Atmospheric Corrosivity on Infrastructures in Hong Kong

Atmospheric Corrosivity on Infrastructures in Hong Kong

1

The Hong Kong Polytechnic University

2

Chinese National Engineering Research Centre

For Steel Construction (Hong Kong Branch)

Innovation and Technology Commission,

The Government of Hong Kong SAR

3

4

Outline

1. Introduction of CNERC

2. Project Overview

3. Atmospheric Corrosivity Field Tests

4. International Collaboration

5

Introduction of CNERC

6

1.Introduction of CNERC

Mission of Hong Kong Branch

In order to enhance the socio-economic developments of Hong Kong

through technological advancement, the Hong Kong Branch of CNERC

for Steel Construction should be established as a high-level

technological platform to promote effective design and construction,

management and quality assurance.

7


Objectives

• To promote effective design and construction as well as sustainable

infrastructure development with enhanced durability.

• To promote export of professional services in structural steelwork.

8


Collaborative research with Imperial College London, Tongji University,

and Tsinghua University.

Strategic professional collaborators include the Construction Industry

Council in Hong Kong, and the Steel Construction Institute, U.K..

9


Challenges of Chinese Steel Construction Industry

Year

Steel production (million metric tons）

Australia China Japan U.K. U.S.A.World

production

1980 7.6 37.1 111.4 11.3 101.5 568.5

1990 6.7 66.4 110.3 17.8 89.7 616.0

2000 7.1 128.5 106.4 15.2 101.8 848.9

2013 4.6 779.0 110.6 11.9 87.0 1582.5

China 49.2%

U.K.0.8%

Japan7.0%

Australia 0.3%

U.S.A.5.5%

Others37.2%

Steel production of

5 countries of interest

in 2013

10


CNERC Overview

Chinese Steel Construction Industry

Supported by CIC

CNERC for Steel Construction (HK)PolyU

Promoting sustainable

infrastructure

development in

Hong Kong

Promoting export of Chinese

Steel Construction Industry

through

Hong Kong Construction

Professionals

Promoting advanced

structural engineering in

modern steel construction

11


CNERC Overview

Hong Kong Construction Industry Chinese Steel Construction Industry

International Engineering Design Centre for Infrastructures

International Engineering Construction Centre for Infrastructures

CNERC for Steel Construction (HK)PolyU

12


CNERC Overview

13

Project Overview

14

2.Project Overview

Work Theme A： Sustainable infrastructure development

Atmospheric corrosivety of exposed structural steelwork

Background

• To confront potential durability problems of the infrastructures in Hong

Kong, it is essential to investigate and understand various controlling

mechanisms in corrosion in exposed structural steelwork.

• Therefore, atmospheric corrositivity of exposed structural steelwork under

local environments in Hong Kong are to be examined.

15

2.Project Overview


Feasibility, expected economic benefits and positive impact

• Current corrosion engineering technology and protection methods to

both reinforced concrete structures and steel-concrete composite

structures.

• Prediction, assessment and protection methods should be developed

under the Hong Kong context.

• Effective implementation of corrosion engineering technology for

sustainable infrastructure development among construction

professionals.

This will bring tremendous economic benefits to Hong Kong as a whole.

Savings on long-term maintenance expenses on residential buildings,

commercial offices and public buildings as well as roads, highways,

railways, tunnels, bridges and ports facilities will be enormous.

16

2.Project Overview


Objectives

⚫ Study the atmospheric corrosivity in local areas in Hong Kong.

Collect local data for Hong Kong site in different areas.

⚫ To compare with predicted corrosion rates to ISO/DIS 9223 and

9224 based on measured climate data.

⚫ To assess corrosion resistances of steel plates with different

corrosion protection systems, such as bare steel plates,

galvanized zinc coating produced by the conventional and the

proposed innovative galvanization processes in outdoor

conditions.

⚫ A corrosion map for the entire Hong Kong will be developed to

establish annual corrosion rates for durability assessment.

17

Atmospheric Corrosivity Field Tests

18


Objectives

⚫ To expose steel plate specimens with different corrosion protection

systems to the atmosphere in rural, urban, industrial and costal areas in

Hong Kong.

⚫ The tests will last for 1 year, starting at the beginning of the worst

corrosive period of the year, i.e. June to July

⚫ Monthly photo record for subsequent image processing analysis.

⚫ Final evaluation of results by photo recording and estimation of mass loss.

⚫ Calculated corrosion rates according to ISO/DIS 9223 and 9224 will be

verified against the measured results of atmospheric corrosion tests.

⚫ A similar test was carried out by Environmental Protection Department at

one location in Hong Kong from 2002 to 2003.

19


ISO/DIS 9223 and 9224: Step 1

20


ISO/DIS 9223 and 9224: Step 2

21


Monitoring stations of Environmental

Protection Department, Hong Kong SAR

Kwun Tong

Central &

Western District

Yuen Long

Data of SO2 concentration

& Cl- deposition

22


SO2 concentration & Cl⁻ deposition

• Yuen Long monitoring station is 3300m from the sea, i.e. inland.

0

10

20

30

40

50

60

00 01 02 03 04 05 06 07 08 09

SO

2C

on

ce

ntr

ati

on

(mg

/m3)

Date (year)

Monthly average

Annual average

SO2Yuen Long

0

20

40

60

80

100

120

140

160

00 01 02 03 04 05 06 07 08 09

Cl-

Dd

y d

ep

osit

ion

(m

g/m

2d

ay)

Date (year)

Monthly average

Annual average

Cl-Yuen Long

23


SO2 concentration & Cl⁻ deposition

• C&W District monitoring station is 630m from the sea, i.e. coastal.

0

10

20

30

40

50

60

00 01 02 03 04 05 06 07 08 09

SO

2C

on

ce

ntr

ati

on

(mg

/m3)

Date (year)

Monthly average

Annual average

SO2C&W District

0

20

40

60

80

100

120

140

160

00 01 02 03 04 05 06 07 08 09

Cl-

Dd

y d

ep

osit

ion

(m

g/m

2d

ay)

Date (year)

Monthly average

Annual average

Cl-C&W District

24


Monitoring stations of Hong Kong Observatory

Tseung Kwan O

Victoria Peak

Lau Fau Shan

Data of temperature &

relative humidity

25


Temperature and relative humidity

0

10

20

30

40

50

60

70

80

90

100

98 99 00 01 02 03 04 05 06 07 08 09 10 11

Me

an

Air

Te

mp

era

ture

oC

/ M

ea

n R

ela

tive

Hu

mid

ity %

Year (Monthly-Yearly Average)

Monthly Mean Air Temperature Monthly Mean Relative Humidity

Yearly Mean Air Temperature Yearly Mean Relative Humidity

Lau Fau Shan

26


ISO/DIS 9223 and 9224

YearCorrosion rate in the first year, Rri (mm/year)

Central & Western District

Yeung Long

2001 3.1 2.0

2002 3.4 2.0

2003 3.3 2.1

2004 3.0 2.1

2005 2.9 2.0

2006 3.0 2.0

2007 2.9 1.9

2008 2.8 1.6

• A corrosion rate of 3.4mm/year in the first year implies an accumulated corrosion attack of 85mm in 50 years of exposure.

27


0

50

100

150

200

0 10 20 30 40 50

Acc

um

ula

ted

co

rro

sio

n

atta

ck, T

ri(m

m)

Exposure time, t (year)

Accumulated corrosion attack of zinc

C&W District

Yuen Long

012345678

0 10 20 30 40 50

An

nu

al r

ate

of

co

rro

sio

n a

ttac

k, R

ri

(mm

/ye

ar)

Exposure time, t (year)

Annual rate of corrosion attack of zincC&W DistrictYuen Long

• This demonstrates that the current provision of 85mm is only sufficient for 20 years, but not 50 years!

85

20

28


Requirements on test sites

⚫ A storage rack of 900mm (L) x 800mm (W) x 900mm (H) will be

placed at an outdoor area that is inaccessible to the public.

⚫ The storage rack should not be sheltered by plants or buildings in

the vicinity. It should be far away from a ventilation system, a cooling

tower or any other machinery.

⚫ Access by working staff to take photos and inspection of the

specimens every three months should be allowed.

29


Different types of locations for field tests

LA

G,H

D

E

JK

M

B

C

Site LocationAtmospheric

condition

ACentral and Western District

EPD Air quality monitoring stationUrban

BYuen Long

EPD Air quality monitoring stationSuburb

CYuen Long

Yau Sang FactoryIndustrial

DTiu Keng Leng

G.T. (Ellen Yeung) CollegeUrban

ETseung Kwan O

Evangel CollegeSeafront

FTung Chung

EPD Air quality monitoring stationSeafront

GCentral and Western District

Sun Yat Sen Memorial Park

Sports CentreSeafront

Waiting for approval

HCentral and Western District

Sun Yat Sen Memorial ParkSeafront

ISai Kung

The Hong Kong University of

Science and TechnologySeafront

JHung Hom

The Hong Kong Polytechnic

UniversityUrban

To be confirmed

KTsim Sha Tsui

Hong Kong Museum of ArtSeafront

LTamar

Central Government OfficesSeafront

M Kwai Chung Seafront

I

F

30


A) C&W EPD Air Quality Monitoring Station

A


condition



31




condition



Photo taken on 31 May 2017

32




33



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness

(mm)Weight (g) Coating Thickness (um) Start Date

A1(0) Steel 150.33 60.52 3.00 211.86 - 16 May 2017

A2(0) Steel 150.70 60.42 2.95 208.77 - 16 May 2017

A3(0) Steel 150.72 60.57 2.98 212.24 - 16 May 2017

A1(1) Zinc 151.42 61.58 3.02 196.11 - 16 May 2017

A2(1) Zinc 150.82 61.52 3.03 196.65 - 16 May 2017

A3(1) Zinc 152.33 60.77 3.01 196.76 - 16 May 2017

A1(2)Conventional

Galvanization151.67 60.53 6.18 433.40 105.8 31 May 2017

A2(2)Conventional


A3(2)Conventional


34


B) Yuen Long EPD Air Quality Monitoring Station


condition

BYuen Long


B

35




condition

BYuen Long



36




37



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness


B1(0) Steel 150.47 60.47 3.00 210.85 - 16 May 2017

B2(0) Steel 150.73 60.55 3.00 211.72 - 16 May 2017

B3(0) Steel 150.42 61.47 2.99 209.88 - 16 May 2017

B1(1) Zinc 150.65 61.55 3.00 195.70 - 16 May 2017

B2(1) Zinc 150.88 60.63 2.99 193.58 - 16 May 2017

B3(1) Zinc 150.47 59.88 2.99 190.34 - 16 May 2017

B1(2)Conventional


B2(2)Conventional


B3(2)Conventional


38


C) Yuen Long YauSang Factory


condition

CYuen Long


C

39




condition

CYuen Long



40




41



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness


C1(0) Steel 150.70 60.53 2.98 206.96 - 16 May 2017

C2(0) Steel 150.75 60.53 2.99 208.54 - 16 May 2017

C3(0) Steel 150.17 60.50 2.99 210.69 - 16 May 2017

C1(1) Zinc 150.48 60.18 3.03 191.05 - 16 May 2017

C2(1) Zinc 150.20 60.40 3.01 191.88 - 16 May 2017

C3(1) Zinc 150.77 59.90 3.00 190.81 - 16 May 2017

C4(2)Conventional


C5(2)Conventional


C6(2)Conventional


42


D) Tiu Keng Leng G.T. (Ellen Yeung) College


condition

DTiu Keng Leng


D

43




condition

DTiu Keng Leng


Photo taken on 22 June 2017

44




45



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness


D1(0) Steel 150.40 60.53 2.95 205.96 - 22 June 2017

D2(0) Steel 150.27 60.33 2.98 210.15 - 22 June 2017

D3(0) Steel 150.53 60.50 2.95 209.47 - 22 June 2017

D1(1) Zinc 150.32 60.00 3.00 190.13 - 22 June 2017

D2(1) Zinc 150.73 59.53 2.98 188.76 - 22 June 2017

D3(1) Zinc 151.08 60.45 3.00 192.56 - 22 June 2017

D1(2)Conventional

Galvanization150.37 61.42 6.15 434.56 120.2 22 June 2017

D2(2)Conventional


D3(2)Conventional


46


E) Tseung Kwan O Evangel College


condition

ETseung Kwan O


E

47




condition

ETseung Kwan O



48




49



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness


E1(0) Steel 150.53 60.40 2.95 207.58 - 22 June 2017

E2(0) Steel 150.65 60.45 2.94 208.25 - 22 June 2017

E3(0) Steel 150.67 60.40 2.98 210.99 - 22 June 2017

E1(1) Zinc 150.17 60.27 3.01 191.27 - 22 June 2017

E2(1) Zinc 150.32 59.88 3.01 191.99 - 22 June 2017

E3(1) Zinc 150.38 60.45 2.99 192.40 - 22 June 2017

E1(2)Conventional


E2(2)Conventional


E3(2)Conventional


50


F) Tung Chung EPD Air Quality Monitoring Station


condition

FTung Chung


F

51




condition

FTung Chung


Photo taken on 17 July 2017

52



Photo taken on 17 July 2017

53



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness


F1(0) Steel 150.73 60.27 2.96 210.97 - 17 July 2017

F2(0) Steel 150.50 60.50 2.95 209.20 - 17 July 2017

F3(0) Steel 150.67 60.48 2.94 206.75 - 17 July 2017

F1(1) Zinc 150.43 60.83 3.13 193.30 - 17 July 2017

F2(1) Zinc 150.35 59.72 3.08 189.68 - 17 July 2017

F3(1) Zinc 150.55 59.93 3.04 191.31 - 17 July 2017

F4(2)Conventional

Galvanization150.40 61.32 6.18 435.63 136.0 17 July 2017

F5(2)Conventional


F6(2)Conventional


54


G) Sun Yat Sen Memorial Park Sports Centre

G


condition




55


G) Sun Yat Sen Memorial Park Sports Centre Site LocationAtmospheric

condition




Photo taken on 21 September 2017

56



Photo taken on 21 September 2017

57



Specimen

InformationType

Length

(mm)

Width

(mm)

Thickness

(mm)Weight (g)

Coating

Thickness (um)Start Date

H1(0) Steel 150.77 60.57 2.95 209.57 - 21 September 2017



H1(1) Zinc 150.35 59.98 2.98 190.42 - 21 September 2017

H2(1) Zinc 150.78 60.27 3.02 191.69 - 21 September 2017

H3(1) Zinc 150.60 59.97 3.06 190.66 - 21 September 2017

H1(2)Conventional

Galvanization149.62 61.30 6.22 435.39 164.0 21 September 2017

H2(2)Conventional


H3(2)Conventional


58


Site LocationStart Date

(Photo Record 1)

1st Inspection

(Photo Record 2)

2nd Inspection

(Photo Record 3)

3rd Inspection

(Photo Record 4)

Last Inspection

(Photo Record 5,

Specimen Collection,

Mass Loss Measurment)


EPD Air quality monitoring

station31 May 2017 31 Aug. 2017 30 Nov. 2017 28 Feb. 2018 31 May 2018

BYuen Long


station31 May 2017 31 Aug. 2017 30 Nov. 2017 28 Feb. 2018 31 May 2018

CYuen Long

Yau Sang Factory31 May 2017 31 Aug. 2017 30 Nov. 2017 28 Feb. 2018 31 May 2018

DTiu Keng Leng

G.T. (Ellen Yeung) College22 Jun. 2017 22 Sep. 2017 22 Dec. 2017 22 Mar. 2018 22 Jun. 2018

ETseung Kwan O

Evangel College22 Jun. 2017 22 Sep. 2017 22 Dec. 2017 22 Mar. 2018 22 Jun. 2018

FTung Chung


station17 Jul. 2017 17 Oct. 2017 17 Jan. 2018 17 Apr. 2018 17 Jul. 2018



Sports Centre21 Sep. 2017 21 Dec. 2017 21 Mar. 2018 21 Jun. 2018 21 Sep. 2018

Inspection Schedule

59


I) The Hong Kong University of Science and Technology

60


I) The Hong Kong University of Science and Technology

61


J) The Hong Kong Polytechnic University

62


J) The Hong Kong Polytechnic University

63


Test Aluminium Rack

Rack size: Length=900m, Width=800mm, Height=900mm

45º，Facing south, exposure to the sun

Aluminium rack, High corrosion resistance

Against overturning and sliding by wind

Small tolerance for specimen support

64


Test Aluminium Rack

Rack size: Length=900m, Width=800mm, Height=900mm

Stainless steel screw and nut, Nylon

spacer, Nylon washer for specimen fixing,

preventing rusting of specimen

Sandbag, more dead load acting against wind load

65


Design calculation for test aluminium rack

66


Design calculation for test aluminium rack

67


Test Specimen

⚫ Specimen Size: Length=150mm, Width=60mm, Thickness=3mm

or 6mm.

⚫ Initial photo, Weight (<500g), Dimension, Thickness is recorded.

⚫ Type and Quantity

Item Type Qty.

1 Black steel 3

2 Zn steel 3

3 Conventional galvanized steel 3

4 5% Al Zn Coating 3

Total 12

68


Test Specimen

Site: A, B, C, D, E, F, G… No.: 1, 2, 3 a) Black Steel

⚫ S275 Smooth, Total Quantity = 60 pcs;

⚫ Specimen Size: Length=150mm, Width=60mm, Thickness=3mm;

⚫ Initial photo, Weight (<500g), Dimension, Thickness is recorded;

⚫ Marking System: Top: X (Site A, B, C…) + No.(1,2,3) &

Bottom: Type (Black Steel: 0);

Type: Black Steel: 0

69


Test Specimen

Site: A, B, C, D, E, F, G… No.: 1, 2, 3

b) Pure Zinc

⚫ Pure Zinc (Tested by HKPC, 13

July 2017), Total Quantity = 60

pcs;

⚫ Specimen Size:

Length=150mm, Width=60mm,

Thickness=3mm;

⚫ Initial photo, Weight (<500g),

Dimension, Thickness is

recorded;

⚫ Marking System: Top: X (Site

A, B, C…) + No.(1,2,3) &

Bottom: Type (Zinc: 1);

Type: Zinc: 1

70


Test Specimen

Site: A, B, C, D, E, F, G… No.: 1, 2, 3…c) Conventional galvanized steel

⚫ S275 Smooth, Total Quantity = 60 pcs;

⚫ Specimen Size: Length=150mm, Width=60mm, Thickness=6mm;

⚫ Initial photo, Weight (<500g), Dimension, Thickness and

Coating thickness is recorded;

⚫ Marking System: Top: X (Site A, B, C…) + No.(1,2,3…) & Bottom: Type

(Galvanized: 2);

Type: Galvanized: 2

71


Test facility

⚫ Vernier calipers (Dimension)

⚫ Scanner (Image)

⚫ Elcometer (Coating thickness)

⚫ Electronic balance with a range of 500g and an accuracy

with±0.01g (Weight)

⚫ Electrothermal furnace and laboratory instrument & Chemical (Mass

loss measurement)

72


Mass loss measurement

Weighing a specimen Mass loss measurement

Chemicals for removing corrosion products

⚫ Assume 200mm deep cleaning solution in a beaker of 100mm diameter is required.

⚫ Volume of the cleaning solution = 1570000mm3 = 1570ml ≈ 1600ml

Designation Base metal Chemical products Total time TemperatureAmount of chemicals to make

1600 ml solution

C3.1 Iron and steel

500 ml of hydrochloric acid (HCl, ρ = 1,19 g/ml)

3,5 g of hexamethylenetetramine ((CH2)6N4)

Distilled water to make 1 000 ml (saturated solution)

10 min 20 °C to 25 °C

800 ml of HCl

5.6 g of (CH2)6N4

C9.3Zinc and zinc

alloys

200 g of chromium trioxide (CrO3)

10 g of silver nitrate (AgNO3)

Distilled water to make 1 000 ml

1 min 80 °C 320 g of CrO3

Chemicals listed in preferred order (extracted from Table A.1, BS ISO 8407:2009)

73



• Specimen Size: 125mm (Length) x 60mm (Width) x 8mm (Thickness)

• Specimen Type: Steel grade S275 specimen with 100mm hot-dip galvanized zinc coating

• ρsteel = 7850kg/m³ & ρ zinc = 7.2 x 10⁻³g/mm³

• Assume 5mm corrosion attack on both sides of the specimen in the first year.

• Mass of steel = 0.125m x 0.06m x 0.008m x 7850 x 10³g/m³ = 471g

• Mass of zinc coating before testing

= 2 x 125mm x 60mm x 0.1mm x 7.2 x 10⁻³g/mm³ = 10.8g

• Mass of zinc coating after testing

= 2 x 125mm x 60mm x 0.095mm x 7.2 x 10⁻³g/mm³ = 10.26g

• Total mass of the specimen before testing = 471g + 10.8g = 481.8g

• Total mass of the specimen after testing = 471g + 10.26g = 481.26g

• Difference between the mass of the specimen before and after testing over a year

=481.8g – 481.26g = 0.54g

74



⚫ Point A represents the mass of corroded specimens before the start of the cleaning.

⚫ Line AB characterizes the removal of corrosion products and may not always be visible.

⚫ Line BC characterizes the removal of substrate after the corrosion products are gone.

⚫ Point D, which characterizes the mass of the pure metal at zero number of cleaning cycles, is

obtained by extrapolation of line BC to the ordinate axis.

⚫ Mass loss = Original mass – D

Mass of specimen

without corrosion product

75

International Collaboration

76


Swedish Research Institute, Sweden

French Corrosion Institute, France

The Singapore Institute of Manufacturing

Technology (SIMTech),

which is a research institute of the Agency for

Science, Technology and Research,

Singapore (A-STAR)

The Corrosion Technology Laboratory,

NASA Kennedy Space Center,USA

77



http://www.institut-corrosion.fr

⚫ French Corrosion Institute is among the largest laboratories in

the field of corrosion and corrosion protection of materials in

the world.

⚫ Provide solutions to various corrosion problems (including

damage analyses, testing and laboratory investigations)

⚫ Competency in investigations, diagnostics and studies is

available for all metallic materials (steel, aluminium, zinc,

copper, titanium and various alloys), paints, polymers and

composites.

⚫ Two sites in France :

1) Brest (French Brittany, headquarters), settled in March 2002.

2) Saint-Etienne (South-East France), the former Correx

laboratory, which integrated the French Corrosion Institute in

July 2009

http://www.institut-corrosion.fr/

78


⚫ 28 specimens (150mm(L)×60mm(W)) at one

seafront site in Hong Kong for 3 years.

⚫ Start in early 2018.

⚫ Galvanized steel & Stainless Steel.

⚫ Zinc-Al coated steel and ZnAlMg coated steel

may be included.

⚫ Same metallic coating but at different coating

thickness could be included.

⚫ The thickness of the metallic coating could be

adjusted as low as possible (without changing

the microstructure in the case of ZM

materials).


Chinese National Engineering Research Centre

For Steel Construction (Hong Kong Branch)

Innovation and Technology Commission,

The Government of Hong Kong SAR

79

Documents

Atmospheric Corrosivity on Infrastructures in Hong Kong