高温后混凝土的碳化与氯离子侵蚀试验研究

Experimental study on carbonation and chloride ion erosion of concrete after elevated temperature

为了研究混凝土在高温后的耐久性能,通过试验对C30混凝土经历100~800℃高温后的残余抗压强度、碳化规律及氯离子侵蚀规律展开研究。将高温后混凝土残余强度与已有成果对比分析,提出高温后抗压强度折减系数的计算式;设计开展高温后碳化试验明确了高温中性化深度与混凝土残余强度的线性关系,并提出了高温后混凝土碳化系数与最高受热温度之间的简化计算式;高温后混凝土抗氯离子侵蚀能力大幅下降,混凝土中不同深度处的氯离子含量随高温温度线性增加,且在200、700℃时出现较大幅提升。

To study the durability of concrete after elevated temperature,the residual compressive strength,carbonization,and chloride ion erosion of C30 concrete after submitted to elevated temperatures of 100~800 ℃ were studied through tests.It compared the residual strengths of concrete after elevated temperatures with the current results,a formula for calculating the reduction coefficient of compressive strength after elevated temperatures were proposed.The carbonization test determined the linear relationship between the burnt layer’ s depth at high temperature and the concrete’s residual strength after high temperature.A simplified formula for calculating the carbonization coefficients of concrete after experience elevated temperatures and the maximum heating temperature was put forward.After experiencing elevated temperatures,the chloride ion resistance of concrete decreased significantly.The chloride ion content in concrete at different depths increased linearly with temperature,and it increases significantly at 200 ℃ and 700 ℃.