重复升温过程中碳纤维水泥基材料的温阻特性

RESISTIVITY-TEMPERATURE CHARACTERISTICS OF CARBON FIBER REINFORCED CEMENT-BASED COMPOSITES DURING REPEATED HEATING

碳纤维水泥基材料(carbon fiber reinforced cement-based composites,CFRC)经过重复升温后,不同碳纤维掺量的CFRC材料的温阻特性各异。低于渗流阈值(碳纤维掺量分别为0．1%和0.2%,质量分数,下同)的低掺量CFRC材料,在20-130℃范围内第1次升温过程中,碳纤维掺量为 0．1％CFRC材料电阻率随温度升高而降低;碳纤维掺量为0．2％的CFRC材料呈弥散性波动,然而在随后的重复升温过程中,在同样的温度范围内, 其电阻率均随温度升高而增大。而碳纤维掺量高于渗流阈值(碳纤维掺量分别为0.3％和1．0％)的CFRC材料在同样的温度范围内,第1次升温和随后的重复升温过程中,其电阻率随温度的升高而单调减小。不同碳纤维掺量的CFRC材料在经历第1次升温后,其常温(20℃)时的电阻率均有不同程度地减小,减小的幅度随碳纤维掺量增加而降低。

During repeated heating, carbon fiber reinforced cement-based composites （CFRC） with different carbon fiber contents show different resistivity-temperature characteristics. For the CFRC with carbon fiber contents below the percolation threshold, in which the carbon fiber content is 0.1% （in mass, the same below） and 0.2% respectively, during the first heating at 20-130℃, the resistivity of the CFRC containing carbon fiber content of 0.1% decreases with the first rise in temperature, while the resistivity of the CFRC containing carbon fibers content of 0.2% changes dispersively with temperature rising. During the later repeated heating, at the same temperature range, the resistivities of the two types of CFRC increase with temperature rising. However, for the CFRC with carbon fiber content （contents of 0.3 % and 1.0% respectively） higher than the percolation threshold, during the first heating and later repeated heating, the resistivity of CFRC decreases with rising temperature. After the VErSt heating, the resistivities of CFRC containing different carbon fiber content all decreased at 20℃, and higher carbon fiber content led to a lower magnitude of decrease.