A visual condition assessment of a reinforced concrete railway bridge subject to alkali silica reaction (ASR) deterioration in Johannesburg

Abstract In the 1940’s, a reinforced concrete (RC) railway bridge located in central Johannesburg was constructed using Witwatersrand Quartzite, at time, unknown to be an alkali-silica reactive aggregate. The currently displays signs of distress form severe map-cracking. This study presents preliminary results series tests that have been conducted characterise severity alkali silica reaction (ASR) deterioration bridge. Twelve cores were extracted for testing from various locations bridge, which displayed varying degrees distress. A visual assessment globally on entire structure as well locally (using modified damage rating index (DRI) approach) cores. findings showed there extensive map-cracking present all thirteen elements examined, revealing Even sheltered exposure direct rain, such underside three arch surfaces, also exhibited Furthermore, DRI method useful technique assess and compare relative extent taken RC structure, local images cylindrical surface Graphical