Concrete vs Cement: What is the Right Mix?
Description: Concrete and cement are terms often used interchangeably by error. In reality, one of these materials is an ingredient for the other.
In construction, the materials used for paving are often mistaken as simple synonyms by the untrained eye, whether we’re talking about concrete, cement, mortar or more. Although the terms are two individual materials, they are used interchangeably on many occasions. However, there’s a clear and distinct difference between cement and concrete that can be explained in simple terms.
What’s the Difference Between Concrete and Cement?
To understand the differences between these two paving fundamentals, first we should define them individually.
Concrete is a material made out of water, paste and aggregates mixed together. The aggregates typically consist of fine material (sand) and coarse material (rocks). The paste that binds together the aggregates is what is known as cement. So, contrary to popular belief, concrete and cement are not only two separate concepts, but one of them is needed to create the other.
In its initial stage, concrete is like clay, wet and able to take different forms. After it dries over time, it hardens to the durable and strong material we know as the foundation of many important types of constructions.
Cement can be defined as a very thin powder built out of crushed minerals. The most common materials used to manufacture cement often include clay, shells, limestone, chalk and more. These minerals are to be combined with other key ingredients, such as clay, sand or iron ore. After this, they are set to be heated, and result in a material called clinker, which is then ground up to become the powder known as cement.
Cement isn’t designed to be used on its own; its primary use is to act as a binder to “glue” together and harden other construction materials.
What about Mortar?
Mortar is another type of construction material that is also made out of cement and water, with a heavier mix of water and sand, and a common addition of lime. Unlike concrete, mortar is weaker in attributes and is therefore unable to be used as an only and primary material like concrete is. Instead, it’s used as a certain type of paste to help hold together other masonry materials. These materials usually consist of stone, bricks or blocks of concrete.
There are several different types of mortar with different uses. Mortar is best suited for (and in many ways, a fundamental element of) masonry not only for its weaker structure when compared to concrete, but also because it is easier and less costly to repair.
What Mix Should I Use?
It should be noted that an ideal mixed ratio of concrete and cement will depend on what is being built with the material. However, there are some general mixing guidelines one can follow in order to create strong and long-lasting concrete for use. The optimal mix needs to be malleable enough to work with easily when fresh, and yet still balanced enough to be very strong once hardened.
Paving experts will recommend that a typical mixture consist of about 10% to 15% cement and 15% to 20% water. The rest of the mixture, of course, should consist of the aggregates. You want to keep the water-cement ratio as low as you can while still being able to easily mold the product while wet.
Too little aggregates and too much cement can seem fine at first, since the concrete mixture will have a smooth texture and be easy to place. Nevertheless, while it might look good on the surface, we have to consider the functionality of the concrete, which will likely be weaker and only a short-term solution before it begins to crack. This information comes in handy when mixing your own concrete, or for checking quality when buying concrete.
For small projects, concrete mix can be bought in pre-made bags, which only need water to be complete. For larger projects, you can also purchase premixed concrete to be delivered by a truck, which is usually referred to as “ready-mix”.
These guidelines can be applied to most cases of concrete mixture, but it can be advised to research the type of construction project you’re working on. Some types of structures will require a variation in water-cement ratio, or it will benefit from only using specific aggregates in the mixture.