In this paper, the fracture properties at temperatures ranging from 20 to -170 °C are reported for a concrete mix similar to those used in the walls of liquid natural gas tanks. Stable three-point-bend tests on notched beams, conducted in…
In this paper, the fracture properties at temperatures ranging from 20 to -170 °C are reported for a concrete mix similar to those used in the walls of liquid natural gas tanks. Stable three-point-bend tests on notched beams, conducted in CMOD control, and standard cylinder-splitting tests were carried out at 20, -20, - 70, -120 and -170 °C. From these tests, typical fracture parameters were determined according to the cohesive crack model: tensile strength, fracture energy, softening curve (stress vs. crack opening), charac- teristic length and modulus of elasticity. The results show that the fracture properties of concrete improve as the temperature is lowered. As the temperature decreases, the tensile strength and the fracture energy increase markedly. From 20 to -170 °C, concrete shows a two-fold increase in tensile strength and a three-fold increase in fracture energy. With regard to the softening curves, the results show that a bilinear approximation is a good estimate even for temperatures as low as -170 °C, and the shape of the curve is very similar for temperatures over -120 °C. A significant difference in the shape, with a much shorter tail, is found at -170 °C. The charac- teristic length, a measure of the intrinsic brittleness of concrete, is not strongly influenced by the temperature in the range investigated.