Roman Concrete Essay

The introduction of concrete as a construction medium and the true arch as a structural component made it possible for the Romans to build strong, elaborate, expansive structures that would endure the test of time.
Concrete
Roman concrete, called opus caementicium, was made by mixing traditional lime mortar with stone aggregate called caementa. This material used less water and was very thick compared to modern concrete; therefore it was laid rather than poured (Roman Architecture, n.d.).
Concrete was an important material for used in construction because it was strong, inexpensive to produce, and versatile. Concrete was cheaper to produce than cut stone and could be finished with a stucco treatment, or clad with brick or marble. This allowed
the Romans to add variety to their construction projects.
In the second century BCE, the Romans discovered that mixing volcanic sand, known as pulvis puteolanus with concrete resulted in a stronger mixture that was capable of curing under water. This product was called pozzolana and its strength was due to the high silica content of the volcanic sand (Roman Architecture, n.d.).
The Arch Prior to the development and use of the arch structure, the Romans used a post and lintel structure.
The post and lintel system was comprised of upright columns with a horizontal member, called a lentil, laid across the top. The drawback to this system was the weight of the posts and lentil components limited the size of the buildings and the necessary inner structure used much of the interior space in the buildings (Ambler, n.d.). The development of concrete as a building material opened the door for the use of the arch in Roman architecture. Traditionally arches were created from corbeled stones, or stones that were moved inward as they were laid upward. A true arch used wedge shaped stones, laid in such a manner to disperse weight downward and outward. The arch was held together using a keystone in the center. Concrete made it easier to construct the arches and led to an arch type structure known as a vault, or domed ceiling (Ambler, n.d.). An arch is capable of spanning a greater distance than the post and lintel system and Romans used this advantage to create massive structures using rows of arches stacked on top of each other. The impressive aqueducts that brought fresh water into the heart of Roman cities was made possible by the strength of the arch structure. Romans also used the arch in the construction of ceiling vaults which limited the amount of posts used within a structure (Ambler,
n.d.).
Conclusion
The development of concrete and the arch structure were complimentary factors that allowed Roman architecture to grow in scale as well as grandeur. Roman architects could use their imaginations as well as these materials to build impressive structures that were beautiful to behold but also stood the test of time.