What’s the Difference Between Concrete & Cement?
You know that cement sidewalk you walked on earlier today? It wasn’t cement. It was concrete. What about that cement mixer truck you saw at the construction site? Sorry. No such thing. It should be a concrete mixer.
Confused? Don’t be. Most of us make the same faux pas. What’s the difference between concrete and cement? Let’s break down the basics:
- Cement = Binder
- Concrete = Stone
Perhaps some more details are required.
Into the Cement Mix
Cement is a binder that hardens into a solid compound not unlike glue but more rocklike. The most common type of cement is called Portland Cement. No, it wasn’t named after the city.
Cement is made when you add water to a fine powder of limestone, calcium, silicon, iron and a bunch of other minerals. All of those ingredients are cooked up in a kiln. When “baked,” they form tiny marbles. Those marbles are then ground up into even more powder. A few dashes of gypsum, and you have a mixture that looks a lot like gray flour.
When water is added to the “flour,” the chemical magic happens, and before you know it, that cement has hardened. Left alone, that cement will just be a hard blob of, well, cement. However, when placed between things like bricks and stones it becomes a durable binding agent. See: glue.
A Recipe for Concrete
Here’s where it gets fun. Concrete is made from crushed-up stone, rock and sand. Those elements form a mineral band called aggregate. What all that aggregate needs to form concrete is some sort of binding agent. If only there was something that is a binder that can harden into stone.
Ding! Ding! Cement! Yes, concrete can’t be made without cement added into the mixture.
All it takes is around 10 to 15 percent of cement to make all the concrete aggregate work together in perfect rock solid harmony. Of course, you’re going to need water to make it all happen. How much water is the kicker.
If you add too much water to concrete, then it becomes a sloppy paste and is hard to work with. Too little water will end up weakening the final product. Next time you see concrete crumbling, snap a picture and post it with the caption: “This is what happens when you don’t use enough water when mixing concrete.” It will totally go viral.
Concrete is a very energy-efficient building material. Concrete walls can significantly reduce the need for heating and cooling. The high rock ratio that makes up concrete creates a very durable material. That is why concrete is used for pools, driveways, roads and foundations. It can even be used underwater. It’s just that strong. Cement is strong, but it’s no concrete.
Concrete is also versatile as a building material — it’s easy to mold, stain, shape and paint. You can even create different textures that look expensive but don’t come with the maintenance or price of a costlier material.
The other great benefit of using concrete is that it is 100% recyclable. Suppose you bust up your driveway. Those concrete chunks can be ground up into the same original powder that was cement. Add water and you know the drill. That means when you buy a bag of concrete mix, look for the recycled label. Just as durable as “original” concrete.
More Concrete Facts to Enlighten
Has your thirst for all things concrete and cement been quenched? There’s more. The word concrete comes from the Latin — of course — “concretus,” which means “compact or condensed.”
The most concrete used in a single structure is the Three Gorges Dam in China. That took 27.2 million cubic meters of concrete goodness to be built. The previous record-holder was the Grand Coulee Dam in Washington with a paltry 9 million cubic meters of concrete. Grand Coulee totally got swamped by Three Gorges.
As for the tallest concrete skyscraper, that honor goes to Trump International Hotel and Tower that tops out at 423 meters.
Thanks to this little cement vs. concrete education, you’ll be the smartest person in the room — provided that room is talking about cement and concrete.