Smart cement for fire alarms and indoor climate control

Fire alarms in buildings are essential for safety. However, due to the poor conductivity of cement, it remains a challenge to detect fire without the assistance of other monitoring equipment. In this study, a fire alarm cement composite containing expandable graphite, carbon fiber, and ordinary Portland cement that can achieve ultrasensitive temperature monitoring and indoor climate control in a building is developed. Homogeneously distributed expandable graphite in this smart cement rapidly expands under high temperatures, forming new electrically conductive pathways. This results in excellent temperature sensing performance, with a temperature coefficient of resistance of - 0.467 %/degrees C in the range of 220 degrees C-400 degrees C. The smart cement can be easily integrated into a building to transmit a fire alert to a computer, mobile phone, or visual alarm device in a timely manner. Furthermore, this smart cement exhibits higher flexural strength in harsh environments compared to ordinary cement. This smart cement exhibits potential to considerably broaden cement applications and be highly desirable for next-generation smart building materials.