搅拌时间对大流动性混凝土拌合物匀质性的影响  

Effect of mixing time on homogeneity of high fluidity fresh concrete

作　　者：侯云芬[1,2] 郑东昊 刘锦涛 司博旸 HOU Yunfen;ZHENG Donghao;LIU Jingtao;SI Boyang(Beijing High Institution Research Center for Engineering Structures and New Materials,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China)

机构地区：[1]北京建筑大学北京市高校工程结构与新材料工程研究中心,北京100044 [2]北京建筑大学土木与交通工程学院,北京100044

出　　处：《混凝土》2018年第11期86-89,109,共5页Concrete

摘　　要：搅拌均匀的混凝土拌合物是保证硬化混凝土性能达到要求的前提。在搅拌设备相似的现状下,合理控制搅拌时间可以使混凝土拌合物达到均匀。研究搅拌时间对现代大流动性混凝土拌合物匀质性的影响,研究发现,在设计的45～120 s搅拌时间内,搅拌时间对大流动性混凝土拌合物流动性影响很小,但是过长的搅拌时间会导致泌水现象,使匀质性变差,尤其是掺入大量需水性小的掺合料,如优质粉煤灰;搅拌时间对大流动性混凝土拌合物含气量没有影响;随着搅拌时间的延长,大流性混凝土拌合物表观密度偏差率降低,到90 s时达到最小,匀质性好;之后随搅拌时间增加而增大,匀质性变差。分析认为,搅拌时间较短时,混凝土拌合物中的组分分散不佳,匀质性不好,搅拌时间合适时(本试验为90 s),组分分散均匀,匀质性好。The symmetrical fresh concrete obtained by mixing was the precondition of harden concreter with good properties.Proper mixing time could make concrete mixture uniformity basing on the same mixing equipment.The effect of mixing time on homogeneity of high fluidity concrete mixture was studied.It was found that when the mixing time was from45s to120s,it could not influence the fluidity of concrete mixture,but much longer mixing time would result in bleeding,especially for the concrete mixture with a lot of admixture whose water requirement was less,such as fly ash;and it could not influence the air content.With the increasing of mixing time,the apparent density deviation ratio decreased,and it reached the minimum when mixing time was90s,which showed that the homogeneity was best;but it increased with mixing time increasing,which showed the homogeneity became worse.It was thought that when mixing time was short,the components of concrete dispersed bad,which resulted homogeneity worse;when mixing time was proper,the dispersion of components was good,and the homogeneity was good too.

关 键 词：搅拌时间 大流动性混凝土 匀质性 掺合料 

分 类 号：TU528.062[建筑科学—建筑技术科学]