Identify the correct methods of surface preparation used for joining old and new concrete to each other.

i) Sandblasting

ii) Chipping

iii) Removal of surface by grinding

While maintaining, restoring, or repairing a concrete floor, it's essential to understand the common surface preparation techniques to ensure proper bonding and durability. Here are three widely used methods:

1. Sandblasting:

• Definition: Sandblasting uses high-pressure air to blast sand onto the concrete surface.
• Purpose: This technique effectively removes contaminants, dirt, and old coatings from the surface. It also creates a rough texture that enhances the bonding of new concrete or coatings to the existing surface.
• Application: Ideal for preparing surfaces before applying new coatings or overlays.

2. Chipping:

• Definition: Chipping involves manually or mechanically removing the top layer of old concrete.
• Purpose: By exposing a rough, clean surface, chipping helps create a strong bond between the old and new concrete layers. This method is commonly used to remove damaged or deteriorated concrete.
• Application: Used in situations where only specific areas of the concrete need repair, such as cracks or surface degradation.

3. Grinding:

• Definition: Grinding is a process that removes the surface layer of concrete using abrasive materials or grinders.
• Purpose: This technique cleans the surface and creates a uniform, rough texture, making it suitable for bonding with new concrete or surface treatments.
• Application: Often used for surface leveling, polishing, and preparing the concrete for sealers or coatings.