The Romans began building with local materials, wood, clay, and tuff (see Episode 3 for local materials and geology of the city). There are many sources from antiquity, but a good place to start is with the writings of Vitruvius (on architecture) and Frontinus (on aqueducts: De Aqueductibus Urbis Romae).
Vitruvius' 10 Books of Architecture is a work that became an essential tool for the Renaissance architect. It is a rare gem that records the formulation of the entire discipline of architecture. Written in the Augustan age, the text provides a neat summary of the evolution of the discipline of architecture in Rome and the materials involved.
Book 1: First Principles and City layout
Book 2: Building materials
Book 3: Temples
Book 4: Corinthian, Doric, Tuscan Temples
Book 5: Public Buildings
Book 6: Private Buildings
Book 7: Finishing (surfaces)
Book 8: Water
Book 9: Sundials, Clocks
Book 10: Machines
Among other things, Vitruvius is our most important ancient source for a discussion on brick (sun-dried). He also discusses sand, lime, and pozzolana, which leads to the creation of cement. He lists and describes the various volcanic tuffs. Facing cement walls in his day involved tuff nodules, opus incertum and opus reticulatum; use of fired brick for wall facing became standard by the reign of Nero. We see many examples of tuff- and brick-faced walls throughout the city today, mostly stripped of their original stucco or fresco coating, leaving many ancient monuments (e.g., firewall of Forum of Augustus or Temple of Antoninus Pius and Faustina) severely challenged and at risk. Constant maintenance is key.
For an excellent assessment of Roman concrete's durability, see Marie Jackson's recent study.
Travertine, a stone from the ancient city of Tibur (modern Tivoli), came into use in Rome as of 200 BC. These quarries have been synonymous with Rome -- until today, when within a generation they will be exhausted. We'll discuss this in more detail when we take a closer look at the Colosseum and Theater of Marcellus.
Vitruvius addresses the post-lintel system in Books 3-4. For the arch and vaulting, we have to turn to the material remains themselves. In particular, there are very good observations and assessments in the studies by MacDonald, Wilson Jones, MacDonald, and Lancaster.
Pliny the Elder's Natural History (Book 36) is our best source for the introduction of various marbles into Rome in the Republican period.
For further reading
The Architecture of the Roman Empire, by W. MacDonald
Roman Building: Materials and Techniques, by J.-P. Adam
Roman Architecture, by F. Sear
Principles of Roman Architecture, by M. W. Jones
Concrete Vaulted Construction: Innovations in Context, by L. Lancaster