The History of Concrete (and a Few Fun Facts)
By Joanie Hollabaugh
As a child, the words “concrete” and “cement” meant the same thing to me; I had no idea there was a difference between the two. As an adult with a career related to the Construction industry, I learned there is indeed, a difference (find out here). As a woman married to a man who LOVES to pour concrete (in cute rubber boots) with a nice broom finish, I was drilled on the proper 3:2:1 recipe and the standard curing time (28 days). But what Mr. Boots couldn’t tell me was who INVENTED it.
It’s Really, Really Old!
First stop was Wikipedia: “The word concrete comes from the Latin word “concretus” (meaning compact or condensed), the perfect passive participle of “concrescere”, from “con-” (together) and “crescere” (to grow).
While unclear of the exact date (having been found in several ancient cultures) Wiki ballparks the origin to dating back at least eight thousand years ago!
Romans were the “earliest large-scale users of concrete technology” – forming the Colosseum in Rome and the concrete dome of the Parthenon. The Roman “recipe” was made from quicklime (calcium oxide), pozzolana (a chemical derivation of volcanic ash), and a pumice aggregate. With the fall of the Roman Empire, concrete was largely forgotten until the 1300s, when it gradually returned.
Please Don’t Crush the Daisies (Pots)
Fast forward to 1867, and a French gardener who was unhappy with clay pots decided to add iron mesh to concrete, and voila! Reinforced concrete is born. The gardener, Joseph Monier, takes his invention to the Paris Exposition of 1867, and patents it the same year. The importance of reinforced concrete is put forward succinctly by Wiki:
The important point of Monier’s idea was that it combined steel and concrete in such a way that the best qualities of each material were brought into play. Concrete is easily procured and shaped. It has considerable compressive or crushing strength, but is somewhat deficient in shearing strength, and distinctly weak in tensile or pulling strength. Steel, on the other hand, is easily procurable in simple forms such as long bars, and is extremely strong. But it is difficult and expensive to work up into customized forms. Concrete had been avoided for making beams, slabs and thin walls because its lack of tensile strength doomed it to fail in such circumstances. But if a concrete slab is reinforced with a network of small steel rods on its undersurface where the tensile stresses occur, its strength will be enormously increased.
Reinforced concrete =the perfect mix of form and strength.
What is Cement, Then?
“Cement” which is an ingredient in concrete, and most commonly referred to as “Portland cement” is a general term for substances which are “cementitious” – mostly oxides of silicon, aluminum and calcium. Other cementitious materials like asphalt or fly ash (a product produced by burning coal), or slag cement (a by-product of iron and steel making containing glass particles) can be added in as binder (what to use when there’s no handy volcanic residue on hand).
- The annual global production of concrete is 5 billion cubic yards (Source: Cement Association of Canada)
- Concrete is used twice as much as any other building material including wood, steel, plastic, and aluminum (Source: Cement Association of Canada)
- Making one ton of cement requires two tons of raw material (Source: http://ecosmartconcrete.com/?page_id=208)
- The production of one ton of cement produces the same amount of CO2 (Source: http://ecosmartconcrete.com/?page_id=208)