warming. Though this technology is being incorporated to reduce emissions and improve workability by lowering the production and compaction temperatures of asphalt mixtures without significantly affecting their mechanical properties, the influence of WMA additives on the properties of crumb rubber modified (CRM) binders has not yet been clearly identified. The main objective of this study is to investigate the effect of different types and quantities of WMA additives on the high and low temperature properties of a 20% CRM binder. Statistical analysis of variance (ANOVA) was applied to determine the significance level of testing temperature and additive content. The results of this study indicate that though the additives lower the viscosity of the CRM binders, they increase the stiffness at low temperatures, therefore increasing the likelihood that the asphalt binder and pavement will crack.