【摘要】 采用扫描电子显微分析、X射线衍射分析研究了不同温度作用后,混凝土内部形貌和物相组成变化;采用NEL法研究了温度作用对氯离子扩散系数的影响;在此基础上,分别采用多因素作用下的混凝土氯离子扩散理论模型和碳化残量模型进行高温后结构服役寿命预测。温度作用3 h,基于氯离子扩散系数的服役寿命预测结果表明:200℃时服役寿命无明显变化,300℃、400℃时服役寿命约降低60%、90%左右;基于碳化的服役寿命预测结果表明:200℃时服役寿命无变化,300℃时服役寿命降低72.4%;400℃以上时,服役寿命为0。更多还原

【Abstract】 Microstructure and chemical composition changes were examined by scanning electron microscopy(SEM) and X-ray diffraction(XRD).Chloride migration coefficient was determined according to NEL method.Impact of high temperature on service life was evaluated by model of chloride migration theory and model of concrete carbonation.Service life evaluation based on chloride migration coefficient revealed that service life changed little exposed to 200 ℃ for 3 h and decreases by 60%,90% repectively exposed to 300 ℃,400 ℃ for 3 h.Evaluation based on concrete carbonation revealed that service life doesn’t change exposed to 200 ℃ for 3 h and decreases by 72.4% exposed to 300 ℃ for 3 h.When temperature was above 400 ℃,service life was zero.更多还原