Liew Yun Ming
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Liew Yun Ming
Official Name
Liew Yun Ming
Alternative Name
Yun-Ming, Liew
Liew, Y. M.
Yun Ming, Liew
Ming, Liew Yun
Liew, Yun Ming
Ming, L. Y.
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Scopus Author ID
57204242778
Researcher ID
S-7164-2019

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Formulation, mechanical properties and phase analysis of fly ash geopolymer with ladle furnace slag replacement

2021 , Ng Hui-Teng , Heah Cheng Yong , Kong Ern Hun , Mohd. Mustafa Al Bakri Abdullah , Liew Yun Ming , Hasniyati Md Razi , Ng Yong-Sing

This paper presents the formulation of fly ash (FA) geopolymer and the incorporation of ladle furnace slag (LFS) as a replacement to FA in geopolymer formation. The formulation of the LFS replacement was set at 10–40 wt.%. The geopolymer was formed by mixing FA and LFS with a sodium-based alkali activator. The FA geopolymer had a compressive strength of 38.9 MPa with the optimum formulation of 8 M NaOH concentration, AS/AA ratio of 3, and AA ratio of 1.5. The compressive strength was affected more significantly by the amorphous content. The most influential factors affecting the properties of FA geopolymer were: AS/AA ratio > AA ratio > NaOH concentration. Replacing LFS led to very little (4.1%) increment in the compressive strength. The LFS had little contribution in supplying Si, Al and Ca for the formation of the N-A-S-H and C-A-S-H network. But LFS acted as a filler and improved the compactness of the FA geopolymer. The mechanical performance of FA/LFS geopolymer was not governed by the amorphous content like the FA geopolymer, as LFS addition contributed to increasing crystalline content. New crystalline phases of calcite and CSH due to the addition of LFS helped to retain the compressive strength of FA geopolymer. Nevertheless, the outcome of the study proved that LFS can be blended with FA to produce geopolymers without severe deterioration in mechanical strength. LFS can be potentially added in geopolymers as filler to produce geopolymer mortar.

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Ladle furnace slag replacement on the flexural strength of thin fly ash geopolymer

2020 , Ng YONG-SING , Liew Yun Ming , Mohd. Mustafa Al Bakri Abdullah , Ng HUI-TENG , Ridho BAYUAJI

This article reports the investigation on the effect of ladle furnace slag replacement on the flexural strength of thin fly ash-based geopolymer. The thin fly ash/slag geopolymers were prepared with the replacement of various percentages of ladle furnace slag (0%, 10%, 20%, 30% and 40%) into fly ash geopolymers with dimension of 160 mm × 40 mm × 10 mm. The thin geopolymerwas synthesised using 12M sodium hydroxide (NaOH) solution with solid-to-liquid (S/L) ratio of 2.5 and Na2SiO3 /NaOH ratio of 4.0. The curing temperature and time of samples were 60°C and 6 hours respectively. The mechanical properties of thin geopolymers was revealed using flexural test after 28 days. Several characterisation tools have been used including Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to correlate the flexural properties with the microstructure and phases of fly ash/slag geopolymers. Results obtained reported that a positive effect on flexural strength was observed with the increasing amount of slag. The thin fly ash geopolymers replaced with 40% of ladle furnace slag showed the highest flexural strength of 7.8 MPa. The rich CaO content in ladle furnace slag boosted the C-S-H gels formation which increased the flexural strength of thin geopolymers.

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Evaluation of flexural properties and characterisation of 10-mm thin geopolymer based on fly ash and ladle furnace slag

2021 , Ng Yong-Sing , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Lynette Wei Ling Chan , Ng Hui-Teng , Ong Shee-Ween , Ooi Wan-En , Hang Yong-Jie

The formulation and flexural properties of thin fly ash geopolymers with thickness of merely 10 mm and replacement of ladle furnace slag to fly ash in thin geopolymer were presented. The formulation was discussed in terms of NaOH molarity, solid aluminosilicates-to-liquid alkali activator (S/L) mass ratio, and alkali activator (Na2SiO3/NaOH) mass ratio. Thin fly ash geopolymers with flexural strength and Young's modulus of 6.2 MPa and 0.14 GPa, respectively, were obtained by using 12 M NaOH, S/L ratio of 2.5 and Na2SiO3/NaOH ratio of 4.0. A high Na2SiO3/NaOH ratio was implemented for thin geopolymer synthesis to produce a more viscous slurry which helped to retain the shape of a thin geopolymer. The incorporation of ladle furnace slag up to 40 wt.% reported an increment of 26% in flexural strength up to 7.8 MPa as compared to pure fly ash geopolymers and the stiffness was increased to 0.19 GPa. Denser microstructure with improved compactness was observed as the ladle furnace slag acted as the filler. New crystalline phases of calcium silicate hydrate (C–S–H) were formed and coexisted with the geopolymer matrix, which consequently enhanced the flexural strength of thin fly ash geopolymer. This proved that the ladle furnace slag has the potential to be utilised in geopolymer synthesis and will enhance the flexural properties of thin geopolymers. The flexural performance of thin geopolymers in this study was considerably good as the thin geopolymers exhibited comparatively similar flexural strengths, but a higher strength/thickness ratio as compared to geopolymers with thickness greater than 40 mm.

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