Development of Geopolymer Concrete from Fly Ash and Bottom Ash Mixture

Abstract

Fly ash and bottom ash, the two main by-products of thermal power plant, have been used synergistically to develop geopolymer concrete. Fly ash has been used as active constituent for geopolymerization whereas bottom ash has been used as replacement of sand. Geopolymerization studies were carried out at ambient (27°C) and elevated (55°C) temperatures using isothermal conduction calorimetry. The reaction product was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The geopolymer concrete prepared at 60°C showed compressive strength in the range of 4-35 MPa. Strength development was studied as a function of alkali concentration and Si/Al ratio. It was observed that strength got improved significantly with higher alkali concentration and Si/Al ratio. Attempt has been made to correlate the structure with properties.

Keywords:

• Geopolymer
• Fly ash
• Bottom ash
• GBFS
• Flexural strength
• Compressive strength
• Aluminosilicate