高频振捣对混凝土含气量和抗冻性的影响

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.

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

Four kinds of air-entraining admixtures,which were frequently used in hydraulic projects,were adopted in the experiments.Concretes made with m_w/m_b 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 m_w/m_b,increasing vibration time resulted in an increasing air loss ratio,and at similar vibration time,concrete with a higher m_w/m_b had a higher air loss ratio.at a m_w/m_b of 0.40,f...