New insights into thermal-mechanical improvement of self-heating conductive high-performance cementitious composite

Strength and heating performance are two key indicators for self-heating cementitious composites towards the high-quality fabrication requirement especially in extreme environment, and nano engineering is a promising way to address the issue. In this work, nano TiO₂ (NT) and nano CaCO₃ (NC) were added in self-heating conductive high performance cementitious composite (SHC-HPCC), and ohmic heating (OH) was used to cure SHC-HPCC in severely cold environment. The mechanical strengths of SHC-HPCC with different nano materials contents were tested, the TG, MIP and BET analyses were conducted to clarify the microstructural evolution of the specimens. For the strength development, NC showed significant promotion comparing with NT, the compressive strengths of SHC-HPCC with 3 % NC met an increase of 75.9 % from 64.2 MPa to 112.9 MPa. The hydration degrees and pore structures of NC modified SHC-HPCC were also enhanced. Moreover, heating performance as the pivotal processing parameter was compared by manufacturing three full-size slabs. At this time, NT exhibited a more substantial improvement, the peak temperature and temperature increasing rate of SHC-HPCC with 3 % NT were 11 % and 67.6 % higher than those of Reference specimen under the same electric power. The increased mechanical and heating performance for nano engineered SHC-HPCC provides new avenues for rapid concrete fabrication towards various application scenarios in extreme environment.