TY - CONF A1 - Gluth, Gregor A1 - Hlavacek, Petr A1 - Reinemann, Steffi A1 - Ebell, Gino A1 - Mietz, Jürgen ED - Alexander, M.G. ED - Beushausen, H. ED - Dehn, F. ED - Moyo, P. T1 - Leaching, carbonation and chloride ingress in reinforced alkali-activated fly ash mortars T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) N2 - Alkali-activated fly ash mortars were studied with regard to durability-relevant transport coefficients and the electrochemical behaviour of embedded carbon steel bars on exposure of the mortars to leaching, carbonation and chloride penetration environments. The transport coefficients differed considerably between different formulations, being lowest for a mortar with BFS addition, but still acceptable for one of the purely fly ash-based mortars. Leaching over a period of ~300 days in de-ionized water did not lead to observable corrosion of the embedded steel, as shown by the electrochemical data and visual inspection of the steel. Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - Alkali-activated materials KW - Steel corrosion KW - Leaching KW - Carbonation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464381 DO - https://doi.org/10.1051/matecconf/201819902025 VL - 199 SP - Article Number 02025 PB - EDP Sciences AN - OPUS4-46438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Gröber, Andre A1 - Böllinghaus, Thomas A1 - Kranzmann, Axel T1 - Corrosion fatigue of 1.4542 exposed to a laboratory saline aquifer water CCS-environment T2 - Energy Procedia N2 - X5CrNiCuNb16-4 has been proven to be sufficient resistant in corrosive environments, but shows rather unusual corrosion behaviour in CCS environment. Therefore a series of 30 specimens was tested at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ∼ 30 Hz). Due to the rather heterogeneous fine machined surfaces (Rz=4) the specimens are comparable with prefabricated parts. X5CrNiCuNb16-4 reached the maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa and lies 60% below the stress amplitude measured in air. The scatter range TN = 1:34 is disproportionately large. Although the fracture surface exhibited the typical striations and corroded surface areas no significant differences were found. The hardness was found to be homogeneous in all specimens tested at 335 HV10. Non-metallic inclusions were found within the microstructure, but no correlation could be found between the inclusions and early rupture. Still specimens that showed inclusions at the fracture surface and its cross section endured lower number of cycles. Additionally Aluminium was analysed in specimens with low number of cycles and may be cause for early rupture during corrosion fatigue tests. These findings reveal a very high sensitivity on a homogeneous microstructure upon the corrosion and corrosion fatigue behaviour of X5CrNiCuNb16-4 and needs to be taken into account when regarding this steel as pipe steel during injection of CO2 into saline aquifers. T2 - 13th International Conference on Greenhouse Gas Control Technologies CY - Lausanne, Switzerland DA - 14.11.2016 KW - Steel KW - Corrosion fatigue KW - Electrochemistry KW - Reliability KW - CCS KW - CO2-storage PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418525 DO - https://doi.org/10.1016/j.egypro.2017.03.1678 SN - 1876-6102 VL - 114 SP - 5219 EP - 5228 AN - OPUS4-41852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maack, Stefan A1 - Villalobos, S. A1 - Scott, D. T1 - Validation of artificial defects for non-destructive testing measurements on a reference structure T2 - MATEC web of conferences N2 - Non-destructive testing was established over the last decades as an important tool for assessing damages, material characterization and quality assurance in civil engineering. For example, Ground Penetrating Radar (GPR) can be used to scan large areas of concrete structures to determine the spatial position of the reinforcement. With the ultrasonic echo method, the thickness of concrete structures can be easily determined even if a high density of reinforcement is given. Various methods and processes have been developed for the validation of NDT procedures aiming at ensuring the quality of measurements in practical use. The Probability of Detection (POD) for example, is an available method to compare different technical devices with each other quantitatively regarding their performance. With this method, the best suited testing device for a specific inspection task under defined boundary conditions can be selected. By using the Guide to the Expression of Uncertainty in Measurement (GUM), it is possible to quantify the measurement uncertainty of an inspection procedure for a specific task. Another important aspect to improve the acceptance of Non-destructive testing methods is the development of reference specimens. Reference specimens serve for the calibration and further development of NDT methods under realistic conditions in different laboratories under the same conditions. A particular challenge here is the most realistic representation of a damage that can occur at building sites. Possible damages include for example horizontal and vertical cracks or honeycombs in concrete. Such a reference structure was built for the development of a new design of power plant constructions. Comparative studies on the manufacturing of realistic honeycombs and delaminations were carried out in advance on a test specimen. The results of this study are presented here. T2 - ICCRRR 2018 - Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 19.11.2018 KW - Zerstörungsfreie Prüfung KW - Nondestructive testing KW - Istzustandserfassung KW - Ultrasonic PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464497 DO - https://doi.org/10.1051/matecconf/201819906006 SN - 2261-236X VL - 199 SP - 1 EP - 9 PB - EDP Sciences CY - Les Ulis AN - OPUS4-46449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Küttenbaum, Stefan A1 - Taffe, A. A1 - Braml, T. A1 - Maack, Stefan ED - Alexander, M. G. ED - Beushausen, H. ED - Dehn, F. ED - Moyo, P. T1 - Reliability assessment of existing bridge constructions based on results of non-destructive testing T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) N2 - The non-destructive testing methods available for civil engineering (NDT-CE) enable the measurements of quantitative parameters, which realistically describe the characteristics of existing buildings. In the past, methods for quality evaluation and concepts for validation expanded into NDT-CE to improve the objectivity of measured data. Thereby, a metrological foundation was developed to collect statistically sound and structurally relevant information about the inner construction of structures without destructive interventions. More recently, the demand for recalculations of structural safety was identified. This paper summarizes a basic research study on structural analyses of bridges in combination with NDT. The aim is to use measurement data of nondestructive testing methods as stochastic quantities in static calculations. Therefore, a methodical interface between the guide to the expression of uncertainty in measurement and probabilistic approximation procedures (e.g. FORM) has been proven to be suitable. The motivation is to relate the scientific approach of the structural analysis with real information coming from existing structures and not with those found in the literature. A case study about the probabilistic bending proof of a reinforced concrete bridge with statistically verified data from ultrasonic measurements shows that the measuring results fulfil the requirements concerning precision, trueness, objectivity and reliability. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - NDT KW - Concrete KW - Probabilistic reassessment KW - Bridge PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467898 DO - https://doi.org/10.1051/matecconf/201819906001 SN - 2261-236X VL - 199 SP - 06001, 1 EP - 9 PB - MATEC Web of Conferences AN - OPUS4-46789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Kühn, Hans-Joachim A1 - Rehmer, Birgit A1 - Skrotzki, Birgit ED - Iacoviello, Francesco T1 - Modeling the lifetime reduction due to the superposition of TMF and HCF loadings in cast iron alloys T2 - Procedia Structural Integrity N2 - The superposition of small amplitude, high frequency loading cycles (HCF) to slow, large amplitude loading cycles (TMF) can significantly reduce the fatigue life. In this work, the combined TMF+HCF loading has been experimentally investigated for a cast iron alloy. In particular, the influence of the HCF frequency of the HCF amplitude and of the location of the superposed HCF cycles has been assessed. It was observed that the HCF frequency has a limited impact on the TMF fatigue life. On the other side, the HCF-strain amplitude has a highly non-linear influence on the TMF fatigue life. A simple estimate for the fatigue life reduction due to the superposed HCF cycles has been derived from fracture mechanics considerations. It is assumed that the number of propagation cycles up to failure can be neglected after a threshold for the HCF loading has been reached. The model contains only two adjustable parameters and can be combined with any TMF life prediction model. The model predictions are compared with the test results for a large range of TMF+HCF loading conditions. T2 - 21st European Conference on Fracture, ECF21 CY - Catania, Italy DA - 20.06.2016 KW - Thermomechanical Fatigue (TMF); High Cycle Fatigue (HCF); Cast iron; Fatigue assessment PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-369550 DO - https://doi.org/doi:10.1016/j.prostr.2016.06.274 VL - 2 SP - 2190 EP - 2197 PB - Elsevier CY - Radarweg 29, 1043 NX Amsterdam, The Netherlands, AN - OPUS4-36955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Kranzmann, Axel T1 - Impact of saline aquifer water on surface and shallow pit corrosion of martensitic stainless steels during exposure to CO2 environment (CCS) T2 - IOP Conference Series: Earth and Environmental Science N2 - Pipe steels suitable for carbon capture and storage technology (CCS) require resistance against the corrosive environment of a potential CCS-site, e.g. heat, pressure, salinity of the aquifer, CO2-partial pressure. Samples of different mild and high alloyed stainless injection-pipe steels partially heat treated: 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 as well as X5CrNiCuNb16-4 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in a CO2-saturated synthetic aquifer environment similar to possible geological on-shore CCS-sites in the northern German Basin. Main corrosion products are FeCO3 and FeOOH. Corrosion rates obtained at 100 bar are generally much lower than those measured at ambient pressure. Highest surface corrosion rates are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4 in the vapour phase at ambient pressure. At 100 bar the highest corrosion rates are 0.01 mm/year for 42CrMo4, X20Cr13 (liquid phase), X46Cr13 and less than 0.01 mm/year for X35CrMo4 and X5CrNiCuNb16-4 after 8000 h of exposure with no regard to atmosphere. Martensitic microstructure offers good corrosion resistance. T2 - 8th International Conference on Future Environment and Energy (ICFEE 2018) CY - Phuket, Thailand DA - 10.01.2018 KW - CCS KW - CO2 corrosion KW - Pipeline PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465896 DO - https://doi.org/10.1088/1755-1315/150/1/012012 VL - 150 SP - 81 EP - 90 PB - IOP Publ. AN - OPUS4-46589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems T2 - MATEC Web of Conferences N2 - Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system. T2 - 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) CY - University of Lisbon, Portugal DA - 26.09.2018 KW - Grout KW - Microfine Cement KW - Superplasticizer KW - Supplementary Cementitious Materials KW - Shrinkage Reducing Admixture PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478319 DO - https://doi.org/10.1051/matecconf/201927801001 VL - 278 SP - Article Number 01001 PB - EDP Sciences AN - OPUS4-47831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -