One-Part Geopolymer Synthesis of Greek Fly Ash

Abstract

With the OPC industry being responsible for the 8% of CO2 global emissions, alternative, eco-friendly building materials, called geopolymers, have been in the center of research interest. Their broader use is limited due to the concentrated alkali solution that is involved in the synthesis process. In this study, a wide range of solid reagents are tested for the development of solid mixtures with suitable alkali and silica content that will substitute the corrosive activation solution. One-part geopolymers were synthesized using Greek fly ash as the aluminosilicate precursor. The produced samples were appropriately characterized by XRD, FTIR and SEM analytical techniques while the mechanical performance was evaluated through uniaxial compressive strength measurements. One-part geopolymers using anhydrous sodium silicates with molar ratios SiO2/Na2O ≤ 2 as solid activators, can successfully substitute the activation solution since they achieve identical mechanical performance to that of the two-part geopolymers (≥ 60 MPa).