A novel eco-sustainable approach for the cleaner production of ready-mix alkali activated cement using industrial solid wastes and organic-based activator powder

The main feature of the present paper is the eco-sustainable use of industrial solid wastes and organic-based activator (OBA) powder in the cleaner production of ready-mix alkali activated cement (RM-AAC) which interacts with water like Portland cement. The reasonable reason behind the preparation of RM-AAC (Just added water) is the corrosive nature of alkaline solutions which negatively affect the mass production and commercial viability of AAC. Accordingly, this work has resolved this shortcoming by the preparation of a novel activator powder which was synthesized by mixing NaOH solution with ethylene glycol, followed by drying and grinding to yield OBA-powder. The designation of RM-AAC was conducted by blending ground granulated blast-furnace slag (GGBFS: from steel-industry) and/or slag-lead bearing sludge (LBS: from glass crystal industry) with OBA-powder. The results revealed that the desirable OBA-content has resulted in a significant improvement in the performance of RM-AAC containing GGBFS. Although a further increase in OBA-content caused a remarkable improvement in the workability of RM-AAC, it represented a negative effect on its compressive strength development. The prepared RM-ACC showed 180-days compressive strength 157% higher than that of the conventional two-part mixture (at the same Na2O and EG contents). This is due to the fact that OBA-powder enhances the polymerization degree and stability of the prepared cement as proved by the suggested reaction mechanism. The inclusion of 10 wt % LBS has a positive impact on the mechanical properties of RM-AAC as it enhances strength-giving-phases formation by providing the alkali activated system with reactive silicate. Moreover, All RM-AAC/LBS composites demonstrated Pb-concentrations in leachate too lower than that of the safe limit of toxicity characteristic leaching procedure (TCLP). This means the high Pb-immobilization property of the prepared cement, reflecting on its beneficial and safe use in the construction sector. (c) 2020 Elsevier Ltd. All rights reserved.