炭黑导电混凝土和碳纤维炭黑导电混凝土电热试验

Experimental Study on the Electro-Thermal Behavior of Conductive Concretes with Carbon Black and Carbon Fiber-Carbon Black

目的为开发出融雪化冰或室内升温用的新型功能混凝土材料,研究炭黑导电混凝土(Carbon Black Conductive Concrete)和复掺碳纤维炭黑导电混凝土(Carbon fiber-carbon Black Diphasic Conductive Concrete)的导电性能以及电热效应.方法通过制作两种材料插有电极的立方体混凝土试块并测量记录不同龄期下的电阻率,比较分析两种材料的导电性能,并考虑碳纤维对导电性的影响作用.将两种材料试块分别串联进直流电路中,观察其通电发热情况并比较发热效果和电阻率的变化情况.结果相对于炭黑导电混凝土,复掺碳纤维炭黑导电混凝土的导电性更好,其中炭黑掺量为1%、碳纤维掺量为2%的试块电阻率低于100Ω·cm.两种材料通电发热速率均比较稳定且升温效果较好.单掺炭黑导电混凝土试块电阻率随通电时间延长变化较稳定,而复掺碳纤维炭黑试块电阻率受极化效应影响较大.结论相对于单掺炭黑导电混凝土,复掺碳纤维炭黑导电混凝土有更好的导电性,但其电阻率稳定性还有待研究.而单掺炭黑导电混凝土在通电发热试验中,其电阻率变化较小,具有较好的电阻率稳定性.

For developing new functional materials which could be used for snow-melting, deicing and indoor heating, electrical conductivities and electric heating effects of conductive concretes with carbon black and diphasic carbon fiber-carbon black were studied. Two kinds of cubic con- crete specimens were made with electrodes inside and connected into direct current circuit to ob- serve heat effects. Electrical resistivities of the specimens were measured along with different con- crete ages, and the corresponding electrical conductivities of the two kinds of materials were com- pared and analyzed, taking into account of influences of carbon fiber on electrical conductivity. It is found that the conductive behavior of diphasic carbon fiber-carbon black concrete is better that that of carbon black concrete. Concrete specimens with 1% carbon black and 2% carbon fiber have e- lectrical resistivities less than 100 ~. cm. The change of heating rate of both kinds of conductive concrete is stable and the heating effect is well. The electrical resistivity change of the carbon black concrete is more stable with time extending. But for carbon fiber-carbon black diphasic conductive concrete, it is influenced by polarization. Conclusion is that in contrast with the carbon black con- crete, conductivity of the carbon fiber-carbon black diphasic concrete is better, but the stability of its electrical resistivity should be further studied. However, electrical resistivity change rate of the carbon black concrete is small and relatively good stable.