高掺粉煤灰大坝混凝土绝热温升试验研究

Experimental study on adiabatic temperature rise of high-volume fly ash dam concrete

混凝土绝热温升模型是大体积混凝土结构温度场仿真分析的重要条件。采用绝热与半绝热两种试验方法,进行基准混凝土和高掺粉煤灰大坝混凝土的绝热温升试验研究。结果表明粉煤灰的掺入可减少混凝土的绝热温升与早期放热速率,降低温升速率峰值,使混凝土的开裂风险减小。采用半绝热模式比绝热模式可得到更接近实际的结构混凝土的绝热温升,绝热模式得到的绝热温升可用于评价混凝土自身的放热能力。结合试验结果,对比分析三种绝热温升模型,提出适用于大坝混凝土温度场仿真的绝热温升模型。

The adiabatic temperature rise model of concrete is an important condition for calculating the temperature field of mass concrete structures by FEM simulation.In this paper,adiabatic temperature rise tests under the adiabatic mode and semi-adiabatic mode of reference concrete and high-volume fly ash dam concrete are conducted.The results show that the addition of fly ash can reduce the adiabatic temperature rise,early heat release rate,peak temperature rise rate,and cracking risk of concrete.The semi-adiabatic mode test can achieve a more real adiabatic temperature rise of structural concrete compared with the adiabatic one.The adiabatic temperature rise obtained by the adiabatic mode test can be used to evaluate the heat release capacity of concrete.By combining the experimental results and comparing three adiabatic temperature rise models,an adiabatic temperature rise model of dam concrete is proposed for calculating the temperature field of dams.