CONCRETE REPAIR

PROCEDURE & MEASURE

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APRIL 25, 2015

SAUDI DIYAR CONSULTANTS ARCHITECTS & ENGINEERS 24 North Jeddah building A & B Prince Sultan Street, Al-Nadha District Kingdom of Saudi Arabia Tel: +966 2 699 9888. Fax: +966 2 699 9777, E-mail: info@diyar.com; web: www.diyar.com

Classification of Repair Minor Concrete Repair Deep Concrete Repair

Honey combed voids

Tie Rod holes

Minor voids

Cavities in concrete

Mass concrete in loose profile

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Range of Void

05 mm to 25mm (Approx)

Range of Void

30 mm to 125mm (Approx)

Execution Sequence Minor Concrete Repair Deep Concrete Repair

• Surface preparation 1. Hammer, chisel, jack hammer

2. Cleaning with air blower/compressed air

• Application of bonding agent on substrata (old concrete)

• Application of Repairing material

• Curing

• Surface preparation 1. Chipping/scabbling of concrete by jack

hammer 2. Remove loose concrete, cleaning with air

blower or brush

• Expose the reinforcement of structural element

• Application of protection coat on the steel surface (against corrosion)

• Application of bonding agent on substrate surface(old concrete)

• Installation of rigid, water tight formwork

• Application of Repairing material

• Curing

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Diagnosis & Treatment (D&T)

Concrete repair, execution sequence

Engr: Adil Rehman

Engr: Emad Hamdy

Area Responsible:

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MINOR CONCRETE REPAIR

TUNNEL WALLS/ COLUMNS:

Fair faced surface/ small voids repair

MATERIAL:

Nitobond AR Renderoc-FC Renderoc-HF

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WORK SEQUENCE:

• Safe Access

• Mark repair area

• Surface cleaning ( Remove dirt, oil, other contaminants)

• Chipping/ scabbling by Hammer & chisel, jack hammer

• Cleaning of surface with air blower & brush.

• Apply Nitobond A.R on substrata surface (old concrete)

• Apply Renderoc-FC by hand tools (Trowels, scrapers)

• Apply Renderoc-HF by hand tools (Trowels, scrapers)

• Curing, Renderoc-FC ( may not be required or cured with A.R)

• Curing, Renderoc-HF ( curing compound)(Concure /A.R

or Traditional way, wet hessian, water etc)

• Review technical data sheets for particular material

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Mixing:

Renderoc-FC: 4 Litres fresh water, 1.2 Litre (20-Kg bag) Nitobond A.R, 4 litre Renderoc-H.F: 3 Litres fresh water (25-Kg bag) Review data sheets particularly each material

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Review the Illustrations

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Comments:

Location:

Honey combed in wall,

Minor voids

Retaining R.C Wall

in tunnel

Honeycombs in

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Honeycombs in

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Unrepaired area

Surface repair area

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Surface repaired area

Unrepaired area

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DEEP CONCRETE REPAIR

COLUMNS:

Deep voids repair

MATERIAL:

Nitoprime Zincrich (for steel protection) Nitobond EP (for concrete bonding agent) Renderoc HF (for repair material) Curing compound (Concure or traditional method)

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WORK SEQUENCE:

Safe Access

Mark repair area

Surface cleaning ( Remove dirt, oil, other contaminants)

Concrete chipping by jack hammer, remove loose concrete, expose steel if necessary.

Cleaning of rebars by steel wire brush, sand blasting if necessary.

Apply Nitoprime Zincrich on clean rebars (two coats)

Apply Nitobond EP on clean substrata (old concrete), two coats

Install formwork (rigid and tight)

Apply silicone to seal the formwork (water tight)

Apply Renderoc-HF

Curing, (use curing compound )(concure/A.R or traditional way, wet hessian, water)

Review technical data sheets & method statement entire material.

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Mixing:

• Renderoc-H.F: 4.3 to 4.5 Litres fresh water, 25-Kg bag • Nitobond EP (slow set base, slow set hardner) • Nitoprime Zincrich (2.5 Litre, ready to apply) • Review data sheets particularly each material

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Review the Illustrations

Requires deep Repair

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Surface preparation

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Breaking by Jack hammer , Debris of concrete

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Application of Nitoprime Zincrich

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Application of Nitobond EP

Install Formwork

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Application of silicone

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Mixing of Renderoc-HF

Measurement of water

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Application of Renderoc-HF

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After remove formwork

Close up

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Cure, Wet Hessain (water)

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NON REPAIRABLE

WORK SEQUENCE:

• Fact and finding

• Cavities probing

• Prepare initial illustrations report

• Get Engr, David & Rehan expert opinion in this regard

• Demolish the structural element by jack hammer or stitch coring etc.

Marked location plan V.B= Very bad columns Colored columns= Need repair

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Column to be

demolished

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Column to be

demolished

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Column to be

demolished

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SPECIAL THANKS;

Sr, Manager, David oxley

Senior Engr, Rehan Ahmed Khan

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