Opus Caementicium

• Opus Caementicium was Roman Concrete.
• From 150 BCE onwards, the Romans created two types of concrete, one durable and the other waterproof, by mixing  Pozzolana with sand. They were then able to build Moles, Docks, Bridges and Domes using this concrete.

Ingredients

• Pozzolana was the volcanic sands from the sandbeds of Pozzuoli (Puteoli) and added to Lime formed concrete.

Vitruvius’ Method

• Structional Lime Mortar
  • Vitruvius recommended 1 part lime to 3 parts Pozzolana for creating Structional Lime Mortar.
• Underwater Lime Mortar
  • He also recommended one part lime to two parts Pozzolana for underwater construction. The same ratio is still used today.

Concrete Domes

• The Pantheon
  • Concrete was used in the construction of the world’s first domed roof on the Pantheon.

Harbour Moles

• The Roman Harbour Moles at Portus, Caesarea Maritima, Dover and elsewhere, were all made of concrete.