Study On The Steam Curing Technology And Temperature Field Of Large-size Concrete Box Girder

The research focuses on the 32m concrete box girder for express railway from Beijing to Shanghai.Adopting the steam curing technology can raise the quality of the beam and shorten construction period. The difficulty of this technology depends on strict and accurate and real-time controls of the temperature. The present situation of the steam curing technology at domestic and abroad are studied and the new technical measure is proposed to improve the quality of 32m concrete box girder. The software of FEM analysis, ANSYS is applied to construct the simulation model of the box beam.By means of simulating the characteristics of cement hydration of concrete and the boundary conditions, the temperature fields are studied, which Based on the analysis a quantitative understanding of the temperature distribution of box beam in steam curing. The temperature on the cross-section of double-railway box girder is changing during the whole hydration process. According to the cause of hydration cracks, effective control methods are presented for this kind of box girder, which consists of single-box and single-room.In terms of this method, the maximum temperature and its occur time can be analyzed, which can be applied to supervise construction, improve the quality of construction, and assure the safety of construction.At last, on the basis of the analysis result of the temperature field and the temperature stress, we developed the temperature auto control system of the concrete box beam steam curing on the basis of the configuration software, monitoring and controlling the temperature difference of the box beam during steam curing, and making sure that the temperature stress is in acceptable value, preventing and controlling the development of the concrete construction cracking, making the concrete steam curing technology more ripe, complete and reliable.