Flexural response of reinforced concrete beams affected by internal swelling reactions: analysis and interpretation of experimental studies

Since the middle of the last century, reinforced concrete (RC) structures in different countries have been diagnosed as suffering from internal swelling reactions (ISRs), such as alkali-silica reaction (ASR) and delayed ettringite formation (DEF), in some cases raising the attention on possible structural safety issues. A thorough comprehension of ISR effects at the structural level is essential for a proper structural assessment of deteriorated structures, in order to obtain safe estimates of the structural capacity, while avoding excessive conservativism. Over the past decades, several experimental campaigns were con-ducted on both reduced-scale and full-scale structural elements. This work collects and discusses results of several experimental tests on ISR-affected RC beams reported in literature, focusing on some of those addressing ISR consequences on the flexural response. Based on experimental evidence from laboratory structural tests, some considerations are proposed regarding main aspects which should be considered when evaluating the structural performance of ISR-affected existing RC members, as well as some aspects relevant for further future research.