高鹏,胡筱,辛建达,程恒,张龑

• 1:新疆额尔齐斯河流域开发工程建设管理局
• 2:中国电建集团成都勘测设计研究院有限公司
• 3: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
• 4:中国水利水电科学研究院水利部水工程建设与安全重点实验室

摘要(Abstract)：

针对BEJSK拱坝所处区域温差大、极端气温低,混凝土易开裂的问题,为了优化混凝土配比并降低混凝土开裂风险,采用材料参数试验耦合数值计算的方法,研究了外加剂和粉煤灰掺量对混凝土材料参数和抗裂能力的影响。试验结果表明:相同水胶比和外加剂条件下,随着粉煤灰掺量从35%增至40%,混凝土的抗压强度在前28 d龄期降低12.5%(水胶比=0.38)～12.8%(水胶比=0.43),180 d龄期基本持平,180 d龄期劈拉强度随粉煤灰掺量增加降低9.5%(水胶比=0.38)～13%(水胶比=0.43),180 d龄期轴拉强度随粉煤灰掺量增加略微增长,180 d龄期弹性模量随粉煤灰掺量增加略微降低。28 d龄期绝热温升随粉煤灰掺量增加下降1℃;混凝土自生体积膨胀变形随粉煤灰掺量增加而降低。联合掺用新疆五杰NF-2缓凝高效减水剂与PMS-NEA3引气剂较联合掺用江苏博特JM-Ⅱ缓凝高效减水剂和GYQ引气剂制备的混凝土自生体积收缩变形略优。数值计算结果表明,混凝土的开裂风险系数与混凝土水胶比和温度历程相关。高水胶比混凝土的开裂风险系数在缓慢温降阶段较低水胶比混凝土偏大,但在快速温降阶段增速更缓。两种水胶比混凝土的开裂风险系数在快速温降阶段呈现"交叉"的现象。总之,高水胶比混凝土的开裂风险系数终值更低,抗裂能力优。

关键词(KeyWords)： 外加剂;粉煤灰;力学参数;热学参数;抗裂能力;混凝土;力学性能

Abstract:

Keywords:

基金项目(Foundation): 国家重点研发计划项目(2018YFC0406706);; 国家自然科学基金项目(51779277);; 中国水科院科研专项(SS0145B712017,SS0145B392016,SS0145B612017,SS0145B932017);; 流域水循环模拟与调控国家重点实验室自主研究课题(SKL2020ZY10)

作者(Author): 高鹏,胡筱,辛建达,程恒,张龑

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