A binder for the production of a layer for road works or civil engineering comprises, with respect to the total weight of the binder:(a) 2 to 98% in weight of at least one purely natural or modified natural resin, of vegetable origin, having a softening point measured of 30 to 200%;(b) 98 to 2% in weight of at least one oil of vegetable origin having a viscosity at 25.degree. C. of 50 mPas to 1000 Pas,(c) the binder having: (c1) either a penetrability at 25.degree. C., of 20 to 300 1/10 mm and a softening point of 30 to 75.degree. C., (c2) or a penetrability at 15.degree. C., of 300 to 900 and a viscosity at 60.degree. C., and (d) the binder being exempt of any natural or synthetic elastomer and of any thermoplastic polymer.