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Oxidative ageing in bituminous materials is considered to be one of the most important factors for distress types in road applications. The increasing interest in oxidative ageing has highlighted the need for a thorough understanding of the oxidation mechanisms at molecular level. This paper offers some insight in the validity of the proposed hypotheses about the oxidation routes of bi-tumen, the fast-and the slow-rate route, reflecting on previous studies. Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spec-troscopy were utilised for this verification. To elucidate the uncertain formation of sulfoxides, an additional surface investigation with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was performed. The findings of the afore-mentioned techniques reveal the existence of the oxidation products reported previously and contribute to the understanding of the oxidation mechanisms. Overall, this research strengthens experimentally the hypotheses of the dual-oxidation routes of bitumen.

SSCI-VIDE+ECI2D:ING+DLA:NOG:CGE; National audience; Les micro-algues sont des micro-organismes capables de croitre très rapidement, dans des photobioréacteursou bassins. Cette biomasse qui compte encore des milliers d’espèces inconnues, est composéede lipides, carbohydrates et protéines. Certaines micro-algues sont exploitées pour l’un de leur composantà forte valeur ajoutée comme par exemple la phycocyanine de la spiruline. Suite à l’extraction de lamolécule souhaitée, les restes des micro-algues ne sont pas exploités alors qu’ils contiennent encore deslipides et autres composés carbonés valorisables. Le projet Algoroute a comme objectif de produire un bioliantpour remplacer le bitume pétrolier (liant des enrobés routiers) à partir de ces déchets. Dans ce but,une liquéfaction hydrothermale a été effectuée sur les résidus et a conduit à l’obtention d’une phasehydrophobe dont les propriétés rhéologiques ont été mesurées.

In the past years a wide discussion has been held among asphalt researchers regarding the existence and interpretation of observed microstructures on bitumen surfaces. To investigate this, the RILEM technical committee on nano bituminous materials 231-NBM has conducted a round robin study combining differential scanning calorimetry (DSC) and Atomic Force Microscopy (AFM). From this, methods for performing DSC and AFM tests on bitumen samples and determination of the influence of wax on the observed phases, taking into account thermal history, sample preparation and annealing procedure, are presented and critically discussed. DSC is used to measure various properties and phenomena that indicate physical changes such as glass transition temperature (T g) and phase transition such as melting and crystallization. In the case of existence of wax, either natural or synthetic, it can further indicate the melting point of wax, that could be used to determine wax content. The results from seven laboratories show that T g temperatures obtained from the heating scans are more repeatable and easier to obtain in comparison to the cooling scans. No significant difference was noted for T g's obtained from the first and second heating scans. AFM is an imaging tool used to characterize the microstructures on a bituminous surface. Using AFM three phases in the materials with wax could be distinguished. The changes in the phases observed with AFM for increases in temperature were correlated with the DSC curve, and it could be established that the so called "Bee" structure disappeared around the melting peak in the DSC curve. Thus, this research has confirmed the relation between the microstructures on a bitumen surface and the wax content. cop. 2013 RILEM.