Best practice guidance on the selection of appropriate repair and remedial strategies to ensure protection of concrete structures that will last put the emphasis on ensuring that the quality of your coat is up to scratch. As well as addressing the underlying issues it’s about repairing a structure so it’s fit for the future.

 

The first stage of every successful concrete repair process starts with identifying the underlying causes of the problem. For concrete deterioration, this can be attributed to any one of four main causes: mechanical, chemical, physical or fire. However, for reinforcement corrosion the three common causes of defects are carbonation, corrosive contaminants and stray currents.

In certain environments, such as in aggressive ground conditions or where the concrete is subject to chloride exposure, these underlying causes can be accelerated.  But with the right treatments in place, including anti-carbonation and barrier coatings and hydrophobic impregnations, corrosion can be controlled.

 

Sika has developed a wide range of protective coating solutions suitable for concrete, steel, tank lining and anaerobic digestion tank applications. These coatings take into account design life, operational requirements, surface design and installation details to deliver high performance protection that stands the test of time.

Providing a barrier between the substrate and the environment to which it is exposed (the cause of the defects), protective coatings can prevent further ingress and provide immediate visual improvement. Specifying a vapour permeable barrier for concrete substrates will reduce the risk of corrosion and avoiding blistering from trapped moisture, while anti-carbonation coatings can minimise the effects of carbonation. A solution like Sikagard 550W offers the best of both worlds, as the protective and decorative coating prevents moisture ingress, is water vapour permeable and provides excellent crack bridging and carbonation barrier.  

But concrete can be porous and damp and applying a barrier system can prove problematic for some. In these cases, a polymer modified cementitious system like Sika MonoTop overcomes many of these issues whilst also providing a levelling system for damaged or uneven substrates. Alternatively, cementitious or ‘fairing’ coats can be used alongside anti-carbonation coatings to prevent delamination and provide additional protection.

 

A surface coating or treatment can provide a relatively simple and cost-effective method for extending the life of concrete and improving its appearance, but it’s important to note – as the CRA document also states – that “these types of systems can only make up one part of an overall concrete protection system and in most cases will not provide the total solution.”

For a complete and comprehensive solution, total corrosion management is the answer. Although the majority of reinforced concrete is relatively trouble-free and low-maintenance, when problems do occur these often occur at depth and most notably to the reinforcement. Sika offers a range of products and systems that covers concrete repair and protection in accordance with the Principles and Methods defined in the European Standard EN 1504. Sika is the only single source supplier of a total corrosion management solution offering design support and product guarantees enabling clients to ensure compatibility with the correct
specification of concrete repair.

 

Architects, specifiers and end users must deal with concrete corrosion using a ‘total’ approach that not only controls corrosion but offers a long term outcome to extend the life of a structure. Total corrosion management incorporates mortars, coatings and reinforcement corrosion protectors and will rehabilitate and restore concrete surfaces to ensure they are fit for the future.