Efflorescence (White marks on pavers)

An Explanation of the Formation, Prevention, and Treatment of Efflorescence on Concrete Pavers

The following explanation and opinions are supplied to give general information on the phenomenon of efflorescence.

Professional advice must be obtained before attempting to identify or treat any concrete units that may exhibit signs of efflorescence.

Introduction

The phenomenon of efflorescence on concrete surfaces is familiar to anyone involved in some way or another in the working or use of concrete and concrete products.

The white deposits which, under certain conditions can stubbornly remain where they form for a very long period of time, impair the appearance not only of concrete paving units, but many other exposed concrete surfaces.

It is a particular nuisance where attempts have been made to render the concrete more attractive by colouring it with inorganic pigments. Although it is now generally acknowledged that the addition of such pigments can neither promote nor hinder the appearance of efflorescence, the whitish deposit is naturally much more striking and upsetting to the eye on coloured surfaces than it is on uncoloured grey concrete.

Although, a great deal of work has been done investigating the phenomenon of efflorescence, there is still no effective additive that can be used by concrete manufacturers to prevent the formation of efflorescence on finished concrete products.

Agreement has however been reached to a large extent by researchers world wide, on the mechanism behind the formation of efflorescence, which at least makes it possible to take certain measures to restrict its formation to a large extent.

The following section will therefore deal with the mechanism behind its formation and explain the precautions that can be taken as a result.

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