大直径钢管内无收缩高抗裂混凝土设计与制备

Design and Preparation of No-shrinkage and High Anti-cracking Concrete in Steel Tube with Large Diameter

依托某过江通道工程的大直径钢管混凝土桥塔结构,评估了不同膨胀性能曲线下的结构界面脱粘和混凝土开裂风险。结果显示基准混凝土条件下界面法向拉应力和混凝土开裂风险均超过安全阈值,而使用膨胀性能达到一定要求的膨胀剂后可同时满足抗脱粘、脱空需求。进一步试验研究了不同钙镁复合膨胀剂掺量下管内混凝土的变温变形历程和强度,结果表明该高性能膨胀剂可显著增大温升阶段膨胀并提供温降阶段补偿收缩,掺量越高,性能越好,且10%掺量下的膨胀效能可满足计算提出的抗脱粘、脱空的混凝土膨胀性能要求,且不影响混凝土强度,可制备出无收缩高抗裂混凝土。

Based on the large-diameter concrete-filled steel tubular tower structure of a pathway project for crossing river,the risk of structural interface disengaging and concrete cracking under different expansion performance curves was evaluated.The results showed that the interface tensile stress and the concrete cracking risk exceed the safety threshold under the reference concrete condition,and the anti-disengaging requirements could be met by using the expansive agent with certain expansion performance.Furthermore,the deformation process and strength of concrete in pipe with different content of HME-V calcium magnesium composite expansive agent were studied.The results showed that the high-performance expansive agent could significantly increase the expansion in the temperature rise stage and compensate the shrinkage in the temperature drop stage.The higher the content was,the better the performance was.And the expansion efficiency of 10%content could meet the anti-disengaging requirements and it did not affect the strength of the concrete.The non-shrinkage high crack resistant concrete can be prepared.