THE FREYSSINET SOLUTION: INNOVATIVE CONCRETE CORROSION PREVENTION 19 December 2011

Freyssinet Limited is able to offer clients a comprehensive, one stop service for the design and installation of concrete corrosion prevention systems. In partnership with their sister company Corrosion Control Services Limited (CCSL), Freyssinet install permanent cathodic protection systems for the continuous protection of concrete structures exposed to chloride contamination or carbonation. CCSL provides expert assessment, design and component supply and Freyssinet undertake the installation, associated concrete repairs and application of coatings. This provides clients with an integrated service supervised by one named contact, offering both time and cost savings for clients who would otherwise need to organise and oversee several sub-contractors. In this way, overall responsibility for the success of each concrete corrosion prevention project is clearly defined. The Problems Reinforcement corrosion is the major element causing concrete deterioration and requiring structural concrete refurbishment. Good quality concrete creates a high alkaline setting for steel reinforcement, but if the level of alkalinity diminishes, the steel becomes increasingly susceptible to corrosion. Corrosive rust formation increases the volume of the reinforcement until the expansive force becomes sufficient to cause the surrounding concrete to crack and spall. There are two main causes of the type of severe concrete deterioration that requires extensive structural concrete refurbishment and long-term concrete corrosion prevention treatment: 1. Carbonation The process of carbonation occurs when atmospheric CO2 dissolves in moisture forming carbonic acid. The acid progressively penetrates and reacts with concrete, decreasing the pH value. When the contamination penetrates as far as the reinforcement layer, the steel is de-passivated and starts to corrode. Freyssinet can assist in halting this carbonation damage by applying re-alkalisation and structural concrete refurbishment methods. 2. Chloride Contamination De-icing salts, marine aggregates and sea water are common sources of chlorides. When chlorides manage to penetrate to the reinforcement layer, they attack the steel aggressively, starting corrosion. The rate of progression of carbonation and chloride contamination depend on: • Quantity of CO2 present in the atmosphere/chlorides on the concrete surface • Concrete permeability/density • Concrete moisture content Cracked or poor quality concrete in need of widespread structural concrete refurbishment will deteriorate more rapidly. Freyssinet are able to halt the corrosion process and provide concrete corrosion prevention by the application of innovative electro-chemical cathodic protection. The Freyssinet Solution Conventional patch repairs to damaged concrete are unlikely to provide successful concrete corrosion prevention when carbonation has penetrated behind the reinforcement layer or where there is severe chloride contamination in the surrounding, untreated concrete. Freyssinet carries out cathodic protection as a long-term concrete corrosion prevention technique, which works by passing a small electric current through the reinforcement. This innovative method has been used in several hundred successful concrete corrosion prevention repairs around the world and offers a number of important advantages over other structural concrete refurbishment techniques: • Continuous concrete corrosion prevention stops corrosion and prevents future attack • Permanent solution that never requires re-application • Highly effective even on severely damaged concrete • Effective against both carbonation and chloride attack • Effectiveness can be controlled and monitored – economically and simply • Conservation of large areas of contaminated but sound concrete • Shorter on-site work duration • Reduced need for temporary propping • More cost-effective than complete replacement • Perfectly suited to marine structures and highways with recurrent contamination One-stop service provider Concrete corrosion prevention and structural concrete refurbishment are becoming increasingly necessary to deal with the cracking and spalling problems of ageing stone and masonry-clad buildings with steel frames. Freyssinet is a leading provider of a comprehensive range of concrete repair and maintenance techniques – able to offer a one-stop contracting service for all concrete repairs and structural concrete refurbishments. Owing to an outstanding track-record in all aspects of concrete repair, The Highways Agency and various Local Authorities are valued clients. Freyssinet offers valuable, impartial advice on the selection of the best methods and high-quality materials for individual projects and their experts are always available to discuss your requirements.

Leave a Comment

Your email address will not be published. Required fields are marked *

*