Alkali-activated materials are potential alternatives for Portland cement. Their use
leads to reductions in CO2 emissions and recycling of various industry by-products. These new
alternative binders have a wide range of uses and high technological properties. In the research
presented in this paper, the influence of additional sulphur slime powder (as accelerator) was
investigated. The biomass bottom ash (BBA) was used as raw material and sodium hydroxide
was used as the alkaline activator. The sulphur slime is a by-product in a fertilizer production
plant. The samples were prepared with different amounts of sulphur slime; the levels of sulphur
slime additive were 0%, 0.5%, 1.0%, 3.0% and 5.0% by weight in the raw material mixtures.
Alkali-activated binders were mixed and conditioned at a temperature of 60 °C for 48 h,
followed by curing at room temperature for 26 days. The microstructure of the material was
analyzed through scanning electron microscopy (SEM) and the composition of the materials
was analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) spectroscopy. The
compressive strength of hardened alkali activated paste was measured after 28 days. In all the
cases investigated, the compressive strength of hardened cement paste samples increases with
the presence of Sulphur slime powder. It was found that during the hardening process sulphur
reacts with sodium hydroxide forming Na2SO4, which acts as an accelerator. According to
some researchers, Na2SO4 shows a significant accelerating influence in alkali-activated binder
systems. The optimal amount of sulphur slime in raw materials mixtures was also evaluated.peer-reviewe