Effect of synthesis parameters on compressive strength of fly ash-slag blended geopolymer

This article outlines the influence of synthesis parameters on mechanical properties of geopolymer synthesized under ambient environmental conditions. Geopolymer binders are prepared from binary blended pozzolanic materials, i.e. the fly ash and slag as source material and sodium hydroxide as alkali activator. The dissolution of alumino-silicates from the source materials under different alkali condition is studied. The compressive strength of blended fly ash-slag geopolymer; synthesized under different conditions is investigated. The relevance of development in compressive strength with the amount of leached alumino-silicate ions is discussed. Further, the mineralogical, chemical and microstructural characterizations are done for the geopolymers. The test results reveal that the dissolution and compressive strength are highly affected by the alkali content and the reactive component of the source material. The reaction products, chemical bonds and microstructural development are different for different raw materials; depending upon the reactive phase present. Statistical analyses are carried out to check the significance of the factors affecting the synthesis process. Also, mathematical relationships are established for factors influencing mechanical behaviour of synthesized geopolymer.