Concrete - Repelling Water Ingress

80% of all concrete failures in buildings and structures in Hong Kong are caused by WATER INGRESS.

An Innovative and Proven Solution for Repelling Water Ingress into Concretes Structure

(Chris Stanley, Chairman HKCRA)

Dr Ian McFeat Smith Technical Directors, Hydrotech Asia Ltd

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Early Stage in Hydration of Portland Cement

Cement Hydration after 25 days

How does Water Ingress Occur ? • Water penetrates concrete fabric by three primary mechanisms: . Capillary action. . Temperature differentials. . Hydraulic pressure. • “Water drawn into concrete by capillary action is over 10,000 times more powerful than gravity”. Prof. Andreas B. Fourie (Australian Centre for Geomechanics) • The smaller the pores the greater the capillary action. 3

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Capillary forces draw water up sides of tube Cohesion and Adhesion

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Horizontal Capillary Action Through Walls

Capillary Action through Pile Foundations, Floor Slabs and Walls

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MPS Can we find a Cost Effective and Permanent Solution to Water Ingress problem?

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MULTI-PULSE SEQUENCING SYSTEM IS A VIABLE SOLUTION TO STOP WATER INGRESS INTO CONCRETE STRUCTURES 9

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What is Multi Pulse Sequencing System and the scientific principle behind it? Multi-Pulse Sequencing (MPS) System is a highly advanced form of electroosmotic technology that uses low voltage and low current to ionise water and direct it to a specific area.

MPS® MPS – Multi Pulse Sequencing System

The MPS System in action

Brief History of the Technology •

1807, the German professor Russ, who was living in Russia discovered the theory and principles behind the movement of liquids in capillary structures.

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in 1930. The Ernst brothers in Switzerland discovered how to move fluids in capillary structures through applying an electrical charge between a cathode and electrode

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in 1962. Principles behind the effect was established by E Franke. Subsequent experiments by Prof. Andreas Fourie at Newcastle U/T University over 10 years to move water in concrete failed, because there was no efficient control system.

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In 1987, the Norwegian inventor Kjell Aage Utklev discovered that a pulsating current would continue to transport water in concrete for as long as the current was applied.

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In 1988 this discovery was patented in 1988. Kjell Aage Utklev is a shareholder and consultant to Hydrotech International.

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MPS is new technology, but the principles are universal.

Underground water source

• Using 240 volt transformed MPS Control Equipment

Negative Electrode

Positive Electrode

down to 40 volts DC • Water molecules are pushed back into the water table. • We can counter up to 60 bar of pressure • The system works continuously however after drying the power usage falls to a minimum level • Normal drying time is ONLY 4 to 8 weeks • The structure stays permanently dry

Reclaimed Land

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DIFFERENCE BETWEEN ELECTROOSMOSIS AND CATHODIC PROTECTION

1. CATHODIC PROTECTION HAS SACRIFICIAL ANODE WHILST ELECTRO-OSMOSIS DO NOT. 2. CATHODIC PROTECTION CONNECTS TO THE REBARS WHILST ELECTRO-OSMOSIS DOES NOT.

MPS System Installation 17

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Alkali - Glass Reaction Deterioration of mosaic clad render

A marine concrete structure in Chai Wan that started to deteriorate before the construction was complete.

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Spalling of concrete from expansion of rebar leading to secondary corrosion

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Water Ingress is One of the Oldest Problems in Civil Engineering For this Tunnel Singapore spent millions fixing the cracks but the water ingress problem remained

Water ingress accelerates the 24 degradation of the structure

Attempts at repair

Examples of Asset Degradation caused by Water Ingress

Water leaking through construction fissures

Large area of water ingress leading to stray 26 current issues.

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Flooding

Mould, Odour, Airbourne Bacteria

Chinese Electronic Periodical Services 21/12/07

Results from Testing Air Quality and Odour Problems in Shenzhen Metro 99.2% of 9460 samples yielded bacteria 100% yielded Mycete 11 Hemolytic Streptococcus How water ingress can manifest itself

CONCLUSION: The contamination in the air of Shenzhen Metro is very serious.

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THE MULTIPLE INSTALLATION PROCESS FOR MEMBRANES IS COMPLEX, TIME CONSUMING, INVOLVES THE USE OF EXPENSIVE MATERIALS AND IS THEREFORE HIGHLY EXPENSIVE

Review of some options for WATERPROOFING CONCRETE • Concrete can be made waterproof using admixtures that are mainly pore-blockers • Concrete structures can be made waterproof by means of sheet or spray membranes • Grouting using Jetting methods can be applied to adjacent ground • Multiple Pulse Sequencing (MPS) using electroosmosis can be installed on walls and slabs of existing and new build structures.

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BUCKLING AND WRINKLING OF MEMBRANES COMMONLY OCCUR. DAMAGE RESULTS FROM INSTALLING ANCHORS, CUTTING MEMBRANE TO SUIT SHAPES

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This had to be grouted as shown.

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Supplier advises that membrane can only be applied to dry surfaces ?

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REPAIRS TO EXISTING STRUCTURES OBJECTIVES

CRACK REPAIRS - SPRAY ON RESINS COATINGS

REPAIRS TO EXISTING STRUCTURES

CRACK INJECTION

OBJECTIVES

CRACK REPAIRS - SPRAY ON RESINS COATINGS

CRACK INJECTION

n/a

n/a

High – does not stop water ingress

High – does not stop water ingress

Savings Heating/Ventilation/A/C

n/a

n/a

Performance Monitoring

n/a

n/a

Preventing capillary action

Preventing capillary action

Sealing large cracks >0.2mm

Sealing large cracks >0.2mm

Minimise cracking from corroding steel

Minimise cracking from corroding steel

Water exclusion

Water exclusion

Long term humidity, mold and odor control

Long term humidity, mould and odour control

Cost - Installation

Cost - Installation Savings Heating/Ventilation/A/C Performance Monitoring

-Effective -Effective

-Partially effective

- Marginal

n/a - not applicable

OBJECTIVES

SHRINKAGE REDUCTION

CAPILLARY ABSORPTION REDUCTION

ADMIXTURES

SPRAY - ON (INSIDE AT AIR INTERFACE)

n/a - not applicable

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MEMBRANES SHEET (OUTSIDE CONCRETE)

- Marginal

WATER INGRESS PROTECTION FOR NEW CONCRETE STRUCTURES

WATER INGRESS PROTECTION FOR NEW CONCRETE STRUCTURES ADMIXTURES

-Partially effective

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GROUTING OF GROUND

SHRINKAGE REDUCTION

AIMS

MEMBRANES SHEET (OUTSIDE CONCRETE)

SPRAY - ON (INSIDE AT AIR INTERFACE)

GROUTING OF GROUND

n/a

n/a

n/a

n/a

n/a

n/a

n/a

CAPILLARY ABSORPTION REDUCTION

Reducing / preventing capillary absorption

Reducing / preventing capillary absorption

Minimise ingress through cracking*

Minimise ingress through cracking*

Long term water exclusion

Long term water exclusion

Prevent corrosion of rebar

Prevent corrosion of rebar

Long term humidity,odour and mould control

Long term humidity,odor and mold control

Heating/Vent/A-C Savings

Heating/Vent/A-C Savings

n/a

n/a

n/a

n/a

n/a

Performance Monitoring

Performance Monitoring

n/a

n/a

n/a

n/a

n/a

*Thermal and shrinkage cracking

n/a

*Thermal and shrinkage cracking - Effective

- Partially effective

- Marginal

n/a - not applicable

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- Effective

- Partially effective

- Marginal

n/a - not applicable

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Examples of Significant Projects

MPS Scope of Application • Underground projects such as railway stations, car parks and all other basement structures

London

Norway Projects

London Underground Railway Station Walthamstow Central Subway

Tafjord Dam Sira Kvina Power Station Drammen Central Railway Station Skien Central Railway Station Oslo Housing Society (OBOS) Norway National Museum

China Projects Hong Kong International Finance Centre Hong Kong Central Station, Airport Express Hong Kong Hang Seng Bank Headquarters City Plaza Taikoo Shing Centre Hong Kong XinHua Agency Zheng Zhou High-tension Electric Cable Tunnel

• Tunnels such as road and rail, pedestrian tunnels, cable and gas and other tunnels. • Hydroelectric and dam projects etc • Marine structures, underwater foundation projects and embankments

Projects under investigation

• Bridges and viaducts. 37

Warehouse Basement, Kowloon Tong (completed) Zhongliang Highway Tunnels, Chongqing Fengman Dam, Jilin Province Guangzhou Metro Railway tunnels, Chonqing, Metro Station

MPS System was installed at the Left behind the Artwork

MTRC Central Station, Artwork Area

No MPS installation at the Right behind of the Artwork

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Before MPS Installation

After MPS Installation

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International Finance Centre One, Hong Kong

Year: 2000 Location: Hong Kong Project: Lift Machine Room Client: Hendersonland Background:

• Severe saline water ingress through the walls resulted in a lift machine room being extensively flooded • All the plant was submerged. • Following installation of MPS in 2000, water ingress has been completely ceased. MPS System Control Unit Installation 41

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• IFC below Car park Area • Machine Room flooded out • Completely dried out after MPS Installation

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CITY PLAZA 4 Loading Area Diaphragm wall was saturated due to flooding from ground water ingress Frustrated, Swire Properties tested several methods for preventing water ingress MPS selected as the only successful method Wall remains bone dry after 10 years of monitoring Maintenance costs are negligible

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Walthamstow London Underground Station Central Subway. MPS Works

Electrode Placement in City Plaza 4

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Walthamstow Station - Central subway. MPS Circuits in Subway

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MPS Layout at Walthamstow

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Electro-Magnetic Compliance Certificate

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Water ingress problem at the Underground Railway in Singapore

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Oslo Central Railway Station Year: 1990 Location: Norway Project: Central Railway Station Client: NSB AS Background: • Water ingress had occurred in block work located 100 meters from the sea and below ground water level. • The wall had been constructed with an external membrane and back filled. • In 1990, anode lines were installed in the inside wall with an external ground spear. •The problem has been completely solved

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TAFJORD Dam Norway Year: 1997 Location: Norway Project: Dam Structure Client: S.N. Electric Company

Sira-Kvina Power Station

Background:

Year:

• The concrete dam in Tafjord is Europe’s second highest at 96meters.

1992

• The structure is 12 meters thick at the top and 40meters thick at its base.

Location: Norway

• By early 1990’s, a number of cracks were appearing that resulted in significant leakage. On the assumption that nothing could be done to remedy the situation, the structure was eventually condemned and schedule for demolition.

Project: Power Station Client: S.N. Electric Company

• Electro-osmotic technology was employed to address the defects and the leakage was stopped. • Following on from the drying process, the physical cracks could be repaired by conventional sealing methods. •The problem did not reoccur 53

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MPS INTELLIGENT SYSTEM Control and Performance Monitoring

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MPS System Permanently Protects your structure from Water Ingress Cost Benefit

FACT MPS Removes the Need to Waterproof Concrete

The cost of MPS is less than HK$ 150/m2 The cost of repairing concrete damaged by water ingress is more than HK$4,000/m2 Enormous savings in life-cycle costs 61

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WATER INGRESS PROTECTION BY MPS OBJECTIVES

SYSTEM PERFORMANCE

Reducing / preventing capillary absorption Minimise ingress through cracking* <0.2mm Minimise ingress through cracking* >0.2mm

n/a

Prevention of Corrosion of steel rebar Prevention of cracking from expansion of corroding steel Long Term Humidity, Mould and Bacterial Control Heating/Vent/A-C Savings Performance Monitoring *Thermal and shrinkage cracking

- Effective

n/a - not applicable

TESTIMONIAL LETTERS

CONCLUSIONS • MPS provides a viable, easily installed and cost – effective solution to STOP WATER INGRESS • Long term humidity, mould and odour control • MPS provides a unique long term control and performance monitoring system. • Operational costs using MPS are negligible and savings in life cycle costs are considerable.

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THANK YOU ANY QUESTIONS?

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