Case 3

Remedial (see also Remedial)

1. Repair of structural crack lines (Procedure of Surface Repair)

Surface repairs can be done on the floor slab if there are no signs of water seepage from underneath or widening of gap with time.

2. Polymer Modified Cementitious Grouting

This can be applied on the crack so that the final appearance of concrete structure closely resembles the concrete being repaired, in respect of strength and long term movement. Its characteristics are improved with regards to bonding, flexibility and time within which strength is gained.

3. Patching (Procedure of Patching)

This method is used to rehabilitate corrosion-damaged infrastructure, where the application of waterproofing membranes prevents, or at least retard, the ingress of chlorides to the reinforcement. However, when the chloride content in the concrete in contact with the rebars equals or exceeds the corrosion threshold, membranes will have no significant impact on reducing the level of corrosion.

The patching method is the most common repair method for minor concrete defects such as surface spalls. Two types of materials are commonly used for patching up by hand:

Cementitious mortars such as cement mortar and polyester-modified cementitious mortar.
Resin-based mortars such as epoxy resin mortar and polyester resin mortar.

4. Repair using epoxy injection (Procedure of Epoxy Injection)

One of the most versatile, crack repair method is epoxy injection.