ABSTRACT
There are many causes of concrete deterioration. Common among these are reinforcement corrosion due to chloride attack or carbonation, freeze/thaw cycling, alkali-silica reaction (ASR) and poor quality of detailing, materials or workmanship. Other causes are sulphate attack, structural defects such as excessive flexural cracking (due to overloading, under-capacity or severe reinforcement corrosion) or differential settlement and defects arising during construction such as plastic or thermal cracking. Corrosion of reinforcing steel is by far the most widespread problem facing those responsible for the management of reinforced concrete structures. Steel in concrete is normally in a passive state due to the high alkalinity of the surrounding cement paste, but reduction in alkalinity by atmospheric carbon dioxide (carbonation), or the presence of chloride ions, may initiate corrosion. Once initiated, corrosion soon causes cracking and subsequent spalling of concrete cover which further accelerates deterioration.
