@article{MotraHildebrandDimmigOsburg,
  author    = {Motra, Hem Bahadur and Hildebrand, J{\"o}rg and Dimmig-Osburg, Andrea},
  title     = {Assessment of strain measurement techniques to characterise mechanical properties of structural steel},
  series = {Engineering Science and Technology, an International Journal},
  journal   = {Engineering Science and Technology, an International Journal},
  doi       = {10.1016/j.jestch.2014.07.006},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170425-31540},
  pages     = {260 -- 269},
  abstract  = {Strain measurement is important in mechanical testing. A wide variety of techniques exists for measuring strain in the tensile test; namely the strain gauge, extensometer, stress and strain determined by machine crosshead motion, Geometric Moire technique, optical strain measurement techniques and others. Each technique has its own advantages and disadvantages. The purpose of this study is to quantitatively compare the strain measurement techniques. To carry out the tensile test experiments for S 235, sixty samples were cut from the web of the I-profile in longitudinal and transverse directions in four different dimensions. The geometry of samples are analysed by 3D scanner and vernier caliper. In addition, the strain values were determined by using strain gauge, extensometer and machine crosshead motion. Three techniques of strain measurement are compared in quantitative manner based on the calculation of mechanical properties (modulus of elasticity, yield strength, tensile strength, percentage elongation at maximum force) of structural steel. A statistical information was used for evaluating the results. It is seen that the extensometer and strain gauge provided reliable data, however the extensometer offers several advantages over the strain gauge and crosshead motion for testing structural steel in tension. Furthermore, estimation of measurement uncertainty is presented for the basic material parameters extracted through strain measurement.},
  subject      = {Baustahl},
  language  = {en}
}
@article{MuellerLudwigTangeHasholt,
  author    = {M{\"u}ller, Matthias and Ludwig, Horst-Michael and Tange Hasholt, Marianne},
  title     = {Salt frost attack on concrete: the combined effect of cryogenic suction and chloride binding on ice formation},
  series = {Materials and Structures},
  volume    = {2021},
  journal   = {Materials and Structures},
  number    = {issue 54, article 189},
  doi       = {10.1617/s11527-021-01779-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20211207-45392},
  pages     = {1 -- 16},
  abstract  = {Scaling of concrete due to salt frost attack is an important durability issue in moderate and cold climates. The actual damage mechanism is still not completely understood. Two recent damage theories—the glue spall theory and the cryogenic suction theory—offer plausible, but conflicting explanations for the salt frost scaling mechanism. The present study deals with the cryogenic suction theory, which assumes that freezing concrete can take up unfrozen brine from a partly frozen deicing solution during salt frost attack. According to the model hypothesis, the resulting saturation of the concrete surface layer intensifies the ice formation in this layer and causes salt frost scaling. In this study an experimental technique was developed that makes it possible to quantify to which extent brine uptake can increase ice formation in hardened cement paste (used as a model material for concrete). The experiments were carried out with low temperature differential scanning calorimetry, where specimens were subjected to freeze-thaw cycles while being in contact with NaCl brine. Results showed that the ice content in the specimens increased with subsequent freeze-thaw cycles due to the brine uptake at temperatures below 0 °C. The ability of the hardened cement paste to bind chlorides from the absorbed brine at the same time affected the freezing/melting behavior of the pore solution and the magnitude of the ice content.},
  subject      = {Beton},
  language  = {en}
}