Alkali-Activated Slag Mortars Containing Alternative Activator: Long-Term Mechanical Fracture Parameters

Abstract

This paper deals with the determination of longterm mechanical fracture properties of alkali-activated slag (AAS) mortars with the alternative activator. Waste sludge from the production of waterglass was used as a sole alkaline activator for ground granulated blast furnace slag. Two types of sand were used to prepare two different mortar sets: standardized siliceous CEN sand consisting of three fractions according to EN 196-1 and natural sand with a nominal grain size up to 4 mm. The results of the elastic, fracture and strength parameters for both sets of AAS mortars determined within the time interval of 3 to 650 days of ageing are summarized in the paper. The obtained results show a different trend in the development of the material properties of AAS mortars compared to the ordinary cement-based mortars which should be taken into the account in the material specification for practical application. It seems that the hardening process influencing the mechanical fracture characteristics is more progressive after the age of 28 days.