Measurement of bitumen–tyre adhesion temperatures at realistic loading rates

Abstract

A small-scale apparatus was constructed to measure the ‘adhesion temperature’, at which bitumen ‘pick-up’ onto tyre rubber (and subsequent tracking) occurs. Loading frequencies equivalent to traffic speeds of over 100 km hr⁻¹ and realistic tyre footprint pressures were used. The adhesion temperature increased with loading frequency, but all of the bitumens and polymer-modified bitumens studied had adhesion temperatures (i.e. the temperature at which the bitumen failed cohesively) at or below 60 °C, a temperature easily reached in the field. The results confirm the findings of an earlier slow-speed study (at 1.6 km hr⁻¹) and indicate that the adhesion temperature under realistic loading conditions is governed by the properties of the bitumen, i.e. the bitumen yield stress is lower than that of the adhesive bond formed as the tyre traverses the bitumen.

Keywords:

• Bitumen adhesion
• flushing
• bitumen tracking
• chip seals
• asphalt adhesion
• asphalt cohesion

Acknowledgements

The author would like to thank Mr Russell Kean and Mr Rick Screen for assistance in the design and construction of the equipment used.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the New Zealand Ministry for Business, Innovation and Employment.