10 – Strategies to Investigate the Redox Biology of Sulfenic Acids in Cells

The stiffness damage test (SDT) is a powerful tool developed for the evaluation of the damage's degree of concrete affected by ASR. This paper presents the assessment of some parameters (test loading and output responses) on the efficiency of the method. The analyses were carried out with three types of concrete (25, 35 and 45 MPa) and two highly-reactive aggregates (New Mexico gravel and Texas sand). The diagnostic character of various output parameters was analyzed and the results showed that the SDT should be carried out with a percentage of the design strength (ideally 40%) instead of working with a fixed load. Parameters such as the hysteresis area and the plastic deformation over the five cycles of loading/unloading as well as the average modulus of elasticity of the second and the third cycles seem to give quite good correlations with the amount of expansion reached by the concrete.