The methodology of road surfaces cold recycling is based on foamed bitumen use, whose process is very simple.

Injecting cold water in the bitumen heated about 180° C, the bitumen spreads out almost explosively up to a multiple of its original volume, becoming the so-called foamed bitumen. Due to the expansion process of bitumen, which may be helped through air insufflations, viscosity is greatly reduced and bitumen can be uniformly distributed, thanks to its greater volume in building granules materials mixing.
Since foamed binder catches on minerals surface, also milled materials with relatively high percentage of small components can be stabilized.

During the cold recycling of asphalt roads, both consistent layers and no consistent ones are milled. Incorporating the binder, as foamed bitumen, a new bearing layer is created, also sized to bear traffic load expected in the future.
Treating no consistent Macadam roads, not only the resistance of the road structure is increased, but also the carriageway acquires a lasting resistance to traffic abrasion and to weather erosion.