This paper presents a study on the 20th century reinforced concrete heritage structures, thier
durability problems, thier repair and restorations according to the conservation principles of
heritage structures and the repair principles of reinforced concrete structures.The common
problems on reinforced concrete heritage structures such as reinforcement corrosion, alkali
aggregate reaction, freeze thaw and overloading of the structure are identified and thier
respective repair methods presented. Even though so many causes exist that contribute for
durability problems of reinforced concrete heritage structures, the mentioned ones are the
most common appearing in most cases