抗冲磨混凝土气泡控制试验研究

Experimental Study on Bubble Control of Abrasion-Resistant Concrete

通过改变振捣位置、振捣时间、调整减水剂和引气剂掺量,对混凝土配合比及振捣工艺进行优化,并借助试模试件对混凝土振捣工艺进行验证,提出了有利于解决气泡问题的振捣参数及振捣工艺方案,以改善双江口水电站泄洪系统抗冲磨混凝土中气泡大、不均匀的现象。结果表明:采用脱模剂的同时采用消泡剂产品复配减水剂使用,可以有效降低大气泡数量;在混凝土中增加浆体用量,可使减水剂在骨料之间充分填充,有效降低气泡产生几率;对比不同振捣参数试验结果发现,Φ100硬轴式振捣棒排除气泡效果更好。

The mix proportion and vibration technique of the abrasion-resistant concrete for the Shuangjiangkou Hydropower Station's flood discharge system were optimized by altering the positions and duration of vibration,and adjusting the dosages of water reducing and air-entraining agents.Vibration technique was validated using test mold specimens.Consequently,favorable vibration parameters and techniques were proposed to address the issues of large and uneven air bubbles in the abrasion-resistant concrete.Results indicate that using the demolding agent in conjunction with the composite defoaming agent and water reducer can effectively reduce the number of large air bubbles.Increasing paste content in the concrete mix can reduce air bubble formation by fully filling the spaces between the water reducing agent and the aggregates.Comparative experiments on different vibration parameters revealed that theΦ100 hard shaft vibrator is more effective in eliminating air bubbles.