How concrete is made | Structure manual

June 6, 2024 Roberto Magalhães

This article deals with concrete production and its production process.

Concrete is a composite material made from fine aggregates, coarse aggregates, water and cement. Additionally, we add additives to the concrete to improve its performance.

Concrete is the second most used building material and the most widely used construction material in the world.

What is concrete?

Concrete is the result of the hydration process. Cement reacts with water. When it hardens, it creates a very resistant material that we call concrete.

We add aggregates as filler to increase volume. To maintain the granulometric distribution and good adhesion of the concrete, we add fine and coarse aggregates to the concrete.

There are different classifications of concrete based on the type of cement used, strength of concrete, intended use, properties of concrete, etc.

The strength of concrete is determined by the Quality of concrete The strength of concrete we use for projects is referred to as: characteristic compressive strength of concrete .

When we discuss how concrete is made, we should always discuss some concrete parameters.

Water-cement ratio
Concrete quality
Cement content and minimum and maximum cement content
Exposure condition
Fire protection class

What is concrete made of?

Concrete consists of the following materials.

cement

Cement is the most important material in the production of concrete. This hard material is created through the reaction of cement and water.

When asked how concrete is made, one of the most appropriate answers is that concrete is created by the reaction of water and cement.

There are many types of cement in the world. Of these types of cement, ordinary Portland cement is the most widely used type of cement throughout the world.

Water

Water is the most used substance in the world. We use water to make concrete.

When using water to mix concrete, you must pay attention to its quality.

Aggregates

The aggregates give volume to the concrete and at the same time ensure adhesion between the cement paste and the concrete. Two types of aggregates are used in the production of concrete: fine and coarse aggregates.

We use sand, manufactured sand or sea sand as fine aggregates.

Additions

Additives are added to concrete as foreign substances to improve its properties.

Delay concrete setting time, retain air in concrete, improve workability, increase strength quickly, etc. are some of the main functions of Additives .

We currently use more advanced additives like Flow Agent to achieve multiple functions with one additive. It should be noted that this type of additive is very sensitive. Therefore, they must be used with great care.

What are the common types of concrete

Normal strength concrete
High resistance concrete
prestressed concrete
Permeable concrete
High Density Concrete
Lightweight concrete

Furthermore, concrete can be classified as follows.

Reinforced concrete
Laminated concrete
Self-compacting concrete
Concrete with air intake
No thin concrete
The Types of Concrete article can be used for other types of concrete.

This is how concrete is made

Let's discuss how concrete is made. This process includes the initial and final stages of concrete production.

Prepare or mix cement

The first phase of concrete production is the production of cement. Cement is the most important material for concrete.

Cement should be made as needed for the concrete mix. For more information about the types of cement, see the article “Types of Cement”.

Dosing process – mixing design

Before mixing the concrete, the mixing proportions must be finalized.

This is done in accordance with the requirements of the construction project. The quality of concrete to be used is determined by the building design. Depending on the type of construction, the type of mixture can be determined.

Regardless of whether we use ready-mixed concrete or manually mixed concrete, the dosage is different. When we mix manually, we generally do volumetric dosing. In these situations we take into account the mixing proportions of cement: sand: coarse aggregate. The concrete mix article For more information, you can refer to the following.

If this ready-made concrete is used, the mix composition is created. The mix composition is checked with sample mixes to ensure it works as expected. Mainly the strength of the concrete, setting time, etc. After verification, we use ready-made concrete for construction.

Mix

After the design mix is complete, we have the mix ratio. Concrete mixing is carried out based on the mixing method determined while finalizing the mixing proportions.

Concrete is mixed by hand or with pre-mixed concrete.

When manually mixing, we add cement, sand and coarse aggregates to the binder and it is rotated. During this process we add water. Typically, no additives are added to concrete during hand mixing.

The same process is used in preparing the ready mix. The material is placed in mixing proportions based on the weight of each individual material.

Concrete

Now we look at how concrete is made. None of this is concrete .

Once the concrete has been mixed in the concrete mixing plant, it must be transported. If the quality of the concrete is higher, attention should be paid to the installation temperature of the concrete. It is usually around 30-32 degrees Celsius.

During this process, attention must be paid to the order of concreting to avoid cold joints in concrete .

Furthermore, the concrete must be sufficiently compacted.

Cure

The final phase of concrete production is concrete curing.

The concrete should take at least seven days to harden. Depending on the type of concrete, the appropriate curing process must be selected.

Hardening of concrete is considered mandatory. We perform curing to prevent evaporation of water from the surface of the concrete, to ensure that there is sufficient moisture to complete the hydration process, to absorb excessive heat generated in thick concrete when using higher quality concrete, to increase the temperature when concreting in cold climates, to maintain the temperature gradient and difference between the core and surface of thick concrete.

Furthermore, we will be aware of factors that affect curing time and concrete curing time as a technical team, especially when we are involved in larger projects.