Laboratory for Corrosion Protection Technology

Introduction

The objectives of the Laboratory for Corrosion Protection Technology

  • To investigate the atmospheric corrosivity in local areas in Hong Kong, and to study the atmospheric corrosion chemicals, corrosion mechanisms, and corrosion rates of exposed steelwork under local environments.
  • To investigate various corrosion monitoring methods in buildings and civil engineering structures using internet-based monitoring systems and corrosion sensors.
  • To investigate the conventional galvanization method with Zinc, and the innovative modern galvanization process with Zinc and Aluminium alloys as well as the control of coating thicknesses, and surface quality, and the prolonged use of various fluxing solutions.
  • To investigate corrosion protection and repair technology including rusts and hydrated iron oxides, rust removal, chemical treatments, service life of rusted steelwork, and service life after repair.

Research Team of the Lab

  • Laboratory-in-charge
Prof K F Chung
  • Deputy Laboratory-in-charge
Mr. JIANG Hao, Research Fellow (CNERC, PolyU)
  • Members
Mr. WANG Yichuan, Research Associate (CNERC, PolyU)
Ms. XIAO Tingyu, Research Associate (CNERC, PolyU)
Mr. Eric YUEN, Research Assistant (CNERC, PolyU)
Two more external advisor from Arup/Fugro

Venue

Water and Waste Laboratories – Laboratories ZS1101, ZS1102 and ZS1112 at Block Z
Department of Civil and Environmental Engineering
The Hong Kong Polytechnic University

Water and Waste Laboratories

High Performance Ion Chromatography

Laboratory research

To confront potential durability problems of infrastructure in Hong Kong, it is essential to investigate and understand various controlling mechanisms of corrosion in exposed structural steelwork. Hence, atmospheric corrosivity of exposed structural steelwork under local environments in Hong Kong are examined. Moreover, corrosion monitoring methods, corrosion engineering technology, prediction, assessment and protection methods to both reinforced concrete structures and steel-concrete composite structures should be investigated and developed under Hong Kong context.

Effective implementation of corrosion engineering technology for sustainable infrastructure development among construction professionals 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.

The research areas are: a) Monitoring of corrosion in MiC buildings, b) Long term monitoring of corrosion in civil engineering structures: bridges, flexible rock barriers and noise barriers, c) Detection of rusting, d) Repair of corroded steel, and prevention of continual rusting, e) Simulation and prediction, f) Atmospheric corrosivity assessment, and g) Innovative galvanic protection.

1. Atmospheric corrosivity

It is important to study the atmospheric corrosivity in local areas of Hong Kong, and to collect local data for various sites in different areas. Comparison with the predicted corrosion rates to ISO/DIS 9223 and 9224 based on measured climate data and concentrations of atmospheric chemicals is also made.

Yearly measurements on mass loss in exposed standard metal specimens to ASTM G50-10 and BS EN ISO 8407:2014 will be conducted to assess corrosion resistances of different metallic plates with various corrosion protection, such as pure zinc plates, bare steel plates, and galvanized steel plates exposed under outdoor conditions. Corrosion rates of different metals will be collected through one- year exposure tests.

A corrosion map for local areas of Hong Kong will be developed to establish annual corrosion rates for durability assessment. Calibration will be conducted with different methodology.

On-line atmospheric corrosion map of exposed steels in various local areas in Hong Kong

 

2. Corrosion monitoring

To confront potential durability problems in civil engineering structures such as bridges, flexible rock barriers and noise barriers, and residential buildings, especially for MiC (Modular Integrated Construction) buildings and transitional housing in Hong Kong, it is essential to investigate and understand various controlling mechanisms in corrosion of the structural steelwork under both internal and external conditions. Hence, it is necessary to monitor and examine atmospheric corrosivity of structural steelwork under both internal and external conditions through various methods of measurements. As a result, general corrosion requirements for steel structures in Hong Kong will be developed.

The project will 1) Perform real time monitoring and collect direct measurements on electrical currents in standard metal sensors to de termine corrosion rates of structural steelwork in both internal and external conditions; 2) Collect real time measurements of climatic data (temperatures, humidity), and monthly atmospheric chemicals (Cl¯ and SO2); 3) Compare with the predicted corrosion rates to ISO/DIS 9223 and 9224 based on measured climate data and concentrations of atmospheric chemicals; and 4) Expose metallic plates with different corrosion protection systems, according to the international standard practice (ASTM G50-10).

 

3. Galvanic protection

It aims to improve the conventional galvanization with Zinc, and develop an innovative modern galvanization process with Zinc-Aluminium alloy with improved coating thicknesses and surface quality through the use of advanced fluxing solutions. This innovative galvanization technique is expected to produce galvanized coatings with enhanced durability and ductility for structural steel members and steel reinforcements.

Task 1: It aims to develop an innovative ‘discrete’ galvanization process to produce galvanization coatings of Zinc-Aluminium alloy with enhanced corrosion resistance and mechanical performance to steel reinforcements. Hence, it is necessary to enhance the process to be ‘adaptive’ with various complementary galvanization procedures to cover various structural steel members used in construction. More specifically, a material research will be conducted, and the fluxing solution will be enhanced with rigorous verification and validation. As a result, galvanization with enhanced corrosion resistance will be obtained in steel reinforcements of various steel grades and diameters.

Task 2: It aims to perform rigorous verification and validation through material characterization on the galvanized coatings of steel reinforcements produced in Task 1 above. Various material characterization techniques will be employed to reveal the micro-structures and to identify the chemical compositions of the galvanization coatings. The results will confirm consistency of the galvanization coatings produced with the process together with various complementary galvanization procedures.

Task 3: It aims to perform rigorous verification and validation on enhanced corrosion resistance and mechanical performance of the galvanized coatings of steel reinforcements produced in Tasks 1 and 2 above. Standards tests on chemical compositions, mechanical performance and corrosion resistance of the galvanization coatings of Zinc-Aluminium alloy will be carried out according to codified methods and industrial practice.

Task 4: It aims to compile a comprehensive technical guide on the application of the proposed process to steel reinforcements together with technical data on verification and validation exercises of the galvanization coatings to assist design and construction engineers in Hong Kong. Technical guidance on specification, inspection and quality control will also be provided to government departments and regulatory authorities for direct adoption in construction projects.

 

4. Corrosion protection and repair technologies

It aims to investigate corrosion protection and repair technology including detection of rust and hydrated iron oxides, rust removal, chemical treatments, service life of rusted steelwork, and service life after repair. The following methodology and objectives will be applied:

1) Detection of rusts and hydrated iron oxides:

  • Methodology A: Non-destructive test (Detect Moisture): To estimate corrosion levels by detection of moisture levels of the local environments.
  • Methodology B: Non-destructive test (Acoustic Monitoring): To identify wire breaks with acoustic detection on specific sound frequencies, and to determine their corresponding locations.

2) Rust removal and chemical treatments:

  • To study and compare the effectiveness of acidic solutions, alkaline solutions and sodium hydroxide solutions in rust removal from corroded steel,
  • To study various chemical reactions in the process of rust removal from steels with various chemical solutions,
  • To study the level of damage caused by various chemical solutions to the steel substrates, d) To study the effects of temperatures, solution concentrations and time of treatment onto effectiveness of rust removal.

The scope of work includes a) To collect corroded steel plates from various building sites for sample preparation, b) To prepare chemical solutions for rust removal under safety environment and protection, c) To establish the most effective solution for rust removal with specified combinations of temperature, concentrations and time of treatment, d) To minimize damage caused to the steel substrates during the cleaning process.

Methodology include:

  • To perform a mass loss measurement according to ASTM G1-03 and BS EN ISO 8407; and
  • To remove corrosion products from rusted steel using the solutions specified in ASTM G1-03 and BS EN ISO 8407.

Mass loss measurement

 

Projects

  • Atmospheric corrosivity was measured through mass loss tests on exposed steel plates in 7 different sites throughout Hong Kong since 2010.
  • Improved galvanization processes for enhanced ductility and durability.
  • Corrosion monitoring in residential houses using internet-based monitoring systems and corrosion sensors – InnoCell Building at HKSTP in Shatin, Nam Cheong Transitional Housing in Sham Shui Po.
  • Corrosion monitoring of steel flexible barriers against rockfall in rural areas.
  • Control of local environments to prevent occurrence of corrosion.

 

Expected deliverables

  • Technical reports/guides,
  • Journal publications, and
  • Patents

About Us

CNERCEstablishment of the Chinese National Engineering Research Centre for Steel Construction (Hong Kong Branch) at The Hong Kong Polytechnic University (PolyU) was approved by the State Ministry of Science and Technology (MOST), People’s Republic of China on 12th October 2015.

Contact Information

Address:
Chinese National Engineering Research Center for Steel Construction (Hong Kong Branch)
The Hong Kong Polytechnic University, Phase 8,
Hung Hom, Kowloon, Hong Kong.

Phone: (852) 3400-8451

Email: cnerc.steel@polyu.edu.hk