Engineering bitumen for future asphalt pavements: A review of chemistry, structure and rheology

Abstract

Bitumen, a product mostly used as a binder in road construction, has been subject of numerous scientific investigations with the goal to optimise its function as an engineering material. Although a lot of research has been devoted to the three main pillars of bitumen characterisation, chemistry, structure and rheology, less attention has been paid to addressing their respective interrelationship. This critical review revisits modern theories, research advancements and methods, with a primary focus on how techniques like spectroscopy, chemical separation, rheology and microscopy can help to identify issues related to processes like modification and ageing of bitumen. Finally, an overview of current advancements of trying to correlate and interrelate these different schools is given. These individual studies highlight that a considerable amount of research is still required to understand the link between chemistry, mechanical behavior and structure of bitumen which can be related to its complex nature that depends on factors like crude oil origin and refinement process. In addition to that, more advanced characterisation tools and statistical methods, via the developing field of bitumen chemomechanics, can also help to solve modern issues related to future questions. Obtaining the required knowledge will ultimately help design and engineer future paving materials.