预制混凝土管片表面气泡影响因素研究

Study on affected factors of surface bubbles for precasting concrete segmental liner

预制混凝土衬砌管片是地铁隧道的主要受力构件,管片质量是地铁隧道结构安全性、耐久性的主要保障。本文针对神华新街TBM斜井工程预制混凝土衬砌管片表面存在不同程度气泡的问题,分析水泥品种、砂率、水胶比及脱模材料等对预制混凝土管片表面气泡的影响规律及改性方法。研究结果表明:水泥品种对混凝土表面气泡的影响不大;砂率对混凝土表面气泡的影响较明显;水胶比对混凝土表面气泡的影响较明显;脱模剂对混凝土表面气泡的改善效果明显,且明显优于液压油。

Segment is the major force-bearing component for the metro tunnel,therefore its quality is of great importance to the safety and durability of the whole structure. However,its surface is prone to grow bubbles at the production stage. Therefore,to address this issue,the paper analyze the type,sand ratio, water to binder ratio and the demoulding agent,and then looks into their potential influence on the formation of such segment bubbles,so as to modify the production technique. The results indicate that the type of the cement has little impact on the quantity of the bubbles,while sand ratio and water to binder ratio on the other hand play an dominant role in the formation of the bubbles. The paper also discovers that the application of demoulding agent may visibly improve the quality of the segment surface,and such material delivers a better performance than hydraulic oil does.