DURABLE CONCRETE BUILDING AND CONCRETE STRUCTURE REPAIR TECHNIQUES 19 December 2011

Freyssinet Limited offer a wide range of products and services to carry out concrete repairs and structural concrete refurbishment to buildings and other concrete structures. Where moisture is present, reinforced concrete structures can develop steel corrosion and even without salt-caused corrosion, carbonation eventually occurs in the majority of concrete structures. Steel-concrete corrosion is a widespread, continuing problem that requires durable, cost-effective concrete structure repairs. Fortunately, concrete repair techniques traditionally applied mainly to bridges and highway structures, are now available to provide cost-effective and durable concrete repairs to buildings and other structures.Expert deterioration survey In cases where steel corrosion is suspected, Freyssinet Limited can provide an expert deterioration survey to identify the cause and extent of the corrosion. They offer a variety of concrete structure repairs and concrete corrosion prevention techniques depending on the type and condition of the structure, the cause of damage and the extent of the problem.

StrengtheningFreyssinet offers a range of highly effective structural concrete refurbishment and strengthening techniques to prolong the life-span of existing structures or allow a change of use. These high-grade concrete structure repairs include: • Column strengthening • Raising allowable floor slab loads • Strengthening around new openings • Modified mortars for patch and thin bond repairs • Pressure and vacuum injection using epoxy, polyester, and cementitious grouts • Sprayed concrete Plate bondingPlate bonding is an excellent strengthening method for under-strength beams and floor slabs. Steel plates are bolted/glued to the tension zone of the structural element with epoxy adhesive, increasing the depth composite section and enhancing the load carrying capacity. Freyssibar high strength barsFreyssibars are versatile, high-strength bars used to introduce pre-stress into existing areas which are subject to bursting forces or with high stress concentrations. In addition, Freyssibars provide a significant increase in load-carrying capacity, remedy over-stressed sections and are a suitable alternative to plate bonding. FRP Composites Freyssinet also offers TFC®, a carbon-fibre product. TFC® has numerous strengthening applications for concrete structure repairs. For example, beam strengthening, column-wrapping, reinforcement around new openings and floor slab strengthening. Design and build serviceStrengthening techniques required for concrete building repairs demand careful consideration of the existing and desired loading regimes to assess what strengthening methods are viable and to facilitate a technically appropriate, cost-effective design. Freyssinet has highly-qualified and experienced staff available to offer clients a comprehensive design and build strengthening service for concrete building repairs. Electro-chemical concrete corrosion protection Freyssinet also provides expert electro-chemical concrete corrosion prevention as part of its range of cost-effective, long-term concrete building repair techniques. Cathodic protection and other electro-chemical methods ensure surrounding concrete is protected from corrosion and provide cost-effective and durable concrete structure enhancement.Cathodic Protection This effective and long term solution to concrete corrosion is an important component of many concrete building repairs. The method utilises permanent anodes, an external power source and monitoring to minimise or completely stop the damaging action of chloride contamination throughout the entire area of concrete. Electro-chemical chloride migration This complementary technique for concrete building repair uses a temporary anode, external power supply and monitoring system to apply electric current to the steel. The positive charge repels the negative chloride ions and re-structures the passive layer. Re-alkalisation – concrete repairs to carbonated concrete Re-alkalisation is the equivalent of the ECCM concrete repairs technique above – but for carbonated concrete building repairs. Freyssinet is always ready to provide the expert advice necessary for selecting specialist techniques for durable concrete building repairs and concrete corrosion prevention to ensure the most appropriate concrete repair technique is used.