Takta sharif corrosiontakta.ir/en/wp-content/uploads/2014/07/Catalog.pdf · Takta sharif corrosion ... of corrosion assessment and protection of reinforced concrete ... European standard

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Takta sharif corrosion

Takta Sharif Corrosion Co.

Energy & Power Technology Incubator,

Niroo Research Institute,

West end of Sharif Dadman Blvd,

Shahrak Ghods, Tehran-Iran

Tel. +9821 8858 1982

Mob. +98912 385 0467

Fax. +921 8931 4999

E-mail: [email protected]

Web: www.takta.ir


mailto:[email protected]

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About us Unique Corrosion Mitigation Services along with Us.

Takta Sharif Corrosion (TSC) Company is a knowledge base company in the field

of corrosion evaluation and corrosion protection of different materials. This

company pioneers in the field of corrosion assessment and protection of reinforced

concrete structures. Design, installation and monitoring of cathodic protection

systems using sacrificial anodes on concrete structures have done by TSC for the

first time in Iran. The Company is proud to have carried out high-end projects with

significant results within allocated time frames. Safety, health and environmental

standards have always been high on our agenda. We are eager to develop our

activities and projects both in Iran and overseas.

Some of Takta sharif corrosion abilities one of follow:

1. Design of cathodic protection systems for corrosion mitigation.

2. Corrosion assessment and life-time estimation of concrete structures.

3. Providing protective coatings to prevent corrosion of steel systems.

4. Providing corrosion mitigation system for galvanic corrosion protection.

5. Providing corrosion protection systems based on using sacrificial anodes to

protect reinforced concrete structures.

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Certificates

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Double shield

The anticorrosion tape “Double Shield” is a new concept of technology based on a double

active-passive protection barrier. The product is a compound between two different layers of

material: a sacrificial anode as inner layer and a sealing membrane as outer layer. The result is a

unique and effective product that provides active protection to the metal surface that has to be

covered with, and a physical-chemical passive protection. “Double Shield” is a free solvent and

environmentally friendly. It is designed to protect permanently underground structures,

providing protection for the life-span of the same and virtually avoiding any future

maintenance.

The product “Double Shield” is a coupling between an electro-conductive adhesive laminar zinc

tape with the main purpose of active protection, and a self-adhesive membrane made from a

polymer- modified bitumen with a HDPE carrier foil that performs as external sealing, working

as a barrier for physical and chemical protection.

FEATURES

Active protection: is provided by the sacrificial action of the high purity laminated zinc (>99.95%)

by its electro- conductive adhesive which ensures a positive electric connections between the

metal substrate and the zinc so that it can act as a sacrificial galvanic anode.

Passive protection: is given by the top coat bonded to the zinc foil, this is composed of a membrane made from a polymer-modified bitumen with HDPE carrier foil which bonds in an excellent way to the zinc, sealing and protecting it against any external attack and any mechanical damages Chemical protection: the special composition of the outer coat provides a

resistance to all the aggressive substances that naturally occur in soils.

Services

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MAIN USES

“Double Shield” is used mainly for:

- underground pipes;

- steel pole for the public lighting;

- underground steel storage tanks;

- joining under-ground and above-ground steel structures

ACTIVPROTECTION

An anticorrosion protection by means of insulating coating (paintings, plastics, rubber and so on)

achieves exclusively a passive protection of the surface.

Double Shield coating with electro-conductive adhesive, represents an effective step ahead in the

technique of protection against spontaneous corrosion phenomena of whichever metal structure.

The Double Shield’s inner layer ensures a positive electrical connection between the metal

substrate and the zinc through the specially formulated electro-conductive adhesive.

The high dissolution tension of zinc tape and its fixing to the steel surface by means of binder in

the electro- conductive film permits, whenever in some areas there is a lack of coating or

whenever an electrolyte infiltrates between the metal structures and the zinc tape, the immediate

formation of a galvanic cell, in which, the zinc becomes an anode dissolving itself and protecting

the metal structure (cell cathode). In this case the product realizes an “active protection” of the

metal surface.

The complete homogeny and isotropy of the zinc lamina avoid, all along the superficial

development, the presence of variations of dissolution tension: it has a very low auto-corrosion

consumption.

TECHNICAL DATA OF PASSIVE

PROTECTION

Double Shield’s outer layer is a self-adhesive bituminous sealing membrane cold-

applied, that is a self- adhesive, flexible, crack-bridging made from polymer-modified

bitumen with HDPE carrier foil on one side.

It is used for underground structures permanently against ground moisture (capillary

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water, retained water) non-accumulating seepage water.

The self-adhesive bituminous sealing membrane with HDPE carrier foil affords

immediate resistance to water and driving rain, is flexible, tear-resistant and cold-

bending. It is environmentally friendly and is resistant to all aggressive substances that

occur in soils. It does not contaminate ground water.

Zinc Tape

Corrosion control made easy using zinc tape.

A zinc tape that provides a corrosion control solution to new and existing above ground plant and

transport system.

Economical many application

Easy to apply proven product

Long lasting

The product consists of a zinc tape of high purity (99.95% of the chemical mass of zinc) with a

nominal thickness of 0.080 mm.

This tape is supplied with an adhesive of a nominal thickness of 0.025 mm, which can resist

continuous operating temperature of 80◦C and which reacts under electro - conductive pressure.

The adhesive layer is covered by a silicone paper tape, which protects the band from getting

damaged or polluted until the tape is applied.

The product is available in two forms: on rolls, whose width and length are shown in the table

below in shapes, based on the client need

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Technical Description

The product is designed to cover the surface of iron, steel, aluminum and light metals in order to

product them from corrosion.

This is achieved by putting our product in contact, through proper pressure, with the surface that

needs to be protected from corrosion.

The adhesive coat, which is applied only on one side of the zinc tape, consist of a matrix of

adhesive and a percentage of zinc powder.

Through the addition of zinc powder, we have achieved the most important effect, which is making

the adhesive itself electro conductive.

This process allows the adhesive to create an electrical couple between the surface that needs to

be protected and the zinc tape, so that the zinc can act galvanic anode.

The diagram on the left shows the application of our zinc tape on a steel surface. It can be seen

that the thickness of the adhesive layer always remains the zinc granules are dispersed evenly

throughout the adhesive layer.

These granules are necessary to enable the adhesive to be electro conductive and to assure a

continuous metallic contact between zinc and steel.

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As a consequence of the unique manufacturing process and the high purity of the employed zinc,

the band has an absolutely homogeneous and isotopic microstructure, which cannot be found in

other protection systems. For this reason. The corrosion process is suppressed with no pitting or

any form of local corrosion attack.

The main features are:

Stopping any direct corrosion;

Active anticorrosive protection thanks to the electrical contact between the surface to be

protected and the zinc layer, which, in the presence of an electrolyte, reacts as a sacrificial

anode;

Presence of an adhesive layer, anchored on the surface to be protected, which is an additional

defense against corrosion,

The coating with a zinc layer assures cathodic protection of metallic surfaces for a time, that,

In most cases, is equal or longer than the lifetime of the structure to be protected.

Prevention of Galvanic Corrosion

The point of contact between light alloys and iron materials can be subjected to corrosion. When

these two materials get in both electrical and electrolytical contact, a galvanic process begins.

The lectrolytical contact arises when a solution (usually rain-water) seeps between the two

surfaces.

This contact can even be caused by moisture between the two surfaces or by a chemical non-

homogeneity of one of the two surfaces because of the presence of oxides, dirt, etc.

Since the electrochemical potentials of steel and iron materials are more electropositive than light

alloys. They can cause corrosion. Therefore light alloys become the sacrificial anode.

These problems can be avoided by means of insulating materials (generally made of plastic or

gum), which can be put between the two surfaces, in order to break the electrical and electrolytical

contact. But, since the insulating material dose not adhere well and since it wears out quickly,

protection against corrosion is no longer guaranteed. Such damage can even cause mechanical

problems, such that the two surfaces are no longer connected correctly.

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This will not happen when employing our zinc tape with electro-conductive adhesive.

Through our zinc coating in contact with iron surface, passive and active protection can be

achieved:

Passive protection due to the composition of the zinc coating and the adhesive, which adhesive

well avoiding any ingress.

Active protection because the difference of potential between the two surfaces decreases.

The potential of zinc is very similar to that of the light alloy and so the zinc tape acts as the

sacrificial anode instead of the light alloy.

TYPICAL APPLICATIONS

Advantage of zinc tape

- A particular cleaning of surfaces is not required

- No Primer required

- Guarantees a double protection compared to other treatments involving a

remarkable saving in the time

- Ensures a much longer life-span (from 1.4 to 2.0 times more) than that of

hot-dip galvanizing or other zinc coatings of the same mean thickness.

- It can be applied in multiple layers, whenever an extra-thick coating is

required

TRANSPORT INDASTRIAL PIPELINES BRIDGES

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- Enables those areas where the hot-dip galvanizing layer has been damaged

to be reconditioned.

- Many "onsite" applications

- Can be over painted

- No maintenance during the structure life

- Ideal for difficult access & dangerous structures

- Economical on long life structure

- Environmentally Friendly

Galvanic Anode

Galvanic Anode Cathodic protection (GACP)

A system utilizes anodes which generate a natural DC current to suppress the corrosion of the steel

in concrete.

The anodes are typically embedded within the concrete or repair mortar and are electrically

connected to the using galvanized ties.

As zinc is less noble than steel it means that the anode has a more electronegative potential than

the reinforcement steel. This makes the zinc the anode and the steel reinforcement the cathode.

Current will flow from anode to cathode inhibiting rebar corrosion thus avoiding concrete cracking

and spalling in the presence of chloride salts within the concrete.

The zinc anode will generate an electrical field whilst immersed in the electrolyte allowing

protective current to be discharged to the steel within the anode area of influence.

This allows a relatively small amount of anodes to be distributed within the structure thereby

reducing manpower requirements and costs if desired, performance can be monitored by on-site

personnel, according to the European standard EN 12696 “Cathodic protection of steel in

concrete”.

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APPLICATION

A) EXISTING STRUCTURES

In existing reinforced structures, CP is an integral part of the rehabilitation concept and is aimed

to decrease the corrosion rate of the steel reinforcement from significant to negligible values.

CP can be used independently irrespective of the chloride concentrations and in fact the electric

field will inhibit chloride ion migration towards the steel.

The re-passivation of the steel due to the different electrochemical reactions forced by the electric

field will make also positive contribution to the structures life span.

B) NEW STRUCTURES

New structures within aggressive environments can be provided with a CP system using a small

amount of DC current that is applied early in its service life.

This type of protection is called cathodic prevention and can be used for new reinforced concrete

structures, or existing structures in which the corrosion process is not yet initiated but corrosion

will most probably occur due to progressive ingress of aggressive electrolytes over time.

For new constructions cathodic prevention can be applied in an easy and simple way as the current

demand will be relatively low and therefore will be a low cost solution to achieve the design life

span of the structure.

RESIDENTIAL STRUCTURE APPLICATION

ZLA is provided in rolls (250mm wide by 25 meters long). After application ZLA should be

finished with an approved cementitious based coating of the specified texture and colour, ensuring

edges and seam are properly over coated to avoid moisture ingress. System monitoring can be

performed according to EN 12696.

INFRASTRUCTURE APPLICATION

Effectiveness: ZLA stops corrosion by placing steel in concrete in a protected cathodic state.

Stopping corrosion helps prevent concrete deterioration. Unlike impressed current systems, the

ZLA is fully self-powered and self-regulating, providing the proper current to maintain steel

polarization. It requires no external power source, no costly electrical work and minimal

monitoring.

Versatility: ZLA can be applied to the top, sides. Or bottom surfaces of concrete structures of

various shapes and any sizes.

Economics: ZLA requires minimal maintenance over its long life. If desired, performance can be

monitored easily by on-site personnel. With a 250 micron zinc layer the calculated life expectancy

will be 21 years. Upon request the anodes can be modified to achieve a life of 40 years plus.

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POLLANODE

Rollanodes anodes are designed for installation in pre-drilled holes in an existing concrete

structure. The electrolyte is sandwiched between the zinc layer rolls to give sufficient current

capacity with additional electrolytic paste added around the anode to maintain electrical continuity

within the concrete (the anode diameter is 25mm and available in lengths from 100mm to 1m).

Rollanodes are utilized in those areas where a high expectancy of corrosion is likely. They

guarantee a strong reduction of corrosion and prevent new locations from corroding the future.

Typical applications:

- Bridge or viaduct beam supports and columns

- Bridge decks

- Zones of newly cast concrete on an existing structure

- Balcony facings and concrete facades

- Flooring /decking

Rollanodes anodes are specifically designed for application in pre-drilled 30mm (minimum

diameter holes to depth corresponding to the anode length + 4-5cm)

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Number of projects

Takta sharif company has down deferent project in corrosive areas of Iran in the flowing table

some of this projects have been mentioned

Client Project Title Item

Hormozgan Regional Electric

Company

Improvement of Earthing

System on Power Transmission

Towers Using Cathodic

Protection of Reinforced

Concrete Foundation

1

Shahid Bahonar Kerman University Cathodic Protection of

Reinforced Concrete Structures 2


Company

Corrosion Assessment of

Concrete structures Using

Neural Network in Hormozgan

Transmission and Distribution

Power Lines

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Company

Corrosion Assessment of

Transmission Line Concrete

Structures and Exhibition of

Scientific and Practical

Methods for Corrosion

Prevention with Cathodic

Protection

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Payeh Beton Company

Prototype Manufacturing of

Corrosion Resistant Reinforced

Concrete Poles for Installation

on the Southern Coasts of the

Country

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Corrosion Assessment of Concrete structures Using Neural Network in

Hormozgan Transmission and Distribution Power Lines

Summary:

Concrete cathodic protection system are designed to overcome corrosion problems

in steel reinforced concrete. The major cause of corrosion in such structures is

presence of salt resulting from the application of de-icing chemicals exposure to

seawater or the use of contaminated aggregate.in the original concrete mixture.

When steel bars in concrete corrode, the formation of rust causes high internal

pressures. Tensile stresses are exerted on the surrounding concrete. Cracks

development will lead to delamination and spalling of the concrete. Cathodic

protection effectively stops the corrosion process and has been determined by the

Federal Highway Administration to be the only rehabilitation technique that is able

to prevent further corrosion in such structures regardless of the salt content in

concrete.

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Prototype Manufacturing of Corrosion Resistant Reinforced Concrete Poles

for Installation on the Southern Coasts of the Country

Summary:

The occurrence of corrosion in reinforced concrete in both coastal dry areas is a

universal problem. At present, it is indicated that for trusting to stability of concrete

structures, in addition to accuracy in force analysis and designation, it is necessary

to attention to durability and corrosion resistance of them. As the physical,

mechanical and chemical damages in concrete and reinforced concrete structures

cause a lot of problems in power industry.

The main target of this project was to investigate various corrosion prevention

methods for reinforced concrete poles that used in corrosive areas of country

especially southern coasts of Iran. Major mechanism of protection methods is barrier

against of attacking and penetrating corrosive ions. Due to the fact that more than

80% of structural degradation in reinforced concrete is caused by reinforcement

corrosion.

In this field, the reinforced concrete specimens have been prepared with different

protection methods and installed in boostano Research center to investigate

performance of protection in field and practical environment.

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Marketing and economical assessment of cathodic protection to corrosion

protection of reinforced concrete structures

Preparation of technical instructions to manufacture durable foundations

Project Documentation:

- Nonmetallic Department; Report of “Literature review” Chemistry &

Materials Research Center; NRI; Dec. 2004.

- Nonmetallic Department; Report of “Determination of deterioration

mechanism in selected structures”; Chemistry & Materials Research Center;

NRI; June 2005.

- Nonmetallic Department; Report of “Feasibility study of cathodic protection

to overcome corrosion of reinforced concrete structures”; Chemistry &

Materials Research Center; NRI; Dec.2005.

- Articles and papers related to the project.

- ASTM, BS, EN…standard related the project.

Reinforced concrete poles

The use of “corrosion Inhibitor” during the mixing process of concrete was

shown to be the most effective method for corrosion prevention in most of

corrosive areas.

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Takta sharif corrosiontakta.ir/en/wp-content/uploads/2014/07/Catalog.pdf · Takta sharif corrosion ... of corrosion assessment and protection of reinforced concrete ... European standard