What is Concrete? Composition, History and Uses

Concrete is a substance composed of cement, aggregate, admixture, and water. As one of the most widely used building materials in existence, concrete has played an essential role in shaping the modern world. Because of its strength, durability, and availability, it is the building block of numerous skyscrapers, bridges, sculptures, and roadways. Concrete is an ideal example of the ways that human invention can shape our world today and into the future.


What is Concrete?

What is Concrete

Concrete is a mixed material that contains specific quantities of cement, fine or coarse aggregate, various types of additives, and water.

Binders

The main component of concrete is usually cement which acts as a binder for the rest of the materials. When it is mixed with water, cement undergoes a chemical reaction known as hydration and forms a paste that connects all the materials. Lime is another binder option in concrete, though this is less common in modern concrete. Lime is primarily used as a binder in concrete for historic restoration, buildings that are created with a historic aesthetic, or as part of concrete used in soil stabilization for under road construction projects.

Aggregates

The aggregates can include gravel, crushed rock, sand, or recycled materials. The aggregate provides the bulk and stability in the mixture. Fine aggregates like sand range in size from .0001-.25 in (.025 – 6.5 mm). Coarse aggregates range from .25-1.5 in (6.5-38 mm) or larger. The size of the aggregate determines how much binder is needed in the mixture as the binder must fill in the gaps between the aggregate. Therefore, the size of the aggregate can impact the cost of the concrete.

Manufacturers must ensure that all of the aggregate is clean and clear of impurities or it can impact the quality and durability of the concrete mixture. Some aggregates like crushed quartzite, crushed glass, or river stones are attractive. Builders mold this concrete so the aggregates are visible. This is a popular option in landscape concrete.

Admixtures

The admixtures include plasticizers, fiber reinforcements, bonding agents, curing compounds, freeze-thaw protectants, air-entrapping agents, and viscosity modifiers, just to name a few. These allow concrete producers to create distinct concrete mixtures that are specifically designed for certain types of applications and environments.


Brief History of Concrete

The history of concrete mixtures dates back to the ancient world. Ancient civilizations used rudimentary materials like mud, clay, and straw to create a concrete-like substance for securing structures.

The Romans made the most significant advances in concrete technology by developing a material called “opus caementicium”, which experts today call Roman concrete. This was a type of hydraulic setting cement mixed with aggregate. Many Roman structures that builders created using Roman cement including buildings, bridges, and aqueducts are still standing today.

Concrete use declined during the Middle Ages and Renaissance but was renewed with new advances in cement technology during the Industrial Revolution. The introduction of new types of hydraulic cement helped create concrete that was more reliable and durable. The 20th century saw new advances in concrete usage including steel reinforced concrete structures. When builders embed steel in the concrete, this allows for the creation of taller buildings, longer bridges, and more complex structures. Concrete has played a prominent role in the creation of modern infrastructure like airports, dams, and highways.

The modern age has seen further advances in the development of concrete. Manufacturers and researchers have focused on creating more durable, sustainable, and stable concrete. They have developed specialized concrete formulas like high-performance concrete, self-compacting concrete, and fiber-reinforced concrete that allow for a wider range of applications and possibilities in concrete construction projects.


Uses of Concrete

Builders value all types of concrete because of its strength, durability, versatility, and cost-effectiveness, so it is useful in diverse building projects.

Building Construction

Builders use concrete in residential and commercial building construction. It is common to use concrete for foundations, walls, columns, beams, slabs, and roofs.

Bridges and Infrastructure

Concrete is popular in various types of bridges and city infrastructure. Engineers and builders use reinforced concrete for the superstructure of bridges, including beams, girders, and piers. Concrete is used in the construction of roads and highways as concrete is a durable surface that can resist rutting and provide a long-lasting usable surface. Other applications include tunnels, retaining walls, drainage structures, and sound walls.

Dams and Water Structures

Water is a valuable resource for humans, but it can also be destructive. Builders use concrete to contain and control water resources in dams, reservoirs, canals, and water treatment plants. Concrete provides the necessary strength to contain water as well as ensure the careful management of this crucial resource.

Pavement, Walkways, and Roads

Concrete is commonly used for providing a stable, smooth, and durable pathway for both vehicular and human traffic. It is the most popular building material for roads, pavement, driveways, parking lots, and sidewalks.

Marine Structures

Concrete’s ability to withstand the corrosive qualities of seawater makes it a vital component of marine projects like piers, docks, seawalls, and breakwaters. Some concrete is enhanced for specific marine applications to help it withstand corrosion including increasing its sulfate resistance, abrasion resistance, and strengthening it for freeze-thaw cycles in extremely cold environments.

Retaining Walls

The ability to change the landscape through retaining walls is one of the primary ways that landscape architects change the topology in the modern era. These builders use concrete in retaining walls to hold back the soil when they have built up an area and to prevent erosion over time.

Industrial Structures

There are only a few types of substances that are stable and durable enough for industrial structures like power plants, factories, warehouses, and storage tanks. Concrete has properties that are especially valuable in these settings including resistance to fire, chemicals, and water.

Precast Elements

Architects and builders build parts of a structure off-site. These elements are shaped and cured and then transported to the site for assembly. Some precast items include concrete walls, stairs, and flooring panels.

Architectural and Decorative Applications

Concrete is not just utilitarian; architects and visual artists use concrete components to express their creative visions. Because concrete is versatile, they can use it to display unique forms, textures, pigments, and facades on indoor and outdoor design projects.