Mohd. Mustafa Al Bakri Abdullah
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Preferred name
Mohd. Mustafa Al Bakri Abdullah
Official Name
Abdulah, Mohd. Mustafa Al Bakri
Alternative Name
Abdullah, M.M.A.
M.M.A. Abdullah
Mustafa Al Bakri, A. M.
Albakri Abdullah, M. M.
Main Affiliation
CeGeoGTech UniMAP
Scopus Author ID
53164519100

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  • Publication
    Effect of rubber sludge on the physical and mechanical properties of low calcium fly ash-based geopolymer
    (Polish Academy of Sciences, 2025)
    Tee Hoe Woon
    ;
    Heah Cheng Yong
    ;
    Ng Qi Hwa
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Jia-Ni Lim
    ;
    Ong Shee-Ween
    ;
    O. Wan-En
    ;
    Hang Yong-Jie
    In this research, experimental work has been carried out to check the feasibility of using rubber sludge (RS) to partially replace fly ash (FA) in the production of geopolymer. RS is employed in this study as disposing of RS has led to an issue and is abundant, especially in countries producing rubber products. RS is classified as hazardous waste. Improper awareness on hazardous waste handling can spread a variety of diseases. Therefore, handling of hazardous waste is not easy as competent personnel is required during the collection, transportation, treatment and final disposal. As a result, the cost of disposing the hazardous waste are relatively high. With that, FA incorporated RS geopolymer will able to solve the landfill problems and used it as building materials will save costs, preserve natural resources, and protect the environment from waste impact and hazards. In this study, the physical and mechanical properties were investigated. It was used to replace fly ash at 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%. Water absorption, apparent porosity, bulk density, and compressive strength were tested. The test result shows that 5 wt.% of RS incorporation to fly ash-based geopolymer is optimum as it has 1752 kg/m3 of density, 9.5% of water absorption, 19.2% of apparent porosity, and 49.9 MPa of compressive strength.
  • Publication
    Improvements of flexural properties and thermal performance in thin geopolymer based on fly ash and ladle furnace slag using borax decahydrates
    ( 2022)
    Ng Yong-Sing
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Phakkhananan Pakawanit
    ;
    Petrica Vizureanu
    ;
    Mohd Suhaimi Khalid
    ;
    Ng Hui-Teng
    ;
    Hang Yong-Jie
    ;
    Marcin Nabiałek
    ;
    Paweł Pietrusiewicz
    ;
    Sebastian Garus
    ;
    Wojciech Sochacki
    ;
    Agata Śliwa
    This paper elucidates the influence of borax decahydrate addition on the flexural and thermal properties of 10 mm thin fly ash/ladle furnace slag (FAS) geopolymers. The borax decahydrate (2, 4, 6, and 8 wt.%) was incorporated to produce FAB geopolymers. Heat treatment was applied with temperature ranges of 300 °C, 600 °C, 900 °C, 1000 °C and 1100 °C. Unexposed FAB geopolymers experienced a drop in strength due to a looser matrix with higher porosity. However, borax decahydrate inclusion significantly enhanced the flexural performance of thin geopolymers after heating. FAB2 and FAB8 geopolymers reported higher flexural strength of 26.5 MPa and 47.8 MPa, respectively, at 1000 °C as compared to FAS geopolymers (24.1 MPa at 1100 °C). The molten B2O3 provided an adhesive medium to assemble the aluminosilicates, improving the interparticle connectivity which led to a drastic strength increment. Moreover, the borax addition reduced the glass transition temperature, forming more refractory crystalline phases at lower temperatures. This induced a significant strength increment in FAB geopolymers with a factor of 3.6 for FAB8 at 900 °C, and 4.0 factor for FAB2 at 1000 °C, respectively. Comparatively, FAS geopolymers only achieved 3.1 factor in strength increment at 1100 °C. This proved that borax decahydrate could be utilized in the high strength development of thin geopolymers.
      3  21
  • 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.
      1  18
  • Publication
    Thin fly ash/ ladle furnace slag geopolymer: Effect of elevated temperature exposure on flexural properties and morphological characteristics
    ( 2022-06-15)
    Yong-Sing Ng
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Pakawanit P.
    ;
    Chan L.W.L.
    ;
    Ng Hui-Teng
    ;
    Ong Shee-Ween
    ;
    Ooi Wan-En
    ;
    Hang Yong-Jie
    The flexural properties and thermal performance of 10 mm-thin geopolymers made from fly ash and ladle furnace slag were evaluated before and after exposure to elevated temperatures (300 °C, 600 °C, 900 °C, 1100 °C and 1150 °C). Class F fly ash was mixed with liquid sodium silicate (Na2SiO3) and 12 M sodium hydroxide (NaOH) solution using aluminosilicate/activator ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 to synthesise thin fly ash (FA) geopolymers. 40 wt% of ladle furnace slag was partially replacing fly ash to produce fly ash/slag-based (FAS) geopolymers. Thermal treatment enhanced the flexural strength of thin geopolymers. In comparison to the unexposed specimen, the flexural strength of FA geopolymers at 1150 °C and FAS geopolymers 1100 °C was increased by 161.3% to 16.2 MPa and 208.9% to 24.1 MPa, respectively. A more uniform heating was achieved in thin geopolymers which favoured the phase transformation at high temperatures and contributed to the substantial increase in flexural strength. The joint effect of elevated temperature exposure and the incorporation of ladle furnace slag further improved the flexural strength of thin geopolymers. The calcium-rich slag refined the pore structure and increased the crystallinity of thin geopolymers which aided in high strength development.
      1
  • Publication
    Thin fly ash/ ladle furnace slag geopolymer: Effect of elevated temperature exposure on flexural properties and morphological characteristics
    ( 2022-06-15)
    Ng Yong-Sing
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Pakawanit P.
    ;
    Chan L.W.L.
    ;
    Ng Hui-Teng
    ;
    Ong Shee Ween
    ;
    Ooi Wan En
    ;
    Hang Yong-Jie
    The flexural properties and thermal performance of 10 mm-thin geopolymers made from fly ash and ladle furnace slag were evaluated before and after exposure to elevated temperatures (300 °C, 600 °C, 900 °C, 1100 °C and 1150 °C). Class F fly ash was mixed with liquid sodium silicate (Na2SiO3) and 12 M sodium hydroxide (NaOH) solution using aluminosilicate/activator ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 to synthesise thin fly ash (FA) geopolymers. 40 wt% of ladle furnace slag was partially replacing fly ash to produce fly ash/slag-based (FAS) geopolymers. Thermal treatment enhanced the flexural strength of thin geopolymers. In comparison to the unexposed specimen, the flexural strength of FA geopolymers at 1150 °C and FAS geopolymers 1100 °C was increased by 161.3% to 16.2 MPa and 208.9% to 24.1 MPa, respectively. A more uniform heating was achieved in thin geopolymers which favoured the phase transformation at high temperatures and contributed to the substantial increase in flexural strength. The joint effect of elevated temperature exposure and the incorporation of ladle furnace slag further improved the flexural strength of thin geopolymers. The calcium-rich slag refined the pore structure and increased the crystallinity of thin geopolymers which aided in high strength development.
      1  21