Multi-scale Damage Assessment of AAR-Affected Mass Concrete Under Various Stress States

Several studies have demonstrated the reliability of the Stiffness Damage Test (SDT) (a mechanical test) and the Damage Rating Index (DRI) (a petrographic test) as diagnostic tools for ordinary concrete (aggregate particle sizes up to 20 mm) under free expansion. There is however limited information on the application of these tools to mass concrete mixtures incorporating large coarse aggregate particles and subjected to several stress states. This paper presents the findings of a study aimed at evaluating the use of these tools for mass concrete with reactive coarse aggregate particle sizes ranging from 5 to 40 mm. The SDT and DRI tests were performed on concrete specimens subjected to different stress states (with or without sustained load and/or passive confinement) at 100% R.H. In total, six stress states were studied ranging from free expansion to triaxial stress states. The SDT results obtained were found to be highly sensitive to the stress states to which the specimens were subjected, depending on the resulting cracking pattern. In contrast, the DRI results can capture the damage state of the specimens, irrespective of the stress states and specimen orientation.