【摘要】 通过借鉴混凝土快冻法，对比研究高性能湿喷混凝土(HPS)、掺速凝剂的模筑混凝土(HPS-Cast)及普通喷射混凝土(NSC)的抗冻性能，并对其内部气泡结构特征进行分析。结果表明：冻融循环作用下，NSC相对动弹性模量和抗压强度显著下降。冻融循环125次后，NSC相对动弹性模量仅为51.34%,冻融循环200次后，抗压强度损失率已达到53.30%,相比之下，HPS、HPS-Cast抗冻性能明显优于NSC,其中HPS抗冻性能最好。HPS-Cast由于采用模筑成型，成型方式与HPS不同，造成HPS-Cast气泡分布特征与HPS明显不同。冻融循环过程中，HPS-Cast平均气泡直径、平均气泡面积、气泡间隔系数均明显高于HPS,同时在0～200μm范围内孔体积率下降速率明显高于HPS,而200～500、500～1 200μm及大于1 200μm孔体积增长速率明显高于HPS。因此在冻融循环过程中，HPS-Cast抗冻性能较HPS下降更为明显。更多还原

【Abstract】 The freeze-thaw resistance of high performance wet-mix shotcrete(HPS), molded concrete mixed with accelerator(HPS-Cast) and ordinary shotcrete(NSC) was studied by reference to concrete quick freezing method, followed by an analysis on their internal air-void structure characteristics. The results show that the relative dynamic elastic modulus and compressive strength of NSC ordinary shotcrete decrease significantly under freeze-thaw cycles. After 125 freeze-thaw cycles, the relative dynamic elastic modulus of NSC is only 51.34%. After 200 freeze-thaw cycles, the compressive strength loss rate reaches 53.30%. By comparison, HPS and HPS-Cast have better freeze-thaw resistance than NSC, among which HPS has the best freeze-thaw resistance. HPS-Cast, due to using mold casting, has a different molding method from HPS, showing a significantly different air void distribution characteristics from HPS. During the freeze-thaw cycle, the average air void diameter, average air void area and air void spacing coefficient of HPS-Cast are significantly higher than those of HPS. At the same time, the decline rate of pore volume fraction in the range of 0～200 μm is significantly higher than that of HPS, while the pore volume growth rate of 200 ～ 500 μm, 500～1 200 μm and >1 200 μm is significantly higher than that of HPS. Therefore, the freeze-thaw resistance of HPS-Cast decreases more obviously than that of HPS during the freeze-thaw cycle.更多还原