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 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 - Dang, V.H. A1 - Francois, R. A1 - L'Hostis, V. A1 - Meinel, Dietmar T1 - Propagation of corrosion in pre-cracked carbonated reinforced mortar N2 - This paper deals with the initiation and propagation of corrosion in mortar specimens pre-cracked under mechanical loading and carbonated in climate accelerated conditions (50 % CO2–65 % RH) for 15–23 weeks. Mechanical loading led to transverse macro-cracks and damage at the steel-mortar interface characterized by micro-cracks (cover controlled cracking) which favour the carbonation of crack walls and the interface with the steel bar. Wetting–drying cycles performed after carbonation favoured corrosion initiation all along the steel bar because of the carbonated interface and corrosion propagation because of the creation of corrosion cracks which appear to develop from the micro-cracks induced by the mechanical load. Results also show that rust develops all around the perimeter of the carbonated steel bar but that the corrosion layer is thicker in the lower half surface of the reinforcement than that observed in the upper half. Results indicate that the distribution and composition of corrosion products depend on the thickness of the rust layer and that the multilayered structure of rust depends mainly on its thickness. KW - Carbonation KW - Crack KW - Steel bar KW - Propagation of corrosion KW - Raman spectra KW - Corrosion product KW - X-ray tomography KW - CT PY - 2014 UR - http://link.springer.com/article/10.1617/s11527-014-0338-z/fulltext.html DO - https://doi.org/10.1617/s11527-014-0338-z SN - 1359-5997 SN - 1871-6873 VL - 48 IS - 8 SP - 2575 EP - 2595 PB - Springer CY - Dordrecht AN - OPUS4-31290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dang, V. H. A1 - François, R. A1 - L’Hostis, V. A1 - Meinel, Dietmar T1 - Propagation of corrosion in pre-cracked carbonated reinforced mortar N2 - This paper deals with the initiation and propagation of corrosion in mortar specimens precracked under mechanical loading and carbonated in climate accelerated conditions (50 % CO2–65 % RH)for 15–23 weeks. Mechanical loading led to transverse macro-cracks and damage at the steel-mortar interface characterized by micro-cracks (cover controlled cracking) which favour the carbonation of crack walls and the interface with the steel bar. Wetting–drying cycles performed after carbonation favoured corrosion initiation all along the steel bar because of the carbonated interface and corrosion propagation because of the creation of corrosion cracks which appear to develop from the micro-cracks induced by the mechanical load. Results also show that rust develops all around the perimeter of the carbonated steel bar but that the corrosion layer is thicker in the lower half surface of the reinforcement than that observed in the upper half. Results indicate that the distribution and composition of corrosion products depend on the thickness of the rust layer and that the multilayered structure of rust depends mainly on its thickness. KW - Carbonation KW - Corrosion product KW - Steel bar KW - X-ray tomography PY - 2015 DO - https://doi.org/10.1617/s11527-014-0338-z SN - 1359-5997 VL - 48 IS - 8 SP - 2575 EP - 2595 PB - Springer AN - OPUS4-39057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -