Crack Control Technology for Concrete of Super-Large Section Precast Immersed Tube

Abstract

As the complex structure, large size, hot climate, aggressive corrosive environment and high concrete strength grade for Super-large Section Precast Immersed Tube of Hong Kong-Zhuhai-Macao Bridge, crack control of concrete was difficult. On the basis of simulating analysis on thermal stress, temperature control design was carried out. Harmful crack could be effective controlled by series of treatment measures during construction period such as optimization of raw materials, preparation of low heat and shrinkage concrete, controlling concrete raw material temperature, mixing concrete with ice shavings and cooling water, setting up automatic maintenance system and automatic temperature monitoring system. From the monitoring results, the temperature monitoring results were consistent with the simulation data, and the maximum temperature and the temperature difference between concrete surface and internal concrete were met the requirement of temperature control standard. Moreover, the precast immersed tube didn’t appear harmful crack.