The characterisation of foamed asphalt cement using a rotational viscometer

Abstract

Warm mix asphalt using foaming technology is a widely used alternative to traditional Hot Mix Asphalt in the USA. However, there has been relatively limited research exploring the behaviour of the foamed asphalt cement, especially using traditional asphalt cement testing equipment. This research used the rotational viscometer to develop four new metrics that quantify the behaviour of foamed asphalt cement. These four metrics showed that increasing the foaming temperature increased the observed viscosity, but the initial observed viscosity decreased with lower asphalt binder grades. However, the point at which the observed viscosity crossed the actual viscosity increased with lower asphalt binder grades. Overall, the Wirtgen foamer had higher observed viscosity vs. the PTI foamer and provided a more robust foaming material. However, it is recommended that the AccuFoamer also be explored in future research, along with comparing laboratory produced foamed asphalt cement with field produced foamed asphalt cement.

Keywords:

• Warm mix asphalt
• foamed asphalt cement
• rotational viscometer
• viscosity
• laboratory foaming

Acknowledgements

The researchers would like to acknowledge Arkansas State Highway and Transportation Department for the funding of this project. In addition, much of this data were collected with the help of undergraduate and graduate students, including Cory Bramlett, Erica Yeung, Kaisha Plambeck and Alex Jackson. Finally, Dr. Stacy Williams contributed greatly to the technical support for this project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was supported by the Arkansas State Highway and Transportation Department [grant number TRC-1304].