干湿环境中碳纤维水泥砂浆的电热性能

Electro-Thermal Properties of Carbon Fiber Reinforced Cement Mortar

研究了碳纤维水泥砂浆在干燥和潮湿状态下的电导率和电热温升.试验结果表明:当碳纤维掺量为0.3%(质量分数,下同)时,碳纤维水泥砂浆导电主要以水化离子导电为主,其在潮湿状态下的电导率和电热温升均较干燥状态的大;当碳纤维掺量由0.3%增加到0.7%时,碳纤维间距离减小,碳纤维水泥砂浆导电逐渐由以水化离子导电为主过渡到以碳纤维隧道效应导电为主,故其在潮湿状态下的电热温升较干燥状态的小,但电导率仍较干燥状态的大;当碳纤维掺量从0.7%增大到1.0%时,碳纤维导电网络形成,碳纤维水泥砂浆导电以碳纤维接触导电为主,水化离子导电相对可以忽略不计,因此其在潮湿状态下的电导率和电热温升均较干燥状态下的小.

The electrical conductivity and electro-thermal temperature rise of carbon fiber reinforced cement mortar under dry and wet conditions were studied separately. Results show that when carbon fiber content is 0.3% mass fraction, electrical conduction depends on the hydrated ion mainly. Electrical conductivity and electro-thermal temperature rise under wet condition are superior to those under dry condition. Increasing the fiber content from 0.3% mass fraction to 0.7 % mass fraction reduces the space between carbon fiber gradually, so that tunnelling effect of carbon fiber becomes more dominant than hydrated ion in governing the electrical conduction. As a result of two kinds of electric conduction mechanisms synergism, electrical conductivity under wet condition are still superior to those under dry condition, but electro-thermal temperature rise under wet condition are inferior to those under dry condition. When carbon fiber content is 1.0% mass fraction, the conductive network is formed by fibers physical contact, electrical conduction mainly depends on the conductive network and the hydrated ion electric conduction is negligible. In this case, electrical conductivity and electro-thermal temperature rise under wet condition are inferior to those under dry condition.