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增黏剂对新拌自密实混凝土性能及模板侧压力的影响
作者：杨飞1，赵翀2，周伟1，张永梁1，盛建松3，孔德玉2，3
（1.浙江宇博新材料有限公司，浙江 台州 318000；2.浙江工业大学 土木工程学院，浙江 杭州 310023；3.浙江加州国际纳米技术研究院台州分院，浙江 台州 318000）
摘要：研究了增黏剂PEG400和PEG800对新拌水泥净浆流变特性、新拌自密实混凝土（SCC）扩展度及经时损失、对模板的初始侧压力及其经时衰减速度的影响。结果表明，未掺增黏剂的水泥净浆呈典型的剪切变稀行为；掺增黏剂后，随剪切时间延长，水泥净浆均呈先剪切变稀后剪切变稠行为，达黏度峰值后，再呈剪切变稀行为，最后又呈剪切变稠行为。掺增黏剂对SCC的初始扩展度影响较小，但2种增黏剂均导致其20 min扩展度损失增大，掺PEG800时20 min扩展度损失更明显。掺增黏剂对减小SCC初始模板侧压力不利，但两者均可有效加快模板侧压力的衰减速度。
关键词：自密实混凝土；增黏剂；黏度；模板侧压力
中图分类号：TU528.042 文献标识码：A 文章编号：1001-702X（2022）02-0075-04
Influence of viscosity-enhancing agent on fresh properties and formwork lateral pressure of self-compacting concrete
YANG Fei1，ZHAO Chong2，ZHOU Wei1，ZHANG Yongliang1，SHENG Jiansong3，KONG Deyu2，3
（1.Zhejiang Yubo Novel Materials Co. Ltd.，Taizhou 318000，China；
2.College of Civil Engineering，Zhejiang University of Technology，Hangzhou 310023，China；
3.Taizhou Branch，Zhejiang-California International Nanosystems Institute，Taizhou 318000，China）
Abstract：The effects of viscosity-enhancing agent（VMA） PEG400 and PEG800 on the rheological behavior of fresh cement paste，slump flow and its loss of the freshly self-compacting concrete（SCC） with time，initial lateral pressure of formwork and its decay rate with time were studied. The results indicated that the cement paste without VMA showed typical shear-thinning behavior. After adding VMA，the cement paste presented a shearing-thinning firstly，then shearing-thickening，and then shearing-thinning again after reaching a peak viscosity，and finally shearing-thickening behavior again. The addition of VMA didn't show obvious influence on initial slump flow of SCC，but both lead to an increase of the slump flow loss after 20 min，and the slump loss showed more obvious while incorporating PEG800. It seemed that the addition of VMA cannot reduce the initial formwork lateral pressure of SCC，but can effectively accelerate the attenuation rate of the formwork lateral pressure.
Key words：self-compacting concrete，viscosity-enhancing agent，viscosity，formwork lateral pressure