计涛,李行星,张秀崧,吴正桥,徐立洲,李曙光,陈改新

• 1:中国水利水电科学研究院流域水循环模拟与调控国家重点实验室
• 2:新疆额尔齐斯河流域开发工程建设管理局
• 3:中水北方勘测设计研究有限责任公司

摘要(Abstract)：

为改善高寒地区大坝混凝土长期遭受冻融循环作用导致的性能衰减问题,基于对抗冻机理的认知进行混凝土配合比定量设计,在低热水泥、粉煤灰胶凝材料体系中掺加了高活性纳米掺合料对混凝土微结构进行协调优化,配制了高抗冻混凝土。研究了冻融循环作用下纳米掺合料混凝土的抗压强度、劈拉强度、氯离子扩散系数、相对动弹性模量和质量损失率,分析了气泡参数对混凝土抗冻性的影响,并与水利工程中普遍采用的大坝混凝土进行性能对比。结果表明,掺入纳米掺合料可使大坝混凝土的用水量降低6 kg/m~3,混凝土和易性得到改善;在长期冻融循环作用下,纳米掺合料混凝土的抗压强度提高了3.1%～8.0%,劈拉强度提高了7.6%～19.3%,抗氯离子渗透性提高了27%～59%;纳米掺合料的掺入使混凝土内部气泡孔径细化,微结构得到优化;混凝土抗冻等级大于F800,气泡间距系数小于0.25 mm,具有优良的抗冻性能。该研究成果为纳米掺合料在高寒地区大坝混凝土的应用提供了参考和依据。

关键词(KeyWords)： 高寒地区;纳米掺合料;大坝混凝土;冻融循环;气泡参数

Abstract:

Keywords:

基金项目(Foundation): 国家重点研发计划资助项目(2018YFC0406701);; 自然科学基金课题(51879286);; 中国水科院“三型人才”培育课题(SM0145B842017);中国水科院基本科研业务项目(SM0145B032021)

作者(Author): 计涛,李行星,张秀崧,吴正桥,徐立洲,李曙光,陈改新

DOI: 10.13928/j.cnki.wrahe.2022.01.019

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