Research purposes: When the 32 m box girderwith girderweight of 800 t for passenger dedicated line is precasted inwinter, the internal temperature of the girderwill rise, the temperature difference between the internalpart and external part is big and the cracks easily happen on the girder surface because the heat is given out due to the cementhydration after concrete pouring. The usage of steam maintenance technology to the precasted concrete box girders can further improve the girder quality, but how to control the temperature of the steam maintenance is very importan.t In this paper, through researching and analyzing the temperature control for the stream maintenance of concrete box girder in four stages, the temperature control parameters for stream maintenance of concrete box girder in winter are offered to guide precasting concrete box girderon site and ensure the precasting quality of the girder.
Research conclusions:Through researching temperature control for the streammaintenance of32m boxgirder inwinter, the temperature control parameters for stream maintenance of concrete box girder in four stages in winter and the precasting technique of the girderare offered. The application shows all the indexes of the precasted concrete box girder meet requirements of"TechnicalSpecifications forConcrete PrecastedGirder forPassengerDedicated Line", the period ofprecasting the box girder is shortened and the precasting quality of the box girder is ensured. All of these create the foundation ofensuring the construction process.
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