Mechanical properties of concrete under different water content and low temperature conditions

The storage of liquified natural gas in concrete tanks is important for the adjustment of imbalance between consumption and supply. The mechanical properties of concrete under different water saturation and low temperature conditions are investigated from the uniaxial compression and splitting tensile strength tests. Both the elastic strain and peak strain at failure increase with the decrease of temperature in the compressive strength tests. The compressive and tensile strengths decrease with the increase of water content at 20 °C due to the water softening effects, while they increase with the water content at subzero temperatures resulting from the ice filling and binding effects. The elastic modulus follows the same trend with that of the compressive strength. Significant increases in the strength and brittleness index occur between − 30 and − 90 °C as the water in the vast nanopores is frozen. The freeze–thaw cycle at − 30 °C induces the increase in the number of larger pores, while the large pores are collapsed or filled after one freeze–thaw cycle at − 90 °C and − 180 °C due to the inward deformation resulting from the inconsistent contraction and expansion deformations between different particles. Our proposed prediction models show better fitting for the compressive and tensile strengths.