Open AccessCorrelation of Microstructure and Flexural Strength of Fly Ash Geopolymer of Varying Molarities
Author(s) -
Ng Yong-Sing,
Liew Yun-Ming,
Heah Cheng-Yong,
Mohd Mustafa Al Bakri Abdullah,
Ng Hui-Teng,
Amir Naveed
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/551/1/012087
Subject(s) - geopolymer , fly ash , sodium silicate , flexural strength , sodium hydroxide , microstructure , molar concentration , materials science , alkali metal , composite material , chemistry , organic chemistry
The present work studies and compares the flexural properties of fly ash geopolymer with varying molarity of sodium hydroxide (NaOH). Different molarities of NaOH solution (6M, 8M, 10M, 12M and 14M) are used to prepare the alkali activator (a mixture of NaOH and sodium silicate). The fly ash geopolymer were synthesised by using the solid/liquid ratio of 2.5 and sodium silicate/NaOH ratio of 2.5. The samples were cured at 60°C for 6 hours. The flexural test and microstructural analysis of fly ash geopolymer are performed after 28 days. Generally, the flexural strength of fly ash geopolymer increases when the molarity of NaOH increases. The 12M geopolymer has the highest flexural strength and a more densified microstructure is observed.