WORLD HISTORY

Detailed explanation-1: -Long before concrete made its appearance on the building scene in Rome, the Romans utilized a volcanic stone native to Italy called tufa to construct their buildings.

Detailed explanation-2: -However, using concrete became the decisive fact for building domes after the last quarter of the second century BCE. Roman concrete prepared with hydraulic mortar, which consists of the material of pozzolana volcanic ash. Domes made with Roman concrete could be built with larger spans.

Detailed explanation-3: -The development of concrete to form the structural core of buildings was one of the most important innovations in Roman architecture. Concrete is easier and quicker to use than cut stone, and its raw materials are cheap and easy to transport.

Detailed explanation-4: -Romans made concrete by mixing volcanic ash with lime and seawater to make a mortar, and then incorporating into that mortar chunks of volcanic rock, the “aggregate” in the concrete.