Influence of bitumen-mineral interactions on bitumen ageing in asphalts and sealing materials

• Applicant: Dr.-Ing. Sandra Weigel
• Subject Area: Construction Material Sciences, Chemistry, Building Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 497373801

Bituminous materials in asphalts and sealing materials are crucial to our infrastructure and thus to our economy and society. The durability of these materials is determined by ageing processes within the binder bitumen. Therefore, bitumen is evaluated concerning the ageing behaviour or rather the ageing sensitivity in practice. For this evaluation, however, only the pure binder is considered. Furthermore, the general ageing processes have only been studied for the pure binder. But it has been known for decades that bitumen ageing is also influenced significantly by the mineral component in asphalts and sealing materials or rather the interactions between the mineral component and the bitumen. Nevertheless, it has not yet been investigated whether and which minerals have an accelerating or retarding effect on bitumen ageing, which characteristics of the minerals or of the bitumen are responsible for the changed ageing behaviour, whether or how the ageing processes of the bitumen are changed by the presence of the mineral component of whether the ageing sensitivity of different combinations can be estimated. The aim of this project is therefore to provide answers of these questions and thus, for the first time, to gain detailed knowledge about the influences of minerals on the ageing of different bitumen. In addition, a model should be developed using statistical methods of Data Mining or Machine Learning, which allows for the prediction of the ageing sensitivity of various combinations of bitumen and minerals based on essential material investigations. With the findings of this project, a detailed scientific understanding of the mineral-influenced ageing process will be achieved. In the long term and after a transfer of practice, the results can contribute to improve the durability of asphalts and sealing materials as well as to optimise the ageing evaluation being currently carried out on the pure binder and to establish alternative methods for the ageing simulation which are urgently needed. To achieve the project objective, bitumen and minerals with varying characteristics should be investigated and combined. After an initial characterisation of the materials and the ageing of pure bitumen and bitumen-mineral mixtures, the binders will be characterised again to evaluate the effects of the minerals and their interactions with the bitumen on the ageing process of the binder. In addition, in first trials, initial findings on the effects of the most frequently used additives will be made in this project.

• DFG Programme: Research Grants