G. Muller

Bio: G. Muller is an academic researcher from University of Rouen. The author has contributed to research in topics: Asphaltene & Scanning confocal electron microscopy. The author has an hindex of 3, co-authored 5 publications receiving 595 citations.

New direct observations of asphalts and asphalt binders by scanning electron microscopy and atomic force microscopy

Abstract: Observations made using AFM and SEM have been combined in order to study the structure of asphalts. Fluorescence microscopy was used to aid in understanding the structural changes occurring when polymer is added to the asphalts. With the atomic force microscope we are able to study the structure of the asphalts without any pre-preparation. Despite very low resolution, our study reveal ed a network of asphaltene molecules with regard to asphalt gel. The same result is obtained by SEM observation but with a much better resolution. SEM observation, however, needs an adequate preparation method. In the presence of polymer we observed a rearrangement of the initial asphaltene association which leads to the assumption that polymer can aggregate the asphaltene phase.

New investigations on the mechanism of polymer-bitumen interaction and their practical application for binder formulation

Abstract: Nowadays plastomers are increasingly being added to bitumen to achieve better performance in road applications. To establish the relationship between the rheological properties and the structure of polymer modified bitumens (PmB), a comprehensive programme was set up to investigate tensile strength and oscillation stress measurements, atomic force-, electronic- and fluorescence microscopy and thin film chromatographic analysis. The obtained results point out that the structure of the pure or modified bitumen governs the rheological properties. The structure itself depends on the colloidal behaviour of the bitumen and the PmB and therefore on the chemical composition of the bitumen. The best rheological performance of the modified bitumens is obtained for a colloidal index of the bitumen typically at 0.3. Under these conditions, the PmB with a sufficient amount of polymer presents a well dispersed mixture of flocculated asphaltene particles in a polymer based matrix. This structure generates a maximum delta phase angle indicative of an emphasized elastic behaviour at the longer loading times. Furthermore, this study clearly shows that a polymer incompatible bitumen can be converted into a high performance PmB when the chemical composition of the bitumen is adjusted. In this paper, a new concept has been developed which will lead to a better monitoring of bitumen selection and polymer compatibilisation. (A) For the covering abstract see IRRD 885061.

Rheological characterisation of bitumen : EVA binders

Abstract: L'ajout de polymere au bitume permet d'obtenir de meilleures performances du liant en application routiere. En vue de trouver un nouveau moyen de selectionner les bitumes pour la fabrication de melanges bitume - EVA, deux tests rheologiques differents ont ete effectues sur des bitumes d'origine variee : un test de rheologie oscillatoire (DSR Bohlin) et un test de traction directe (Instron). Les resultats obtenus mettent en evidence la relation directe existant entre la composition du bitume et les proprietes rheologiques du liant conduisant ainsi a ameliorer la selection des bitumes.

Atomic Force Microscopy—A New and Complementary Tool in Asphalt Research Compared to Scanning Electron Microscopy

Abstract: AFM is an easy, nondestructive tool to study the structure of asphalt and the association and size of its individual particles. Best observation conditions were obtained with rigid cantilevers and a very smooth surface (drop form). In comparison to AFM, SEM needs an adequate preparation method to prevent artefacts by the deoiling step. This was obtained by using filter paper, which keeps the structure in place.