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

• Published in: Construction & building materials Vol. 293; p. 123464
• Main Authors: Lesueur, Didier, Elwardany, Michael D., Planche, Jean-Pascal, Christensen, Don, King, Gayle N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 26.07.2021; Elsevier
• Subjects: Asphalt rheology; Civil Engineering; Construction durable; Engineering Sciences; Géotechnique; Infrastructures de transport; Linear viscoelasticity; Materials; Rheological cracking surrogates; ΔTc parameter; Rheological cracking surrogates; Asphalt rheology; Linear viscoelasticity; ΔTc parameter
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.123464

•The current US grading system determines limiting temperatures for asphalt binder use.•The low limiting temperature is based on creep modulus and its slope vs loading time.•Current specifications are being challenged and a new criterion has been proposed, called ΔTc.•ΔTc is mostly controlled by the rheological index R that governs its sign.•Care must be taken when trying to predict cracking results from rheological data only. 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 ΔTc; its ability to better predict thermal cracking is the subject of intense discussions. In this paper, we mathematically show how ΔTc relates to other binder rheological properties. Then, we discuss the practical consequences in order to highlight the relevant parameters controlling ΔTc. Experimental data are used to substantiate the main findings. This shows that ΔTc is of “pure” rheological origin and care must be taken when trying to predict cracking results from rheological data only.