Effect of short-term and long-term ageing on dynamic modulus of foamed warm mix asphalt

ABSTRACT

This study investigated the effect of short-term and long-term ageing on the dynamic modulus of foamed warm mix asphalt (WMA) produced by water injection and traditional hot mix asphalt (HMA). Four asphalt binders (PG 64-22, PG 64-28, PG 70-22 and PG 76-22) and one aggregate (limestone NMAS 12.5 mm) were used in the preparation of the laboratory-produced asphalt mixtures. The short-term and long-term ageing of the asphalt mixtures were simulated using AASHTO R 30. The experimental test results showed lower dynamic modulus values for foamed WMA than those obtained for traditional HMA for both short-term and long-term oven-aged specimens. By comparing the dynamic modulus values of the short-term and long-term oven-aged specimens, it was observed that some mixtures, such as those prepared using PG 64-22, had a smaller increase in dynamic modulus for foamed WMA mixtures than traditional HMA mixtures, while a comparable increase in dynamic modulus for both foamed WMA and HMA was observed for other mixtures, such as those prepared using PG 70-22 and PG 76-22. This suggests that the binder type plays a significant role in determining the ageing characteristics of foamed WMA and HMA mixtures.

KEYWORDS:

• Hot mix asphalt
• warm mix asphalt
• short-term ageing
• long-term ageing
• and dynamic modulus

Acknowledgements

The authors would like to thank Mr David Powers and Mr Eric Biehl of ODOT Office of Materials Management for their valuable contributions to this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was partially sponsored by the Ohio Department of Transportation (ODOT) and the Federal Highway Administration (FHWA) under State Job No. 134707.