【摘要】 为了研究冻融循环作用对掺加淡化海砂等原材料含有氯离子的粉煤灰钢筋混凝土结构的损伤规律，通过内掺氯盐的方法模拟海砂混凝土并设计了室内快速冻融循环试验。以海砂钢筋混凝土试件外观变化、质量损失率、损伤层厚度和相对动弹性模量4个评价指标探究了不同粉煤灰掺量对海砂钢筋混凝土的影响规律。将内掺盐冻复合作用下与已有研究中的气冻、水冻、外渗盐冻作用下的粉煤灰混凝土评价指标进行了对比分析。结果表明：随着冻融循环次数的增加，海砂粉煤灰混凝土的表层砂浆、细骨料和粗骨料依次脱落，其质量损失率及损伤层厚度增加，相对动弹性模量降低，混凝土抗冻性能有所下降，但其冻融损伤速率出现先增加后减小的趋势；粉煤灰掺入量越多，混凝土质量损失率及损伤层厚度越大，其相对动弹性模量越小，粉煤灰混凝土受到冻融循环损伤的程度越大，因此粉煤灰的加入虽能增加混凝土密实性，但不利于混凝土抗盐冻作用；相较于已有研究中的其他冻融方式，盐-冻双重作用加速了混凝土冻融损伤的发展，因外渗盐冻和内掺盐冻造成了混凝土内部氯离子分布差异，外渗盐冻作用对混凝土的影响更集中在外层区域，其中外层损伤的增加速度要快于内掺盐冻作用，但内掺盐冻对混凝土内部结构造成的损伤最大。更多还原

【Abstract】 In order to study the damage rule of fly ash reinforced concrete structures mixed with desalinated sea sand and other raw materials containing chloride ions caused by freeze-thaw cycles, the sea sand concrete is simulated by using the method of internal mixing chloride salt, and the indoor rapid freeze-thaw cycle experiment is designed. The influence rules of different fly ash contents on sea sand reinforced concrete are explored by 4 evaluation indicators, including the appearance change, mass loss rate, thickness of damage layer and relative dynamic elastic modulus of the sea sand reinforced concrete samples. The evaluation indicators of fly ash concrete under the combined action of internal mixing salt freezing are compared and analyzed with those under the action of air freezing, water freezing and exosmosis salt freezing. The result shows that(1) With the increase of freeze-thaw cycle, the surface mortar, fine aggregate and coarse aggregate of sea sand fly ash concrete peel off sequentially. The mass loss rate and damage layer thickness of sea sand fly ash concrete increase, the relative dynamic elastic modulus decreases, and the frost resistance of concrete decreases, but the freeze-thaw damage rate appears the trend of decreasing after increasing.(2) The more fly ash is added, the greater the concrete mass loss rate and the damage layer thickness, the less the relative dynamic elastic modulus, and the greater the extent of fly ash concrete damaged by freeze-thaw cycles. Therefore, although the addition of fly ash can increase the compactness of concrete, it is not conducive to the salt freezing resistance of concrete.(3) Compared with other freeze-thaw modes in existing studies, the dual action of salt-freeze accelerates the development of freeze-thaw damage to concrete. Because of the differences in the distribution of chloride ions within the concrete caused by exosmosis salt freezing and internal mixing salt freezing, the influences of exosmosis salt freezing on concrete are more concentrated in the outer region, where the outer layer damage increases faster than the situation caused by internal mixing salt freezing, but the internal mixing salt freezing causes the most serious damage to the internal structure of the concrete.更多还原