A basic realization of cause underlying deficiencies in concrete is essential for proper evaluation of meaningful repair. If we can determine or understand cause of particular deficiencies, it is easy to choose appropriate repair techniques which leads successful restoration of concrete structure or member. Obviously proper repair will provide maximum life of repair which is the main objective of this restoration process.
Now come to the point-‘symptoms’ and ‘cause’ of repair. Symptoms are deficiencies of concrete that is can be observed under naked eyes in most case they appeared as cracking, spalling, corrosion, discolor of concrete surface and access of fluids etc.
In most case, they are consequence of internal/external causes. So symptoms/observations of deficiencies should be properly differentiated from actual cause or causes of deficiencies.
Sometimes more than one cause may result one symptom and if we treated for one causes and another causes left untreated, the result will be temporary repair and very soon untreated cause will be expressed as some symptom.
Sometimes one cause of deficiency results another deficiency say a case that cause crack may lead to corrosion of reinforcement, which will lead structural cracking and also dealmination of concrete. Dear reader we have provided information about cracking, spalling and delamination of concrete in our previous posts.
So it is advisable to deal with causes not with symptoms as most case it lead to failure of repair process. Only when we know the cause/causes, we can make decisions about rationale repair system.
Example: we have to select repair method for cracking-
Cracking may occur due to:
Freezing and thawing cycles in one word alternate thermal cycles
and may from many reasons
The symptom, cracks can be resulted from above reasons if you treated for drying shrinkage and cause lies in freezing and thawing or due to expansion of foundation soil/shrinkage of the same(not listed above), the repair work will be failed.