Mechanical and fracture properties of alkali activated concrete containing different pozzolanic materials

Abstract

Environmental considerations have caused the alkali-activated slag (AAS) cements to emerge as a promising sustainable substitute for the ordinary Portland cement (OPC). This study is aimed to the results of some comprehensive experimental researches performed on the AAS concrete with different types of partial replacement of binder including fly ash, silica fume, and red mud in terms of mechanical and different-mode fracture properties. According to the results, all AAS concrete mixes made with mineral admixtures (except 70% fly ash) exhibited mechanical strength comparable to that of the OPC concrete, and results of the fracture toughness in pure mode I (tensile opening), mode II (shear in-plane), and results of the fracture toughness in pure mode I (tensile opening), mode II (shear in-plane) and mode III (shear out-plane) showed that the trend of tensile and shear performance of concrete mixes are nearly similar. Based on the results of pull-off adhesion test and image processing, the high paste strength in different AAS concrete mixes caused a better aggregates-paste bonding strength.