A process and apparatus for forming a coherent refractory mass on the
surface of a road wherein one or more non-combustible materials are mixed
with one or more metallic combustible powders and an oxidizer, igniting
the mixture so that the combustible metallic particles react in an
exothermic manner with the oxidizer and release sufficient heat to form a
coherent mass under the action of the heat of combustion and projecting
this mass against the surface of the road so that the mass adheres
durably to the surface of the road.