What’s the Difference Between Cement and Concrete?

(Last Updated On: December 5, 2019)
What's the Difference Between Cement and Concrete?

Part of being a professional in any field is having access to a lot of information that the layman doesn’t, and construction is no different. The professionals who help put up the buildings and structures we need likely cringe when hearing ordinary people talk about their work, from how to construct a building to the types of materials used. Comparing cement to concrete is a key example of this. If you were to start up a conversation with anyone on the street, chances are that these would be used interchangeably. In reality, though, they have two different natures and purposes. Here’s how this breaks down.

Understanding Cement

In essence, the easiest way to understand cement is that it’s technically a component of concrete as well as mortar, serving as a key binding element. If you look at cement in a store, it will generally appear as a sort of powder. This powder is commonly made from a combination of clay, limestone, silica sand, and shells, with limestone taking the bulk of the percentage. All these different materials end up getting crushed together, mixed with additional ingredients like iron ore, then heated to up to 2,642°F. This new mixture is then crushed up, cooled, and mixed together once again. The final material you see is packaged in order to be mixed into various building materials.

For one last point regarding cement, you may have also heard of it described as Portland cement. This doesn’t mean it’s from Oregon; it is a reference to the compound’s origins. Cement was first created in the 1800s by Joseph Aspdin, a mason in Leeds, England. After creating cement, he noted that the color was similar to the stone quarries on the English island of Portland. Today, it’s the most common cement variant used for building.

Understanding Concrete

In and of itself, cement needs to be combined with water to have any practical use. However, to create concrete, you need to take a step further. When cement is mixed with water and an aggregate like rock or sand, it comes together to create a moldable paste, concrete. Concrete has a few unique traits that have made it one of the most popular building components in the world. For example, when water is added, it goes from a semi-dry state to a flexible, semi-liquid form. By pouring it into a mold or something similar, it can take just about any shape. Along with this, when it dries, it is as hard and durable as rock. While concrete is quite durable, it can crack over time. As a result of this, many builders combine concrete with metal reinforcements like rebar or wire mesh for added protection.

Not all concrete is created equal. To have the optimum traits in terms of durability and strength, it’s important to mix and proportion the different components properly. To give you an example, if you create a concrete mixture that’s heavy on aggregates (gravel, rock, sand) but low on paste, there won’t be enough paste to cover all the open areas. This leads to rough surfaces and a porous set of concrete. On the other side of things, if you put in too much paste, while it may look smooth, it will be much more likely to crack.

Understanding Mortar

We mentioned mortar before, also, so let’s talk about how that fits in. Much like concrete, cement serves as a base, but in mortar, fine sands, water, and lime are the main components. When the water is added, the mixture hardens, just like concrete, but it’s not as strong. Generally, mortar is treated as a sort of glue to hold together masonry materials like stone or bricks. 

So, to conclude the conversation, if all concrete has cement as a component, does that mean that cement is useless on its own? Not necessarily. In a greater construction context, you need concrete. All the major buildings and components of our infrastructure like bridges, sidewalks, and other structures need concrete. However, a lot of amateur home improvement/DIY projects can get by with just cement when performing jobs like grout work or certain masonry projects. In addition, if there is concrete that’s getting cracked or starting to crumble, cement helps with repairs. 

Since we’re on the topic of construction, see if you can recognize some of these famous landmarks from pictures taken while they were being constructed.

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