Moisture damage potential of cold asphalt

Abstract

This paper presents a study of the effects of moisture ingress on the mechanical properties of a cold-laid grave emulsion asphalt mixture. A vacuum moisture saturation technique has been developed to induce different moisture levels in laboratory-prepared specimens, which simulate site conditions deduced from a field trial. For comparison purposes, a hot mix with the same aggregates and base binder was also used in the study. The stiffness of both materials was monitored under different curing conditions for an extended duration. Semi-circular specimens loaded in a three-point bending test were used to determine fracture properties: fracture toughness and fracture energy. Results showed that, although the hot mixture had good fracture properties, the cold mixture's results were only marginally lower. The vacuum saturation treatment led to enhanced yield performance at low temperatures of both mixtures in the fracture test. The high level of moisture treatment given to the cold mixture made it behave like the hot asphalt mixture at low temperatures.

Keywords:

• cold asphalt
• moisture damage
• fracture properties
• vacuum saturation

Acknowledgements

The authors extend their sincere gratitude to Colas Ltd and especially to Mr John Richardson, for the technical and financial support of the project.