The proposed CD Laboratory is focused on bitumen and bituminous materials. These materials are used as binding component in road pavements and for roofing membranes and sealing purposes. Bitumen as a crude oil derivative exhibits a complex chemical composition, a temperature dependent, viscoelastic mechanical behavior and microstructures, which are affected by the composition and affect the mechanical behavior. In addition, bitumen is prone to oxidation and other ageing effects due to its organic origin. Ageing leads to changes in the chemical composition, structure and mechanical behavior. This limits the technical lifetime, as well as it affects the recyclability.
Currently, bitumen is analyzed by macroscopic, mechanical test methods for product classification and quality control. Effects of ageing are only taken into account partially. The applied test methods cannot capture changes in the chemical composition and microstructure although these changes have a significant impact on the performance in short- and long-term. Thus, there is a considerable risk for bitumen producers and the application industry, since suitability and long-term changes of base products can only be inadequately assessed, or in terms of long-term changes, not at all.
The main goal of this CD Laboratory is to generate fundamental knowledge on the interplay between chemical composition, structure and mechanical behavior and to develop a comprehensive chemo-mechanical analysis tool on this basis. With this tool, methods will be at hand to understand crucial bitumen parameters in a fast and abstracted way throughout the complete production and application chain. To reach this goal, an existing microstructural model of bitumen will be validated and expanded for polymer-modified binders. Samples of different origin will be analyzed by a broad spectrum of microscopic, spectroscopic and mechanical analysis methods. Based on analysis results and the refined model, an increased understanding of interrelations between composition, structure and mechanics, as well as the impact of ageing on these three items on the micro-level will be achieved.
In addition, a realistic, efficient lab simulation of ageing of bitumen will be developed. Temperature and pressure will be kept close to field conditions, increased oxidation will be realized by increased concentration of reactive oxygen species (ROS), UV radiation and moisture. Impact of single ROS, as well as combined ROS, UV and moisture will be studied and the method will be validated to field aged samples.
Based on the model and ageing simulation, a chemo-mechanical tool will analyze bitumen under more realistic conditions in a faster and simpler manner than before, while essential parameters to describe short- and long-term performance will be obtained. Important parts of this tool are micro-sized viscosity sensors based on MEMS (microelectromechanical systems) in combination with a fluorescence-scanning device. These implements will allow for a quality control of bitumen over the complete process chain and provide information on suitable bitumen additives to improve properties for specific fields of application.
In the further course, existing additives will be studies with this analysis set. These additives will comprise of rejuvenating agents and oxidation inhibitors. Their effect on different bitumen samples on the micro-level will be studied to understand why some classes of additives work more effectively than others.
The outcomes of the CD Laboratory are aimed at lowering the risk of industrial partners in choosing, processing and applying bitumen on the one hand and enable them for targeted optimization of bitumen with effective additives on the other hand.
