Impact of the asphalt binder rheological behavior on the value of the ΔTc parameter

The current Performance Grading system for asphalt binders in the USA, determines limiting temperatures for appropriate binder use. Practically, the low limiting temperature is based on rheological measurements made using the Bending Beam Rheometer (BBR). The absolute value of the creep modulus and/or its slope vs loading time in a log scale, are being used. However, the current specifications are being challenged and it has been proposed adding a new criterion, called Delta Tc; its ability to better predict thermal cracking is the subject of intense discussions. In this paper, we mathematically show how Delta Tc relates to other binder rheological properties. Then, we discuss the practical consequences in order to highlight the relevant parameters controlling Delta Tc. Experimental data are used to substantiate the main findings. This shows that Delta Tc is of pure rheological origin and care must be taken when trying to predict cracking results from rheological data only. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This paper examines the addition of a new criterion, Delta Tc, to the current Performance Grading system for asphalt binders in the USA, discussing its relationship with other binder rheological properties and highlighting the relevant parameters controlling Delta Tc. Experimental data confirm that Delta Tc is of pure rheological origin.