Liew Yun Ming
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Liew Yun Ming
Official Name
Liew Yun Ming
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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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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.

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Primary insights into the effects of organic pollutants and carbon-based cathode materials in a double chambered microbial fuel cell integrated electrocatalytic process

2021-12-01 , Yap K.L. , Ho Li Ngee , Ong Soon An , Guo K. , Liew Yun Ming , Oon Y.S. , Thor S.H. , Tan S.M. , Teoh T.P.

Cathode plays an important role on the oxygen reduction reaction (ORR) reactivity in the microbial fuel cell integrated electrocatalytic process for the effective degradation of organic pollutants. Comparative study of caffeine and phenol as the organic pollutants in the cathodic chamber was investigated in terms of removal efficiency and bioelectricity generation. Results revealed that the highest removal efficiency of phenol (96.89 ± 1.26%) and maximum power density (33.37 ± 4.62 mW m−2) were attained by copper (II) oxide loaded carbon felt (CuO/CF) cathode. Besides, the removal efficiency of phenol was nearly 12-fold higher (24.85 ± 1.36%) using CuO/CF cathode compared with that of caffeine (2.14 ± 0.36%) at the first 24 h. The effect of carbon-based cathode materials on the mineralization of caffeine in the cathodic chamber was evaluated using carbon felt (CF) and carbon plate (CP). Both CuO/CP and bare CP cathodes surpassed CuO/CF and bare CF cathodes in the chemical oxygen demand (COD) removal and bioelectricity generation. Higher crystallinity nature and electrical conductivity (3.57 × 105 Ω−1 m−1) of CP compared with that of amorphous structure and lower electrical conductivity of bare CF (3.33 × 104 Ω−1 m−1) contributed to higher ORR reactivity and efficient transport of electrons for bioelectricity generation. The COD removal efficiency of synthetic wastewater in the anodic chamber and bioelectricity generation of this integrated system were affected by the types of organic pollutants and carbon-based cathode materials in the cathodic chamber.

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Low Density, High Compressive Strength: Experimental Investigation with Various Particle Sizes of Sand for Different Mix Designs of Cement Mortar Manufacturing

2020-07-09 , Rmdan Amer A.A. , Mohd. Mustafa Al Bakri Abdullah , Liew Yun Ming , Faheem Mohd Tahir M. , Wazien Ahmad Zailani W. , Meor Ahmad Faris Meor Ahmad Tajudin

Concrete density was optimised by substituting part of the normal-density aggregates (fine aggregate, coarse aggregate, or both) with that of comparable quantities of low-density aggregate, which enhanced structural efficiency (strength to density ratio), improved hydration and decreased transportation costs. These days, focus is given on enhancing the characteristics of concretes in order to make them more efficient. A factor associated in compressive strength, packing particle, water absorption and density is concrete proportioning. A good proportioning mix results in greater strength for concrete at optimum density and specified age. The filler effect is regarded as a physical feature pertaining to small particles for a concrete material since it allows generating extra compressive strength by filling voids by making mortar or concrete more homogeneous. This behaviour allows conferring additional compressive strength as well as optimise or minimise the concrete's density without having to use a pozzolanic reaction or a chemical reaction. Mainly, this objective has been implemented through using three different lightweight particle sizes of sand group a-(1.18 mm ≤ Sand size < 200 m), b-(2.36 mm ≤ Sand size < 1.18 mm) and (5.0 mm ≤ Sand size < 2.36 mm). The parameters that are taken consideration during the investigation were sand particle size, water/cement ratio, cement/sand ratio. In general, the results demonstrated that there was a decrease in compressive strength when the sand's particle sizes increased. In case the particle size group (b) and (c) used the decrease rate in compressive strength was 7.97% and 12.39% respectively in comparison with particle size group (a) where the optimum values of the water/cement and cement/sand ratio were used. On the other hand, low density was achieved at the point of the higher compressive strength, whereas 4.4% and 3.66 % increase in the density was recorded over the particle sizes of sand (b and c) respectively. Meanwhile, we put forward the relationships existing between the compressive strength as well as density of concrete mixtures with various proportions of the lightweight aggregates as given above. The conducted experimental studies showed that there were tendencies to possibly utilise various quantities of fine lightweight aggregates as well as their combinations to yield concrete mixtures based on the requirements in practical application. As per the study conclusion, the considered mixtures could be used to yield structural elements that need high compressive strength and lower density.

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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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Preparation of Fly Ash-Ladle Furnace Slag Blended Geopolymer Foam via Pre-Foaming Method with Polyoxyethylene Alkyether Sulphate Incorporation

2022-06-01 , Ng Hui Teng , Heah Cheng Yong , Liew Yun Ming , Mohd. Mustafa Al Bakri Abdullah , Rojviriya C. , Razi H.M. , Garus S. , Nabiałek M. , Sochacki W. , Abidin I.M.Z. , Ng Yong Sing , Śliwa A. , Sandu A.V.

This paper uses polyoxyethylene alkyether sulphate (PAS) to form foam via pre-foaming method, which is then incorporated into geopolymer based on fly ash and ladle furnace slag. In the literature, only PAS-geopolymer foams made with single precursor were studied. Therefore, the performance of fly ash-slag blended geopolymer with and without PAS foam was investigated at 29–1000 °C. Unfoamed geopolymer (G-0) was prepared by a combination of sodium alkali, fly ash and slag. The PAS foam-to-paste ratio was set at 1.0 and 2.0 to prepare geopolymer foam (G-1 and G-2). Foamed geopolymer showed decreased compressive strength (25.1–32.0 MPa for G-1 and 21.5–36.2 MPa for G-2) compared to G-0 (36.9–43.1 MPa) at 29–1000 °C. Nevertheless, when compared to unheated samples, heated G-0 lost compressive strength by 8.7% up to 1000 °C, while the foamed geopolymer gained compressive strength by 68.5% up to 1000 °C. The thermal stability of foamed geopolymer was greatly improved due to the increased porosity, lower thermal conductivity, and incompact microstructure, which helped to reduce pressure during moisture evaporation and resulted in lessened deterioration.

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Elevated-temperature performance, combustibility and fire propagation index of fly ash-metakaolin blend geopolymers with addition of monoaluminium phosphate (MAP) and aluminum dihydrogen triphosphate (ATP)

2021-04-02 , Khairunnisa Zulkifly , Heah Cheng Yong , Liew Yun Ming , Bayuaji R. , Mohd. Mustafa Al Bakri Abdullah , Ahmad S.B. , Stachowiak T. , Szmidla J. , Gondro J. , Jeż B. , Khalid M.S.B. , Garus S. , Ong Shee-Ween , Ooi Wan-En , Ng Hui-Teng

Thermal performance, combustibility, and fire propagation of fly ash-metakaolin (FAMK) blended geopolymer with the addition of aluminum triphosphate, ATP (Al(H2PO4)3), and monoaluminium phosphate, MAP (AlPO4) were evaluated in this paper. To prepare the geopolymer mix, fly ash and metakaolin with a ratio of 1:1 were added with ATP and MAP in a range of 0–3% by weight. The fire/heat resistance was evaluated by comparing the residual compressive strengths after the elevated temperature exposure. Besides, combustibility and fire propagation tests were conducted to examine the thermal performance and the applicability of the geopolymers as passive fire protection. Experimental results revealed that the blended geopolymers with 1 wt.% of ATP and MAP exhibited higher compressive strength and denser geopolymer matrix than control geopolymers. The effect of ATP and MAP addition was more obvious in unheated geopolymer and little improvement was observed for geopolymer subjected to elevated temperature. ATP and MAP at 3 wt.% did not help in enhancing the elevated-temperature performance of blended geopolymers. Even so, all blended geopolymers, regardless of the addition of ATP and MAP, were regarded as the noncombustible materials with negligible (0–0.1) fire propagation index.

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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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Effect of anisotropic pores on the material properties of metakaolin geopolymer composites incorporated with corrugated fiberboard and rubber

2021-09-01 , Nur Ain Jaya , Liew Yun Ming , Heah Cheng Yong , Foo Wah L. , Mohd. Mustafa Al Bakri Abdullah , Zainal Abidin I.M. , Azaman N. , Ooi Wan-En

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.

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Elevated-Temperature performance, combustibility and fire propagation index of Fly Ash-Metakaolin blend geopolymers with addition of Monoaluminium Phosphate (MAP) and Aluminum Dihydrogen Triphosphate (ATP)

2021 , Khairunnisa Zulkifly , Heah Cheng Yong , Liew Yun Ming , Ridho Bayuaji , Mohd. Mustafa Al Bakri Abdullah , Shamsul Bin Ahmad , Tomasz Stachowiak , Janusz Szmidla , Joanna Gondro , Bartłomiej Jeż , Mohd Suhaimi Bin Khalid , Sebastian Garus , Ong Shee-Ween , Ooi Wan-En , Ng Hui-Teng

Thermal performance, combustibility, and fire propagation of fly ash-metakaolin (FA-MK) blended geopolymer with the addition of aluminum triphosphate, ATP (Al(H2PO4)3), and monoaluminium phosphate, MAP (AlPO4) were evaluated in this paper. To prepare the geopolymer mix, fly ash and metakaolin with a ratio of 1:1 were added with ATP and MAP in a range of 0–3% by weight. The fire/heat resistance was evaluated by comparing the residual compressive strengths after the elevated temperature exposure. Besides, combustibility and fire propagation tests were conducted to examine the thermal performance and the applicability of the geopolymers as passive fire protection. Experimental results revealed that the blended geopolymers with 1 wt.% of ATP and MAP exhibited higher compressive strength and denser geopolymer matrix than control geopolymers. The effect of ATP and MAP addition was more obvious in unheated geopolymer and little improvement was observed for geopolymer subjected to elevated temperature. ATP and MAP at 3 wt.% did not help in enhancing the elevated-temperature performance of blended geopolymers. Even so, all blended geopolymers, regardless of the addition of ATP and MAP, were regarded as the noncombustible materials with negligible (0–0.1) fire propagation index.

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Studies of geopolymerization route for metakaolin geopolymeric materials

2014 , Liew Yun Ming

Investigation on production of metakaolin geopolymeric powder was aimed to increase the productivity and application of geopolymer products. Geopolymerization process was applied in the manufacturing of metakaolin geopolymeric powder to be used in geopolymer synthesis. Geopolymer slurry was made by alkaline activation of metakaolin in alkali activator solution (a mixture of NaOH and sodium silicate solutions). The geopolymer slurry was heated in an oven to produce pre-cured paste and then pulverized to get uniform particle size geopolymeric powder. By adopting the concept of “just add water”, the metakaolin geopolymeric powder was mixed with water and then oven-cured to produce resulting geopolymer pastes. The physical and mechanical properties of geopolymeric powder and resulting geopolymer pastes, such as workability, setting time, bulk density and compressive strength were studied. These geopolymeric powder and resulting geopolymer pastes were also characterized by using SEM/EDX, XRD and FTIR analyses. The results showed that the optimum conditions for producing highest strength resulting paste are by using 8M of NaOH solution, solids/liquid ratio of 0.80, an activator ratio of 0.20, pre-curing of 80°C for 4 hours, 22% of mixing water and curing regime of 60°C for 72 hours. The resulting geopolymer pastes have low bulk density and were potential for a lightweight material. Upon the mixing of water with geopolymeric powder, densification of the structure occurred with the formation of compact geopolymer gels. The geopolymeric powder and resulting pastes showed the combination of amorphous and crystalline phases as analyzed by XRD. After ageing, the intensities of zeolites crystalline phases increased and this emphasized the benefit of zeolites in strength development of resulting pastes. Moreover, FTIR analysis revealed the growth of geopolymer bonding with ages. The optimum SiO2/Al2O3, Na2O/SiO2, H2O/Na2O and Na2O/Al2O3 oxide-molar ratios were 3.10, 0.37, 14.23 and 1.15, respectively. Study on the oxide-molar ratios concluded that mechanical properties of geopolymer paste were influenced most significantly by Na2O/Al2O3 and H2O/Na2O molar ratios. This study clearly demonstrates that the production of metakaolin geopolymeric powder was able to be used in manufacturing geopolymer pastes.

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