Bitumen (or asphalt binder) is a by-product of crude oil distillation and is heavily used as a binder for transport infrastructures, especially for the surface paving of roads, highways, bridges, and airport runways, with additional applications in house roofing and structural joint sealing. Asphalt materials (AMs) are referred in this project to the bitumen-based construction materials including asphalt binder and mixtures such as mortar, mastic and concrete when mixed and compacted with mineral aggregates. It has been demonstrated that bitumen is an extremely complex compound material composed of thousands of different types of hydrocarbons, paraffinic, aromatic, and naphthenic with varying saturations, polarity, function groups and heteroatoms such as oxygen, nitrogen and sulfur. Complexity becomes more serious for the asphalt mixtures due to the adhesion characteristics between bitumen and aggregates as well as the inclusion of air voids and pores in the mix. A further layer of complexity is added by the ageing nature of the AMs. It has been observed that the AMs will age with extension of service time and long-term exposure to natural environments such as solar radiation, oxygen, and moisture. The ageing of the AMs leads to degradation of the material’s physical, chemical, and mechanical properties, which can cause the deteriorations of the materials and distresses in the structures, and eventually result in the reduction of the structural service life and waste of natural resources. Thus an increasing demand has been raised for a comprehensive understanding and prediction of the AMs’ ageing performance and the development of new materials, additives and technologies for anti-ageing and rejuvenation of the aged AMs.
The overall objectives of this project included five aspects: 1) training of the Fellow’s academic expertise, professional skills and inter-sectoral collaboration; 2) investigation of multiphysics ageing mechanisms of AMs; 3) Modelling of multiphysics circular dependences and computational performance prediction of AMs; 4) development of anti-ageing materials and evaluation technologies for AMs used in industry; and 5) industry application of ageing evaluation framework and anti-ageing materials in new and recycled AMs. The project potential benefits were achieved by: 1) a better understanding of AMs’ ageing mechanisms to accelerate the material suppliers in developing and improving anti-ageing additives for bitumen to be used in transport infrastructures for service life extension; 2) an accurate performance prediction of aged AMs to allow transport consultancy, construction contractors and highway agencies to optimize standards, design, construction, and maintenance of the infrastructures; and 3) anti-ageing modelling and materials used in sustainable technologies, e.g. warm mix asphalt (WMA), reclaimed asphalt pavement (RAP), alterative renewable binders (e.g. bio-bitumen), etc. for construction projects to reduce greenhouse gases and save natural resources.