Sarkar, Madhuchhanda and Dana, Kausik and Das, Sukhen (2015) Microstructural and phase evolution in metakaolin geopolymers with different activators and added aluminosilicate fillers. Journal of Molecular Structure, 1098. pp. 110-118. ISSN 0022-2860

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This work aims to investigate the microstructural and phase evolution of alkali activated metakaolin products with different activators and added aluminosilicate filler phases. The added filler phases have different reactivity to the alkali activated metakaolin system. Microstructural evolution in the alkali activated products has been investigated by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscope (FESEM). Variation in strength development in alkali activated metakaolin products was followed by compressive strength measurement test. Microstructural study shows that in case of metakaolin with NaOH activator crystalline sodalite formed in all the product samples irrespective of the added filler phases. The microstructure of these NaOH activated products investigated by FESEM showed crystalline and inhomogeneous morphology. Mixed activator containing both NaOH and sodium silicate in a fixed mass ratio formed predominantly amorphous phase. Microstructure of these samples showed more homogeneity than that of NaOH activated metakaolin products. The study further shows that addition of alpha-Al2O3 a powder, non reactive phase to the alkali activated metakaolin system when used in larger amount increased crystalline phase in the matrix. alpha-Al2O3 a powder addition increased the compressive strength of the product samples for both the activator compositions. Added phase of colloidal silica, reactive to the alkali activated metakaolin system when used in larger amount was found to increase amorphous nature of the matrix. Addition of colloidal silica influenced the compressive strength property differently with different activator compositions. (C) 2015 Elsevier B.V. All rights reserved.

Item Type: Article
Subjects: Microstructure and Characterization
Divisions: Refractory
Depositing User: Bidhan Chaudhuri
Date Deposited: 04 Jan 2016 11:52
Last Modified: 04 Jan 2016 11:52

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