膨胀剂在沉管混凝土裂缝控制中的应用研究

Application of Expansion Agent in Crack Control of Immersed Tube Concrete

研究了镁质膨胀剂、钙质膨胀剂、钙镁复合型膨胀剂对现浇沉管混凝土的补偿收缩规律,通过裂缝观测分析了不同成分膨胀剂的裂缝控制效果。结果表明,早龄期2~3 d钙镁复合膨胀剂补偿收缩效果最明显,最大中心微应变补偿值为288;膨胀剂能有效降低沉管混凝土的开裂风险,实际裂缝数量降低超过40%,裂缝平均宽度降低了39%。

The effect of magnesium expansion agent,calcareous expansion agent and calcium magnesium compound expansion agent on shrinkage compensation of immersed tube concrete was studied.The crack control effect of different components of expansion agent was analyzed by crack observation.The results show that the shrinkage compensation effect of calcium magnesium complex expansion agent at early age of 2~3 d is the most obvious,and the central microstrain compensation value is up to 288.The expansion agent can effectively reduce the cracking risk of immersed tube concrete,the actual crack number is reduced by more than 40%,and the average crack width is reduced by 39%.