- 摘 要
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（1 中水東北勘測設(shè)計研究有限責任公司， 長春 130061; 2 哈爾濱工業(yè)大學土木工程學院， 哈爾濱 150006）
［摘要］基于緊密堆積理論和微粒級配數(shù)學模型，設(shè)計水泥基材料的配合比，研究了不同水膠比下，膨脹劑A+聚丙烯纖維PP和膨脹劑B+纖維素纖維C的復(fù)合摻入對砂漿的強度、自收縮、干燥收縮及對圓環(huán)約束砂漿收縮開裂和二級界面結(jié)構(gòu)的影響。試驗結(jié)果表明，二級界面的改善可減小硬化漿體內(nèi)部的微裂縫。相對于基準試件，兩種不同類型的膨脹劑和纖維的復(fù)合摻入均降低了砂漿的強度，但兩者相差幅度較??；摻入膨脹劑后，對砂漿早期自收縮的補償作用顯著，并且砂漿有適量的殘余膨脹量；在干燥收縮和圓環(huán)約束應(yīng)力作用下，膨脹劑A抑制砂漿收縮開裂的效果明顯優(yōu)于膨脹劑B。對復(fù)合摻入膨脹劑A+聚丙烯纖維PP的砂漿試件，其在0-26和0-4水膠比下的殘余膨脹量分別約為200×10-6和300×10-6。砂漿殘余膨脹量的形成源于網(wǎng)狀結(jié)構(gòu)的鈣礬石，其不僅能抵抗收縮變形和開裂，而且可以應(yīng)對后續(xù)服役中的干燥收縮應(yīng)力。
［關(guān)鍵詞］膨脹劑和纖維； 開裂； 收縮； 圓環(huán)約束試驗； 水膠比
中圖分類號：TU528文獻標識碼：A文章編號：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
*牡丹江公司寒冷地區(qū)抽水蓄能電站混凝土面板阻裂技術(shù)研究與應(yīng)用（MDJ-GC-JSFW［2015］8號），水利部948項目（201418）。
作者簡介：肖陽，碩士，工程師，Email:xiaoyang_hit@126.com。
