Effect of cryogenic temperature on static fracture of concrete having different structural sizes: Experimental tests

Cryogenic temperature is one of the extreme environments for the application of concrete. Compared with the vast amounts of researches on the size effect of concrete at ambient temperature, the investigation on size effect at cryogenic temperature is very limited. This work presents a series of experimental investigations on the static uniaxial-compressive/ splitting-tensile failure of concrete with different structural sizes (100, 150, and 300 mm) at four target temperature levels (+20 degrees C, -30 degrees C, -60 degrees C, and - 90 degrees C). The experimental results indicate that when the temperature decreases, the concrete specimens present more brittle failure patterns and the number of damaged aggregate particles on the failure surface increases. Additionally, both the measured uniaxialcompressive and splitting-tensile strengths increase linearly, and structural size exhibits a significant influence on the nominal strengths. The obvious size effect can be observed on compressive and splitting-tensile strengths at cryogenic temperature. Compared to uniaxial-compressive strength, cryogenic temperature performs more significant effect on the splitting-tensile strength and its corresponding size effect. Finally, based on the statistical size effect law, a modified prediction formula considering quantitative coupling effect of temperature and structural size was proposed, which can predict the nominal strength of concrete with different structural size at different cryogenic temperatures.