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An environmentally friendly alkali activated cement powder was prepared by the transformation of air cooled slag (ACS), with low reactivity, into high reactive cementitious material. The recycling process was carried out by thermal activation of ACS in the presence of fluxing materials followed by quenching and crushing to produce cement powder with a fixed particle size, yielding alkali activated cement powder, which can react with water like Portland cement. Type and content of fluxing material were investigated in this communication. The results proved that there is no change in the crystalline structure of ACS when it exposed to 1200 °C (with no fluxing materials). Meanwhile, it can convert to amorphous material with a complete vitreous structure in the presence of sodium hydroxide and feldspar. The dissolution/condensation process of the amorphous aluminosilicate initiated after adding water to the prepared cement powder, yielding hardened cement pastes with higher mechanical properties as compared to untreated alkali activated ACS.

The goal of this study is to produce an environmentally, and user friendly ready-mix alkali activated cement (RM-AAC) by thermal activation of concrete waste (CW) in the presence of sodium hydroxide (NaOH). Two major compositional factors, which play an important role in the performance of RM-AAC, i.e. temperature and NaOH percentage, were investigated. The CW showed high stability under thermal treatment up to 1200 °C; meanwhile it can be converted to distorted structure with high amorphicity in the presence of appropriate NaOH content. RM-AAC powder can react with water, forming hardened material with an acceptable compressive strength. Due to the white color of RM-AAC powder, it can be beneficially used in prestige construction projects and decorative works.