Preliminary examination of chipseals prepared with epoxy-modified bitumen

• Application of epoxy-modified bitumen binders in model chipseals.
• Increased durability of chipseals.
• Reduced flushing and tracking of bitumen in chipseals.
• Reduced chip loss from chipseals.
• Retention of chip in wet conditions.

The properties of model chipseals constructed with epoxy modified bitumen binders (EMB) have been investigated. Changes in the shear modulus, needle penetration and cohesive energy of the EMB were used to monitor changes in the material as it cured at either 35 °C or 45 °C. Wheel-tracking tests demonstrated that model EMB seals were highly effective at resisting chip embedment into a soft substrate and could be a method of controlling or eliminating chipseal flushing in the field. EMB chipseals demonstrated excellent chip adhesion and resistance to water stripping without the need for additional adhesion agents. The long-term durability of the EMB was investigated via accelerated oxidation to the equivalent of approximately 3.5 years in the field and suggests that the EMB will continue to increase in strength as the chipseal ages. Further investigation is needed to properly characterise low temperature behaviour, long term oxidation resistance and long term field trial behaviours.