Composition analysis of crumb rubber during interaction with asphalt and effect on properties of binder

Investigating the mechanism of interaction between crumb rubber modifier (CRM) and asphalt indicates that the modification is mainly done through exchange of materials between these two components. The type and amount of materials exchanged depend highly on interaction conditions. This research investigates the effect of CRM dissolution on final properties of asphalt. CRM composition before and after interaction with asphalt is analysed and compared through thermogravimetric analysis. Results show the differences in composition of two types of CRM and the composition changes under different interaction conditions. Moreover, viscoelastic analysis on crumb rubber modified asphalt (CRMA) samples shows that two different CRMs affect final properties of CRMA in different ways. Viscoelastic analysis reveals that at low interaction conditions, modified asphalts with two different CRMs show the same physical properties while at higher interaction conditions different CRMs can modify the same asphalt differently. Viscoelastic analysis reveals that percentage of dissolution, regardless of CRM source, affects the liquid phase of binder, which contains the released polymeric compounds.