TABLE OF CONTENTS

1. GENERAL

2. INVESTIGATION AND EVALUATION OF DAMAGED CONCRETE SURFACES

3. CONCRETE REMOVAL

3.1 Impacting method (for honeycombed and exposed re-bar)

3.2 Grinding (for abrupt or gradual irregular surfaces)

3.3 Cutting

3. SURFACE PREPARATION

4. REPAIR MATERIALS

5. REPAIR AND FINISHING PROCEDURE

APPENDICES

ATTACHMENT 1: PRODUCT DATA SHEET & MANUFACTURER’S APPLICATION METHOD

1. GENERAL

This following Method Statement covers surface preparation and repair of

damaged or defective concrete surfaces for building works.

The repair method consists of Investigation and evaluation, concrete removal,

preparation for repair, repair materials and concrete repair method and

rehabilitation of concrete surfaces.

2. INVESTIGATION AND EVALUATION OF DAMAGED CONCRETE SURFACES

Before performing repairs on damaged or defective surfaces, a visual

inspection of the exposed concrete on site shall be performed. The purpose of

such an examination is to locate, Identify and define areas of distress.

Typical construction faults that may be found during visual inspection:

● Bug holes

● Cold joints

● Exposed reinforcing steel

● Honeycombing

● Irregular Surface

3. CONCRETE REMOVAL

All weak, damaged and easily removable concrete should be chipped away.

Classification of concrete removal method to be applied:

3.1 Impacting method (for honeycombed and exposed re-bar)

- Generally employ the repeated striking of a concrete surface with a

mass to fracture and spall the concrete

● Hand-held breaker

- Using hand-held breaker or chipping hammer for removal of

unsound concrete.

● Steel chisel and hammer

- Dismounting unsound and loose concrete and trimming the

repaired surfaces

3.2 Grinding (for abrupt or gradual irregular surfaces)

● Rubbing carborundum on gradual irregular surfaces

● Using grinding machine with concrete grinding disc

● By bush-hammering

3.3 Cutting

- Method applicable for making cutouts through concrete members

and employ full depth perimeter cuts to disjoint concrete for removal as

a unit: Using concrete wheel cutter

4. SURFACE PREPARATION- One of the important steps in the repair or rehabilitation of a concrete structure is the preparation of the surface to be repaired-To achieve a sound clean and rough textured, and wet or dry surface, adopt the following method of surface preparation:● Mechanical preparation

- Using variety of mechanical devices available for cleaning concrete surfaces such as breakers, chisel or impact tools

● Cleaning- Using water to cleaning

● Scrubbing- Using wire brush manually or electrical powered wire brush

* Other method of preparation are mentioned on manufacturer’s preparation procedure

GRINDER

CONCRETE WHEEL CUTTER

HAND BREAKER

RUBBING

5. REPAIR MATERIALS

Type of material to be used

Bonding material Patching Material Remarks

Sika Sika Monotop 610 Sika Monotop R

CormixSaturated with water

on surfaceConpatch 600

Refer to Attachment 1 for product data sheet.

5. REPAIR AND FINISHING PROCEDURE

Refer to Attachment 1 manufacturer’s application method.

SCRUBBING

CLEANING BY WATER

MECHANICAL PREPARATION USING IMPACT TOOLS

ATTACHMENT 1:PRODUCT DATA SHEET & MANUFACTURER’S APPLICATION METHOD

1. SIKA MONOTOP 610 (BONDING BEFORE APPLY SIKA MONOTOP R)

2. SIKA MONOTOP R

3. CONPATCH 600