Renewable energy sources are developed worldwide due to high oil prices and to limit greenhouse gas emissions. In this context, some groups have focused their work on vegetable oils, and particularly, on microalgae. The last decade has seen an increasing scientific interest in the extraction of lipids from microalgae for the production of biodiesel. Microalgae present main advantages, compared to other energy crops including a high growth rate, a high biomass production, and do not compete with human feeding production. For economical and ecological reasons, the by-products resulting from the microalgae culture have to be valorised. This is what we propose to do in the “Algoroute” project, trying to understand if it could be used as a binder for aggregates. To achieve this goal, we need to figure out the composition of those by-products, and see the influence of each class of compounds on the rheological properties. Extraction and transformation steps have also to be studied taking into consideration low energy and environmentally friendly processes. Interesting preliminary results have been obtained. Several fractions from micro-algae have been extracted and characterized by IR, NMR (1H and 13C) and GC-FID. The complex modulus was also determined on these different fractions. The comparison of rheological and chemical analyses allows to highlight some chemical species which show a thermodependent behaviour comparable to asphalt.
