Investigation of the prolonged effect of electric stress into the cement mortar incorporating silicon carbide

Abstract

This study examines the impact of electric stress on the electrical, thermal, and phase composition properties of cement mortar with silicon carbide (SiC) as a conductive filler. The results indicate that SiC specimens enhance the electrical conductivity of the cement mortar by 4.35% to over 50% compared to the control. However, as the curing progresses, the electrical resistance increases due to reduced ionic conduction and an increase in conduction through free electrons. SiC significantly raises the surface temperature and thermal conductivity of the cement mortar, with SiC specimens experiencing a temperature rise exceeding 30 °C within the first hour of electric stress, while the control remains below 30 °C. SiC also enhances thermal conductivity up to eight-fold, attributed to improved particle movement and electron transport. The crystalline structure remains largely unaffected by electric stress after 28 days. Thermogravimetric analysis (TGA) indicates that SiC hinders the hydration process, leading to a reduction in weight loss associated with the depletion of hydrated cement phases. SEM images demonstrate a denser matrix in SiC specimens, while CT images show increased pore volume and decreased sphericity with higher SiC content. Under electric stress, the mechanical performance of SiC specimens exhibits lower compressive strength compared to the normal state, with decreasing strength as the SiC replacement ratio exceeds 50%. This study provides insights into the effects of electric stress on SiC-incorporated cement mortar properties, highlighting its potential for diverse construction industry applications.