作者：宋晶颖, 许玲玲, 买哲

作者单位：新乡学院，河南 新乡 453000

关键词：冻融循环;硫酸盐侵蚀;纳米SiO₂;质量;抗压强度;劈裂抗拉强度;相对动弹性模量;SEM微观

摘要：

针对西北地区盐渍土环境中混凝土长期受冻融循环与硫酸盐侵蚀耦合作用而遭受严重破坏的问题，制备纳米SiO₂掺量分别为0 kg/m³、2 kg/m³、4 kg/m³、6 kg/m³、8 kg/m³的混凝土试件，测试试件在冻融循环与硫酸盐侵蚀耦合作用下的质量、抗压强度、劈裂抗拉强度、相对动弹性模量等研究。结果表明：随着冻融循环与硫酸盐侵蚀耦合作用的进行，试件的力学性能逐渐弱化，混凝土内部的损伤越来越严重；质量先增大后迅速降低，抗压强度、劈裂抗拉强度和相对动弹性模量逐渐降低，损失率逐渐提升；综合上述4种指标的数据分析得出，当纳米SiO₂掺量为4.0 kg/m³时，各项性能表现最佳。最后借助SEM微观扫描对冻融循环与硫酸盐侵蚀耦合作用混凝土损伤机理进行分析。

Study on the effect of nano-SiO₂ on concrete performance under the combined action of freeze-thaw cycle and sulfate erosion
SONG Jingying, XU Lingling, MAI Zhe
Xinxiang University, Xinxiang 453000, China
Abstract: In view of the severe damage to the concrete in the saline soil environment in the northwestern region due to the long-term freeze-thaw cycle and sulfate erosion coupling effect, nano-SiO₂ content of 0 kg/m³, 2.0 kg/m³, 4.0 kg/m³, 6.0 kg/m³, and 8.0 kg/m³ were prepared. For concrete specimens, the quality, compressive strength, split tensile strength, and relative dynamic elastic modulus of the specimens under the combined action of freeze-thaw cycles and sulfate erosion were tested. The results show that with the progress of the coupling effect of freeze-thaw cycles and sulfate erosion, the mechanical properties of the specimens gradually weaken, and the internal damage of the concrete becomes more and more serious; the quality first increases and then rapidly decreases, the compressive strength and splitting tensile strength. The strength and relative dynamic elastic modulus gradually decrease, and the loss rate gradually increases. Based on the data analysis of the above four indicators, it is concluded that the performance of each performance is the best when the content of nano-SiO₂ is 4.0 kg/m³. Finally, with the help of SEM microscopic scanning, the concrete damage mechanism of the coupling effect of freeze-thaw cycle and sulfate attack was analyzed.
Keywords: freeze-thaw cycles;sulfate erosion;nano-SiO₂;quality;compressive strength;split tensile strength;relative dynamic modulus of elasticity;SEM microscopic
2022, 48(11):174-179  收稿日期: 2021-04-25;收到修改稿日期: 2021-06-03
基金项目:
作者简介: 宋晶颖（1982-），女，河南新乡市人，讲师，硕士，研究方向为建筑土木、建筑设计、建筑材料
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