Obtaining road binders based on bitumen and a new range of fluxes has basic derivatives of functionalized fatty acids

The invention relates to a fluxing agent for bitumen based on natural fats do not initially comprising reactive functions capable of reacting with the chemical functions present in the bitumen, these natural fats being chemically functionalized with at least one functional group selected from dicarboxylic acids functions, groups having an epoxy function; peroxide; carboxylic acid, aldehyde, and groups having at least one carbon-carbon double bond conjugated.