Abstract: A method is provided for making road surface coatings by depositing a layer of chippings on a hydrocarbon binder in the form of a foam and wherein the thickness of the foam is substantially equal to the maximum dimension of the chippings and thereafter compacting the resulting product mixture.

Abstract: The novel cationic emulsions of this invention contain 50 to 75% by weight in water of bitumen, such as asphalt, coal tar and the like or a mixture of different bitumens, and emulsifying system preferably consisting of an N-hydrocarbyl alkylene diamine and a mineral acid, especially hydrochloric acid, and a second amine capable of reacting with the acidic anions present in the water phase, the pH of the emulsion ranging from 1 to 7. The emulsions have utility as binders, paving materials and coating materials, either used alone or combined with granulates. Preparation of these cationic emulsions of controlled pH and improved adhesion to conventional granulates are also disclosed.

Abstract: An anisotropic road surface is provided comprising a road-bed having superimposed thereon a mastic binder, upon which is superimposed a layer of coated gravel particles, characterized by the fact that by close contact between the gravel particles in a particular direction, maximum resistance of the road-surface to crushing is obtained and wherein, by insertion of the mastic binder between at least a portion of the gravel particles, deformability of the finished road-surface is obtained in a perpendicular direction.