  This paper presents fracture response of alkali-activated slag (AAS) mortars
with up to 30% (by volume) of slag being replaced by waste iron powder which
contains a significant fraction of elongated particles. The elongated iron
particles act as micro-reinforcement and improve the crack resistance of AAS
mortars by increasing the area of fracture process zone (FPZ). Increased area
of FPZ signifies increased energy-dissipation which is reflected in the form of
significant increase in the crack growth resistance as determined from
R-curves. Fracture response of notched AAS mortar beams under three-point
bending is simulated using extended finite element method (XFEM) to develop a
tool for direct determination of fracture characteristics such as crack
extension and fracture toughness in particulate-reinforced AAS mortars.
Fracture response simulated using the XFEM based framework correlates well with
experimental observations. The comprehensive fracture studies reported here
provide an economical and sustainable means towards improving the ductility of
AAS systems which are generally more brittle than their conventional ordinary
portland cement counterparts.
