Sal Rota

Sal Rota (from the Latin sal meaning salt and rota meaning wheel or rotation) refers to a type of ancient Roman road surfacing technique. This method involved embedding rough stones or pebbles into a bed of mortar made with a high proportion of salt. The salt acted as a desiccant, drawing moisture from the mortar during the curing process. This accelerated the hardening and strengthened the overall road surface, making it more resistant to wear and weather. The resulting surface was also less prone to the formation of mud and dust, important considerations for roads used by heavy wheeled traffic, like carts and chariots. While the precise recipe and application methods may have varied regionally, the presence of significant salt content in the road mortar is a key identifying characteristic. Historians and archaeologists often look for traces of salt and related mineralogical alterations in excavated road remains to identify examples of sal rota construction. The use of sal rota indicates an understanding of the chemical properties of salt and its beneficial effects on mortar durability.