Concrete - Repelling Water Ingress

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An Innovative and Proven Solution for Repelling Water Ingress into Concretes StructureDr Ian McFeat Smith Technical Directors, Hydrotech Asia Ltd

80% of all concrete failures in buildings and structures in Hong Kong are caused by WATER INGRESS.(Chris Stanley, Chairman HKCRA)

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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 4

Capillary forces draw water up sides of tube Cohesion and Adhesion

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Capillary Action through Pile Foundations, Floor Slabs and Walls

Horizontal Capillary Action Through Walls

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

MULTI-PULSE SEQUENCING SYSTEM IS A VIABLE SOLUTION TO STOP WATER INGRESS INTO CONCRETE STRUCTURES9 10

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.

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MPS Multi Pulse Sequencing System MPSBrief 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. 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 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. 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. In 1988 this discovery was patented in 1988. Kjell Aage Utklev is a shareholder and consultant to Hydrotech International. MPS is new technology, but the principles are universal.13

The MPS System in actionUnderground water source MPS Control Equipment

Using 240 volt transformeddown 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

Negative Electrode

Positive Electrode

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 Installation17 18

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

Alkali - Glass Reaction Deterioration of mosaic clad render

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Spalling of concrete from expansion of rebar leading to secondary corrosion

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

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Water ingress accelerates the 24 degradation of the structure

Examples of Asset Degradation caused by Water Ingress

Attempts at repair

Water leaking through construction fissures

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

Flooding

Mould, Odour, Airbourne Bacteria

Chinese Electronic Periodical Services 21/12/07

Results from Testing Air Quality and Odour Problems in Shenzhen Metro99.2% of 9460 samples yielded bacteria 100% yielded Mycete 11 Hemolytic Streptococcus How water ingress can manifest itselfCONCLUSION: The contamination in the air of Shenzhen Metro is very serious.

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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.

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

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

This had to be grouted as shown. Supplier advises that membrane can only be applied to dry surfaces ?

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REPAIRS TO EXISTING STRUCTURESOBJECTIVES Preventing capillary action Sealing large cracks >0.2mm Minimise cracking from corroding steel Water exclusion Long term humidity, mold and odor control Cost - Installation Savings Heating/Ventilation/A/C Performance Monitoring CRACK REPAIRS - SPRAY ON RESINS COATINGS CRACK INJECTION OBJECTIVES

REPAIRS TO EXISTING STRUCTURESCRACK REPAIRS - SPRAY ON RESINS COATINGS n/a CRACK INJECTION n/a

Preventing capillary action Sealing large cracks >0.2mm Minimise cracking from corroding steel Water exclusion Long term humidity, mould and odour control Cost - Installation Savings Heating/Ventilation/A/C Performance Monitoring-Effective

High does not stop water ingress

High does not stop water ingress

n/a n/a

n/a n/a

-Partially effective

- Marginal

n/a - not applicable

-Effective

-Partially effective

- Marginal

n/a - not applicable

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WATER INGRESS PROTECTION FOR NEW CONCRETE STRUCTURES ADMIXTURES OBJECTIVESReducing / preventing capillary absorption Minimise ingress through cracking* Long term water exclusion Prevent corrosion of rebar Long term humidity,odour and mould control Heating/Vent/A-C Savings Performance Monitoring *Thermal and shrinkage cracking - Effective - Partially effective - Marginal n/a - not applicableSHRINKAGE REDUCTION CAPILLARY ABSORPTION REDUCTION

WATER INGRESS PROTECTION FOR NEW CONCRETE STRUCTURES ADMIXTURES GROUTING OF GROUND AIMSReducing / preventing capillary absorption Minimise ingress through cracking* Long term water exclusion Prevent corrosion of rebar Long term humidity,odor and mold control Heating/Vent/A-C Savings Performance Monitoring *Thermal and shrinkage cracking - Effective - Partially effective - Marginal n/a - not applicable n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aSHRINKAGE REDUCTION CAPILLARY ABSORPTION REDUCTION

MEMBRANESSHEET (OUTSIDE CONCRETE) SPRAY - ON (INSIDE AT AIR INTERFACE)

MEMBRANESSHEET (OUTSIDE CONCRETE) SPRAY - ON (INSIDE AT AIR INTERFACE)

GROUTING OF GROUNDn/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

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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 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 Bridges and viaducts.37

LondonLondon Underground Railway Station Walthamstow Central Subway

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

China ProjectsHong 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

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

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MTRC Central Station, Artwork Area

MPS System was installed at the Left behind the Artwork

No MPS installation at the Right behind of the Artwork

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Before MPS Installation

After MPS Installation

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 Installation41 42

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

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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Electrode Placement in City Plaza 4

Walthamstow London Underground Station Central Subway. MPS Works

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Walthamstow Station - Central subway. MPS Circuits in Subway