1. TITLE Method Statement for Concrete Crack Repair 2. SCOPE OF WORKS 2.1 General Description ·          The scope and pur...

Method Statement for Concrete Crack Repair

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1. TITLE

Method Statement for Concrete Crack Repair

2. SCOPE OF WORKS

2.1 General Description

·         The scope and purpose of this method statement is to outline the general requirements and precautionary measures in working with the cracks occurred in all concrete elements such as raft, slabs and wall. This should ensure that the works will be done with good quality as per the project specification, standards and drawings.

2.2 Plant and Equipment

·         Hand Mixer, mixing paddle

·         Steel Brush

·         Air Compressor (if necessary)

·         Grinder

·         Chisel

·         Trowel

2.3 Materials

S.N	Material	Reference Submittal	Status (approved or rejected)
1	Repair material
2	Potable water
3	Curing compound

2.4      Site Planning and Preparation

·         Contraction joint for every 10m length must be provided in all areas of retaining wall (inside).

·         Surface must be fully dry and free of loose materials.

2.5      Work Methodology

2.5.1 Surface or Substrate Preparation

A.      External Wall

·         The cracks to be filled shall be marked out in detail on the concrete elements.

·         Following cleaning, the cracks and adjacent surface or substrate must be clean from dust, laitance and foreign particles. Remove loose concrete until a sound and solid surface is achieved.

·         All cracks shall be done in V-groove or Square Groove the surface of the cracks using the grinder or hand chipping tool to a nominal width of 5 mm and 5 mm depth enough to receive and penetrate the repair material.

·         Cleaning out the crack using wire brush and air compressor. Apply small amount of water to make the area wet.

2.5.2           Preparing Mix of Repair Material

·         The slurry or mortar is obtained by mixing the approved grout material for repair with water. The amount of water used shall be as per manufacturer’s recommendation to attain the workability required.

·         Add the powder to the water and mix for 3 minutes. To ensure a homogeneous and uniform mix, an electric mixer must be used.

 

·         Do not mix with other hydraulic binders. The use of additives is absolutely prohibited.

·         Ideal application temperature is between + 5ºC and + 35ºC. If the application temperature is higher than 35 ºC, make sure to use cool water to keep the mixed grout temperature below 30 ºC.

2.5.3           Application of Repair Material

·         Build a solid leak-proof formwork. Saturate the concrete substrate with water for at least few hours prior to pouring. Remove all residual water. Pour the grout continuously, in one direction to avoid air pockets.

·         Material can be applied by means of trowel to be compacted on the groove.

 

·         The choice of installation method depends on the grouting thickness and the length of the gap. Once the grout starts to set, it should be cured by a curing compound or if the configuration and the tightness of the forms allow by pouring 1 to 2 cm of cool water over the surface and maintaining it until the striking of the forms.

·         Protect the work against rapid drying from wind, sun and excessive heat by using a curing compound.

B.      Internal Wall

Refer to detailed Method Statement for Injection Works for Dry Cracks attached in appendix 6.1.

2.5.4           Working Platform

·         All activities in elevated areas shall be fully coordinated with HSE department. Ensure that the working flat form is inspected and approved by HSE officer.