石墨掺量及骨料种类对混凝土导热系数的影响与内在机理研究

Influence of graphite content and aggregate type on thermal conductivity of concrete and study of its internal mechanism

为了探究石墨、粗骨料种类对混凝土导热系数的影响,揭示石墨混凝土导热系数变化的内在机理。利用DRE-Ⅲ多功能快速导热系数测试仪,对不同石墨掺量、不同粗骨料种类的导热系数进行测试,采用对比分析法考察石墨掺量、粗骨料种类对石墨混凝土导热性能的影响,探究其作用机理;并以普通混凝土导热系数计算公式为基础,提出骨料影响系数Ⅰ、推导出可供工程利用的石墨混凝土导热系数预测公式。结果表明:混凝土的导热系数随粗骨料导热系数的增大而增大,增长幅度为5%~6%;混凝土导热系数随石墨取代率的升高而增大;石墨混凝土骨料影响系数Ⅰ与导热系数之间存在显著的线性关系,改良的导热系数公式计算值与试验值吻合较好,可为以后的实际应用提供一定的借鉴。

It uses DRE-Ⅲ multi-function rapid thermal conductivity tester to test the thermal conductivity of different graphite content and different coarse aggregate types.To explore the influence of graphite and coarse aggregate types on the thermal conductivity of concrete,and reveal the internal mechanism of the change of thermal conductivity of graphite concrete.The effect of graphite content and coarse aggregate type on the thermal conductivity of graphite concrete was investigated and the mechanism of action was explored by comparative analysis.Based on the calculation formula of ordinary concrete thermal conductivity coefficient,the influence coefficient Ⅰ of aggregate is proposed,and the prediction formula of thermal conductivity of graphite concrete available for engineering is derived.The results show that the thermal conductivity of concrete increases with the increase of thermal conductivity of coarse aggregate,and the growth rate is 5%~6%.The thermal conductivity of concrete increases with the increase of graphite substitution rate.There is a significant linear relationship between the influence coefficient Ⅰ and the thermal conductivity of the graphite concrete aggregate.The calculated value of the improved thermal conductivity formula agrees well with the experimental values,which can provide some reference for future practical applications.