Electrothermal Test Of Carbon Black Cement Mortar Slabs And Analysis Of Heat Transfer

Conductive concrete can be used in many fields,such as health monitoring of civil engineering structures,melting snow and deicing,shielding of electromagnetic waves etc.In this paper,experimental,analytical and numerical investigations were conducted on electrical properties and electrical heating effect of carbon black cement mortar(CBCM)board.Main conclusions are drawn up as follows.1)CBCM containing carbon black with larger specific surface area has lower resistivity.The infrared paint makes little influence on the electrothermal effect as it is coated on CBCM plate.While,using lightweight cement as the matrix can improve the electrothermal effect.2)The heating test lasting over 300 hours has shown that the heating power and resistivity have good stability.The temperature of CBCM and indoor air,energy consumption under different indoor control temperature and different outdoor temperature are measured.Energy consumption decreases more than 10 percent as the furniture is laid in the room.3)Coefficients of convection and radiation are affected by several factors such as the shape of board and surrounding.Coefficients of convection and radiation under different situations are calculated.The result indicates that the heat radiation occupies up to 58%of the total heat quantity generated from the floor.According to the heat conduction differential equation and the energy conservative law,the temperature rising function of CBCM and the heat balance equation of the room are drived.4)By means of the finite element method,the heating process and temperature distribution are simulated.The calculating results are in agreement with the experimental ones.Thermal stress in the CBCM board is small.The studies of CBCM for indoors heating and other engineering applications are of great importance.