MANAGEMENT OF CONCRETE STRUCTURES AFFECTED BY ALKALI-AGGREGATE REACTION

The problem of managing concrete structures affected by alkali-aggregate reaction (AAR) is quite complex, particularly in relation to the prognosis of damaged structures. Until now, a reliable method to determine the potential for further deterioration was not available. In this work, an approach is suggested for the management of AAR damaged structures. Cores were taken from one of these structures and subjected to stereomicroscope and scanning electron microscopy observations to identify the cause of concrete deterioration. Once AAR pathology was diagnosed, parts of these cores were used for laboratory tests for prognosis purposes. The cores were immersed in 1N sodium hydroxide solution at 40 degrees C and changes in dynamic elastic modulus were monitored for up to six months of exposure in order to determine the potential for further reaction. In addition, based on the concrete compressive strength at the time of coring, it was possible to rank the structures in terms of priority of intervention for restoration. For the covering abstract see ITRD E123168.