Influence of red mud on performance enhancement of fly ash-based geopolymer concrete

This paper presents the strength, durability and microstructural characteristics of fly ash based geopolymer concrete in addition to red mud. The study explores the influence of other parameters on the compressive strength of GC such as Na2SiO3 to NaOH ratio (liquid-to-liquid), and alkaline solution to binder ratio. The presence of high alkalinity in the red mud was enough to dissolve FA, thus ensuing the formation of aluminosilicate gels. The X-ray diffraction analysis showed the geopolymerization process and confirmed the composition of end products. Based on the experimental results, it could be recognized that GC with 10% replacement of FA with RM has shown better strength and durability properties. The results depicted that the GC mix M8 attained enhanced compressive strength i.e., 47.6 MPa indicating that the GC can be used as materials for load-bearing members in structures. The SEM images showed that a huge quantity of geopolymeric products was generated in a geopolymer by the reaction of OH- with the aluminosilicate components in FA and RM in a strong alkaline nature. Due to minor porosity, good pore structure and lower chloride ion permeability, GC can be significantly better than conventional cement concrete.