Liew Yun Ming
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Preferred name
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.
Main Affiliation
Scopus Author ID
57204242778
Researcher ID
S-7164-2019

Research Output
Now showing 1 - 6 of 6
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Publication

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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Thermal insulation and mechanical properties in the presence of glas bubble in fly ash geopolymer paste

2021 , Noor Fifinatasha Shahedan , Mohd. Mustafa Al Bakri Abdullah , Norsuria Mahmed , Liew Yun Ming , Shayfull Zamree Abd. Rahim , Ikmal Hakem A Aziz , Aeslina Abdul Kadir , Andrei Victor Sandu , Mohd Fathullah Ghazli@Ghazali

The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/ ely, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3 K), and thermal diffusivity(0.572 mm2/s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material

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Cold-pressed fly ash geopolymers: effect of formulation on mechanical and morphological characteristics

2021 , Ong Shee-Ween , Heah Cheng Yong , Lynette Wei Ling Chan , Mohd. Mustafa Al Bakri Abdullah , Ho Li Ngee , Liew Yun Ming , Ooi Wan-En , Ng Yong-Sing , Nur Ain Jaya

This research uses low alkali activator content and cold pressing technique for fly ash-based geopolymers formation under room temperature condition. The geopolymers were prepared using four different parameters: fly ash/alkali activator ratio, sodium hydroxide concentration, sodium silicate/sodium hydroxide ratio and pressing force. The results indicated that the compressive strength (114.2 MPa) and flexural strength (29.9 MPa) of geopolymers maximised at a fly ash/alkali activator ratio of 5.5, a 14 M sodium hydroxide concentration, a sodium silicate/sodium hydroxide ratio of 1.5 and a pressing force of 5 tons (pressing stress of 100.0 MPa and 155.7 MPa for compressive and flexural samples, respectively). The degree of reaction (40.1%) enhanced the structure compactness with minimum porosity. The improved mechanical properties confirmed that a high strength pressed geopolymer could be formed at low alkali activator content without the aid of temperature.

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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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Effect of sodium aluminate on the fresh and hardened properties of fly ash-based one-part geopolymer

2021 , Ooi Wan-En , Liew Yun Ming , Heah Cheng Yong , Ho Li Ngee , Mohd. Mustafa Al Bakri Abdullah , Ong Shee-Ween , Andrei Victor Sandu

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.

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Flexural properties of thin fly ash geopolymers at elevated temperature

2021 , Yong-Sing Ng , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Hui-Teng Ng , Lynette Wei Ling Chan

This paper reports on the flexural properties of thin fly ash geopolymers exposed to elevated temperature. The thin fly ash geopolymers (dimension = 160 mm × 40 mm × 10 mm) were synthesised using12M NaOH solution mixed with designed solidsto-liquids ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 and underwent heat treatment at different elevated temperature (300°C, 600°C, 900°C and 1150°C) after 28 days of curing. Flexural strength test was accessed to compare the flexural properties while X-Ray Diffraction (XRD) analysis was performed to determine the phase transformation of thin geopolymers at elevated temperature. Results showed that application of heat treatment boosted the flexural properties of thin fly ash geopolymers as the flexural strength increased from 6.5 MPa (room temperature) to 16.2 MPa (1150°C). XRD results showed that the presence of crystalline phases of albite and nepheline contributed to the increment in flexural strength.

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