Effect of steel slag and curing temperature on the improvement in technological properties of biomass bottom ash based alkali-activated materials

In this research the effect of the incorporation of black steel slag (BSS) (25, 50 and 75 wt%) into biomass bottom ash (BBA) as precursor in the synthesis of alkali-activated materials was studied. The alkali-activated pastes were cured at two temperatures, 60 and 20 degrees C. Thermal curing at 60 degrees C produced an increase in mechanical properties at early curing ages obtaining similar properties at older ages of 90 days. The addition of up to 50 wt% of BSS resulted in alkali-activated cements with increased compressive and flexural strengths. The increase in mechanical properties could be due to the formation of a higher amount of calcium aluminosilicate gel (C-A-H-S) with respect to potassium aluminosilicate gel (K-A-H-S) or to the synergistic formation of CK ASH gel. Therefore, these specimens can be used as a binding material for concrete production to replace Portland cement, which can lead to significant environmental and socio-economic improvements by reducing CO2 emissions and consumption of natural resources.

Automated summary

This study investigated the effects of incorporating black steel slag (BSS) into biomass bottom ash (BBA) on the synthesis of alkali-activated materials. It was found that adding up to 50% BSS resulted in alkali-activated cements with increased compressive and flexural strengths. These findings suggest that BSS could be a potential alternative to Portland cement in concrete production, leading to environmental and socio-economic benefits.