不同养护组合对连续刚构箱梁混凝土早期温度场的影响研究

Study on the early temperature field of concrete box girder in continuous rigid frame with different curing methods

混凝土水化热导致混凝土内部早期湿温度的变化,易使混凝土出现早期裂缝.根据桥梁所处的实际情况确定具体的养护方法是非常重要的.合理控制混凝土箱梁截面温度是防止混凝土开裂,确保混凝土质量的关键,但因夏季气候的原因,箱梁温度控制成为施工中的难点重点.以连续刚构桥主梁0#段为研究对象,利用有限元软件Midas/FEA研究在自然养护法、甲组合养护法和乙组合养护法等不同方法养护下的作用效果,分析了不同养护方法下箱梁温度场云图、截面各关键节点温度时程曲线和截面各位置内外温差时程曲线,以选出适合夏季的最佳早期养护工艺.研究结果发现模贴法+自动喷水雾法可以箱梁混凝土温控措施更好.研究结果可为解决箱梁夏季施工的温度难题提供技术支持。

The hydration heat of concrete causes the change of humidity and temperature inside the concrete,which is easy to cause early cracks in the concrete.It is very important to determine the specific maintenance method according to the actual situation of the bridge.Reasonable control of concrete box girder section temperature is the key to prevent concrete cracking and ensure the quality of concrete.However,due to the summer climate,the temperature control of box girder has become a difficult point in the construction.Taking the 0#segment of continuous rigid frame bridge as the research object,using the finite element software Midas/FEA to study the effect of different curing methods,such as natural curing method,a combined curing method and B combined curing method,analyzed the temperature field nephogram of box girder under different curing methods,the temperature time history curve of each key node of the section and the temperature difference time history curve inside and outside each position of the section,so as to select the best early curing process suitable one for summer.The results show that the temperature control measures of box girder concrete can be better by the method of mould sticking and automatic spray fog.The research methods and results can provide technical support for solving the problem of temperature construction of box girder bridge.