Recommended
More Related Content
What's hot
What's hot (20)
Similar to Corrosion resistance in building
Similar to Corrosion resistance in building (20)
Recently uploaded
Recently uploaded (20)
Corrosion resistance in building
- 1. CORROSION RESISTANCE IN BUILDING By: Giri Prasad Gurunathan B. Tech Civil (16TA2208) ACET
- 2. What is corrosion? • The chemical or electrochemical reaction between a material and its environment that produces a deterioration of the material and its properties
- 3. Due to corrosion !! • There is no single figure for loss to the nation due to corrosion. • It can be a minimum of 3.5% of the nation's GDP. • Losses due to corrosion could be around Rs. 2.0 lakh crores per annum in India
- 4. Forms of Corrosion • General Identified by uniform formation of corrosion products that causes a even thinning of the substrate steel • Localized Caused by different in chemical or physical condition between adjoining sites • Bacterial Caused by formation of bacteria with an affinity for metals on the surface of the steel • Galvanic Cased when two dissimilar metals come in contact
- 5. Factors Influencing Corrosion The nature and extent of corrosion depend on the metal and the environment. The important factors which may influence the corrosion process are (i) Nature of the metal (ii) Environment (iii)Concentration of electrolyte (iv) Temperature (v) Electrode potential and (vi) Hydrogen over voltage
- 6. Concrete and Mortar • Concrete and mortar is a mixture of... •Portland Cement •Aggregates •Water •Admixtures
- 7. Properties of cement-based materials •Structure •Chemical reactivity
- 8. Structure of cement-based materials • Gel pores in CSH-Cluster • Capillary pores between the Cluster Pores 1. Compacting pores (comp) 2. Air pores (entraining) 3. Capillary pores (w/c) 4. Gel pores (Hydration)
- 9. Carbonation of reinforced concrete • Brief historical abstract •1879 Cement cover prevents iron from oxidizing (rust) •1908 Realization that the alkaline ambience prevents this corrosion • 1916 “Corrosion of highly importance because of security reasons “ •1919 1.5 cm cover concrete shall be enough to prevent
- 10. Volume Change of rod
- 12. TYEPS OF CORROSION • There are basically eight types of corrosion I. Uniform corrosion II. Pitting corrosion III. Trans granular and Intergranular (Intercrystallite ) corrosion IV. Exfoliation corrosion V. Stress corrosion
- 13. Concrete: Rebar Corrosion (Step)
- 14. Methods of Corrosion Control • Barrier Protection Provided by a protective coating that acts as a barrier between corrosive elements and the metal substrate • Cathodic Protection Employs protecting one metal by connecting it to another metal that is more anodic, according to the galvanic series • Corrosion Resistant Materials Materials inherently resistant to corrosion in certain environments
- 15. Barrier Protection • Paint • Powder Coatings • Passive film
- 16. Cathodic Protection • Impressed Current (source of direct current power) • Galvanic Sacrificial Anode (an active metal placed in contact with the corrosive environment and are electrically connected to the structure) • Galvanic Zinc Application 1. Zinc Metallizing (plating) 2. Zinc-rich Paints 3. Hot-dip Galvanizing
- 17. Corrosion Resistant Materials • Four Types of Metal That Are Corrosion Resistant or Don’t Rust 1.Stainless steel 2.Aluminum metal 3.Copper, bronze or brass 4.Galvanized steel
- 18. Queries???