A novel experimental setup for the determination of the thermal expansion coefficient of concrete at cryogenic temperatures

This article presents the design of a test device for cryogenic testing of concrete samples. Cryogenic tests consisted of compression and expansion tests of liquid nitrogen on cylindrical concrete specimens and their scope was to determine the linear coefficient of thermal expansion of the concrete material at temperatures from zero to minus 160 degrees C. This article presents a design. The test chamber and the new strategies that were used; along with the corresponding challenges posed by the heating and measurement problems. Affected heat transfer transient and steady state problems, which were realized using digital analysis using commercial FEM software, are presented along with the measurement equipment and methods that were used to match the numerically calculated temperature profiles along with the measured ones. In addition, the sample temperature measurement topology that was chosen for the experiments is compared with conventional ones in their ability to provide information representing the temperature state of the sample. Finally, the raw data from three tests are analyzed and the results are presented in appropriate graphs, taking into account the systematic errors introduced by thermal compression of the metrological equipment used for measuring length. The results are consistent with those available in the concrete literature.