Modulated differential scanning calorimetry study of wax-doped asphalt binders

In order to better understand how wax constituents affect thermoreversible aging phenomena, three kinds of n-alkanes were doped into a base asphalt binder. Modulated differential scanning calorimetry (MDSC) analysis was performed on a series of binders containing increasing wax contents. It was discovered that the addition of n-alkanes not only changes the non-reversible thermal signal but also the reversible one. For asphalt doped with n-C20, the thermal behavior shows significant time-dependent behavior, while those doped with n-C32 and n-C40 do not. The size of both endothermic peaks in the total heat flow and non-reversible heat flow curves decreases with oxidation of wax-doped asphalt binders. The appearance of crystallizable fractions in wax-doped asphalt binders with varying thermal history can be modeled in both isothermal Avrami and non-isothermal Ozawa theoretical frameworks. A possible mechanism for the thermoreversible aging phenomenon has been proposed but it will need further work for validation and refinement.

Automated summary

This study utilized MDSC analysis to investigate the impact of adding n-alkanes to asphalt binders, finding that it alters the thermal behavior of the asphalt, with varying effects depending on the type of n-alkane used. As the wax oxidizes, the heat flow peaks in the asphalt decrease, and the crystallizable fractions can be modeled using different theoretical frameworks.