Corrosion of rebar is a major cause of damage to reinforced concrete structures. It occurs when water and oxygen penetrate the concrete and reach the rebar. Kryton's crystalline waterproofing admixture, called KIM, can significantly improve the durability of concrete structures and protect rebar from corrosion by reducing permeability. A long-term field study in Hawaii found that concrete containing KIM performed significantly better than alternatives, with no signs of corrosion even after 10 years of exposure to marine conditions. By sealing cracks and pores through crystallization, KIM is able to self-seal concrete and inhibit the penetration of water and chemicals that can cause rebar corrosion.

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.

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WHAT IS CORROSION?
ASTM defines corrosion as:
The chemical or electrochemical reaction between
a material and its environments
that produces a deterioration of the material.

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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.

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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.

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WHY STEEL IS NEEDED IN CONCRETE?
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WHY STEEL IS NEEDED IN CONCRETE?
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WHY STEEL IS NEEDED IN CONCRETE?
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Weight

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WHY STEEL IS NEEDED IN CONCRETE?
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Weight
Compression
Tension

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WHY STEEL IS NEEDED IN CONCRETE?
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WHAT IS THE SOLUTION?
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Weight
Tension Steel

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WHY STEEL IS NEEDED IN CONCRETE?
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WHAT ARE THE REQUIRMENTS FOR CORROSION
TO OCCUR?
Iron (Fe)
Oxygen Water
Corrosion

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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

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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

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Steel
Product
Steel
Corrosion
Ore
Mining
Smelting
Iron oxide
Iron Un‐Stable
Stable
WHY DOES CORROSION OCCUR?

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WHY DOES CORROSION OCCUR?
Iron oxide is the natural state of iron, and it is more
thermodynamically stable.

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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

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Cover Cracking and Spalling of the Concrete
HOW DOES CORROSION AFFECT INTEGRITY OF A
CONCRETE SRUCTURE?

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HOW DOES CORROSION AFFECT INTEGRITY OF A
CONCRETE SRUCTURE?

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WHAT ARE THE STEPS ON DETERIORATION OF
REINFORCED CONCRETE?

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WHAT IS THE PREMATURE CORROSION
DETERIORATION?

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WHAT IS THE EFFECTIVE CORROSION CONTROL SYSTEM?
Either
• Extend the time to corrosion initiation; or
• Reduce the corrosion rate of embedded steel; or
• Both

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WHAT ARE THE STEPS OF DETERIORATION OF
REINFORCED CONCRETE?

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WHAT ARE THE STEPS OF DETERIORATION OF
REINFORCED CONCRETE?

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A crack is a direct path for corrosive agents to penetrate and reach the steel.
An experiment performed in the Middle East found that concrete exposed to hot
climates had significantly higher permeability and up to a 70% reduction in the time
to corrosion‐induced‐cracking compared to concrete exposed to moderate
conditions.
The loss of durability was attributed to micro‐cracking due to thermal cycling, which
was designed to simulate a hot, Middle Eastern climate.
HOW CRACKING INFLUENCES CORROSION OF REBAR?

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HOW CRACKING INFLUENCES CORROSION OF REBAR?

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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

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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.

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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?

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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?

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Sheet membranesFluid-applied
membranes
Membrane forms a barrier against water penetration
Membrane
HOW TO REDUCE PERMEABILITY OF CONCRETE?

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Traditional waterproofing system apply
a barrier to the concrete
Alternative:
Make the concrete the barrier
HOW TO REDUCE PERMEABILITY OF CONCRETE?

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Admixture can replace the need for external
waterproofing membranes
HOW TO REDUCE PERMEABILITY OF CONCRETE?

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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?

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Regular Concrete
ICW Concrete
HOW TO CONSTRUCT DURABLE STRUCTURES?

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Crystallization
Reduce Shrinkage
cracking
Reactive
Improve SS
Water
Concrete
ICW
HOW DOES KIM AFFECT WATER PENETRATION?

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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.

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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

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HOW TO SELECT THE BEST SOLUTION?
Long Term Hawaii Study
Corrosion
Inhibitor
Control
Waterproofing
admixture (densifier)
Kryton
(KIM)

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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.

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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

44. THANK YOU
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