关键词: 混杂纤维混凝土, 冻融循环周次, 孔结构特征, 冻融损伤

Abstract: In order to study the effect of freeze-thaw cycle on the performance of hybrid fiber concrete, the rapid freeze-thaw cycle tests of concrete with different fiber volumes were carried out, focusing on the variation law of mechanical behavior and pore structure characteristics of hybrid fiber concrete. The test results show that with the increase of freeze-thaw cycle, the compressive and splitting tensile strength of hybrid fiber concrete decreases, and the amount of freeze-thaw damage increases, while the addition of fiber reduces the amount of freeze-thaw damage and the strength reduction caused by freeze-thaw. This phenomenon becomes more and more significant with the increase of fiber volume. From the microscopic analysis, the pore parameters of fiber reinforced concrete, such as air content, bubble spacing coefficient and average chord length, are negatively correlated with the compressive and splitting tensile strength of the specimen, but positively correlated with the amount of freeze-thaw damage. When the volume content of fiber is constant, the more freeze-thaw cycles, the greater the air content, bubble spacing coefficient and average chord length of concrete, and the smaller the specific surface area of pores.

Key words: hybrid fiber concrete, freeze thaw cycles, pore structure characteristics, freeze thaw damage