为探究高性能水泥基复合材料(HPCC)抗冻性能,以天然河砂替代集料中的石英砂,替代率分别为0, 25%,50%,75%,100%,设定水胶比为0.16~0.32,步距为0.04,在5%的Na2SO4溶液中进行冻融循环试验,测定了不同冻融循环次数的质量损失、动弹模量及孔隙结构参数,引入气泡分布分形维数分析了HPCC抗盐冻性能及微观孔隙结构变化对其影响规律.结果表明:水胶比为0.16时,各试验组完成500次冻融循环,相对动弹模量基本不变,未发生冻融破坏;随冻融循环次数的增加,各试验组质量并未损失,反而出现增加现象;不同水胶比的HPCC冻融前后气泡分布曲线变化规律基本相同,即气泡孔径均向大孔方向迁移;随着气泡分布分形维数的增大,HPCC抗冻耐久性大致呈线性上升趋势.%To explore the performance of high-performance cement-based composites (HPCC) antifreeze, the quartz sand aggregate is replaced with natural river sand, the replacement rate are 0, 25%, 50%, 75%, 50%. The water-cement ratio is set as 0.16~0.32 and the step distance as 0.04. A freeze-thaw cycling test is carried out in 5% Na2SO4 solution, the quality loss of different freeze-thaw cycles and the parameters of dynamic modulus and pore structure parameters are measured, the influences of HPCC salt frost resistance and the microcosmic pore structure change are analyzed with the bubble distribution fractal dimension. Results show that when the water cement ratio is 0.16, the experimental group complete 500 freeze-thaw cycles, the relative dynamic modulus is basically constant with no freeze-thaw damage. With the increase of freeze-thaw cycles, the quality of the experimental group does not lose, it increases instead. The bubble curve distribution change rule before and after HPCC freezing and thawing of different water-binder ratios are basically the same, the bubble sizes are migrating to big holes. With the increase of fractal dimension of bubble distribution, HPCC frost resistance durability roughly shows a linear upward trend.
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