TY - JOUR A1 - Ghantous, R.M. A1 - François, R. A1 - Poyet, S. A1 - L’hostis, V. A1 - Bernachy-Barbe, F. A1 - Meinel, Dietmar A1 - Portier, L. A1 - Tran, N.-C. T1 - Relation between crack opening and extent of the damage induced at the steel/mortar interface JF - Construction and Building Materials N2 - Cracks are inevitable in reinforced concrete structures and promote the diffusion of aggressive agents towards the reinforcement. In Eurocodes, for some exposure conditions, a threshold not to be exceeded for crack width near the rebar is recommended in order to limit risks of corrosion development and ensure structure durability. On the other hand, several studies show that the steel/mortar interface quality at the intersection with a crack strongly influences corrosion development. The aim of this study was therefore to test whether a relation exists between the extent of mechanical damage at the interface and the corresponding residual crack opening. To this end, specimens were cracked using three point bending test apparatus and the evolution of crack opening was determined on the outer surface and deep within the specimen. It was observed that the crack opening measured on the outer surface of the specimen was very close to that measured at various depths within the specimen at the same height level. In addition, the length of the mechanically damaged interface was determined for each residual crack opening. It was deduced that cracks induced significant steel/mortar Interface damage independently of the size of their openings. The length of the mechanically damaged interface increased proportionally to the residual crack opening without showing marked variation after a certain crack opening value. Based on the observed results, it is deduced that defining thresholds on crack openings is logical for esthetic reasons but is not articularly relevant for corrosion risk assessment. KW - Reinforced concrete KW - Cracks KW - Load-induced damage KW - Micro-CT PY - 2018 DO - https://doi.org/10.1016/j.conbuildmat.2018.10.176 VL - 193 SP - 97 EP - 104 PB - Elsevier Ltd. CY - Oxford, GB AN - OPUS4-46623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poyet, S. A1 - Dridi, W. A1 - L'Hostis, V. A1 - Meinel, Dietmar T1 - Microstructure and diffusion coefficient of an old corrosion product layer and impact on steel rebar corrosion in carbonated concrete JF - Corrosion Science N2 - Corrosion is the major degradation pathway affecting reinforced concrete structures. In the long-term, the rust layer might become thick and slow down the diffusion of oxygen from the atmosphere to the steel. With this in mind, the mineralogy, microstructure and diffusion properties of an old and thick corrosion product layer were investigated. Despite the presence of macropores, the gas diffusion coefficient was found to be low. The impact of the layer on the oxygen diffusion was evaluated using Fick’s law. The results showed that the layer could reduce the flux of oxygen only in a specific configuration. KW - Steel reinforced concrete KW - Rust KW - X-ray computed tomography KW - Micro-CT PY - 2017 DO - https://doi.org/10.1016/j.corsci.2017.06.002 VL - 2017 IS - 125 SP - 48 EP - 58 PB - Elsevier B.V. CY - Radarweg 29, 1043 NX Amsterdam, The Netherlands AN - OPUS4-41784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -