STRUCTURAL ENHANCEMENT SPECIALISTS 05 April 2012

Concrete deterioration is mostly caused by the combination of reinforcement corrosion which has been made worse by a surrounding concrete suffering from a reduction of alkalinity. The principle instigators of this form of deterioration can be carbonation and chloride attack. Carbonation can be caused by carbon dioxide that exists in the atmosphere, whilst chloride attacks are most likely the result of marine aggregates, de-icing salts or seawater. To minimise the effects of these elements, some form of concrete corrosion prevention is required.

To address the challenge of concrete corrosion prevention, there are several structural enhancement techniques to look at. These techniques include cathodic protection, coatings, grout injection, resins and wax injection. Freyssinet have been using these techniques for over thirty years, so you know that you are in good hands. Cathodic protection is a concrete corrosion prevention technique that can be used where patch repairs are likely to be unsuccessful. Situations where cathodic protection may be the best form of concrete corrosion prevention are where there are sufficient amounts of chlorides in untreated areas of adjacent and untreated concrete. Cathodic protection may also be the best course of action where carbonation has managed to get behind the reinforcement layer.

The process of cathodic protection is achieved by passing a small amount of electric current through the reinforcement layer and offers several advantages over other concrete corrosion prevention techniques that can be used. Being a continuous process, it not only stops the existing corrosion; but also prevents further corrosion attacking the structure at a later date. There is also no need for any reapplication, it can be used on very badly damaged concrete, protects against both carbonation and chloride and can be adjusted and controlled through constant monitoring. Furthermore, it is a more economical alternative form of concrete corrosion prevention than concrete replacement. Cathodic protection is especially well suited to marine and motorway structures, which are highly susceptible to corrosion. To prevent chemical attack whilst providing waterproofing, with limited maintenance costs and a long life expectancy; coating treatments are the answer. Freyssinet can provide clients with an extensive and full range of coatings to inhibit corrosion, provide anti-carbonation, waterproof and resist chemicals.

Void filling solutions can be applied using the injection of resins and grouts in both structural and non-structural applications. The latest vacuum assisted grouting technology, resin and polyester epoxy is used along with both high and low pressure injection equipment to deal with fine cracks within reinforced concrete structures. A wide range of different injection techniques are employed by Freyssinet’s teams of highly trained specialists. Whatever the problem, you can be assured that they have the expertise, experience and equipment to do the job.

For the full range of treatment work, from post-tensioning to ground anchors, more often now Freyssinet find it better to use wax injection, rather than more traditional grouts. The two major benefits for wax are its properties as a modern semi-solid bonding substance make it, more corrosion resistant, and a more flexible bonding agent to work with than traditional grouts. No matter how big the job, Freyssinet can provide the equipment needed, whether it’s a project needing 2 litre ‘top hat’ caps, or a 2000 litre application.

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