Sika FerroGard Surface Applied Corrosion Inhibitor for Reinforced Concrete

Transcription

1 FerroGard Surface Applied Corrosion Inhibitor for Reinforced Concrete

2 Corrosion in Reinforced Concrete Structures Corrosion Management with Ferrogard Technology Aggressive Influences on Reinforced Concrete Description In reinforced the steel is normally protected against by the passivating alkalinity of the cement matrix. Due to the ingress of aggressive environmental influences the steel can corrode. Three conditions must exist for reinforcing steel to corrode: The passivation of the steel must have been destroyed by chlorides or by carbonation The presence of moisture as an electrolyte The presence of oxygen Carbonation Carbon dioxide ingress causes carbonation of the cement matrix progressively reducing the passivating alkaline protection of the steel reinforcement to a level where can occur. Chloride attack Chloride ions from deicing salts or marine exposure are carried into the in solution in water. At the steel surface, even in alkaline, they attack and break down the passivating layer and then accelerate the steel process. The Effect of the Aggressive Influences /Carbonation As soon as sufficient chloride ions (from deicing salts or marine exposure) or the carbonation front have reached the steel surface, the passive layer is destroyed and accelerates. Contact with water (moisture) The original neutral iron will receive a negative charge as the positively loaded ions have the tendency to dissolve. The water film around the metal turns positive. Contact with oxygen The oxygen takes on the negative charge of the iron ions which have gone into solution. The result is iron hydroxide, the first stage of rust. Rust Anode Cathode FerroGard is a unique blend of non toxic, organic inhibitor based on amino alcohol and salts of amino alcohol technology, designed for use as an impregnation on hardened reinforced. FerroGard is a multifunctional inhibitor which controls the cathodic and anodic reactions. This dual action effect significantly retards both the onset and the rate of and increases the time to future maintenance. FerroGard is normally applied as part of a management strategy. It is compatible and a component of all the Sika repair and protection systems. Performance and Durability FerroGard penetrates the and forms an adsorbed protective film on the surface of the steel reinforcement. The protective adsorbed film of FerroGard reduces the rate of in carbonated and chloride contaminated. Many studies have been carried out on inhibitor technology around the world. Assessment of the technology has been investigated by Mott MacDonald and the Monarch University. A more detailed investigation into the behaviour in carbonated was done by the University of Cape Town and additionally with chloride contaminated by the BRE, UK and the European project SAMARIS. The Performance of FerroGard Protective layer FerroGard forms an adsorbed protective film on the reinforcement. The process of forming this protective film takes place even in carbonated and even with the presence of chlorides in the. Delay of the process The dissolution of the iron in contact with water will be reduced thanks to this passivating protective film This film is also a barrier to the reduction of oxygen which will be prevented Rust Anode Cathode Application FerroGard is applied as an impregnation by spray, roller or brush onto the surface of the. The inhibitor penetrates into the and protects the reinforcement by forming a protective film on the steel surface. Through this the onset of is delayed and the rate of reduced. FerroGard is a clear colourless liquid which does not itself normally alter the aspect of fair-faced. (Check if used in conjunction with chemical cleaners). FerroGard penetrates to a depth of 25 to 40 mm in 1 month dependent on porosity of the. FerroGard reaches the surface of the steel through different transport mechanisms: During application of FerroGard transportation is mainly by capillary suction-like water FerroGard is later carried in solution by the penetration of water-like chlorides FerroGard also travels by gas diffusion-like carbon dioxide 2 I 3

3 Existing Conditions and Aggressive Influences on the Structure Reinforcement Protection Principles Using FerroGard New Construction Objectives and Requirements Principles Based on Remediation Techniques According to EN Performance and Durability New building/new e.g. high quality architectural without. The steel reinforcement is protected by the passivating alkalinity of the cement matrix, ph 12.5 to With the ingress of aggressive environmental influences, steel reinforcement can corrode. The will be carbonated or passivation broken down by penetrating chlorides. Increasing service life of structure Preservation of architectural aspects Preserving protection to reinforcement No s Corrosion protection will be increased by FerroGard from the beginning, even to surfaces with cracks or inadequate to cover over the reinforcement. Onset of Corrosion On set of Corrosion No further treatment Development of Doubling of the service life Avarage quality without FerroGard Avarage quality with FerroGard y = rate of y / ² = rate of No visible Increased protection Up to double the service life of the structure compared to unprotected structure Concrete properties and aspects will not be changed Well Advanced Corrosion Risk but no Corrosion Damage Concrete façade or civil engineering structure without. Steel reinforcement in a carbonated environment Perhaps light already exists No visible Crack Start of Carbonated Corrosion Damage. Concrete Repair Necessary Prevention maintenance Protection against possible Re-passivation of steel Long term protection against further environmental influences (carbonation, deicing salt, etc.) Increased resistivity 1. Application of FerroGard to protect reinforcement 2. Application of a Sikagard hydrophobic impregnation or Sikagard Development of Avarage quality without FerroGard Onset of Corrosion y = rate of Extension of service life y / ² = rate of Onset of Average quality after application of FerroGard New start after FerroGard application This is the last opportunity to protect reinforcement Corrosion process is retarded Increased protection Protection against water/moisture ingress (coatings/hydrophobic impregnations) Concrete surface (façade or civil engineering structure) without coating but with visible. e.g. spalling, cracks, etc., repair is necessary. Crack Carbonated Active maintenance Repair of d surfaces only Structurally sound carbonated/chloride contaminated remains Controlled breakout Re-passivation of steel Protection against the development of latent Prevent the possibility of incipient anode Long term protection against further environmental influences Concrete restoration Increased resistivity 1. Concrete repair using MonoTop system 2. Application of FerroGard to protect reinforcement 3. Application of a Sikagard hydrophobic impregnation or Sikagard Development of Concrete without FerroGard steel protection Onset of Corrosion Extension of service life Concrete with FerroGard steel protection Repair of d structure Reinstatement and protection of surface Protection against latent s Improved appearance No visible up to 10 years to next maintenance without coatings years to next maintenance with Sikagard coatings / hydrophobic impregnations 4 I 5

4 FerroGard Examples of Uses The Sika Qualitative Colour Test Kit for Penetration Depth testing Corrosion Rate Maintenance Monitoring System Courtesy of C-Probe Technologies Horizontal application Permeability Testing of Concrete Reinforced Corrosion Controls of Bridge Repair and Protection of Building Facades Repair and Protection Multi Storey Car Park Repair and Protection Concrete Silos Reinforced bridge structure Chloride induced to internal and external deck surfaces Localised Low cover to reinforcement Reduce active rates and maintain passive levels Control by anodic and cathodic principles Provide up to 10 years additional protection before next maintenance Testing to prove penetration of FerroGard to depth of reinforcement Clean surfaces Concrete repairs using e.g. MonoTop -612 or SikaCem 133 Gunite Application of FerroGard Application of e.g. Sikagard 700 S Hydrophobic Impregnation External precast cladding panels carbonated with local Chloride contaminated internal stairwells with local Low cover to reinforcement. Defective waterproof joints between panels Limit noise and dust around building Repair, control, enhance and protect Up to 15 years maintenance free period Maintenance monitoring system Re-sealing of cladding joints Clean surfaces Application of FerroGard Concrete repair with e.g. MonoTop -615 Application of e.g. MonoTop -620 Levelling mortar Application of e.g. Sikagard -550 W Elastic Application of e.g. Sikaflex AT Facade for movement joints Embedded probes for maintenance monitoring Reinforced decks with cracked and spalling Corrosion of reinforcement in carbonated and chloride contaiminated Reduce high and low rates by anodic, cathodic control and resistivity principles Repair cracked and delaminated and protect from future chlorides and carbonation Controlled beakout Minimum 10 years to next maintenance Cost effective solution Clean surfaces Application of FerroGard Concrete repairs and reprofiling with e.g. Rapid Repair Mortar Application of Protective Deck Coating System Application of e.g. Sikagard -675 W carbonation protective coating to soffits Cracked and spalled cladding panels with low cover to reinforcement Defective waterproof joints between panels Corrosion of reinforcement in carbonated and chloride contaminated Limit noise and dust Controlled breakout Short repair program Control of steel by anodic, cathodic and resisitivity principles Up to 15 years maintenance free period Re-sealing of cladding joints Depth of penetration and permeability assessment trials to prove suitability of FerroGard Clean surfaces Application of FerroGard Concrete repairs and reprofiling with e.g. MonoTop -615 light weight mortar Application of e.g. Sikagard -550 W Elastic anti-carbonation/ Application of e.g. Sikaflex AT-Connection for construction joints 6 I 7

5 Sika Worldwide Sika - Your Local Partner with a Global Presence The information, and, in particular, the recommendations relating to the application and end use of Sika products, are given in good faith based on Sika s current knowledge and experience of the products when properly stored, handled and applied under normal conditions. In practice, the differences in materials, substrates and actual site conditions are such that no warranty in respect of merchantability or of fitness for a particular purpose, nor any liability arising out of any legal relationship whatsoever, can be inferred either from this information, or from any written recommendations, or from any other advice offered. The proprietary rights of third parties must be observed. All orders are accepted subject to our current terms of sale and delivery. Users should always refer to the most recent issue of the Product Data Sheet for the product concerned, copies of which will be supplied on request. Sika Limited Head Office Watchmead Welwyn Garden City Hertfordshire AL7 1BQ Tel: Fax: sales@uk.sika.com Certificate No. EMS Certificate No. FM 12504