Pavers, concrete, colour differences, efflorescence

Suitable materials
Use of concrete
Methods of sourcing suitable material
Most popular questions and answers

Paving products are prefabricated elements made of concrete using vibropressing technology (simultaneous vibrating and pressing). Their high durability allows them to be used for the construction of road surfaces, car parks, pavements.

The most popular way of making paving elements is the two-layer technology. This is an optimal solution ensuring high durability and strength of paving blocks, which is ensured by the lower, construction layer, and aesthetic appearance, which is guaranteed by the upper, texture layer.

For the production of all paving products such as paving stones, records or kerbstones materials of natural origin are used. These are mainly cement and various aggregates combined with each other. Although the aggregates and cements are sourced from a reliable source, the manufacturer has no influence on their colouring.

Suitable materials

This applies to aggregates, especially sand. The deposit from which they are drawn often has a large surface area and it is difficult to maintain consistency in its properties and particularly in its colour. This can result in slight discrepancies in the colour of the finished products.

To compensate for differences in colour, it is advisable to ensure that the purchased goods come from a single production batch. And the paving should be laid from at least three pallets at the same time.

However, the main reason for complaints about paving products is efflorescence.

It is worth knowing that the white deposit appearing on the surface is a natural process associated with the maturation of concrete, the material from which paving products are made.

Use of concrete

As concrete matures (hardens), chemical reactions produce a calcium hydroxide compound which then reacts with carbon dioxide in the air in the presence of water. The product of this transformation is calcium carbonate, which manifests itself as a white, hardly soluble precipitate.

This whole process, as mentioned, is related to the natural setting reactions of the cement and does not affect the quality or properties of the products.

Fortunately, at a certain point, calcium hydroxide-producing reactions cease to take place in the concrete, marking the end of efflorescence formation. Therefore, the visual changes caused by the white tarnish on the surface of the material are reversible and, as a result of the natural use of the pavement and the action of water, can be eliminated over time. However, this process can take several years.

Methods of sourcing suitable material

There are ways in which it is possible to remove efflorescence much more quickly than the natural process of wiping it off and washing it away. These include: washing out the white deposit with low-percentage acid solutions and mechanical sanding or grinding. These methods interfere with the surface structure of the paving stones by dissolving it in the case of acid, and by removing a layer of it in the case of mechanical action.

ABW Superbruk as producer paving products does not recommend the use of these methods, due to the possibility of damage to the pavement and the fact that this does not guarantee the recurrence of efflorescence in the future.

How to prevent colour variations in paving blocks?

Differences in the colour of the paving blocks may be due to the natural characteristics of the materials used, such as aggregates. It is recommended that purchased products come from a single production batch and are laid from at least three pallets at the same time to compensate for these differences.

What is efflorescence on paving stones and how do I remove it?

Efflorescence is a white deposit that appears on the surface of paving stones, a natural process associated with the maturation of concrete. It can be removed by the natural use of the pavement, the action of water or more quickly with low-percentage acid solutions, sandblasting or grinding, although these methods can damage the pavement.

What are the advantages of double-layer technology in the production of paving stones?

The two-layer technology ensures high durability and strength of the paving blocks thanks to the lower, structural layer and an aesthetic appearance thanks to the upper, textured layer.

Does efflorescence affect the quality of pavers?

The efflorescence does not affect the quality or properties of the paving products, it is a natural phenomenon related to the setting of the cement and may disappear over time.

How long can it take for the efflorescence to disappear?

The process of efflorescence disappearance is reversible and can take up to several years, depending on the operating conditions and the action of external factors such as water.