陶粒预湿程度对轻骨料混凝土拉伸徐变的影响

摘要

采用U型管微压测定装置测定不同预湿程度陶粒在轻骨料混凝土中的吸水返水过程,采用扫描电子显微镜(SEM)观察轻骨料混凝土界面结构形貌,采用新型环形约束收缩装置研究了部分约束条件下轻骨料混凝土的拉伸徐变特性.结果表明:随着陶粒预湿程度的提高,陶粒在轻骨料混凝土中的吸水能力下降,返水能力提高,陶粒与水泥石界面结合程度加强,轻骨料混凝土的拉伸徐变值减小.%The water absorption and desorption process of ceramsites with different prewetting degree embedded in lightweight aggregate concrete were monitored by a U-tube micro-pressure measurement device. The interfacial structure between ceramsites and hardened cement paste in lightweight aggregate concrete was scanned by SEM. By a new-ring restrained shrinkage equipment, the tensile creep characteristics of lightweight aggregate concrete was also investigated. The study reveals that with the increase of ceramsite prewetting degree the ability of water absorption declines and the ability of water desorption increases for ceramsites embedded in lightweight aggregate concrete; the interfacial transition zone(ITZ) between ceramsites and hardened cement paste becomes denser, and the tensile creep of lightweight aggregate concrete declines.