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The aim of the present research is to ascertain the effect of the nature and concentration of the alkaline activator and temperature on the rheological behaviour of alkali-activated fly ash (AAFA) pastes. Furthermore, the reaction process of fly ash has been investigated from rheological measurements. Results have shown that the increase of the activator concentration and the temperature leads to an increase of yield stress and apparent viscosity, mainly at temperatures above 65 oC when dissolution of fly ash and precipitation of hydration products is raised. In general, similar activation energies were determined for alkaline-activated fly ash pastes, regardless of the concentration and silica modulus of the activator, concluding that the underlying reaction mechanism is the same independently on the nature of the activating solution.

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Nowadays polyethylene is one of the polymers produced in the greatest volume and the amount of generated waste high‐density polyethylene (w‐HDPE) is significant as well. Valorization and recycling of w‐HDPE can be realized by blending with different types of polymers and/or elastomers for example, ethylene‐vinyl acetate (EVA). For the purpose of boosting of interfacial interactions between these two polymers experimental olefin‐maleic‐anhydride based additives have been incorporated into the blends after optimization of the processing temperature. Impact and tensile tests have been carried out in our research work besides microscopy measurements and investigation of the effects of additive structure by FT‐IR and rheology. At higher processing temperature (220°C) both tensile properties and Charpy impact strength were increased, latter one improved by 245% measured at 5°C while elongation at break enhanced by 182% with incorporation of some experimental additives compared to the neat 70/30 w‐HDPE/EVA. Changes in the hydrocarbon molecular chains of experimentally compatibilized blends were observed based on FT‐IR results and rheological measurements. It can be concluded that one of the most basic notions of sustainability, the 4R's (reduce, recycle, reuse, recover) has been satisfied in a successful way.