Fracture properties of self-compacting mortar in terms of contents and high temperatures

In this research, the effects of five parameters such as water to cementitious materials ratio, limestone powder, high temperatures, polypropylene and steel microfibers on the fracture energy (GF) and the critical stress intensity factor (KIC) of the notched self-compacting mortar beams were investigated. Four levels were assumed using the Taguchi method with an L16 orthogonal array for each parameter, and 32 mix designs were considered instead of 512. After the preparation of the specimens, they were placed in a furnace and exposed to three temperature levels of 200, 400, and 600 °C at a heating rate of 2 °C /min. Mortar specimens to each target temperature were kept for 6 h. As a result, the fracture properties of the specimens initially improved but then decreased after exposure to temperatures above 400 °C. At 200 °C, the density of self-compacting mortar increased and reached its maximum value, which in turn increased the fracture energy and critical stress intensity factor of the specimens at this temperature compared with those at the ambient temperature. Above this temperature up to 600 °C, increasing the temperature had destructive effects on the fracture properties. Furthermore, the reliability of the results was discussed and confirmed by using the analysis of variance.