Architects use concrete for all kinds of projects, from the typical building to the most unusual. Concrete is ideal for the latter because it can provide a simple, strong foundation-and not just for low buildings. It also lends itself well to abstract structures, such as the steel framework of bridges and tunnels, or for sculptural applications such as mosaics or stone-like paving.
Concrete is an essential ingredient in modern architecture. As early as the 1950s, when Le Corbusier designed his famous Unité d’Habitation in Marseille, it was used to give buildings a more sophisticated look that had been missing in the International Style.
The words “concrete” and “cement” are often used interchangeably. This isn’t quite right. A building made of concrete and cement is a building made of two elements, concrete and cement.
Concrete and cement are different things. Concrete is a mixture of sand, gravel, and water. Cement is a powder made from limestone or dolomite (a kind of limestone). Concrete contains both the stuff that makes it hard and the stuff that makes it sticky. Cement is just the powder; it doesn’t have any other function.
Concrete and cement are each in their own way unusually useful: you can do something with them that you can’t do with anything else (build with them) and they make things stick together better than anything else. They don’t have any competitors: no other materials exist that can perform exactly what they do or can be mixed in such quantities to make the results uniform.
There are plenty of people who aren’t architects who use concrete in buildings; I’m not one of them. But as an architect I rely on concrete as part of my toolkit: as a material for making shape, for keeping place, for making certain forms stick together.
Concrete is one of the oldest building materials, but it has been an underappreciated one.
In ancient Greece, concrete was used to build classical temples and monuments. The first use of concrete in England is generally considered to be the construction of St. Paul’s Cathedral in London in 1707.
Since it is stronger than other materials, it is ideal for building foundations, retaining walls and steps. It is also used to form the decorative elements of buildings, like cornices, door and window surrounds, and balustrades.
It is often combined with other materials for strength or aesthetic reasons. For example, cement may be used in place of concrete when the latter washes away too easily or does not have a smooth surface that is easy to paint.
Masonry has been used for thousands of years. Stone masonry was the first building material used by humans, and was crucial in the development of civilization. It is estimated that at least one third of all buildings in the world are masonry structures.
Masonry is occasionally confused with concrete, which is a modern material invented by the nineteenth century engineer Joseph Aspdin. Masonry is also sometimes confused with brick, but here again masonry refers to the building materials and brick refers to the form. Brick architecture, like concrete architecture, uses masonry as a base material.
There are many types of structural masonry structures. These include:
The problem with concrete is not that it’s hard to make; in fact, there are big manufacturing companies that specialize in making it. The problem is that concrete has a bad reputation. As in:
The truth is that concrete is as easy to use as wood or stone, and much easier than bricks or tile. Put the materials together and you get a building. It’s true that concrete buildings are heavy; they’re also very strong and reliable. But they’re not harder to build than wood buildings, and they’re cheaper than brick buildings. In fact, if you wanted an office building with glass walls and a steel frame, you would have trouble finding one made of brick or stone, because they are so heavy. Concrete is a poor choice as a surface material for buildings, because it’s hard to paint over, but it makes great flooring.
It turns out that almost any material can be used for almost any purpose if you put your mind to it.
The word “cement” comes from the Latin, meaning “to bond by glue.” In ancient Rome and Greece, the glues they used were made of different elements in order to produce stronger or more flexible glues. The cements they used were not what we think of as cement today: They were not really all that hard and weren’t very durable.
The Romans also made use of a kind of cement that was almost pure lime, which is harder and lasts longer than normal cement.
Today we think of concrete as something you mix with sand and water and then heat up until it sets. But that’s only a little bit of what it is. Concrete sets when water and oxygen are both excluded–that is, when it has been dried out. Which means that you can add water to concrete after it is set–which allows you to make concrete suitable for most kinds of building, and stacks of concrete bricks are usually easier to handle than ordinary brick.