Because concrete is part of our visual horizon and is therefore familiar, one hardly stops and reflects on its importance and its impact on history and our daily lives. Here are ten interesting facts that you probably didn’t know about concrete.
1. Concrete is the most used material in the world
Concrete is the second most common substance on the planet (after water). It is estimated that around 20 billion tons are used each year.
2. Concrete and cement are not the same thing
Thinking that “cement” and “concrete” are synonyms is a common misconception. Concrete is a composite material which is obtained by adding other materials such as aggregate or sand to cement. Cement is to concrete what flour is to cakes and bread.
3. Ancient Romans gave impetus to the use of concrete
Assyrians, Egyptians and Greeks were already using similar compounds but it was the Romans who employed something similar to concrete in different works, roads, foundations and temples. The most famous of these, the Pantheon in Rome, built around 120 AD, features the world’s largest Roman concrete dome.
4. Portland cement is named after limestone
Joseph Aspidin was the first to start the industrial production of concrete in 1824. The cement used in the production was called Portland, due to the similarity in colour between the concrete created with that cement and the limestone from the Isle of Portland in England.
5. Concrete was used as a “strategic weapon” during WWII
During the conflict, concrete “sound mirrors” were used to provide a signal of the approach of enemy military aircraft. These concave structures could pick up the sound waves of enemy aircraft enabling the British forces to anticipate their flight paths and prepare for defence.
6. Concrete gets stronger over the years
Concrete reaches about 90% of its final strength after approximately four weeks. It continues to strengthen, however, for decades to come, due to its conversion of calcium hydroxide to calcium carbonate and its absorption of carbon dioxide over time.
7. The largest dam in the world
27 million cubic metres of concrete were used to build the Three Gorges Dam in China (185 metres high and 2,309 metres long).
8. An entirely concrete-made house
Amongst his thousand and more patents, Thomas Edison imagined a house built entirely in concrete. The design included everything, “the sides, the roof, the partitions, the furniture, the tubs and the floors”.
9. Concrete is both fire and water-resistant
Concrete has excellent fire resistance capabilities. It does not burn, cannot be ignited and does not generate harmful emissions when exposed to flames. Concrete can also be made almost waterproof if treated with suitable additives and products.
10. Concrete has excellent compressive strength
Compressive strength refers to the force required to crush a material.