For large-scale projects, such as buildings, concrete should last up to 100 years if properly cared for. Concrete projects that experience more wear and tear, such as pavements and driveways, have a service life of about half that 50 years. For larger projects, such as buildings and houses, concrete should last 30-100 years or more, depending on the style of construction and method of installation. Often, the concrete frame of a building or house can be reused when other materials, such as wood, begin to deteriorate.
The structural material of concrete is used because it resists the elements of nature, including regular weather and natural disasters. Engineers in the early 20th century thought that reinforced concrete structures would last a long time, perhaps 1,000 years. In reality, their service life is more like 50 to 100 years, and sometimes less. Building codes and policies often require buildings to survive several decades, but deterioration can begin in as little as 10 years.
The design life of most buildings is typically 30 years, although buildings often last 50 to 100 years or more. Because of their durability, most concrete and masonry buildings are demolished due to functional obsolescence rather than deterioration. However, a concrete frame or structure can be reused if the use or function of the building changes or when the interior of the building is renovated. Concrete, both as a structural material and as an exterior building envelope, has the ability to withstand the normal deterioration mechanisms of nature as well as natural disasters.
Since all concrete buildings look the same to the untrained eye, it is very difficult to determine how long a building will last without needing serious structural repairs. While some buildings will last more than 50-60 years without problems, others will begin to develop problems within a few years of construction. Concrete made with this type of sand usually results in durable structures. Most buildings last between 50 and 100 years.
Concrete and masonry buildings are demolished because of functional obsolescence rather than deterioration. But a concrete structure is reused when the interior of a building is renovated. In general, it is important to consider the environment, the installation process, the concrete used and the climate of the area to determine how long the concrete will last. Concrete resists weathering, chemical attack and abrasion while maintaining its desired engineering properties.
Concrete installation experts know what needs to be done in every aspect to ensure a quality installation and overall use, avoiding weathering or deterioration. Reinforced concrete competes with more durable construction technologies, such as steel framing or traditional bricks and mortar. This ruins the durability of concrete structures in ways that are difficult to detect and costly to repair. In addition to construction materials and design, the longevity of a concrete building also depends on the foundation.
If cracks or breaks in the concrete become visible over the years, concrete experts can repair them. Muzenski and his consultant have been trying to create a concrete with superhydrophobic - water-repellent - qualities, which also has the ability to be constantly monitored from a distance. If the installation is not done properly, perhaps without sealing or with inadequate levelling, the concrete will eventually warp or crack, and possibly deteriorate when it comes into contact with salt or other chemicals. Rust can expand reinforcing bars up to four times their size, widening cracks and forcing the concrete to fracture in a process called spalling, better known as 'concrete cancer'.
Rome's magnificent Pantheon, the largest unreinforced concrete dome in the world, is in excellent condition after nearly 1,900 years. The room-sized slab is now embedded with electrodes that monitor the stresses in the concrete and can alert researchers to any developing dangers. However, many concrete structures of the last century - bridges, roads and buildings - are crumbling. Concrete with a low water-cement ratio (0.40 or less) is more durable than concrete with a high water-cement ratio (0.50 or more).