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General Requirements for Quality Repair of concrete structure


Repairing a concrete structure required good knowledge and long experience. The responsible person or team should be able to determine the type of defects. The reason behind this defect. Recently a Bridge Collapse at Florida International University. The photos were taken before the bridge collapse showing large and long cracks. The evaluation of the engineering team was wrong, and this lead to the bridge collapse, unfortunately. Therefore the maintenance and repairing of a concrete structure should be assigned to an expert team who can evaluate the defects and the possible repairing methods. 




The failure rate of the repaired concrete structure is high (Goodwin, 2008); therefore the proposed method of repairing and the proposed materials should be approved by a knowledgeable and trained person in the field of concrete repair. The repairing material should be compatible with existing concrete. The exposure condition of the repaired area should be considered. If the area is exposed to seawater. Then the repaired surface should be waterproofed to prevent the ingress of aggressive chemical. Also, the used materials should have low permeability. to achieve successful repairing. The reason behind the deterioration of the old structure should be eliminated.

Choosing repairing materials is a daunting task. The difficulties of selecting the repairing materials arise from the insufficient information about the repairing material available at the market. Also, manufacturers are unwilling to provide all the information about their materials. Therefore the selected materials should be tested according to ACI International Concrete Repair Institute (ICRI) data sheet protocol (ACI 364.3R, 2009) (ICRI 320.3R, 2012).

Figure 1


The repairing of a concrete structure can vary from shrinkage crack, bolt holes, chemical deterioration to structural failure. The process of repairing should be followed carefully. Omitting or unproper performing a step of repairing procedure will adversely affect the serviceability of the whole repair. Inadequate workmanship, procedures, or materials will result in inferior repairs, which will likely fail prematurely.


  • Workmanship
Workmanship and skilled personals are the keys to the success of any repairing process. The repairing in most cases is manual operations. Therefore persons who involved in this operations should have enough knowledge of the process of repairing. Using skilled person will ensure a durable repair, good bonding of materials, and no cracks. Some products may require that personnel are certified by the material manufacturer before a material’s use. Inspection should be performed to verify the correctness of repairing operation and compliance with standards.


  • Procedures
Implementing the proper methods of repairing will result in durable concrete repair. Wrong methods, coupled with poor workmanship, will lead to poor repairing that will not last. 

Repairing the surface of new concrete should performed early. Immediately after striping, the shutter repairing of the surface should be done. The curing of the concrete surface will be stopped for the repaired area only. After the completion of repairing the curing should begin again. For better result. Repairing should be done when concrete is still green. Repairing should be performed after 24 hours of removing shutter to a maximum of 72 hours. The early repairing will ensure the best bonding between the concrete surface and the repairing materials.

For old structures to ensure durable repairs. The deteriorated area should be removed completely. The remaining concrete should be prepared to receive the repairing materials. Then repairing materials should be mixed and placed in according to manufactures guidelines. 


  •    Materials
Materials should be of high quality. It should meet the specification requirement for the intended use. Testing reports should be supplied by the manufacturers to prove the quality of the materials. Materials shall be selected carefully. In case of choosing the wrong materials with poor quality. The cost of removing and applying new materials is high.  






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