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.
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Scopus Author ID
57204242778
Researcher ID
S-7164-2019

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  • Publication
    Compressive strength and thermal conductivity of metakaolin geopolymers with anisotropic insulations
    ( 2020-03-18)
    Jaya N.A.
    ;
    Liew Yun Ming
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    ;
    Heah Cheng Yong
    ;
    Bayuaji R.
    ;
    Muhammad Faheem Mohd. Tahir
    This research investigated the properties of thermally insulating geopolymer prepared using waste filler (fibreboard and rubber) to act as anisotropic pore/insulation. The geopolymer matrix was synthesised using metakaolin and an alkaline solution consists of sodium hydroxide solution and sodium silicate mixture. Geopolymers with varying content (0, 3, 5 and 7 layers) of coin-shaped fibreboard and expanded polystyrene are produced to examine the anisotropic insulation effect on the material characteristics. The compressive strength and thermal conductivity were determined experimentally. From the results, it is proved that the use of anisotropic insulations can improve the thermal conductivity and minimizing the reduction of compressive strength. Geopolymer incorporated with fibreboard had better performance in terms of strength while geopolymer incorporated with rubber had better thermal conductivity.
      3  27
  • Publication
    Thermal insulation and mechanical properties in the presence of glass bubble in fly ash geopolymer paste
    ( 2022-01-01)
    Noor Fifinatasha Shahedan
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Norsuria Mahmed
    ;
    Liew Yun Ming
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Ikmal Hakem Abdul Aziz
    ;
    Kadir A.A.
    ;
    Sandu A.V.
    ;
    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/ cm3 and 42.5 MPa, respectively, 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/m3K), 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.
      1  37
  • Publication
    Thermal Insulation and Mechanical Properties in the Presence of Glas Bubble in Fly Ash Geopolymer Paste
    ( 2022-01-01)
    Shahedan N.F.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Norsuria Mahmed
    ;
    Liew Yun Ming
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Aziz I.H.A.
    ;
    Kadir A.A.
    ;
    Sandu A.V.
    ;
    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/ cm3 and 42.5 MPa, respectively, 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/m3K), 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.
      40  8
  • Publication
    Correlation between pore structure, compressive strength and thermal conductivity of porous metakaolin geopolymer
    ( 2020-06-30)
    Jaya N.A.
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    This paper investigates the effect of mixing parameters (that are, alkali concentration, AA ratio, and MK/AA ratio) on the thermal conductivity of metakaolin geopolymers. The combination effect of foaming agent (H2O2) and surfactant (Tween 80) on the physical properties, compressive strength, and pore characteristic was also elucidated. Results showed that metakaolin geopolymer with maximum compressive strength of 33 MPa, bulk density of 1680 kg/m3, porosity of 18% and thermal conductivity of 0.40 W/mK were achieved with alkali concentration of 10 M, AA ratio of 1.0 and MK/AA ratio of 0.8. Gradation analysis demonstrated that AA ratio was the strength determining factor. Whilst, thermal conductivity was dependent on the MK/AA ratio. Adding H2O2 and surfactant produced geopolymer foam with acceptable compressive strength (0.4–6 MPa). The geopolymer foam had bulk density of 471–1212 kg/m3, porosity of 36–86% and thermal conductivity of 0.11–0.30 W/mK. Pore structure, size, and distribution were governed by H2O2 and surfactant dosages that have a great impact on the compressive strength. Narrower pore distribution and smaller pore diameter were achieved when both foaming agent and surfactant were used instead of foaming agent alone. The pore size and distribution varied to a greater extent with varying H2O2 contents. Surfactant illustrated distinct pore stabilizing effect at low H2O2 (<0.75 wt%) which diminished at high H2O2 content. In terms of thermal conductivity, even with increasing porosity at high H2O2 and surfactant content, the thermal conductivity did not show substantial reduction due to the interconnected pores as a result of pore coalescence.
      1
  • Publication
    Thermal insulation and mechanical properties in the presence of glass bubble in fly ash geopolymer paste
    ( 2022-01-01)
    Noor Fifinatasha Shahedan
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Norsuria Mahmed
    ;
    Liew Yun Ming
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Ikmal Hakem Abdul Aziz
    ;
    Kadir A.A.
    ;
    Sandu A.V.
    ;
    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/ cm3 and 42.5 MPa, respectively, 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/m3K), 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.
      1
  • Publication
    Effect of Solid-to-Liquid Ratio on Thin Fly Ash Geopolymer
    ( 2020-03-18)
    Yong-Sing N.
    ;
    Liew Yun Ming
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Hui-Teng N.
    ;
    Kamarudin Hussin
    ;
    Heah Cheng Yong
    ;
    Nurul Aida Mohd Mortar
    ;
    Sandu A.V.
    The present work studies the effect of solid-to-liquid (S/L) ratio on the properties of thin fly ash-based geopolymer. The fly ash geopolymers with dimension of 160 mm × 40 mm × 10 mm were synthesised by using various S/L ratios (1.5, 2.0, 2.5, 3.0 and 3.2). The alkali activator was prepared by mixing 10M sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) with the Na2SiO3/NaOH ratio of 2.5. The samples were cured at 60°C for 6 hours. The performance of fly ash geopolymers was evaluated by testing the flexural strength after 28 days. Results showed that the S/L ratio had an effect on flexural strength. The optimum flexural strength of 5.12 MPa was achieved by the fly ash geopolymer with S/L ratio of 2.5. However, the flexural strength dropped with higher S/L ratio as the workability decreases. However, further experimental lab work should be carried out as there is less knowledge in the study on the flexural strength of thin fly ash geopolymer.
      1  28
  • Publication
    Behaviour changes of ground granulated blast furnace slag geopolymers at high temperature
    ( 2020-10-01)
    Aziz I.H.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Heah C.Y.
    ;
    Liew Yun Ming
    In this paper, the thermal performance of ground-granulated blast furnace slag (GGBFS) geopolymers is investigated. The geopolymers were prepared with sodium-based alkali activator and exposed to elevated temperature (200 to 1000°C) after 28 d of curing at room temperature. The unexposed geopolymers exhibited excellent compressive strength of 95 MPa. The compressive strength reduced to 8·9 MPa at 800°C and increased to 19·8 MPa at 1000°C. The strength regained by 122·5% as compared to the residual strength at 800°C. The crack reduction and partial melting in geopolymers treated at 1000°C signifies crack healing at elevated temperature, which in turn increases the compressive strength. In addition, the formation of crystalline phases of gehlenite (Ca2Al2SiO), mayenite (Ca12Al14O33) and larnite (Ca2SiO4) filled the geopolymer matrix and formed an ordered structure. This further enhanced the strength and high-Temperature stability of GGBFS geopolymers.
      1  20
  • Publication
    Effect of phosphate addition on room-temperature-cured fly ash-metakaolin blend geopolymers
    ( 2021-02-08)
    Khairunnisa Zulkifly
    ;
    Heah Cheng Yong
    ;
    Liew Yun Ming
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ong Shee-Ween
    ;
    Khalid M.S.B.
    This paper details the influence of NaOH concentration, solid-to-liquid (S/L) and sodium silicate-to-sodium hydroxide (Naâ‚‚SiO3/NaOH) ratios, and the role of aluminum phosphate on the compressive strength development of the fly ash-metakaolin (FA-MK) blend geopolymer. The blended geopolymer was prepared with FA: MK at a ratio of 1:1, activated with a sodium-based alkali activator and then cured at room temperature. The optimum FA-MK blend geopolymer was formulated using a 10 M NaOH solution, a S/L ratio of 1.2, and a Naâ‚‚SiO3/NaOH ratio of 2.6. Monoaluminium phosphate (MAP) and aluminum dihydrogen triphosphate (ATP) were added as the source of aluminium phosphate. The FA-MK blend geopolymers have compressive strengths of 63.7 MPa and 55.5 MPa after being cured for 28 days with the addition of 1 wt% of MAP and ATP, respectively. The strength enhancement was assumed to be dictated by the formation of a matrix with a higher cross-linking geopolymer framework. The microstructure of blend geopolymer with MAP and ATP was smoother and compact compared to those without phosphate addition. In comparison, MAP addition in blend geopolymer yielded better physical and mechanical properties.
      1  26
  • Publication
    The Effect of Sodium Carbonate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer
    ( 2020-07-09)
    Wan-En O.
    ;
    Liew Yun Ming
    ;
    Ho Li Ngee
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Shee-Ween O.
    One-part geopolymer utilized dry activator(s) which undergo geopolymerization by "just add water"mechanism. There are wide varieties of dry binders to develop one-part geopolymer. This work presents an investigation of fresh and hardened properties of fly ash-based one-part geopolymer activated by mixture of anhydrous sodium metasilicate (Na2SiO3) with sodium carbonate (Na2CO3). The ratios of alkali activator-to-fly ash (AA/FA) were set as 0.15, 0.20 and 0.25. The substitution of Na2CO3 was set as Na2SiO3/Na2CO3 ratio of 1. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Porosity, compressive strength and microstructural properties of developed specimens were also analyzed after 28 days of curing. The result showed that the partial substitution of Na2CO3 resulted in a shorter setting time and lower porosity. Besides that, the one-part geopolymer activated by the mix of Na2SiO3 and Na2CO3 achieved 78.23 MPa at AA/FA ratio of 0.20. The findings suggest that Na2CO3 is a potential alkali activator for one-part geopolymer.
      2  27