The Durability of Repaired Concrete Structures

This paper addresses the performances of concrete repairs in practice as opposed to accelerated laboratory testing. The performances were assessed through case-histories obtained from European countries ranging from Finland in the north to Greece in the south. Some 230 case-histories were obtained for structures up to 150 years old. Corrosion was the most common mode of deterioration occurring in 55 per cent of the cases, other modes included frost damage, cracking and AAR. Types of repair included patching, sprayed concrete, crack injection and restoration of strength. Performances of the repairs were generally disappointing; 20 per cent failed in 5 years, 55 per cent failed in 10 years and 90 per cent failed in 25 years. The longest repair life was 52 years. The types and causes of the failures are discussed.