Durable Concrete Building and Concrete Structure Repair Techniques
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.
Strengthening
Freyssinet 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 bonding
Plate 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 bars
Freyssibars 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 service
Strengthening 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.
Concrete Bridge and Highway Structure Repairs, Strengthening and Hydro-Demolition
Freyssinet Limited is an expert provider of concrete bridge repairs and structural concrete refurbishment. Owing to their experience and excellent track-record in bridge and highway structure repair and all aspects of concrete repair, the Highways Agency and numerous Local Authorities are regular clients.
Coatings
Pore-lining impregnants are often applied to bridges exposed to chlorides before they are opened to traffic. However, when the level of chloride reaches reinforcement depth the coating will not stop corrosion and permanent concrete bridge repairs will need to be done.
Patch Repairs
Patch concrete repairs have historically been the conventional method of concrete bridge repair. However, this method requires the removal of undamaged (but chloride-contaminated) concrete which is otherwise in sound condition. In addition, patch repairs inevitably increase the corrosion in surrounding areas of concrete.
Electro-chemical Cathodic Protection (CP) – Concrete Corrosion Prevention
The Cathodic Protection method does not require the removal and replacement of chloride-contaminated, but otherwise sound, concrete. This significantly cuts concrete quantities and reduces on-site working time, minimising the cost of concrete repairs to bridges and highway structures.
Hydro-demolition for Bridge and Highway Structure Repair
As part of its forward-thinking approach to structural concrete refurbishment, Freyssinet offers clients the advantages of hydro-demolition concrete removal by their own in-house teams.
Efficient Concrete Removal Hydro-demolition is a high-pressure, water-jetting technique for the efficient removal of both damaged and sound concrete. It can be used with equal effectiveness on small areas of localised damage, for extensive concrete repairs preparation and for removing existing concrete coatings. Hydro-demolition is an excellent preparation for concrete repairs, leaving a perfect bonding surface for new coatings and all types of concrete repair material.
Advantages of Hydro-demolition for Bridge and Highway Structure Repair Hydro-demolition offers a number of important advantages in comparison to conventional concrete removal methods used in concrete bridge repairs and other concrete structures e.g. jackhammer removal.
• Eliminates all dust and debris
• Cleans existing reinforcing steel
• More efficient process reducing on-site programme
• No damage to reinforcing steel
• No hand-arm vibration injuries
• No vibrations ensures no cracking or micro fractures in the structure
• Surfaces are prepared perfectly to key-in new concrete and receive mesh overlay
Experienced Team The Freyssinet Limited hydro-demolition team is highly trained with more than 20 years of solid experience in hydro-demolition applications including concrete bridge repairs and all types of concrete structures.
Health, Safety and Quality The hydro-demolition team wears the latest TST PPE, including 2000 bar-rated bib and brace, TST safety gaiters to cover safety wellington boots and TST waistcoats.
Freyssinet Limited is an Accredited Full Member of the Water Jetting Association – with a representative on the Technical Committee. All of their work is carried out with rigorous adherence to the Water Jetting Association’s Code of Practice.
Hydro-demolition is an important component of Freyssinet Limited’s unique, one-stop service for concrete bridge and highway structure repairs. Other services include:
• Bearing replacement
• Carbon-fibre strengthening
• Cathodic protection
• Coatings
• Concrete repairs
• Core drilling
• Grit blasting
• Jacking
• Wall sawing
Comprehensive Range of Freyssinet Services for Durable Concrete Repair and Refurbishment in Scotland
Freyssinet Limited has been providing first-class structural concrete repairs in Scotland and the rest of the UK for more than 30 years, offering a comprehensive range of structural concrete refurbishment and long-term repair techniques depending on the type of structure, the type of damage and the extent of concrete deterioration.
Concrete Bridge and Concrete Building Repair in Scotland
Freyssinet is a specialist bearing manufacturer producing standard and customised bearing design for concrete bridge repairs. If required, prior to bearing replacement, inspection and testing is carried out by our experts in Scotland. Freyssinet’s expert services include every other aspect of a high quality concrete bridge repair.
The range of techniques available for concrete bridge and concrete building repairs in Scotland includes:
• Modified mortars for patch and thin-bond repairs
• Pressure and vacuum injection using epoxy, polyester and cementitious grout
• Sprayed concrete – both wet- and dry-sprayed concrete structural repairs
• Expert hydrodemolition concrete removal
Hand- and machine-applied concrete repair mortar is appropriate for structural and non-structural concrete repairs. Hand application is suitable for small-scale concrete repairs and sprayed concrete is used on large-scale structural concrete refurbishment.
Strengthening
Freyssinet offers a range of highly effective strengthening techniques for structural concrete refurbishment in Scotland to prolong the life-span of existing structures or allow a change of use. These high-grade concrete structure repairs include:
• Column strengthening,
• Bridge deck strengthening
• Raising allowable floor slab loads
• Strengthening around new openings
External post-tensioning
This method is especially suitable for concrete bridge strengthening and Freyssinet offer an expert in-house design and installation service of supplemental post-tensioning to existing structures. Additional tendons can be fitted within the structure or externally depending on the size of the bridge. External post-tensioning is also a highly effective concrete structure repair technique for upgrading circular storage tanks in Scotland and the rest of the UK.
Plate bonding
Plate bonding is carried out by Freyssinet to provide an excellent strengthening method for under-strength beams and floor slabs.
Freyssibar high-strength bars
Freyssibars are versatile, high-strength bars used to introduce pre-stress into existing areas which are subject to bursting force or high stress concentrations. For example, concrete structure repair to bridge deck diaphragms, anchorage regions and column heads. In addition, Freyssibars provide a significant increase in load-carrying capacity and are a suitable alternative to plate bonding.
FRP Composites
Freyssinet also offers TFC®, a carbon-fibre product developed by the Freyssinet Group. TFC® has numerous strengthening applications for concrete structural repairs in Scotland. For example, beam strengthening, column-wrapping, reinforcement around new openings and floor slab strengthening.
Freyssinet One-stop Design and Build Service
Strengthening techniques required for concrete bridge and 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 a highly-qualified and experienced team available to offer clients a comprehensive design and build service for concrete repairs in Scotland.
Innovative Techniques
Innovative Cathodic Protection (CP), Chloride Migration and Re-alkalisation are modern techniques which have been used with success in hundreds of structures worldwide. Furthermore, electro-chemical methods have been approved by the Highways Agency for use in concrete corrosion prevention in Scotland and the rest of the UK. Chloride Migration is available as a technique for structural concrete refurbishment in Scotland, providing an excellent concrete corrosion prevention treatment. Re-alkalisation is the newest method for carbonated concrete structures in Scotland and worldwide.
Freyssinet Limited is a forward-thinking and highly experienced company, offering technically sound and cost-effective concrete repair and structural concrete refurbishment techniques in Scotland and the UK.
The Freyssinet Solution: Innovative Concrete Corrosion Prevention
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.