Mitigation of environmental problems using brick kiln rice husk ash in geopolymer composites for sustainable development

Brick kilns uses assorted amount of rice husk as fuel to fire the stacks of soil bricks. In India, the rice husk ash (RHA) created during the burning process of bricks has yet to be properly exploited. The main focus of this study is to enhance the structural properties of geopolymer composites using brick kiln incinerated rice husk ash waste. The Physico-chemical analysis of brick kiln rice husk ash indicates the presence of high silica (88%) content with the evidence of XRD and FTIR analysis, SEM images shows high porous structure and PSD analysis gives a bonding nature of particle size as binding ingredient. The geopolymer mixes were made manually with different percentage of RHA 0%, 10%, 20% and 30% replaced partially in Siliceous Flyash. To identify suitability of the mixture for geopolymer concrete production, properties like workability and fresh density of the mixture was investigated using manually casted cubes having a size of 100 mm and keeping for oven drying at 40° ±2 °C upto 24 h. Compressive strength as destructive structural test method was investigated at the respective duration of curing. The findings led to the conclusion that increasing the percentages of RHA in the combination improves the mixture for geopolymer concrete composites with the increase of curing time. At 10% RHA addition, the optimal compressive strength of 42.19 N/mm2 was achieved. The compressive strength of the RHA was found to decrease by 0.8% at 10% addition, which is negligible when compared to the control geopolymer mix (i.e., mix with 0% RHA), implying that the RHA from brick kilns can be employed to improve the structural qualities of geopolymer concrete composites.