Concrete is a mixture of cement, gravel or sand, and water. It’s used more than any other man-made material, yes, even more than plastic.
Rock Hard. People knew about concrete thousands of years ago. The ancient Mesopotamians, Assyrians, Chinese and Egyptians all used types of concrete. The oldest concrete ever found was used to make the floors of Stone-Age homes built near the River Danube over 7,000 years ago.
The ancient Romans used a type of concrete quite similar to the kind we use today. They discovered that adding volcanic ash made it set under water, and adding horse hair made it less likely to shrink.
Everyone forgot about concrete for a few centuries. Eventually, French architect Philibert de l’Orme wrote about the ingredients of the concrete he used in the 16th century.
In the 18th century, engineer John Smeaton invented a hard concrete using quicklime. He also came up with a new concrete that hardened under water, and used it to rebuild Eddystone Lighthouse in Cornwall in 1793.
Today extremely strong concrete can be made by reinforcing it with steel. It’s even possible to make concrete that conducts electricity and concrete that transmits light.
Concrete production has high energy costs that make it very bad for the environment. But the use of recycled material is becoming more common.
Cement is a substance used to bind other materials, because when mixed with water it sets and hardens. Concrete, mortar and grout use cement, which is usually ‘ made from a calcium source, like limestone, and a silicone source, like clay.
There are some incredible buildings and monuments around the world, built for a variety of reasons and out of a variety of materials.