What Is Concrete Made Of?
There is a considerable amount of confusion surrounding what exactly concrete is made of, as well as the differences between concrete and cement. Although many people seem to refer to concrete and cement interchangeably, they are in fact two separate things. Cement is a binding material, and one of the key ingredients of concrete. Concrete, on the other hand, is a compound material composed of water, cement and aggregates (for example, sand and gravel).
To clear the confusion further, we will take a more detailed look at the two materials, gaining a better understanding of concrete in the process.
The difference between concrete and cement
So, as already stated, cement is a binding material and a key component of a standard concrete mix. Cement is composed of calcium, aluminium, iron and silicon, and is created by mixing clay, limestone and sand, although this may vary.
These materials are then crushed and grinded together and heated to extreme temperatures in a kiln, after which the ingredients undergo a chemical reaction, forming a new substance: ‘clinker’. After being ground further, the final substance is identifiable as what we know to be cement.
Upon completion, the cement is ready to form part of a concrete mix.
The concrete mix
So, we’ve established that the three basic ingredients of concrete are as follows: cement, water and aggregates. Now, we’ll look in greater detail at the individual roles of these ingredients:
- Cement: When mixed together, the cement and water form a paste which coats the various aggregates in the mix. The paste then hardens and binds the aggregates together.
- Water: To create the aforementioned paste, water is the key; it chemically reacts with the cement and makes the concrete workable. The amount of water added to the mix alters the water/cement ratio which, in turn, dictates the strength of the concrete upon completion.
- Aggregates: Aggregates pad out and strengthen the concrete, and can be split into fine and coarse varieties; sand is considered a fine aggregate, where gravel is a coarse aggregate.
How is concrete made?
The process of making strong, durable concrete begins with correct proportioning. For example, a mix that doesn’t have enough paste to fill the space between aggregates will produce a rough finish. Conversely, a mix that contains too much space will be more likely to crack.
Once the proportions have been finalised the and ingredients combined, the mixture will begin to harden through a chemical reaction known as hydration.
Once the concrete is properly mixed and workable, it’s then placed into forms before the mix becomes too stiff. This process helps to eliminate any flaws within the concrete such as air pockets. Following this, the concrete can then be floated and trowelled depending on the specific requirements of the batch.
The Concrete Network provide quality on-site mixed concrete to numerous customers, both domestic and commercial, across the UK, with a variety of grades and concrete mix designs to suit various applications. With a wealth of experience and an impressive fleet of mixing trucks, we can tailor each batch of concrete to meet your exact specifications. For more information or advice on your requirements, get in touch today.