Utilization of high carbon fly ash and coal gangue in blended cement: a case study

The purpose of this work is to present an effective alternative to combined use of high carbon fly ash (HCFA) and coal gangue. HCFA, coal gangue, together with some additives and water, were mixed, dried, and clacinated at 700 degrees C similar to 900 degrees C to produce a cement admixture (FGA),which is used to produce environment friendly cementing material by mixing and co-grinding with granulated blast-furnace slag (GBFS) and alkali activator. The optimized formulation of the cementing material for Strength Grade 42.5 (G812958-1999) was obtained with the aid of orthogonal array technique: FGA-47%, GBFS-47%, activator-6%. The hydration products, studied by SEM and XRD, are mainly ettringite and C-S-H (I).