中高温及低温作用后超高韧性水泥基复合材料的力学性能

Study on mechanical properties of ultra-high toughness cementitious composites after medium-high temperature and low temperature

为研究超高韧性水泥基复合材料(UHTCC)在200~−100℃温度作用后的力学性能,设计了不同纤维体积掺量的UHTCC,经中高温和低温作用后进行基本力学性能试验,通过UHTCC强度和变形等参数评价了中高温和低温作用后UHTCC的力学性能。结果表明:纤维的掺入能有效改善基体的脆性,提升材料的韧性;同时温度作用导致材料内部出现初始缺陷,对UHTCC的力学性能有明显的影响,且低温作用的影响要明显高于高温作用,当温度降低至−100℃时,UHTCC强度最大降低约75%,变形最大降低约92%,但温度作用未对UHTCC的泊松比产生明显影响。在此基础上提出了中高温及低温作用后UHTCC轴压和轴拉应力-应变关系回归模型,为UHTCC材料在极端温度环境下的性能设计和工程应用提供参考。

In order to study the mechanical properties of ultra-high toughness cementitious composites(UHTCC)after temperatures of 200-−100℃,UHTCC with different fiber volume content was designed.The basic mechanical properties of UHTCC after medium-high temperatures and cryogenic temperatures were tested,and the mechanical properties of UHTCC after medium-high temperatures and cryogenic temperatures were evaluated by parameters such as strength and deformation of UHTCC.The results show that the incorporation of fibers can effectively improve the brittleness of the material and enhance the toughness of the material.The temperature effect makes the initial defects appear inside the material,which has a significant effect on the mechanical properties of UHTCC,and the effect of low temperature is significantly higher than that of high temperature.When the temperature is reduced to−100℃,the strength of UHTCC is reduced by about 71%at most,and the deformation is reduced by about 92%at most,but the temperature has no significant effect on the Poisson's ratio of UHTCC.On this basis,the regression model of axial compression and axial tensile stress-strain relationship of UHTCC after medium-high temperatures and cryogenic temperatures is proposed,which provides a reference for the performance design and engineering application of UHTCC materials at extreme temperatures.