Role of particle fineness on engineering properties and microstructure of fly ash derived geopolymer

Nath, S K (2020) Role of particle fineness on engineering properties and microstructure of fly ash derived geopolymer. Construction and Building Materials .

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Abstract

Fly ash is ball milled for 30 and 90 min duration to obtain two finer fractions. The degree of size reduction is very significant at the early stage of milling, then because of agglomeration effect size reduction becomes sluggish. The effect of particle size on physical, mechanical and microstructural properties of resultant geopolymer is elucidated. The physical properties and mechanical strength improvement with milling time is attributed with formation of higher amount of alkaline alumino-silicate (N-A-S-H) hydrated gel. The weight loss profile in Thermo-gravimetric analysis (TGA) indicates more hydrated gel formation and lower carbonation with finer fraction. Different techniques such as Fourier transforms infrared spectroscopy (FTIR), X-ray diffractometer (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) have been used for microstructural evaluation of geopolymers. In FTIR, the asymmetric stretching of Si–O–T (T is Si/Al) has been shifted towards lower frequency due to structural alteration of Al–Si network. The crystalline peak intensity has been decreased because of formation of amorphous gel after geopolymerization, detected by XRD. Under SEM and TEM, finer fraction is characterized with formation of more reaction product. The counts of un-reacted and non-bridge particles are decreased with size reduction.

Item Type:Article
Official URL/DOI:https://doi.org/10.1016/j.conbuildmat.2019.117294
Uncontrolled Keywords:Fly ash geopolymer Particle size Mechanical properties Geopolymer gel Morphology
Divisions:Metal Extraction and Forming
ID Code:8063
Deposited By:Dr. S K Nath
Deposited On:27 Dec 2019 12:02
Last Modified:27 Dec 2019 12:02

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