Quasi-static and dynamic compressive behaviours of wet-sieved mortar at low temperatures

This study experimentally investigated the quasi-static and dynamic compressive stress-strain behaviours of wet-sieved mortar (WSM) at 20 °C–−165 °C. Quasi-static and dynamic compression tests were carried out on 129 WSM cylinders using a 2000-kN universal test machine and a Ø75-mm split Hopkinson pressure bar device combined with a high-speed camera. Strain rates and low temperatures greatly influenced the failure processes and modes of WSM materials subjected to dynamic compression loadings. Test results showed that the decreasing temperature enhanced the strain rate effects on compressive strength and strain, modulus of elasticity, and specific energy absorption. Specifically, compared with the static compressive strength at ambient temperatures, the compressive strength at a strain rate of 200 s-1 was increased by 106.7 % and 251.2 % as the temperature equalled to 20 °C and −165 °C, respectively. Furthermore, empirical equations of low-temperature dynamic increasing factors were established through regression analyses. Finally, a modified low-temperature dynamic stress-strain model was proposed for WSM materials. Validations confirmed that the developed model reasonably described the stress-strain behaviours of WSM materials at 20 °C–−165 °C. The study results can be utilized to optimize the design of concrete at low temperatures, and the proposed stress-strain relationships can be employed to conduct more precise dynamic mesoscopic numerical simulations.