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 - 5 of 5
  • Publication
    Effect of anisotropic pores on the material properties of metakaolin geopolymer composites incorporated with corrugated fiberboard and rubber
    ( 2021)
    Nur Ain Jaya
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Low Foo Wah
    ;
    Ooi Wan-En
    ;
    Ilham Mukriz Zainal Abidin
    ;
    Noorhazleena Azaman
    This paper compares the compressive strength and thermal conductivity of metakaolin geopolymer (MKG) incorporated with anisotropic and isotropic pores. MKG was prepared by activation with sodium hydroxide and sodium silicate. Corrugated fiberboard and rubber were included to create anisotropy of pores, and they were added in 3, 5, and 7 layers. Hydrogen peroxide and surfactant were added to generate isotropic pores. For geopolymer with corrugated fiberboard (MKG-C) and rubber (MKG-R), compressive test and thermal conductivity measurement were performed in perpendicular and parallel direction to the flat surface of fiberboard and rubber. The result showed that MKG-C and MKG-R exhibited mechanical and insulation anisotropically. The highest compressive strength was achieved in the parallel loading direction while the lowest thermal conductivity was attained in the perpendicular direction. MKG-C possessed better compressive strength of 26.9 MPa loaded in the parallel direction. The compressive strength performance of MKG-C was greater than MKG-R because of the fibrous-like structure, which further contributes to the strength. The thermal conductivity was low (0.15–0.20 W/mK) for both MKG-C and MKG-R. The anisotropy of pores led to high strength retention and improvement of thermal insulating properties. These properties were contrary to geopolymer with isotropic pores (MKG-F), which have excellent thermal insulating properties but low compressive strength to be eligible for structural applications.
  • Publication
    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.
      9  1
  • Publication
    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.
      3  2
  • Publication
    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.
      21  9
  • Publication
    Unveiling physico-mechanical and acoustical characteristics of fly ash geopolymers through the synergistic impact of density and porosity
    ( 2024-08-15)
    Jia-Ni L.
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Tan Wei Hong
    ;
    Part Wei Ken
    ;
    Phakkhananan Pakawanit
    ;
    Tee Hoe-Woon
    ;
    Hang Yong-Jie
    ;
    Ong Shee-Ween
    ;
    Ooi Wan-En
    This paper investigates the physico-mechanical and acoustic properties of fly ash geopolymers via casting and pressing methods. The existing research lacks comprehensive insight into the relationship between variations in geopolymer density and their impacts on both physico-mechanical properties and sound insulation and absorption capabilities. Geopolymers, as sustainable construction materials, are pivotal in mitigating noise and providing structural strength. To surpass these limitations and achieve either higher or lower densities in geopolymers, alternative approaches are necessary. Casting (non-foamed and foamed with 1.0, 2.0 and 3.0 foam-to-geopolymer paste ratio) and pressing methods were employed to produce a range of geopolymer densities between 1400 kg/m3 – 2200 kg/m3. The pressing method produced a highly dense geopolymer with an excellent compressive strength of 116 MPa. While the lightest geopolymer produced by adding a foaming agent had a compressive strength of 13 MPa. Good sound transmission loss (66.1 dB) was achieved by highly dense pressed geopolymers. Highly porous geopolymers achieved an excellent sound absorption coefficient of 0.79. The density variation and preparation methods greatly affected the pore size and distribution which subsequently affected the acoustical properties of the geopolymers. Manipulating the density and porosity of the geopolymers is essential for creating spaces with optimal acoustics to meet building codes and noise control regulations.
      5  11