Heating and electrical characteristics of CNT- and CF-incorporated cementitious composites exposed to various temperature and deterioration conditions

Abstract

CNT- and CF-incorporated cementitious composites have received significant attention, owing to their potentials for utilizing as heating material. The electrical and heat generation characteristics of this composite have been continuously investigated through numerous studies. However, some issues still remain before this composite can be utilized on practical sites. In this regard, this dissertation explores the heating and electrical characteristics of CNT- and CF-incorporated cementitious composites exposed to various temperature and deterioration conditions. The heating test of CNT- and CF-incorporated cementitious composites was performed to understand the NTC and PTC effects of the composites, and monotonic and cyclic heating tests were conducted under various temperature conditions involving 25, 0, and -20℃. In addition, the composites were exposed to various deterioration conditions including carbonation, chloride penetration, sulfate attack, and freeze-thaw action to investigate the change in electrical resistivity of CNT- and CF- incorporated cementitious composite. The influence of freeze-thaw deterioration on the electrical properties and heating performance of cementitious composite incorporating CNT and CF was examined for long-term use in winter environments. Finally, the electrical and heating performance of the CNT- and CF-incorporated cementitious composite with various sizes and electrode spacing was studied to determine the efficient electrode design and relationship between energy consumption and temperature increase. The obtained results provide new insight into the electrical and heating performance of the composites, which establishes fundamental knowledge of heating mechanisms in CNT- and CF-incorporated cementitious composite. The thesis is concluded by summarizing the implication of the results and potential topics of future studies.