Final answer:
Roman architects utilized concrete to create expansive interiors like the Pantheon's coffered dome, exploiting the material's versatility for structural efficiency and innovative design. The concept of poché allowed for the carving out of spaces within walls, showing Romans' architectural ingenuity.
Step-by-step explanation:
As Roman architects began to utilize concrete more extensively, they discovered a wealth of visual and compositional opportunities. This innovative material, combined with the use of arches and vaulting, enabled the design of expansive interior spaces, drastically altering the way buildings were constructed. Concrete's adaptability led to the creation of monumental structures without the reliance on numerous interior supports, giving rise to impressive interior architectural innovations such as the Pantheon's coffered dome and oculus.
The exploitation of these opportunities is particularly evident in the Pantheon, which features a vast unobstructed space beneath its grand dome, and the imperial bath complexes, such as the Baths of Caracalla. These buildings demonstrate the Romans' mastery of engineering, leveraging concrete not only for structural integrity but also for carving out spaces within walls, like alcoves and apses, a concept known as poche. This versatility allowed for creative freedom in designing both the interiors and exteriors of buildings, blending functionality with monumental aesthetics.
Roman engineers optimized the structure of buildings such as the Pantheon by grading concrete with varying densities and incorporating lightweight volcanic rock within the dome. The structural efficiency and flexible design afforded by these methods are hallmarks of Roman architectural achievements, showcasing their advanced understanding of materials and their willingness to push traditional boundaries.