含气量对新拌及硬化自密实混凝土气泡间距系数的影响

摘要

采用压力法、AVA仪和硬化混凝土孔隙结构分析仪测试了自密实混凝土的含气量、气泡间距系数与气泡比表面积,研究了含气量和龄期对自密实混凝土气泡间距系数的影响,讨论了具备良好抗冻性能自密实混凝土的临界含气量,探究了新拌自密实混凝土气泡间距系数与硬化自密实混凝土气泡间距系数之间的相关性.结果表明:新拌与硬化自密实混凝土气泡间距系数均随着自密实混凝土拌合物含气量的增加而减小,二者具有良好的相关性;随着混凝土龄期延长,气泡间距系数减小;当自密实混凝土拌合物含气量达到4%及以上时,其硬化体具备良好的抗冻性能.%The air content,air-void spacing factor and air-bubble specific surface area of self-compacting concrete ( SCC ) were measured by pressure method,air-void analyzer ( AVA ) and hardened concrete pore structure analyzer. The influence of air content and age on the air-void spacing factor of SCC was studied. The critical air content of SCC with good frost resistance was discussed,and the correlation between the air-void spacing factors of fresh SCC and hardened SCC was investigated. The results show that the air-void spacing factors of fresh SC C and hardened SCC decrease with the increase of the air content of the SCC mixture,which means the air-void spacing factor and air content are in good correlation. As the age of concrete increases,the air-void spacing factor decreases. When the air content of the SCC mixture is not less than 4%,the hardened SCC has good frost resistance.