气泡对纤维混凝土阻尼性能的影响

Effect of air bubbles on damping behavior of fiber concretes

利用自主开发的三点弯曲梁阻尼测试装置对不同掺量引气剂纤维混凝土的阻尼性能进行了测试,通过含气量测定仪和压汞仪研究不同掺量引气剂对纤维混凝土气孔结构的影响,利用扫描电镜观察了引气前后纤维混凝土的微观形貌。结果表明,随着引气剂掺量的增加,纤维混凝土的阻尼能力提高,但是当引气剂掺量达到0.015%后,阻尼能力不再有明显提高。一定掺量的引气剂在纤维混凝土内部引入大量丰富的气泡,当混凝土材料遭受外界的振动时,这些气孔起到了柔性缓冲包的作用,可提高混凝土材料的阻尼能力。

Damping property of 4 kinds＇ fiber reinforced concrete with various contents of air-entraining agent is measured by self-designed 3-point flexure beam damping measurement instrument.The effects of various contents of air-entraining agent on pore structure of fiber concrete are investigated by the air contained instrument and the mercury intrusion porosimetry,and the micro-structures of fiber concrete with various pores are observed by the scanning electron microscopy.The experiment results show that the increase of the contents of air-entraining agent in the fiber concrete results the enhancement of damping ability of the fiber concrete,but the enhancement of damping ability is not obvious when the content is up to a certain value.The plentiful pores and air bubbles like soft cushion which induced by the certain content of air-entraining agent contributed to the damping ability of fiber concrete when the concrete suffered by the external vibration.