Strength, permeability and micro-structural characteristics of low-calcium fly ash based geopolymers

Test results indicate that workability of low-calcium fly ash based geopolymer concrete decreased with increase in OPC content. Further, inclusion of OPC enhanced the compressive strength and reduced the permeability at all ages (3, 7 and 28 days). However optimum results were obtained for geopolymers with 20% OPC. SEM, EDS and XRD analysis confirmed the modifications in matrix making it denser, compact and less permeable.