Abstract

Properties of asphalt concrete after aging are important parameters in determining the long-term performance of these materials. With the popularity of reduced temperature mixtures the question remains how this reduced temperature in short-term aging affects the long-term properties. This paper focuses on developing a robust and fundamental understanding of the effect of temperature on aging by connecting the chemistry of bitumen to its mechanics. To this end, round robin experiments are being currently conducted within 8 laboratories using four binders of the same grade 70/100 pen from different crude sources. In developing chemo-mechanical characterization techniques at the nano- and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature needs to be taken into consideration. Furthermore, the development of uniform specimen preparation procedures for these bituminous materials at the nano- and micro-structural level is the focus. The chemical characterization is performed using Fourier transform infrared spectroscopy (FTIR). For the mechanical characterization rheological data is used using the dynamic shear rheometer (DSR) as well as conventional tests, e.g. needle penetration and softening point using the ring and ball method. It is shown that the short-term aging temperature affects the increase in softening point, while the consequent effect on long term aging is less pronounced.

Highlights

  • Bituminous materials can have very different long-term properties, depending on the source they come from and production refining process

  • Most of the research towards enhanced properties of bituminous materials is largely split into separate efforts towards understanding its chemistry or its mechanics

  • In developing chemomechanical characterization techniques at the nano- and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature and aging need to be taken into consideration

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Summary

Introduction

Bituminous materials can have very different long-term properties, depending on the source they come from and production refining process. Most of the research towards enhanced properties of bituminous materials is largely split into separate efforts towards understanding its chemistry or its mechanics. In developing chemomechanical characterization techniques at the nano- and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature and aging need to be taken into consideration. The goals of this cooperative research effort are: i. Properties were selected and the appropriate chemo-mechanical experimental procedures were chosen To this end, specimen preparation and test protocols were refined as outlined in (ii) and (iii) above. There is an on-going scientific debate on whether temperature reduction for asphalt mixture production, which leads to reduced short-term aging, brings additional benefits in terms of reducing long-term aging

Microstructural considerations
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Preliminary conclusions
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