The Effects of Fly Ash Addition on the Properties of Porous Clay-Fly Ash Composites

Porous ceramics have a great potential to be utilised for adsorption purposes. In this study, the effects of fly ash addition in porous clay-fly ash composites via polymeric replica technique were investigated. The results shows that the fly ash addition from 1:1 to 1:1.5 (clay:fly ash ratio) have promoted favourable results for compressive strength (0.228-0.284 MPa), porosity (97.0-97.4 percent) and densities (2.358-2.439 g/cm3) respectively. When the fly ash ratio addition was increased up to 1:2 (clay:fly ash ratio), the compressive strength (0.18 MPa) reduced significantly. However, the density was bounced back to 2.404 g/cm3 at the same ratio. This condition was occurred due to high concentration of mineral contents when fly ash addition has increased. Based on XRD pattern, the intensities between mullite and quartz was reduced when clay:fly ash ratio increased from 1:1 to 1:1.5. As the clay:fly ash ratio was increased up to 1:2, the intensities of mullite and quartz showed an increment in XRD pattern. However, there were only 4 percent of changes in porosity when the fly ash addition was 1:2 (clay: fly ash ratio). The reticulated structures of porous clay-fly ash composites were similar although fly ash addition has increased from 1:1 to 1:2.