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

Abstract

In this research, the effects of five parameters, namely, water/cementitious materials ratio, limestone powder, high temperatures, polypropylene and steel microfibres, on the fracture energy (GF) and critical stress intensity factor (KIC) of 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. The prepared specimens 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 were kept at each target temperature 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 a maximum value; this, in turn, increased the fracture energy and critical stress intensity factor of the specimens at this temperature, compared with those at an 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 are discussed and confirmed by using analysis of variance.