基于正交试验的寒区混凝土导热系数影响因素研究

Research on influence factors of thermal conductivity of concrete in cold region based on orthogonal test

为研究寒区混凝土的导热系数,利用正交试验方法,选用水胶比、骨料体积分数、饱和度、粉煤灰掺量、矿渣掺量作为影响因素,每个因素取四个水平,采用QTM-500导热仪测试上述混凝土在不同温度条件下(-30、-20、-10、0、10、20℃)的导热系数,考察不同温度下混凝土导热系数的变化规律,并对试验结果进行极差、方差分析,确定各因素对混凝土导热系数影响程度、显著性。研究结果表明:混凝土的导热系数与温度呈负相关性,水胶比、饱和度较大的混凝土导热系数随着温度的降低在温度敏感区(-10～0)℃范围内骤增;在(0～20)℃范围内,各影响因素对混凝土导热系数影响的大小顺序为:骨料体积分数>饱和度>水胶比>矿渣掺量>粉煤灰掺量,(-10～-30)℃时,顺序稍有改变,饱和度对混凝土导热系数的影响最大;在(-30～20)℃范围内,骨料体积分数、饱和度对混凝土导热系数的影响特别显著。研究结果为寒区混凝土导热特性提供更为重要的理论依据。

To study the thermal conductivity of concrete in cold region,used orthogonal test method,selected water to cement ratio,aggregate volume fraction,saturation,fly ash content and slag content as the influencing factors,four levels per factor,The influence of temperature on the thermal conductivity of concrete is tested by using QTM-500 thermal conductivity meter at low temperature(-30,-20,-10,0,10,20℃).Study on the change law of thermal conductivity of concrete under low temperature.Determine the influence degree of various factors on the thermal conductivity of concrete and its significance through analyzed the test results for extremely poor and the variance.The results show that there was a negative correlation between thermal conductivity of concrete and temperature,the thermal conductivity of concrete with high degree of saturation and high water to cement ratio have greater undulate at temperature sensitive area(-10~0℃);The influence of aggregate volume fraction on the thermal conductivity of concrete is maximum at 0~20℃range.The size of the order of the effect of various factors on the thermal conductivity of concrete the aggregate volume fraction>saturation>water to cement ratio>slag>fly ash,the order of the influence factors on thermal conductivity of concrete is slightly altered at-10^-30℃,saturation on the thermal conductivity of concrete is maximum.The results provide a more important theoretical basis for the thermal conductivity of concrete in cold region.