Today’s Wonder of the Day was inspired by Will. Will Wonders, “How is concrete made?” Thanks for WONDERing with us, Will!
It’s one of the most popular building materials in the world. It’s fire resistant and stands up to moisture. It gets stronger over time and is used to build roads, bridges, and tunnels! What’s today’s Wonder of the Day? Concrete, of course!
Concrete is everywhere. Look around you. Do you see any concrete? If you’re in a school, it’s likely that the floor or even the walls are made of concrete. At home, it probably makes up the building’s foundation. Peek outside and you might see concrete in sidewalks and roads.
Despite seeing it almost every day, many people don’t know a lot about concrete. What is it made from? How strong is it? How long does it last? What’s the difference between concrete and cement? We have so many questions!
Many people think concrete is the same thing as cement, but that’s not true. Instead, cement is an ingredient used to make concrete. Cement is made from limestone and clay. It’s the paste that binds with the other ingredients to hold the concrete together.
To make concrete, you need air, water, cement, and aggregates. Concrete contains fine aggregates, like sand, and coarse aggregates, like rocks. Makers of concrete mix these ingredients together in the right amounts to make one of the strongest building materials in the world.
Concrete as you know it today has only been around for about 200 years. That’s when Portland cement, the type of cement used to make today’s concrete, was first made. However, other types of concrete were used by ancient peoples thousands of years ago.
The earliest recorded use of concrete are from Syria and Jordan in 6500 B.C.E. Later, people in China and Egypt used different forms of concrete to build structures around 3000 B.C.E. Ancient Romans also used concrete in construction starting in 600 B.C.E. Concrete has been around and changing for a very long time!
What makes concrete so popular? It’s very strong, for one thing. Each square inch of today’s concrete can withstand 3,000 pounds of pressure. It’s no WONDER it’s the go-to material for building bridges and tunnels. Often, concrete continues to get stronger for years after it’s poured. That’s because of the reaction between water and cement as concrete dries.
Concrete is also very inexpensive, considering how strong it is. In the U.S., each cubic yard costs about $110. This also contributes to concrete’s widespread use. From making roads to building skyscrapers, concrete’s strength and affordability make it a favorite.
What other uses for concrete can you think of? Have you ever seen a concrete statue? How about a concrete fountain? When you think about it, you may find that this very strong material is even more common than you realized!
Standards: CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.SL.1, CCRA.W.4, CCRA.SL.2, CCRA.W.2, CCRA.W.9, CCRA.L.1, CCRA.L.2, CCRA.W.10