Assessment of the residual expansion potential of concrete from structures damaged by AAR

The determination of the residual expansion potential can provide important information on the prognosis of AAR in concrete structures. However, there are still uncertainties about the test protocol and data analysis. In this study, residual expansion of cores from several concrete structures damaged by AAR was measured. The expansion during the test can be divided into different phases with different expansion rates. The results indicate that the expansion in the first phase, that takes place after sample conditioning but before a linear expansion rate is reached, is specific for each concrete and proportional to the further expansion of the cores during the test. Therefore, it can be used to distinguish concrete with different residual expansion potentials. The residual expansion correlates both with the expansion rates on the investigated structures and the expansion of lab concrete, having a similar composition as the on-site concrete, determined with a concrete performance test.