( SE18--1276) Role of SiO2/Al2O3 Ratio and SiC Whisker in the Curing Mechanism of Alkali Accelerated Alumino-Silicate Binder for Structural Composites

摘要

The current project focused on the development of earth-friendly cementitious binder for the composite that is processable near room temperature but applicable to high temperature. The project involved a poly-condensed alkali accelerated inorganic polymer matrix system, known as Geopolymer. The primary objective of this study was to understand the role of the mole ratios in the inherent strengthening mechanism of this binder. It is critical to estimate the Si/Al ratio and unreacted SiO2 particle size in order to understand the degree of non-stoichiometry and dispersion strengthening. The formulation of this binder included Fly Ash based geopolymer in an Alkali silicate medium. The proposed geopolymer is formed by a polycondensation reaction with the specific ratios of Al2O3/M2O, SiO2/Al2O, M2O/SiO2 (M=k or Na). Several characterization techniques were involved in this study such as mechanical testing, Scanning Electron Microscopy, fire resistance test. It was found that Si/Al ratio between 2-4 is optimum for improved compressive strength. SiO2 particle size between 0.5 μm-2 μm resulted in the optimum mechanical strength including compressive and flexure strength. Fire resistance study showed some pitting formation in the range of 250 to 500 c which suggests removal of entrapped air bubbles.