A contribution to the thermo-mechanical characterization of cement mortars at high temperature

The association of cement mortars with fibers, textiles and FRP reinforcement is keeping interest high for both high/ultra-high performance mortars and ordinary/bed-fixing mortars, as these composite materials can effectively contribute to structural safety and durability. Since structural safety comprises fire safety, having further information on mortar behavior at high temperatures and in fire is welcome. The thermo-mechanical behavior of a bed-fixing reference mortar (cube strength Rc = 5 MPa), and of two higher-grade mortars (Rc = 10 and 15 MPa) is investigated in this project past a high-temperature cycle at 200, 400 and 600°C. On the whole, the heat-induced mechanical decay turns out to be fairly close to that of ordinary concrete. The mortars, however, exhibit a greater mass loss and a greater insulating capability at any temperature, the latter being related to the markedly lower thermal conductivity and diffusivity compared with ordinary concrete.