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抽水蓄能电站混凝土面板阻裂技术研究*
肖阳1,黄如卉1,隋伟1,李艳萍1,巴恒静2
摘 要

(1 中水东北勘测设计研究有限责任公司, 长春 130061; 2 哈尔滨工业大学土木工程学院, 哈尔滨 150006)

[摘要]基于紧密堆积理论和微粒级配数学模型,设计水泥基材料的配合比,研究了不同水胶比下,膨胀剂A+聚丙烯纤维PP和膨胀剂B+纤维素纤维C的复合掺入对砂浆的强度、自收缩、干燥收缩及对圆环约束砂浆收缩开裂和二级界面结构的影响。试验结果表明,二级界面的改善可减小硬化浆体内部的微裂缝。相对于基准试件,两种不同类型的膨胀剂和纤维的复合掺入均降低了砂浆的强度,但两者相差幅度较小;掺入膨胀剂后,对砂浆早期自收缩的补偿作用显著,并且砂浆有适量的残余膨胀量;在干燥收缩和圆环约束应力作用下,膨胀剂A抑制砂浆收缩开裂的效果明显优于膨胀剂B。对复合掺入膨胀剂A+聚丙烯纤维PP的砂浆试件,其在0-26和0-4水胶比下的残余膨胀量分别约为200×10-6和300×10-6。砂浆残余膨胀量的形成源于网状结构的钙矾石,其不仅能抵抗收缩变形和开裂,而且可以应对后续服役中的干燥收缩应力。

[关键词]膨胀剂和纤维; 开裂; 收缩; 圆环约束试验; 水胶比

中图分类号:TU528文献标识码:A文章编号:1002-848X(2018)06-0021-05

 

Study on crack resistance technique of concrete face slab for pumped storage power station

Xiao Yang1, Huang Ruhui1, Sui Wei1, Li Yanping1, Ba Hengjing2

(1 China Water Northeastern Investigation, Design & Research Co.,  Ltd., Changchun 130061,  China; 2 School of Civil Engineering, Harbin Institute of Technology, Harbin 150006, China)

Abstract:Based on the theory of dense packing and the grain grading mathematical model, the mix proportions of cementitious materials were designed. Under different water to binder ratios, the influences of the combination of expansive agent A and polypropylene fiber PP and expansive agent B and cellulose fiber C on the mortar strength, autogenous shrinkage, free drying shrinkage and ring restraint on mortar cracking as well as mortar secondary interface microstructure were studied. Experiment results indicate that the improvement of the secondary interface structure can reduce internal micro-cracks of hardened mortar. The results show that compared to benchmark specimens, the combination of two kinds of expansive agents and fiber reduces the mortar strength, with a small gap between the two kinds. Adding the expansive agent has remarkable compensatory effect on the early autogenous shrinkage of the mortar, and the mortar has a proper amount of residual expansion. Under free drying shrinkage and ring restraint shrinkage cracking, the combination of expansive agent A  has more obvious effect on restraint on mortar shrinkage cracking than the combination of expansive agent B. For specimens with expansive agent A and polypropylene fiber, the residual expansion value is about 200×10-6and 300×10-6 for 0-26 and 0-4 water to binder ratio of mortar, respectively. The residual expansion value is formed by the reticular structure of ettringite, which not only can resist shrinkage deformation and shrinkage cracking but also resist the drying shrinkage stress in service life.

Keywords:expansive agent and fiber; cracking; shrinkage; ring restraint test; water to binder ratio

 

*牡丹江公司寒冷地区抽水蓄能电站混凝土面板阻裂技术研究与应用(MDJ-GC-JSFW[2015]8号),水利部948项目(201418)。

 

作者简介:肖阳,硕士,工程师,Email:xiaoyang_hit@126.com。

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