Stamped concrete is the result of an embossing and texturing process that’s currently gaining many fans around the world.
This is due to the remarkable aesthetic benefits it grants concrete surfaces, accompanied by appealing economic benefits.
Stamped concrete also stands out for keeping the concretes most important properties intact. That is, its resistance and durability, requiring only a simple maintenance to guarantee its functionality in high traffic areas.
Stamped concrete or imprinted concrete?
There are many types of concrete used in architecture, stamped concrete is one of them. Its main function is completely aesthetic, using the plasticity of the mixture during the curing process.
It can be considered as an in-situ architectural process, which consists of incorporating textures and colours on the surface of rigid floors.
To achieve stamped concrete, the appropriate pigment must be spread on the fresh concrete surface, and then the moulds must be placed, which will be pressed against the concrete.
The finished print tends to be defined by geometric shapes or imitations of wood, stone, brick, tile, cobblestone, etc.
The advantages of stamped concrete
Most of stamped concrete’s characteristics are, in practice, considered to be an advantage because it doesn’t vary the concrete in any way, after the setting and curing processes.
However, we shouldn´t forget that it’s an aesthetic treatment to make concrete surfaces attractive and sophisticated.
Here we highlight some of the most important stamped concrete advantages:
- High mechanical resistance to relatively frequent traffic.
- They have the ability to be anti-slip.
- Resistance to solar ultraviolet radiation.
- Thermal resistance to sudden fluctuations, especially during frost and thaw.
- It can be used in large lengths of continuous paving.
- Reduced execution time compared to other finishing processes.
- Maintenance almost null, due to its simplicity.
- They have a wide selection of shapes, colours and designs.
- Molecular stability against the attack of aggressive and abrasive chemical substances, such as acids, fats and oils.
Stamped concrete floors are often compared to polished concrete floors, as both have effective results and provide an optimal surface for transit.
That flooring comparison refers only to those effective results, because stamped concrete floors and polished concrete floors are 2 types of flooring used for different types of construction.
Before proceeding with the concrete stamping, it’s necessary to establish some preliminary aspects related to the floor surface, the colouring and the resin finish, all explained in the following points:
- The base must be stable against any external influences, as well as being properly levelled and compacted.
- The floor base mustn`t affect the concrete’s mechanical resistance or its volumetric stability. Furthermore, it must be chemically compatible with lime, but without being susceptible to decomposition during the setting process of the cement.
- It must provide uniformity to create regular colourings. Likewise, it must contribute to the rigid flooring’s surface resistance.
- The colouring mustn’t affect the properties of the concrete. Being stable and chemically compatible.
- The resin must fill the pores of the concrete to seal its surface, generating a durable and resistant layer to thermal changes and abrasion.
Now, regarding the concrete, it is worth taking into account:
- Its resistance must be higher than 220 kgf / cm2. In the worst case, a minimum compressive strength of 200 kgf / cm2 is allowed.
- The maximum value of the water / cement ratio should be 0.55, to avoid the adverse effects of shrinkage.
- The consistency of the concrete needs to be soft.
- It’s recommended that water used for mixing should be clean and potable, without traces of sulphates and carbohydrates.
Stages to stamped concrete
Once all the important preliminary aspects are known, it should be known that the stamped concrete process is mainly done in 3 steps, the first 2 consist of colouring processes and the last one, stamping.
To stamp the concrete, you first have to add the base colouring, which will be the primary colour that gives a natural appearance in order to achieve the coating which we want to replicate.
The base colouring is created by adding hardening colouring to the concrete, this is a powder pigment.
There are 2 ways to do the base colouring. The first is an integral coloration, in which the entire volume of concrete is coloured, whereby the pigment is added during the mixing of the concrete.
The second option consists of applying the pigment on the surface of the flooring, in a plastic state.
In order to achieve the desired colour, a second colouring is needed. This second colouring is a pigment that’s responsible for texturing and adding a more detailed finish, it’s also non-stick, making it impossible for the stamping moulds to stick to the surface.
Like the previous stage, to apply the dye there are 2 ways of doing so, in accordance with its state, since it can be a powder or a liquid (solvent).
Powder colouring is the most commonly used product, which only needs to be spread on the surface before stamping. The liquid pigment is part of the content of sprays, so it is sprayed on the molds, prior to stamping.
This last stage consists of placing the moulds over which we apply the necessary pressure, each one with a particular geometric pattern, normally being the imitation of some cladding material, such as wood, tiles, paving stones, stone or slate among others.
The moulds are generally made of polyurethane, although neoprene has recently been used, since it’s a material with greater versatility to simulate more varied shapes.
To finish the stamped concrete floor, resins are used to seal the entire surface of the concrete, to enhance its water resistance.
How to maintain stamped concrete floors?
Maintenance is a key point regarding the benefits of stamped concrete, since it has such a high resistance and durability that its maintenance is almost unnecessary.
However, this type of flooring must be subjected to a periodic inspection, to renew the surface treatments, since the probability of defects will never be completely null; Joints are the structural elements to which greater consideration must be given.
Restorations are recommended to compensate for the accumulated abrasion.
Even the cleaning of the flooring must never be neglected, since spills of harmful liquids, such as oils, may occur, which can damage the appearance of the concrete. Also, the removal of miscellaneous dust and debris is necessary.