Final answer:
In high-rise residential buildings constructed with site-cast reinforced concrete bearing walls using tunnel forms, floors, and roofs are generally made from lightweight concrete, which offers reduced load and improved building rates.
Step-by-step explanation:
In high-rise residential buildings built with site-cast reinforced concrete bearing walls using tunnel forms, the floors and roofs are generally constructed of lightweight concrete. This type of concrete includes lightweight coarse aggregate mixed with fine aggregates like shale, clay, or slate, which contribute to its reduced load, improved building speed, and thermal protection capabilities.
Over the centuries, innovations in concrete work, such as the introduction of lightweight concrete, have made significant advancements in structural engineering, aiding in the creation of durable and efficient high-rise structures that cater to the modern demands of urban living.
This is evidenced by ancient Roman construction techniques, such as the Pantheon's dome, which employed a gradation of concrete mixed with materials like scoria to reduce the weight at the top of the structure, demonstrating an early understanding of the principles behind lightweight concrete.
Today, the benefits of lightweight concrete sustain its popularity in the construction of modern edifices, in particular, high-rise buildings where weight and energy efficiency are critical considerations in design and construction.