借助激光闪光法研究高强混凝土的低温热学性能

Thermal Properties of High-strength Concrete with Laser Flash Analysis at Cryogenic Temperatures

低温环境中混凝土的热学性能是影响全混凝土LNG储罐安全高效运行的重要因素。本工作评价了一种新型耐低温高性能混凝土(CHC)的低温性能,并对其孔结构特征和低温环境中的热流变化、力学和热学性能进行了分析。结果表明:CHC基体中毛细孔和气孔的体积以及总孔隙率均低于C60混凝土。低温环境中,CHC基体的热流曲线在-36℃达到峰值;其热流曲线放热峰、比热容、热扩散系数和热导率均低于C60混凝土。当温度由25℃降至-90℃时,CHC基体和C60混凝土的峰值应力、弹性模量及热扩散系数增加;比热容和热导率降低。低温环境中,CHC的力学性能及其基体的热学性能均优于C60混凝土。

The thermal properties are key factors affecting the safety and operating efficiency of all-concrete LNG storage tank.However,the thermal properties of concrete at cryogenic temperatures are still unclear.The performance of a new type of cryogenic temperature resistant high-performance concrete(CHC)was evaluated in this paper.The pore structure,heat flow behavior,mechanical and thermal properties of CHC at cryo-genic temperatures were investigated.The results showed that the volume of capillary pores and air pores and the total porosity of CHC matrix were less than that of C60 concrete.At cryogenic temperatures,the heat flow curve of CHC matrix reached its peak at-36℃.The height of heat flow peak,specific heat capacity,thermal diffusivity,and thermal conductivity of CHC matrix were less than that of C60 concrete.When the temperature decreased from 25℃to-90℃,the peak stress value,elastic modulus,and thermal diffusion coefficient of CHC matrix and C60 concrete increased;while the specific heat capacity and thermal conductivity decreased.The mechanical properties of CHC and the thermal properties of CHC matrix are superior to C60 concrete at cryogenic temperature.