Concrete is commonly described as a mixture of Portland cement, sand, gravel, and water. Ingredients are mixed by hand or machinery. A thick slurry is created which may then be transported to a site or applied immediately.
The introduction of concrete, or cement, as a building material, dates back to the Roman Empire. Many structures built by the Romans still stand today. The Romans knew that by adding volcanic ash, concrete would set underwater. This allowed the Romans to construct large piers for their merchant marine and naval vessels which greatly enhanced their economic and military superiority.
For centuries, concrete has been used in the construction of not only buildings, but piers, hydroelectric dams, roadways, tunnels, bridges, sewers, and simply for ornamentation. Incredible innovations from talented architects have been built with concrete. Virtually all economies in the world today rely on concrete construction in one form or another.
Use In Building Construction
Positive aspects to constructing a structure out of concrete,
- Freedom of form and shapes
Concrete is a very malleable material. This enables architects the freedom to experiment with new shapes and designs in order to push the boundaries of architecture.
Postmodern architecture would not be possible without the innovative use of concrete.
- Concrete is easy to transport and handle
Unlike steel which can be cumbersome and dangerous to maneuver, concrete can be efficiently transported and poured to exact dimensions on site.
Most major cities have concrete plants nearby which allows for easier access to the material.
Most major cities do not have steel mills close by. Therefore, steel needs to be ordered to exact specifications and transported from, in many cases, China, South Korea or India, the world's leading steel producers.
- Thermal Resistance
Concrete is incredibly resistant to heat and fire.
The producers of safes line their products with concrete to protect its contents from fire.
Challenges to using Concrete
- Pouring concrete can be a time consuming process
Concrete needs time to cure properly and can be sensitive to temperature fluctuations during the pouring process.
- Limited tensile strength
The properties of concrete limit its resistance to tensile forces.
- Concrete is not considered a premium construction material and remains one of the most affordable means for construction.
- Concrete is less costly to produce, easy to transport and is readily available.
- Concrete can be poured to exact specifications resulting in less waste, further reducing costs. 
Concrete in Condominiums
- Concrete is an optimal material for condominiums for a number of reasons:
- Concrete resists acoustics much better than other materials such as wood. This enables a much quieter building to the delight of residents and neighbors.
- Concrete is very durable and is more impervious to the effects of weather, resulting in a longer lasting structure. The Hoover Dam, (also made from concrete) is so strong that engineers refuse to estimate a lifespan.
- Concrete has excellent thermal mass. Meaning that it maintains a consistent temperature much better than comparable building materials. Reducing the amount of energy needed to heat/cool a structure.
- Due to these benefits, condominiums made of concrete retain their value better in comparison to buildings made from alternative materials.