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
    Assessment of geopolymer concrete for underwater concreting properties
    ( 2021)
    Fakhryna Hannanee Ahmad Zaidi
    ;
    Romisuhani Ahmad
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Wan Mastura Wan Ibrahim
    ;
    Ikmal Hakem Aziz
    ;
    Subaer Junaidi
    ;
    Salmabanu Luhar
    For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.
      4  17
  • 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.
      1  23
  • 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.
      1  36
  • Publication
    Fly ash-based geopolymer lightweight concrete using foaming agent
    ( 2012)
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    ;
    Mohamed Bnhussain
    ;
    Khairul Nizar Ismail
    ;
    Zarina Yahya
    ;
    Rafiza Abdul Razak
    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.
      3  36
  • Publication
    Evaluation on the mechanical properties of Ground Granulated Blast Slag (GGBS) and fly ash stabilized soil via geopolymer process
    ( 2021)
    Syafiadi Rizki Abdila
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Romisuhani Ahmad
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Małgorzata Rychta
    ;
    Izabela Wnuk
    ;
    Marcin Nabiałek
    ;
    Krzysztof Muskalski
    ;
    Muhammad Faheem Mohd. Tahir
    ;
    Muhammad Syafwandi
    ;
    Marek Isradi
    This study intended to address the problem of damaged (collapsed, cracked and decreased soil strength) road pavement structure built on clay soil due to clay soil properties such as low shear strength, high soil compressibility, low soil permeability, low soil strength, and high soil plasticity. Previous research reported that ground granulated blast slag (GGBS) and fly ash can be used for clay soil stabilizations, but the results of past research indicate that the road pavement construction standards remained unfulfilled, especially in terms of clay’s subgrade soil. Due to this reason, this study is carried out to further investigate soil stabilization using GGBS and fly ash-based geopolymer processes. This study investigates the effects of GGBS and ratios of fly ash (solid) to alkaline activator (liquid) of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1, cured for 1 and 7 days. The molarity of sodium hydroxide (NaOH) and the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) was fixed at 10 molar and 2.0 weight ratio. The mechanical properties of the soil stabilization based geopolymer process were tested using an unconfined compression test, while the characterization of soil stabilization was investigated using the plastic limit test, liquid limit test, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results showed that the highest strength obtained was 3.15 MPA with a GGBS to alkaline activator ratio of 1.5 and Na2SiO3 to NaOH ratio of 2.0 at 7 days curing time. These findings are useful in enhancing knowledge in the field of soil stabilization-based geopolymer, especially for applications in pavement construction. In addition, it can be used as a reference for academicians, civil engineers, and geotechnical engineers.
      8  24
  • Publication
    Contribution of interfacial bonding towards geopolymers properties in geopolymers reinforced fibers: a review
    ( 2022)
    Muhd Hafizuddin Yazid
    ;
    Meor Ahmad Faris bin Meor Ahmad Tajudin
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Marcin Nabiałek
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Marwan Kheimi
    ;
    Andrei Victor Sandu
    ;
    Adam Rylski
    ;
    Bartłomiej Jeż
    There is a burgeoning interest in the development of geopolymers as sustainable construction materials and incombustible inorganic polymers. However, geopolymers show quasi-brittle behavior. To overcome this weakness, hundreds of researchers have focused on the development, characterization, and implementation of geopolymer-reinforced fibers for a wide range of applications for light geopolymers concrete. This paper discusses the rapidly developing geopolymer-reinforced fibers, focusing on material and geometrical properties, numerical simulation, and the effect of fibers on the geopolymers. In the section on the effect of fibers on the geopolymers, a comparison between single and hybrid fibers will show the compressive strength and toughness of each type of fiber. It is proposed that interfacial bonding between matrix and fibers is important to obtain better results, and interfacial bonding between matrix and fiber depends on the type of material surface contact area, such as being hydrophobic or hydrophilic, as well as the softness or roughness of the surface.
      22  2
  • Publication
    Crumb rubber geopolymer mortar at elevated temperature exposure
    ( 2022)
    Ahmad Azrem Azmi
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Che Mohd Ruzaidi Ghazali
    ;
    Romisuhani Ahmad
    ;
    Ramadhansyah Putra Jaya
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Mohammad A. Almadani
    ;
    Wysłocki, Jerzy J.
    ;
    Agata Śliwa
    ;
    Andre Victor Sandu
    Low calcium fly ash is used as the main material in the mixture and the crumb rubber was used in replacing fine aggregates in geopolymer mortar. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) which were high alkaline solution were incorporated as the alkaline solution. The fly ash reacted with the alkaline solution forming alumino-silicate gel that binds the aggregate to produce a geopolymer mortar. The loading of crumb rubber in the fly ash based geopolymer mortar was set at 0%
      3  18
  • Publication
    Contribution of interfacial bonding towards geopolymers properties in geopolymers reinforced fibers: A review
    ( 2022)
    Muhd Hafizuddin Yazid
    ;
    Meor Ahmad Faris bin Meor Ahmad Tajudin
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Marcin Nabiałek
    ;
    Shayfull Zamree Abd. Rahim
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Marwan Kheimi
    ;
    Andrei Victor Sandu
    ;
    Adam Rylski
    ;
    Bartłomiej Jeż
    There is a burgeoning interest in the development of geopolymers as sustainable construction materials and incombustible inorganic polymers. However, geopolymers show quasi-brittle behavior. To overcome this weakness, hundreds of researchers have focused on the development, characterization, and implementation of geopolymer-reinforced fibers for a wide range of applications for light geopolymers concrete. This paper discusses the rapidly developing geopolymer-reinforced fibers, focusing on material and geometrical properties, numerical simulation, and the effect of fibers on the geopolymers. In the section on the effect of fibers on the geopolymers, a comparison between single and hybrid fibers will show the compressive strength and toughness of each type of fiber. It is proposed that interfacial bonding between matrix and fibers is important to obtain better results, and interfacial bonding between matrix and fiber depends on the type of material surface contact area, such as being hydrophobic or hydrophilic, as well as the softness or roughness of the surface.
      6  18
  • 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.
      7  17