高频振捣对混凝土含气量和抗冻性的影响  

Effect of High-Frequency Vibration on Concrete Air Content and Freeze-Thaw Durabilities

作　　者：刘艳霞[1] 陈改新[1] 鲁一晖[1] 

机构地区：[1]中国水利水电科学研究院结构材料研究所,北京100038

出　　处：《建筑材料学报》2009年第1期76-80,共5页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50579075)

摘　　要：采用4种水利水电工程常用的引气剂,配制水胶比为0.40,0.45,0.55(质量比)的二级配混凝土,检测高频振捣对混凝土含气量和抗冻性的影响.结果表明,水胶比相同时,含气量损失率基本上随着高频振捣时间的延长而增大;高频振捣时间相同时,含气量损失率随着水胶比的增大而增大;水胶比为0.40时,掺优质引气剂的混凝土其抗冻性对高频振捣并不敏感;水胶比为0.45时,高频振捣60,90 s后混凝土的抗冻性明显下降;水胶比增加至0.55时,混凝土的抗冻性随着高频振捣时间的延长迅速下降;引气剂的品质对高频振捣后混凝土的抗冻性能也有明显影响.根据试验结果,对混凝土的高频振捣时间提出了要求,可供施工参考.Four kinds of air-entraining admixtures, which were frequently used in hydraulic projects, were adopted in the experiments. Concretes made with mw/mb of 0.40, 0.45 and 0.55 were subjected to high- frequency vibrations. The test results indicated that high-frequency vibration had a great effect on concrete air content. At similar mw/mb, increasing vibration time resulted in an increasing air loss ratio, and at similar vibration time, concrete with a higher mw/mb had a higher air loss ratio, at a mw/mb of 0.40, freeze-thaw durabilities of concrete made with high-quality air-entraining admixtures were not sensitive to high-frequency vibration; at a mw/mb of 0. 45, freeze-thaw durabilities were adversely affected at a vibration time of 60 s and 90 s; when mw/mb was further increased to 0.55, freeze-thaw durabilities of concrete were quickly dropped with the increase of vibration time. At the same time, quality of air-entraining admixture also had obvious effect on frost resistance of high-frequency vibrated concrete. In terms of the test results, appropriate high-frequency vibration time for concrete with different mw/mb were proposed, which had an instructive effects on concrete placement.

关 键 词：高频振捣 引气剂 含气量 抗冻性 混凝土 

分 类 号：TU528.063.2[建筑科学—建筑技术科学]