How does Krystol affect corrosion of rebar
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Provides insights and solutions regarding corrosion of rebar.
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How does Krystol affect corrosion of rebar
- 1. HOW DOES KRYSTOL AFFECT CORROSION OF REBAR ALIREZA BIPARVA Research & Development Manager / Concrete Specialist Kryton International Inc. www.kryton.com
- 2. www.kryton.com WHAT IS CORROSION? Corrosion is a natural and costly process of destruction, like earthquakes and floods. but : • It is silent; and • Can be prevented or at least controlled.
- 4. www.kryton.com WHAT IS THE COST OF CORROSION? Corrosion is the main cause of damage and early failure of reinforced concrete structures. Makes up more than 80% of all damages of the reinforced concrete structures. In the United States alone, the total annual repair costs associated with concrete deterioration is estimated to be $300 billion. Nearly 95% of concrete damage in the GCC’s coastal region is caused by reinforcement corrosion and consequent spalling of concrete.
- 5. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? Concrete is one of the most widely used construction materials with many advantages such as: • Formability; • Durability; • High compressive strength‐Typical Compressive Strength: 20‐40 MPa; But • It is weak in tension ‐ Typical Tension Strength: 2‐5 MPa.
- 6. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.com
- 7. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.comwww.kryton.com
- 8. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.comwww.kryton.comwww.kryton.com Weight
- 9. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.comwww.kryton.comwww.kryton.comwww.kryton.com Weight Compression Tension
- 10. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.comwww.kryton.comwww.kryton.comwww.kryton.com
- 11. www.kryton.com WHAT IS THE SOLUTION? www.kryton.comwww.kryton.comwww.kryton.comwww.kryton.com Weight Tension Steel
- 12. www.kryton.com WHY STEEL IS NEEDED IN CONCRETE? www.kryton.comwww.kryton.comwww.kryton.comwww.kryton.com
- 13. www.kryton.com WHAT ARE THE REQUIRMENTS FOR CORROSION TO OCCUR? Iron (Fe) Oxygen Water Corrosion
- 14. www.kryton.com WHY DOES STEEL IN CONCRETE CORRODE? Due to the high‐alkalinity of concrete, the steel reinforcing bars are passivated by an iron oxide film (Fe2O3) that protects the steel. SO Concrete normally provides reinforcing steel with excellent corrosion protection. UNTIL The passive layer breaks down. Photo Courtesy of PCA
- 15. www.kryton.com WHY DOES STEEL IN CONCRETE CORRODE? Different systems such as chloride ions can break down this passivity and allow the steel to actively corrode. The Corrosion Cell
- 16. ww.kryton.com Steel Product Steel Corrosion Ore Mining Smelting Iron oxide Iron Un‐Stable Stable WHY DOES CORROSION OCCUR?
- 17. www.kryton.com WHY DOES CORROSION OCCUR? Iron oxide is the natural state of iron, and it is more thermodynamically stable.
- 18. www.kryton.com HOW DOES CORROSION AFFECT THE INTEGRITY OF A CONCRETE SRUCTURE? Products of corrosion (rust), occupy a greater volume than the original steel Staining, cracking, and spalling of the concrete This expansion creates tensile stresses in the concrete
- 19. www.kryton.com Cover Cracking and Spalling of the Concrete HOW DOES CORROSION AFFECT INTEGRITY OF A CONCRETE SRUCTURE?
- 20. www.kryton.com HOW DOES CORROSION AFFECT INTEGRITY OF A CONCRETE SRUCTURE?
- 21. www.kryton.com WHAT ARE THE STEPS ON DETERIORATION OF REINFORCED CONCRETE?
- 22. www.kryton.com WHAT IS THE PREMATURE CORROSION DETERIORATION?
- 23. www.kryton.com WHAT IS THE EFFECTIVE CORROSION CONTROL SYSTEM? Either • Extend the time to corrosion initiation; or • Reduce the corrosion rate of embedded steel; or • Both
- 24. www.kryton.com WHAT ARE THE STEPS OF DETERIORATION OF REINFORCED CONCRETE?
- 25. www.kryton.com WHAT ARE THE STEPS OF DETERIORATION OF REINFORCED CONCRETE?
- 27. www.kryton.com HOW CRACKING INFLUENCES CORROSION OF REBAR?
- 28. www.kryton.com WHAT ARE THE TYPICAL CORROSION PROTECTION SYSTEMS? Traditional measures to mitigate corrosion are: • Cathodic Protection • Corrosion Inhibitor admixtures • Anti‐corrosion coating And • Using less permeable and durable concrete
- 29. www.kryton.com HOW TO CONSTRUCT DURABLE STRUCTURES? The penetration of water into concrete is a critical factor in the corrosion of steel reinforcement. • Water acts as a carrier for chloride ions, and • Water is required for corrosion to occur. Therefore, the first line of defense against corrosion is to prevent the penetration of water into the concrete.
- 30. www.kryton.com With the exception of mechanical damage, all the adverse influence on durability involve the transport of fluids through the concrete. (Properties of Concrete, Neville) Water Permeability determines the rate of deterioration Service life - Durability HOW TO CONSTRUCT DURABLE STRUCTURES?
- 31. www.kryton.com Concrete is a hard material with a network of openings (capillaries, pores, cracks and micro cracks) Water can pass through unprotected concrete Water can directly damage concrete (Freeze – Thaw). Water acts as a carrier of aggressive chemicals (Chloride). HOW TO REDUCE PERMEABILITY OF CONCRETE?
- 32. www.kryton.com Sheet membranesFluid-applied membranes Membrane forms a barrier against water penetration Membrane HOW TO REDUCE PERMEABILITY OF CONCRETE?
- 33. www.kryton.com Traditional waterproofing system apply a barrier to the concrete Alternative: Make the concrete the barrier HOW TO REDUCE PERMEABILITY OF CONCRETE?
- 34. www.kryton.com Admixture can replace the need for external waterproofing membranes HOW TO REDUCE PERMEABILITY OF CONCRETE?
- 35. www.kryton.com Crystalline waterproofing as an admixture (KIM) was invented and pioneered by Kryton during the 1980’s. Powdered form: • Added into the concrete mix at 2% of the cementitious content • Added directly to ready mix truck or at the batch plant • Effective against hydrostatic pressure WHAT IS INTEGRAL CRYSTALLINE WATERPROOFING?
- 36. www.kryton.com Regular Concrete ICW Concrete HOW TO CONSTRUCT DURABLE STRUCTURES?
- 37. www.kryton.com Crystallization Reduce Shrinkage cracking Reactive Improve SS Water Concrete ICW HOW DOES KIM AFFECT WATER PENETRATION?
- 38. www.kryton.com HOW TO SELECT THE BEST SOLUTION? Long Term Hawaii Study Which product is best to do the job of protecting your steel from corroding? A long‐term field exposure study was conducted (2002‐2012) to evaluate the durability of reinforced concrete specimens exposed to an aggressive marine environment.
- 39. www.kryton.com
- 40. www.kryton.com Twenty five reinforced concrete panels containing various: • Pozzolans; and • chemical admixtures; were exposed to a marine environment. HOW TO SELECT THE BEST SOLUTION? Long Term Hawaii Study
- 41. www.kryton.com HOW TO SELECT THE BEST SOLUTION? Long Term Hawaii Study Corrosion Inhibitor Control Waterproofing admixture (densifier) Kryton (KIM)
- 42. www.kryton.com HOW TO SELECT THE BEST SOLUTION? Long Term Hawaii Study The key findings in the reports are as follows: • The panel using KIM outperformed all other chemical admixtures. • KIM panel showed significant reduced half‐cell reading when compared with the control specimen. • In addition, after 10 years exposure, KIM panel does not have any signs of corrosion.
- 43. www.kryton.com HOW DOES KIM AFFECT CORROSION OF REBAR? KIM Self‐Sealing Crystallization Reduce Permeability Cont. Heat of Hydration Control Bleeding Reduce Cracking Inhibit Water and Chemical Penetration Extend Initiation Reduce Corrosion Rate Reduce Corrosion of Rebar
- 45. www.kryton.com THANK YOU FOR ATTENDING A wealth of presentations and reports are available at www.middleeastconcrete/presentations PLEASE DON’T FORGET TO COLLECT YOUR ATTENDANCE CERTIFICATE