🕑 Reading time: 1 minute
Post concreting defects in structures are defects which are seen after the removal of formwork. Repair of these post-concreting defects, materials, equipments required and methods of repairs are discussed.Repair of Post Concreting Defects in Structures
The four essential features of a successful repair are: 1. Expediency: The longer the repair is left, the more work has to be done, and the less likely that the repair will blend in.![](jpg/clip_image0027a6c9.jpg)
![Cleaning of concrete surface prior to repair Cleaning of concrete surface prior to repair](jpg/clip_image0044dd7e.jpg)
![correct technique for repair of concrete structures correct technique for repair of concrete structures](jpg/clip_image00637f37.jpg)
![](jpg/clip_image008181b5.jpg)
Materials for Repairing Post Concrete Defects:
Before commencing the repair, the operative must have all the necessary materials and equipment. The materials normally used for patch repairs are:![Materials for Repairing Post Concrete Defects Materials for Repairing Post Concrete Defects](jpg/clip_image0102a3cc.jpg)
Equipment for repairs of concrete:
The below fig. shows the general equipments required for concrete repairs.![Equipment for repairs of concrete Equipment for repairs of concrete](jpg/clip_image0121e79a.jpg)
![Equipment for repairs of concrete Equipment for repairs of concrete](jpg/clip_image0141ff10.jpg)
Repairing of Honeycombed Concrete:
![Repairing of Honeycombed Concrete Repairing of Honeycombed Concrete](jpg/clip_image01617acd.jpg)
Structural repairs post concreting:
If the honeycombing is deep or as occasionally happens, passes through a section, the concrete will need to be removed and the whole section recast. Before starting this exercise the column or section above the repair area will need supporting by an appropriate form of propping. The defective area can then be broken out. This will usually need more than a hammer and chisel, such as Pneumatic hammer as shown in figure below.![Pneumatic hammer for breaking of concrete Pneumatic hammer for breaking of concrete](jpg/clip_image018b816.jpg)
![Structural repairs post concreting Structural repairs post concreting](jpg/clip_image0201dc53.jpg)
Repair of blow holes in concrete structure:
A technique called “Bagging in: is used to repair excessive blow holes in the surface of concrete. This technique involves using a hessian pad to rub a cement paste into the holes. No other vibration or compaction is required. The repair mix is normally made from a 1:4 mix of cement and fine grade sand (silver sand is often used) with sufficient water to make a very stiff paste, so that it holds together when squeezed, but no water escapes. The treatment is most effective if done as soon as the formwork is struck, preferably the day after casting. A carborundum stone should be used to scour the surface and to expose any other blow holes close to the surface. The grinding of the surface will also expose more unhydrated cement particles that can bond with the repair work.![Repair of blow holes in concrete structure Repair of blow holes in concrete structure](jpg/clip_image02213606.jpg)
Repair of cracks in post concrete structures:
Cracks should always be reported to the relevant supervising authority. A small degree of cracking is quite common in most concrete structures, and can sometimes be ignored depending on how prevalent they are. Of course cracks can also indicate that there is something wrong.![Repair of cracks in post concrete structures Repair of cracks in post concrete structures](jpg/clip_image0241d3a9.jpg)