Application of mechanically foamed asphalt binder in warm-mix asphalt (WMA) is the most widely accepted WMA technology. This study evaluates the effect of foaming water content (FWC) on high-temperature rheological characteristics of foamed asphalt binder. To facilitate the study, a performance grade (PG) asphalt binder has been foamed at six different FWCs using a laboratory foaming device. Laboratory tests such as dynamic shear rheometer (DSR) and rotational viscometer (RV) have been conducted for rheological evaluation. Change in continuous performance grade has also been evaluated at different FWCs. Analysis of tested results showed that injection of a higher FWC causes a slight reduction in binder stiffness. Statistical analysis revealed that viscous behavior (loss modulus) of the foamed binder is strongly correlated with FWCs. However, elastic behavior (elastic modulus) of foamed binder showed no correlation with FWCs. Finally, the study concludes that changes in rheological characteristics are not statistically significant in terms of FWCs that led foamed binder equivalent to the conventional unfoamed binder in terms of rheology.
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