Bituminous binders fluxed with vegetable oil methyl esters and asphalt mixtures with these binders

In this research, conventional bitumen solvents were replaced with environmentally-friendly fluxes obtained from vegetable oils. These binders are hardened by cross-linking unsaturated fatty acids due to oxidation instead of evaporation of the solvent. The binders have an ignition point above 200degreesC, so their application does not cause safety problems. Rapeseed and linseed oils were used, as well as their methyl esters. Rapeseed oil and rapeseed methyl ester need oxidation in the presence of a catalyst before they are mixed with bitumen. A binary catalyst composed of cobalt and zirconium naphthenates was found to be most effective. Linseed oil and linseed oil methyl ester do not need oxidation before they are mixed with bitumen, but the addition of a catalyst is necessary. Vegetable oil methyl esters proved to be better bitumen fluxes than their respective oils. Of the liquid binders tested, the one with linseed oil methyl ester used as a flux had the best properties. It changed its consistency with time to a greater extent than did other fluxed bitumens and a smaller amount of this solvent was used to obtain a binder with good properties. Using an ecological fluxed binder, it is possible to reduce the temperature of asphalt mix production below 110degrees and the compaction temperature to about 70degrees. Asphalt mixtures containing these binders fulfil technical requirements and are resistant to permanent deformation. For the covering abstract see ITRD E157233