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International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin Sc.D. International Zinc Association Durham, NC USA

Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

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Page 1: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Production Technology and Performance of Corrosion-Resistant

Zinc-Coated Rebar

Frank E. Goodwin Sc.D.International Zinc Association

Durham, NC USA

Page 2: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Production of Rebar by General Galvanizing

Page 3: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

General Galvanized Coating

3

125 μm Coating(915 g/m2)

______

______

Page 4: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

General Galvanized Rebar Products

Straight bars

Mesh

Stirrups and ties

Page 5: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Effect of galvanizing on grades of reinforcing steel

Page 6: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Effect of General Galvanizing on Mechanical Properties of Carbon Steels

Degrease 3 minutes, Pickle 18.6% HCl 50 minutes, Flux 25 minutes, Zn dipping 2.5 minutes

Page 7: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Surface preparation

Induction Heater

Zinc / zinc alloy trough Black, uncoated

rebar from mill

Air knife

Pre-heat

Galvanizing

Shot Blasting

Spray-On Flux

In-Line Rebar Galvanizing Process

Galvanized rebar

Page 8: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

In-Line Galvanized Coating

60 μm Coating

Zinc Layer

SmallFe2Al5-xZnx

Layer

Page 9: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

CGR Galvanizing Section at Supergalvanising, Dubai

Page 10: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Some details of the In-Line Process

• Blasting with S330-S280 steel shot

• Rinse in water to remove dust

• Optional short pickling in 11% HCl

• Flux in Ferrotech G-Flux-R at a target SG of 1.7-1.8

• Dry using high frequency induction heating to heat only a thin outer part of the rebar (200 KW per rebar is typical)

• Galvanizing in flooded tube for 1.8m, pumped from 35T kettle (for 8 rebars capability) 0.2%Al in Zn bath

• Control coating with gas wiping ring

• Line speed maximum 22 m/min

Page 11: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Excellent ductility of in-line coating

Page 12: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Excellent bending, galvanized and galvanized + epoxy

Page 13: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Bond Strength in Concrete

Page 14: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Results of 88h of Salt Spray Testing

Page 15: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Xiamen Newsteel Metal Products Co., LtdSalt Spray Test

Epoxy resin coatedsteel rebar

Zinc alloy coatedsteel rebar

Zinc+epoxy compositecoated rebar

Quantity 3 3 3

Dimensions, mm

14mm D x 25 cm L 14mm D x 25 cm L14mm D x 25 cm L

Surface finish

Make three man-made 3 mm diameter defects holes on each side ofthe rebar, the hole should penetrate the coating and reach to the steelbase, the holes located between ribs.

Neutral Salt spray test

Test solution:Concentration 5% Nacl solutionPH=6.8Test temperature: 35±Sample placement: Sample tilted 20 degrees from vertical, defect holestowards the cabinet side, after 24 hours continuous spray check samplesurface respectively.

Test result

1. After 24h, epoxy resin coated steel rebar corroded seriously (redrust) at defect hole area, epoxy coating loss of adhesion to rebar2. After 24h, zinc alloy coated rebar shows white rust corrosion but nored rust (steel attack).3. After 24h, zinc+epoxy composite coating show slight red rust inhole, no loss of adhesion of epoxy.

Page 16: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Page 17: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Final Report on 100-Year Bridge Research Program

Florida Atlantic University

About 11 years of exposure

Page 18: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Coated Concrete

Block

Upper Level

Reinforcement

Bottom

Reinforcement

(2)

Electrical Circuitry

for Potential and

Macro-Cell Current

Measurements

Salt Water

Bath

Exposed

Concrete

within Bath

ASTM G-109 Sample

Page 19: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Potential evolution of GV and BB bars with FA41 concrete, using standard sample

Potential evolution of GV and BB bars with CT41 concrete, using bent bars

Page 20: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Rebar Corrosion Model

Page 21: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Zn (eta) phase current density = 2.38 A/cm2 ( ______ line)Zeta (Zn-Fe) phase current density = 3.98 A/cm2 ( _ _ _ line)Therefore Zn 1.7 times more corrosion resistant than Zn-Fe in the concrete corrosion cell

pH=13NaOH

How does the 50 μm In-Line coating corrosion resistance compare to the 125μm General Galvanized coating? Results of potentiodynamic polarization tests

Page 22: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

In the 125 μm general galvanized coating, the Zn layer is 52 μm and the ZnFe layers are 73 μm. The ZnFe

layers contribute the same as an additional 42 μm of Zn layer protection (Total is same as 92 μm Zn)

125 μm coating

Page 23: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Sydney Opera House, Sydney, Australia

• Work started in 1958, with 10,000 builders employed, and

opened in 1973

• Commissioned by the Queen of England 3,000 events annually

• Precast concrete shells reinforced with galvanized wire mesh.

Shells corrosion free for 42 years

• Foundation has been refurbished twice due to uncoated rebar

use

Page 24: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Lincoln Road Parking Garage, Miami, Florida

• Designed by Swiss firm Herzog & de Meuron, which also

designed Beijing's famed "Bird's Nest" Olympic Stadium

• 7 Story structure built with galvanized concrete

reinforcement in the slabs, columns, and ramps

• Juvia is a 10,000 sq/ft Asian restaurant and lounge on the

penthouse level

Page 25: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Brazil Museum of Art, Rio De Janeiro, Brazil

• “MAR” opened in 2013

• “MAR” design combined two adjacent structures Dom Joao

Palace and Police station into one new use structure

• 320 cubic meters of concrete and 70 tons of galvanized rebar

were used to construct the adjoining roof

Page 26: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Lotus Temple, New Delhi, India

• Design inspired by the lotus flower, and the structure is

surrounded by 9 ponds and completed in 1986

• The façade is marble

• The reinforcements used in the white concrete shells and the

binding wires were entirely galvanized to prevent the long-term

rusting of the reinforcement and staining the white concrete

Page 27: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Longbird Bridge, Bermuda

• Built by the US Navy and completed in 1953

• Extreme harsh environment (warm sea water)

• Deck is reinforced with galvanized rebar

• Rebar was inspected in 1984 with 98% of the galvanized

rebar in perfect condition

• Now 62 years old with no rebar maintenance necessary

Page 28: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Route 66 Bridge, Kittanning, Pennsylvania

• Built in 1973

• Concrete deck reinforced with galvanized rebar

• Median barrier wall upgraded in 2003 for safety reasons and

rebar was inspected

• Galvanized rebar in near perfect condition after 30 years

• Now 42 years old with no rebar maintenance necessary

Page 29: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Cape Town Sea Wall, Cape Town, South Africa

• 85 year old sea wall and popular tourist attraction

• “AKA” Sea Point promenade

• Side by side section (Built in 1990) below shows standard

rebar vs. Galvanized rebar performance

Page 30: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Shenzhen Metro Line No. 11, Shenzhen, China

• Currently under construction

• Opening later this year

• Fastest Metro line in Shenzhen with speeds of 120 km/h

• Galvanized rebar is being produced by Xiamen Newsteel

Page 31: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

G7 Beijing–Ürümqi Expressway

Connects the cities of Beijing, China, and Ürümqi, Xinjiang. When complete, it will be 2,540 km (1,580 mi) in length.Galvanized rebar is being produced by Xiamen New Steel

Page 32: Production Technology and Performance of Corrosion ... · International Zinc Association Production Technology and Performance of Corrosion-Resistant Zinc-Coated Rebar Frank E. Goodwin

International Zinc Association

Conclusions

• Both General Galvanized and In-Line Galvanized rebar will greatly extend the service life of reinforced concrete

• The production technologies for both products are settled

• The bond strengths of uncoated and galvanized rebar are equivalent

• New construction products will benefit greatly from Zn-protected rebar